Pelican Parts Forums

Pelican Parts Forums (http://forums.pelicanparts.com/)
-   911 Engine Rebuilding Forum (http://forums.pelicanparts.com/911-engine-rebuilding-forum/)
-   -   Trakrat's 3.2 Engine Rebuild (http://forums.pelicanparts.com/911-engine-rebuilding-forum/974356-trakrats-3-2-engine-rebuild.html)

KTL 11-28-2017 08:48 AM

The main bearings look pretty good? If you don't see any major streaks or marks on them, I would consider re-using them.

The inboard intermediate shaft bearing looks like it's showing base metal in two separate places. As alarming as that may appear, it's actually pretty common for the I-shaft to show wear on the bearings and thus it isn't a sign of a major problem. Just put new bearings in and you're good to go.

proporsche 11-28-2017 10:39 AM

i am with ktl..leave the bearings...it is a pain in a butt to get the right quality in these days....i heard a pretty bad stories even when purchased at the dealer...

Just replace the inter shaft as said above..

Ivan

bpu699 11-28-2017 10:59 AM

Another vote for leaving the main bearings alone...

If you want, see my thread on having them coated by HM ELLIOT. I did it, looks great, and makes me feel like I "did something" to them...

The coating adds very little to the clearance change. Supposed to add .0003 per bearing. Mine added way less than that...

I reused my main bearings, but broke down and bought new Porsche dealer rod bearings. The old ones looked fine, but it just seemed less risky to do that...

Keep in mind the glyco and clevite increase clearance by .001...

The Porsche dealer bearings do not, measured the same thickness as the old ones...

The porsche dealer bearings were only $36X6 or $240 for the set. Way cheaper than I would have thought...

You mentioned that on your case you felt that one side way a bit proud by the IMS shaft... Before you get too far, look at your IMS bearing thrust faces, and see if one side is down to copper, and the other side isn't... The glyco thrust bearing I bought wouldn't work without rubbing due to that miniscule case difference...

Trakrat 11-29-2017 07:58 AM

Quote:

Originally Posted by KTL (Post 9829510)
The main bearings look pretty good? If you don't see any major streaks or marks on them, I would consider re-using them.

The inboard intermediate shaft bearing looks like it's showing base metal in two separate places. As alarming as that may appear, it's actually pretty common for the I-shaft to show wear on the bearings and thus it isn't a sign of a major problem. Just put new bearings in and you're good to go.

Actually... a couple of the main bearings weren't there. They were stuck on the crank. I just about $#!^ when I saw the bearing missing... only to find it stuck on the journal.


I just pushed it back in... it slides around and doesn't stay, as though the curve doesn't match the case.

Trakrat 11-29-2017 08:05 AM

ANYONE have a suggestion on the best way to ship this case???

Should I ship the case in separate halves? Or should I put them together and ship them in one piece?

(My concern is all the bolts sticking out could puncture a box or worse... break) *I don't trust UPS or Fed-Ex to handle with care*

KTL 11-29-2017 08:21 AM

You definitely want to remove all the protruding studs from the case halves. Those are just begging to get bent or break the case where they're threaded in. Don't risk it.......

One guy I know who used to sell a lot of used parts said he wrapped engine case halves in carpeting when shipping them. I would use something thick and robust like that and keep the halves separate in separate boxes. I know the last thing you want is to lose one half of the case in shipping. But in my opinion you're better off keeping them separate to keep the weight down and that keeps the box manageable. When you put the case together, it's a pretty heavy lump and that makes the box handler get careless with it because it's a big enough box and not excessively heavy. So it can be dealt with by hand (instead of needing a cart/dolly) but it's still a slight struggle since it's pretty heavy even for a dude who's job is to pick up and carry boxes all day long.

Pack your stuff like it's going to be dropped, because it will be. The people loading trucks are working fast and tossing boxes all the time. To be completely honest, I think this is the worst time of the year to be shipping stuff given the holiday activity. Might be better to do it after Christmas? Although there's the return shipping period after Christmas as well........

bpu699 11-29-2017 08:29 AM

Quote:

Originally Posted by Trakrat (Post 9830764)
ANYONE have a suggestion on the best way to ship this case???

Should I ship the case in separate halves? Or should I put them together and ship them in one piece?

(My concern is all the bolts sticking out could puncture a box or worse... break) *I don't trust UPS or Fed-Ex to handle with care*

Consider a large box, preferably wood. Then go to home depot and buy the pink foam insulation sheets in 6 inch thickness. Line all sides of the box, put in the case, and fill with peanuts/newspaper.

6 inches of foam absorbs a lot of damage...

Ken911 11-29-2017 09:00 AM

Quote:

Originally Posted by Trakrat (Post 9830764)
ANYONE have a suggestion on the best way to ship this case???

Should I ship the case in separate halves? Or should I put them together and ship them in one piece?

(My concern is all the bolts sticking out could puncture a box or worse... break) *I don't trust UPS or Fed-Ex to handle with care*

cheapest safest way to ship a case is a large plastic igloo cooler. They cost about 50 dollars. Cheaper than wood for a crate and lighter. remove the head studs and all the small suds sticking out the sides for chain boxes etc. Bolt the case halves back together, if shipping the crank leave it in the bearings. Then seal it shut with a banding tool. Sent mine to turbo Kraft like that and they have most customers ship them that same way. weight for an engine case, crank, rods and pistons is 135 pounds. Also as soon as you tell the shipper (ups or whoever) that it's an engine case a plastic cooler shows it will not leak oil during shipping. Make sure you tell them there is also absorbent in the bottom of the box.

Ken911 11-29-2017 09:21 AM

http://forums.pelicanparts.com/uploa...1511979589.jpg
this is a pic as described above about how well it fit in a cooler

KTL 11-29-2017 09:43 AM

Nice ken!

Trakrat 11-29-2017 01:58 PM

Quote:

Originally Posted by Ken911 (Post 9830856)
http://forums.pelicanparts.com/uploa...1511979589.jpg
this is a pic as described above about how well it fit in a cooler

That's a pretty good idea... I may just do that.

However, I was told to leave all the studs in the case... as removing them would mean I'd have to buy new ones.

Trackrash 11-29-2017 02:36 PM

Quote:

Originally Posted by Trakrat (Post 9831211)

However, I was told to leave all the studs in the case... as removing them would mean I'd have to buy new ones.

????

bpu699 11-29-2017 03:41 PM

Quote:

Originally Posted by Trakrat (Post 9831211)
That's a pretty good idea... I may just do that.

However, I was told to leave all the studs in the case... as removing them would mean I'd have to buy new ones.

Not an expert by a long shot, but I believe if you are machining your case you need to pull all the studs out...

Trakrat 11-30-2017 05:37 AM

Quote:

Originally Posted by bpu699 (Post 9831351)
Not an expert by a long shot, but I believe if you are machining your case you need to pull all the studs out...

Correct... that's what I was told... but its uncertain if my case needs to be machined. It may just be fine with it being hot tanked/cleaned once checked over.

All I know is I asked Ollie's and they said to just leave them all in and if they find they need to remove them, then they'll do that.

Trakrat 11-30-2017 05:41 AM

Quote:

Originally Posted by Trackrash (Post 9831272)
????

apparently there is a consensus that dilavar studs shouldn't be reused, as they have a tendency to break.

Also... if I'm going to take them out... then I will end up buying ARP or Raceware studs so that I know EXACTLY what I'm using. Which is expensive.

KTL 11-30-2017 05:55 AM

You just can't leave the head studs in the case if you're going to ship it. They stick out too far and are at too much risk for being bent. Just take them out and install new ones. I'd suggest going with all steel. If you really feel compelled to go with something more than plain steel, i'd recommend the Supertec studs.

bpu699 11-30-2017 06:11 AM

Quote:

Originally Posted by Trakrat (Post 9831840)
Correct... that's what I was told... but its uncertain if my case needs to be machined. It may just be fine with it being hot tanked/cleaned once checked over.

All I know is I asked Ollie's and they said to just leave them all in and if they find they need to remove them, then they'll do that.

If there is not anything obviously wrong with your case, and you are machining it only if an inspection shows issues, then why risk shipping it and paying for that?

My understanding is that mag cases may need to be line bored. Other than that, what issues are you anticipating? You have an aluminum case, correct?

I only risked shipping things that I could replace if FedEx lost them. Not sure of the benefit of shipping a case and risking damage to it and the studs just to have it cleaned...

Trakrat 11-30-2017 01:38 PM

Quote:

Originally Posted by bpu699 (Post 9831870)
If there is not anything obviously wrong with your case, and you are machining it only if an inspection shows issues, then why risk shipping it and paying for that?

My understanding is that mag cases may need to be line bored. Other than that, what issues are you anticipating? You have an aluminum case, correct?

I only risked shipping things that I could replace if FedEx lost them. Not sure of the benefit of shipping a case and risking damage to it and the studs just to have it cleaned...

If it gets 'lost'... then that's what insurance is for. I'm estimating $15,000 declared value for everything.

I have enough bubble wrap (from a recent house move)... to wrap a complete engine in bubble wrap about 6 inches deep. Soo...I'm thinking I just may wrap the heck out of the case halves and ship them in some crazy big box. :D

Believe me... I would rather NOT have to ship anything to Ollies. But I can't find anyone local to even do a simply cleaning on my engine parts. I found 1 shop local who will do bead blasting, but I'm only giving them my tin parts... none of my engine parts (like the chain housing, etc...). as they seem a little sketchy.

Nonetheless, I'm going to hold off on shipping anything out right now. As the holiday shipping time tends to bring the worst out in the delivery companies because they are so over worked.

Best to wait it out.

LarsM 12-01-2017 03:00 AM

Hi there, just stumbled over this thread here. I'm doing exactly the same job as you and I'm at the same stage as you aswell. I have a Instagram profile where I post some of pictures (LarsMK). Maybe I should start my own thread here...

That said, I've just shipped of my engine to one of the three Posche Classic Centres in the world for them the evaluate the engine longblock parts. I'll probably ask them to finish of the longblock as I will get some good papers on the job. The rest of the job I do entirely by myself. They charge 25 hours to build the longblock since I've already have it in parts. I'd probably spent 2 months doing the same job over the weekends I've got.

I'd love to share some experience. The biggest challenge I've had this far is a rounded off head stud barrel nut.... that was a real PITA!

Looking forward to follow your progress.

Trakrat 12-01-2017 07:31 AM

Quote:

Originally Posted by LarsM (Post 9832917)
Hi there, just stumbled over this thread here. I'm doing exactly the same job as you and I'm at the same stage as you aswell. I have a Instagram profile where I post some of pictures (LarsMK). Maybe I should start my own thread here...

That said, I've just shipped of my engine to one of the three Posche Classic Centres in the world for them the evaluate the engine longblock parts. I'll probably ask them to finish of the longblock as I will get some good papers on the job. The rest of the job I do entirely by myself. They charge 25 hours to build the longblock since I've already have it in parts. I'd probably spent 2 months doing the same job over the weekends I've got.

I'd love to share some experience. The biggest challenge I've had this far is a rounded off head stud barrel nut.... that was a real PITA!

Looking forward to follow your progress.

Definitely start your own thread and post up pics.
I had thought about sending mine to the classic center in Atlanta, as I've been there and was impressed with their facility. But I imagine their cost is much higher than anywhere else.

CBRacerX 12-01-2017 10:10 AM

Quote:

Originally Posted by LarsM (Post 9832917)
Hi there, just stumbled over this thread here. I'm doing exactly the same job as you and I'm at the same stage as you aswell. I have a Instagram profile where I post some of pictures (LarsMK). Maybe I should start my own thread here...

That said, I've just shipped of my engine to one of the three Posche Classic Centres in the world for them the evaluate the engine longblock parts. I'll probably ask them to finish of the longblock as I will get some good papers on the job. The rest of the job I do entirely by myself. They charge 25 hours to build the longblock since I've already have it in parts. I'd probably spent 2 months doing the same job over the weekends I've got.

I'd love to share some experience. The biggest challenge I've had this far is a rounded off head stud barrel nut.... that was a real PITA!

Looking forward to follow your progress.

Please start your own thread around working with the Porsche Classic Center, that will be very interesting! For the OP - don’t be afraid to clean the case yourself with toothbrushes, green scrubbing pads, razor blades, simple green, brakeKleen, water and elbow grease, followed by a high pressure air blast (leaf blower is good). It will take a while but the results will be good.

Trakrat 02-26-2018 12:32 PM

As of today.. everything except my fan and fan housing, and intake runners have been delivered to Ollie's Engineering. (I need to have the intake runners cleaned and ported and polished and the fan media blasted to give it that new look)

The have the following:
1.) case
2.) crank
3.) rockers
4.) pistons @ cylinders
5.) cam towers
6.) pulley
7.) flywheel
8.) pressure plate
9.) upper and lower valve covers
10.) chain housing and covers
11.) head assemblies

I'm going to have them clean and inspect everything, fix any damage, port & polish everything that can be, and then figure out what performance upgrades to go with.

I expect to get everything back by May, as I'm estimating 10 weeks out.

While they are working on the engine, I'll plan on taking the front end of the car apart and getting as much hardware (oil lines, front fenders, etc...) off the car to have it towed to the local body shop to have some rust spots repaired.

Trakrat 05-08-2018 01:39 PM

ok.. so an update from Ollie's today...

crank looks good everything is STD/STD (that's a relief)
Case needs line boring, as they are starting to get oval shaped
along with barrel shims (?)
everything else is just going to be cleaned up and resurfaced & polished.

I'm also going to have the crank knife edged, as it seems this give the best benefit in 'bang for your buck'.


That 's the good news... the bad news???

The piston/cylinders are Alusil and aren't salvageable... was planning on going with 3.4 anyways, but hadn't planned on doing it this year.
Anyone have any recommendations? Can I buy a used set and still get the same benefit?

Trackrash 05-08-2018 02:30 PM

You could have your cylinders bored and plated with nicasil, then get matching pistons. $$ Search for Dracos build, I think that was the way he went.

Or a new set of pistons and cylinders. $$$$

Worth looking for a good used set, I guess. I had a bad cylinder on my 3,0 and found a good used replacement. So it's possible. $

Will the case use standard bearings? Are oversized bearings available?

KTL 05-09-2018 09:08 AM

I was thinking the same thing about the pistons and cylinders. If you're going to 3.4, there's no reason why you can't have those cylinders bored and re-plated with nikasil. Some have said the alusil cylinders are actually better candidates for the overbore and re-plate because the KS cylinder is a bit more structurally stable than the Mahle http://forums.pelicanparts.com/911-engine-rebuilding-forum/936361-98mm-nickies.html#post9368267

but if you were just planning on reusing the pistons and cylinders as-is, then I can see how they may be deemed not serviceable. Since you were planning 3.4 anyway, now appears to be the time to do it since your hand is force. I agree with Gordon that the way to go is JE or CP Carrillo pistons. By the way you get a better "base" piston design from CP Carrillo with their standard X-forging- this is extra on the JE and called FSR (Forged Side Relief).

So you can get the cylinders bored & re-plated accordingly for the pistons and you're all set. Typical clearance is 0.0015" for JEs, 0.0020" for Carrillos. Note that if you have EBS Racing do the cylinders, they send them to Millenium Technologies. It's been found that their honing roughess was a bit too rough for various ring brands and they weren't sealing well, causing oil usage. So you would want to make sure they spec the fine honing. I have a friend here on the forums, who prefers to remain nameless, that had a similar problem as VFR750 experienced

http://forums.pelicanparts.com/911-engine-rebuilding-forum/912382-millenium-cylinder-fine-grit-honing-right-way-go.html#post10029476

I'd be very careful with the knife edge approach. Not saying Ollie's doesn't know what they're doing. Just saying that you don't get much gains by doing it since they're only going to remove a rather small amount. And it's rather expensive.

My one personal experience is I had Marine Crankshaft do the knifing on a 70.4mm SC crank for me and it was a small amount at the ends.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/778290-rod-weight-difference-other-993-engine-build-advice.html

I don't think i'd do it again because it was a large cost of the overall crank work and the benefit is simply lighter weight (engine revs easier) vs. the downside being much more technical. The knifing simply lightens the crank, since there's no real windage losses here in a dry sump engine. So our cranks aren't spinning in a large bath of oil like a wet sump engine. The technical downside is there's a questionable benefit in messing with those counterweights since the the size is there for a reason- to counteract the weight of the piston and rod. So any knifing done should be minimal to avoid upsetting that balance between the counterweights and the piston + rod combo. Then I guess that begs the question, if the pistons and the rods are changed (let's say you chose to use CP 98mm pistons and lightweight Pauter rods) then should the crank counterweights be modified to reflect that change in piston and rod mass?

Here's a page from Neil Harvey's website to give you his take on it.

Living on the “Knife” Edge – performancedevelopments.com

Trakrat 05-09-2018 03:49 PM

Quote:

Originally Posted by KTL (Post 10031000)
I was thinking the same thing about the pistons and cylinders. If you're going to 3.4, there's no reason why you can't have those cylinders bored and re-plated with nikasil. Some have said the alusil cylinders are actually better candidates for the overbore and re-plate because the KS cylinder is a bit more structurally stable than the Mahle http://forums.pelicanparts.com/911-engine-rebuilding-forum/936361-98mm-nickies.html#post9368267

but if you were just planning on reusing the pistons and cylinders as-is, then I can see how they may be deemed not serviceable. Since you were planning 3.4 anyway, now appears to be the time to do it since your hand is force. I agree with Gordon that the way to go is JE or CP Carrillo pistons. By the way you get a better "base" piston design from CP Carrillo with their standard X-forging- this is extra on the JE and called FSR (Forged Side Relief).

So you can get the cylinders bored & re-plated accordingly for the pistons and you're all set. Typical clearance is 0.0015" for JEs, 0.0020" for Carrillos. Note that if you have EBS Racing do the cylinders, they send them to Millenium Technologies. It's been found that their honing roughess was a bit too rough for various ring brands and they weren't sealing well, causing oil usage. So you would want to make sure they spec the fine honing. I have a friend here on the forums, who prefers to remain nameless, that had a similar problem as VFR750 experienced

http://forums.pelicanparts.com/911-engine-rebuilding-forum/912382-millenium-cylinder-fine-grit-honing-right-way-go.html#post10029476

I'd be very careful with the knife edge approach. Not saying Ollie's doesn't know what they're doing. Just saying that you don't get much gains by doing it since they're only going to remove a rather small amount. And it's rather expensive.

My one personal experience is I had Marine Crankshaft do the knifing on a 70.4mm SC crank for me and it was a small amount at the ends.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/778290-rod-weight-difference-other-993-engine-build-advice.html

I don't think i'd do it again because it was a large cost of the overall crank work and the benefit is simply lighter weight (engine revs easier) vs. the downside being much more technical. The knifing simply lightens the crank, since there's no real windage losses here in a dry sump engine. So our cranks aren't spinning in a large bath of oil like a wet sump engine. The technical downside is there's a questionable benefit in messing with those counterweights since the the size is there for a reason- to counteract the weight of the piston and rod. So any knifing done should be minimal to avoid upsetting that balance between the counterweights and the piston + rod combo. Then I guess that begs the question, if the pistons and the rods are changed (let's say you chose to use CP 98mm pistons and lightweight Pauter rods) then should the crank counterweights be modified to reflect that change in piston and rod mass?

Here's a page from Neil Harvey's website to give you his take on it.

Living on the “Knife” Edge – performancedevelopments.com


All good stuff...
I'm keeping my stock rods, but using ARP bolts.
I'm looking at getting MAHLE motorsports piston & cylinder set. I believe the brands you mentioned are more expensive.
I'm also going to have them install a set of AASCO titanium valve springs rated at 360lbs. (I've flip flopped on this decision a few times, but in the end, I plan on revving higher rpms than normal)
And finally, going to get the 964 cams for certain.
Unfortunately, due to life... I'll have to hold off as long as I can in ordering the piston/cylinders and cams.

I'm curious about your comments on crank counterweights and knife edging.
First off, out of all the optional performance mods they have available (boat tailing, moon cut, and knife edge)... they HIGHLY recommended knife edging the crank.

As for the counterweights... I'm not sure why that would be a concern as long as everything is balanced. A new set of piston SHOULD be all equal weight, which wouldn't have any counterweight effect on the crank... again, as long as everything was balanced, which it should be.

Trakrat 05-09-2018 04:08 PM

Quote:

Originally Posted by KTL (Post 10031000)

Here's a page from Neil Harvey's website to give you his take on it.

Living on the “Knife” Edge – performancedevelopments.com

This was an interesting read...
I was curious about his comment "Taking mass away from the counter weights has a huge effect on the amount of twist the crankshaft would be placed under."

Is this a huge positive effect? or a huge negative effect?

also, he shows some pics of a damaged crank... but what I don't understand is what this has to do with knife edging? Clearly the crank in the pic was not knife edged... and I have NEVER heard of or seen a crank damaged from being knife edged.

I'm personally on the fence on whether or not to get the crankshaft knife edged. I've heard everything from that it will allow for faster revs, simply due to the lower mass, to improving oil flow through the engine.
I haven't heard any negative theories that show why this is a bad idea... other than if it was done by a semi-professional who didn't know what they were doing.

KTL 05-10-2018 12:50 PM

Actually if you have your cyls bored and get new JE or CP Carrillo for them, you're looking at approximately $2500-$3000. My costs are based on:

CP 98mm pistons are around $1100 retail
JEs are $1700.
US Chrome pricing for boring, plating and honing cylinders is $230 each retail.

A new set of 98mm Mahle Motorsport 9.8:1 pistons and cylinders from Patrick MS is $4680 on their site. So you gotta decide if the new Mahle is worth it to you for another $1700?

I think in your case the springs are primarily going to provide some insurance against overrev if you miss a shift or money shift it and catch it. Because you don't absolutely NEED the higher rate springs since your 964 cams are nothing super aggressive. And i'm not sure how much higher in revs you can expect to go when you have the stock rods (even with ARP bolts) and the original intake. That intake hits a pretty big wall at 6200, based on numerous dyno plots i've seen.

Let's not mix apples and bananas and oranges here when talking about internal modifications. Boat-tailing and mooning are modifications to the engine case and cylinders respectively. Only the highest of high strung engines see any benefit with those modifications. They're all about trying to smooth the airflow created inside the engine case from the rapid spinning of the crank and rods. Whereas the knife-edging is about lightening rotating mass (and cutting through the oil in a wet sump engine).

Actually you'd be surprised by the weights of new pistons. I measured my new JE pistons a handful of years ago and the spread of weight was 569.9 to 571.3 grams, including wrist pins. The factory spec book says the allowable variance for both Mahle and KS pistons is 4 grams. I think most doing a detailed build are usually shooting for all to be within 0.5 grams.

You're right that the crank certainly must be balanced in terms of having equal counterweights. But the crank remains balanced regardless of whether you're talking about unmolested counterweights or modified counterweights. Modifying the counterweights would of course absolutely require that the crank be re-balanced. Ignoring the actual & equal weight of the counterweights, the crank is going to be what's called internally balanced. However, the point i'm making is that the actual weight of the counterweights has importance and that's what Neil is referring to. Otherwise, why wouldn't the crank have the smallest of counterweights to begin with? Check this out for some more general technical detail about crankshaft balancing

Understanding Crankshaft Balancing - Engine Builder Magazine

That said, I think in Neil's article he's mixing two of his un-favorite things about the early crankshafts- modifying them by knifing AND the lack of a harmonic damper? But i'm not going to go correcting him because he knows way more about engine design than I could ever learn in five lifetimes. He has another article on his site about the importance of having a harmonic damper and I recall he doesn't like that the early engines don't have one. Look at the top/header of Neil's website page and put your pointer on the "Technical Articles" to see the other articles. The article about torsional dampers and the other about harmonic failure seem to be applicable to what we're talking about here.

I think what you're missing here is that the knifing has a negative effect on the crank. The counterweights are sized based on the weight of the pistons and the rods that the crank is throwing around. If you change the weight of the counterweights, then you technically should in turn change the weight of your pistons and rods to maintain that counterweight-to-piston+rods relationship. That said, I don't know that any of the DIY'ers here do that. We just throw different pistons (and sometimes rods) on our engines to hotrod them. Not an ideal thing to do, but seems to work OK because folks' crankshafts here aren't breaking all the time.

Trackrash 05-10-2018 01:53 PM

I doubt knife edging a crank will have any noticeable affect unless you have, say, titanium rods and are revving to 8K rpm.

If you want the motor to rev or respond faster a lightened flywheel / clutch will do more than knife edging.

Probably you would want to do some mods to the fuel injection system as well to get that quick revving motor, if that is your desire.

panzerfaust 05-11-2018 07:58 AM

im not sure if removing weights from crank is a good idea for street motor in terms of longevity. i recall on the early 911, the hot models added more counter weights to the crank to counter the effects destructive harmonics for their motors with elevated revs.

honda B series type R motors that red lined at a stratospheric 8400 rpm 20 years ago also substantially added extra counter weights to keep the motor stitched together.

new modern motors run light cranks due to the ability to design out and isolate the origin of the harmonics.

Trakrat 05-13-2018 04:37 PM

Quote:

Originally Posted by panzerfaust (Post 10033260)
im not sure if removing weights from crank is a good idea for street motor in terms of longevity. i recall on the early 911, the hot models added more counter weights to the crank to counter the effects destructive harmonics for their motors with elevated revs.

honda B series type R motors that red lined at a stratospheric 8400 rpm 20 years ago also substantially added extra counter weights to keep the motor stitched together.

new modern motors run light cranks due to the ability to design out and isolate the origin of the harmonics.

So here's what I've learned from researching this...
1.) I haven't found any info that stated that knife edging the crank has been the cause of any damage or decreased life expectancy of the engine.
2.) I haven't found any info that stated that knife edging has made the engine run better, faster, or stronger.
3.) Most say that this crank mod is mostly for larger V8s.
4.) the 600hp 3.x Porsche engines that are built by some of the best engine builders in the business have knife edged cranks. (of along with ALOT more mods)
5.) Finally... Ollie's engineering said that if there is one mod I would have them do, it would be to knife edge the crank. Not even boat tailing the mains, or mooning the cylinders.

So I guess having this done is like having a runner buy some heel molded gel insert with a curved inner sole because they think they will run faster with it.

Trackrash 05-13-2018 06:04 PM

I imagine that Porsche added the counter weights to counter the flexing of the crank at speed.

Remember the T models had cranks without counter weights. Those are safe to 6500 rpm.

The question I have for the gurus is this. Did Porsche ever knife edge any of their race cranks? What about the motors that had titanium rods? With less reciprocal mass would there be less counter weight needed?

Ken911 05-14-2018 05:17 AM

On the subject of mooning of the cylinders. When i sent mine to L&N engineering to have them replated I wanted the this done to my cylinders. They told me that if you cut them into Mahle cylinders it creats a stress riser that willl make them crack and they dont recommend it. Thiers are manufactured with them in the cylinders already to prevent that. So I went with boat tailing but skipped having the cylinders moon cut.

Neil Harvey 05-14-2018 11:14 AM

The subject of knife edging cranks has been over many years, diluted into some sort of performance gain. Unfortunately, you get nothing for free.

Engine balance is about two main areas. Dynamic and harmonic. Both very different. Knife edging in my opinion is about dynamic balancing and the gains had with spinning a lighter mass within the engines block. Harmonic balance is about controlling the effects of the torque pulses aplied to the crankshaft.

Counter weights are placed on the crankshaft to control the counter forces as the pistons go up and down. You have two “moments” happening at the same time, rotating and reciprocating.
The depth of engineering is vast and requires some real understanding of what is going on and how to evaluate. Way too much of the average engine builder and I have tried to study this and have found some of it beyond my tiny brain’s capability.

Typically, in most in-line and V engines, the counterweight added to the crankshaft is 50% of the reciprocating mass. Porsche have reduced this due to the even balance of boxer engine design. We have even reduced this more in some of the performance engines we have built in the past, but there are side effects that need to be understood.

There is very little oil held in the engine case in these engines compared to wet sump engines. Secondly, what is held in the engine case is all stacked up against one side of the case and almost none in the path of the crankshaft. What is happening in a huge war between the oil being spun by the rotating crank and the air pressure pushing against it as the pistons retreat to BDC.

A crankshaft of lessor weight will accelerate quicker than a heavier crankshaft, that is simple physics. But that same crankshaft will be affected by the harmonic forces as it has less mass. The major critical changes to the crank’s ability to counter these harmonic forces is not changed by knife edging, but the total mass of the crank does have some effect.

The counter shaft (1st motion shaft) or intermediate shaft gear and the gear on the crank also cause and add some harmonics into this problem. Steel gears running against other steel gears without any sort of dampening crate huge harmonics, in some engines, “torsion bar” type dampers are included here. The old DFV has these.

I have always believed that when you make a modification, do so understanding the consequences. Don’t just do it because it is considered to be effective. Too many modifications done to Porsche engines are historic and since computer simulations have been available to us, many have been found to be ineffective and cause other issues.

Knife edge at your own peril but understand it is more about how it makes you feel than any gains found in the engine. I would spend more time controlling the cam timing due to a twisting crankshaft, and poorly designed camshaft profiles inducing harmonics into the valve train.

Since the late 80’s when I first was introduced to the 962C race engines, I have not seen a race crank in a Porsche engine with “knife edging”.

If you want the engine to accelerate quicker, maybe install lighter Pistons and Connecting rods. These two components have continued to be produced in their heaviest form since the 70’s, something we are changing with our new Piston and connecting rod designs.

Trakrat 05-14-2018 11:38 AM

Shipping these to Ollies...
(on a side note, I was looking at getting titanium valves, but Del West engineering isn't answering their phone. :( )

http://forums.pelicanparts.com/uploa...1526326602.JPGhttp://forums.pelicanparts.com/uploa...1526326642.jpg

Trakrat 05-17-2018 05:19 AM

I sent out my intake runners to Ollie's this week to have them clean them and polish the insides, as well as to port the intake mating points if needed so that the connection is seamless.

panzerfaust 05-18-2018 09:56 AM

Quote:

Originally Posted by Neil Harvey (Post 10036778)
The subject of knife edging cranks has been over many years, diluted into some sort of performance gain. Unfortunately, you get nothing for free.

Engine balance is about two main areas. Dynamic and harmonic. Both very different. Knife edging in my opinion is about dynamic balancing and the gains had with spinning a lighter mass within the engines block. Harmonic balance is about controlling the effects of the torque pulses aplied to the crankshaft.

Counter weights are placed on the crankshaft to control the counter forces as the pistons go up and down. You have two “moments” happening at the same time, rotating and reciprocating.
The depth of engineering is vast and requires some real understanding of what is going on and how to evaluate. Way too much of the average engine builder and I have tried to study this and have found some of it beyond my tiny brain’s capability.

Typically, in most in-line and V engines, the counterweight added to the crankshaft is 50% of the reciprocating mass. Porsche have reduced this due to the even balance of boxer engine design. We have even reduced this more in some of the performance engines we have built in the past, but there are side effects that need to be understood.

There is very little oil held in the engine case in these engines compared to wet sump engines. Secondly, what is held in the engine case is all stacked up against one side of the case and almost none in the path of the crankshaft. What is happening in a huge war between the oil being spun by the rotating crank and the air pressure pushing against it as the pistons retreat to BDC.

A crankshaft of lessor weight will accelerate quicker than a heavier crankshaft, that is simple physics. But that same crankshaft will be affected by the harmonic forces as it has less mass. The major critical changes to the crank’s ability to counter these harmonic forces is not changed by knife edging, but the total mass of the crank does have some effect.

The counter shaft (1st motion shaft) or intermediate shaft gear and the gear on the crank also cause and add some harmonics into this problem. Steel gears running against other steel gears without any sort of dampening crate huge harmonics, in some engines, “torsion bar” type dampers are included here. The old DFV has these.

I have always believed that when you make a modification, do so understanding the consequences. Don’t just do it because it is considered to be effective. Too many modifications done to Porsche engines are historic and since computer simulations have been available to us, many have been found to be ineffective and cause other issues.

Knife edge at your own peril but understand it is more about how it makes you feel than any gains found in the engine. I would spend more time controlling the cam timing due to a twisting crankshaft, and poorly designed camshaft profiles inducing harmonics into the valve train.

Since the late 80’s when I first was introduced to the 962C race engines, I have not seen a race crank in a Porsche engine with “knife edging”.

If you want the engine to accelerate quicker, maybe install lighter Pistons and Connecting rods. These two components have continued to be produced in their heaviest form since the 70’s, something we are changing with our new Piston and connecting rod designs.

we said...

i recall knife edging were popular with american muscle cars that could benefit from this back in the 60's and 70's with the massive long stroke 90 degree cranks and deep wet sumps. then again those motors ran only to redline momentary or mere seconds on the 1/4 mile drag strips.

some of the older endurance italian race cars for instance knife edged their motors as well. the alfa 33 endurance racers lighten and knife edge their cranks on an already lighter v8 180 flat crank vs 90 degree but reloaded the weight back in the counterweights with heavy tungsten slugs. the nature of the track back then like le mans, mozna and spa, required to motor to sustain high rev for longer periods. these long straights are all gone today partitioned out with some sort of "senna chicanes". still they alfa have a stellar record of finishing races like porsche did whether is crank related or not. :-)

Trackrash 05-18-2018 11:15 AM

Quote:

Originally Posted by Trakrat (Post 10036812)
Shipping these to Ollies...
(on a side note, I was looking at getting titanium valves, but Del West engineering isn't answering their phone. :( )

Titanium valves? :eek:

KTL 05-21-2018 10:07 AM

Typically guys have found it worthwhile to have the 3.2 intake extrude honed to balance the flow amongst all the runners.

The titanium valves are nice choice to reduce the stress on the valve train. Reducing the valve mass goes a long way toward reducing the load on the valve springs. You also don't need excessively stiff springs when you use lighter valves. But keep in mind that you need to install new valve seats in the heads to properly cool the titanium valves. Titanium valves typically like copper-beryllium or nickel-aluminum-bronze seats

mikedsilva 01-02-2020 04:14 AM

[QUOTE=KTL;9807838]
http://forums.pelicanparts.com/uploa...1510176657.jpg


http://forums.pelicanparts.com/uploa...1510183066.jpg


Is it just me, or are the rails installed back to front? ie long ramp facing wrong way?


All times are GMT -8. The time now is 08:06 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website


DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.