1982 3.0L rebuild - need advice
 

Hi all,
Finally got my 73 911 and its current 2.7L transplant. I am planning a rebuild of a ’82 3.0L that I picked up tonight in order to replace the 2.7. The 3.0 will be a hot rod street and track car and I hope to hear some feedback on my current plans. Starting with a ’82 3.0 with 60k miles, I do not plan on splitting the case. The Alusil cylinders are off and not going to be reused. Instead, the following build is in order.

Mahle 95mm pistons and cylinders with 10.5 cr
’84 3.2 heads with valve job, 8mm valves, springs and retainers and twin plug
Modified S cam or similar from Web, Elgin or DC
Twin plug with Electromotive XDI crank fire ignition
Drill lower valve covers with twin plug
Resize rods and new ARP rod bolts
PMO 46 carbs/intakes

I have more details but that is the basic parameters of the build. Any advise or suggestions is welcome.

What other parts do I need to consider or coordination items that must be addressed?

Why not throw 98mm C's and P's at it since you are already planning on replacing the stock ones...

Shawn,

I would have for just that reason except I got a deal on 95mm's, and they are Mahle and the had the c/r I was looking for,
Tony

This is a very nice package. You should have no surprises as many have built this before. I just finished a similar build but with 98mm PC set. In fact, I should be able to start for the first time tonight.


If you are going to resize rods and replace rod bolts then split the case and replace the crank main bearings as well. The stock rod bolts will be good for the rpm range that a Mod_S cam will provide. If the rods are tight I would just use them. This of course, would depend on how many miles the donor longblock has.

I would make sure and measure everything. This includes CC the heads and piston crowns to verify compression and check valve clearance. I would do a dry build first (no sealants) to verify fitment and then take it apart and reassemble with sealants. If this is your first build you will notice that the build will not be entirely intuitive during the dry build. Better to take the extra time while there are no "ticking clocks" for hardening sealants. the second time around will be smooth and efficient and you are assured of getting a dry motor with the sealants.

Read the ultimate sealant thread. There is much good info.

Thanks Jamie,

All good advice. I think I am leaning to not do the rod bolts, rod re-sizing and splitting the case with 60k miles. Definitely will do a dry build and check valve clearance. Is there a simple way to cc the heads and pistons?

You can expect something like this:

http://forums.pelicanparts.com/porsche-911-technical-forum/246563-another-rsr-clone-project-dyno-day.html?highlight=dyno+day

Here is how I did the CC on my heads and pistons.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/422194-time-teardown-another-3-0-rebuild.html

You could also do the same with a calibrated syringe and be close enough. The error would be higher due to less precise markings and the multiplication of runs.

Jamie,
Did you get it fired up the other night? ANd did you ever cc the cyclinder and head by bolting up a cylinder and head on the lower end like the method cgarr mentioned? If so, do you just bolt up a dry-build and prior to checking/shimming for valve and piston clearance?
Tony

Today, I received the '84 3.2L heads with 40mm/38mm intake and exhaust ports. They look in good condition, but I really don't know how to tell. I'm gonna send them off to cgarr or xtreme head to do the valve job and go with TRW 8mm valves, EBS vmax springs and retainers for a little extra protection. Still need to pick up the 46 PMO's.

I have the 3.0L all torn down and today, I took the upper head studs out and cut two grooves perpendicular to the threads in one of the old studs to use as a thread cleaner. Ran thru all the head stud holes and it worked great. Now I am ready to install all 24 new head studs.

I also soda blasted the engine, valve covers, cam housing, cam covers and fan and fan housing. Man they are clean are looking good, I will crinkle paint the valve covers and timing covers black which I think will look good, be low maintenance (not show dirt) and supposedly, cool better. The fan and housing will be painted too, not sure with what and not the edges of the fan that are next to the housing (to avoid clearance problems). I noticed the fan has been rubbing the housing pretty bad. Rubbed the housing for about 8" long and 2 " wide. Dunno why. Looks like a slight crack in the fan housing also, on one of the four tabs that hold the inner ring to the outer ring. Maybe weld it up?

This will be my first rebuild and I have enjoyed all of the posts that I can find but I still have some questions. Does anyone know of any issues or things I need to consider in putting the 3.2 heads on the 3.0 cylinders?
Tony

SPLIT THE CASE!!! its not much more work once your down that far....its not your orignial engine so you dont know much about it. my opinion your looking to do some performance mods and race it so why not change the bearings, change rod bolts, new chains, and make sure the base of the engine is in good shape..plus from experiance how do you know its only a 60k mile engine? were you told? odometer? neither of them i trust 100%. also you should perform a leakdown before you install rockers to make sure all is ok....

+++++1 as a vastly experienced poster here says, " do or don't... never try" I think are the words. I second what 175mph951 says.
Unless you don't mind frequently wondering what condition the bottom end is in... especially at 6800 rpm and wondering if this might be a $$$$$$$$$$$$$ (money) shift as its called. It is up to you in the end & it is your money, but, who likes to play russian roulet with an engine going to be asked to perform at its upper ends some times or mostly ??????????????????????????
Good luck & I hope all works out as you hope !
Bob

Hey Tony, sounds like your moving right along.....

For those concerned, I am the previous owner of this engine and Tony is a friend of mine. I bought this car with 56k miles from the original owner and put about 6k miles on it over the last 4years. The engine runs like a sewing machine. The only reason the engine was pulled was it had developed a leak at the cam shaft O ring....most likely from lack of use. My intention was to reseal it and put it right back on the road but a family situation interupted my plans....

I expect Tony will get years of pleasure with his project....

regardless if its planning to be raced id change the bearings and rodbolts and chains....noone has x-ray vision...its just a precausion especially being its only a few extra hours work since the engine is all the way broken down. ive rebuilt 30 plus engines over the last few years....some from 30k all the way to 200k and i would never not split case and check everything. just my 2 cents....doent mean everything will be perfect inside but the fact is unless you check you dont know....and this car is planned to be RACED!!

175mph and 911 tweaks,

Thanks!!! and all definitely good advise. Trust me, I would love the peace of mind but this slippery slope has to have a bottom and being that it is not a full on race engine and my first track engine, I am falling on the willing to risk it side. The costs for rod bolts, bearings and chains is what, another $1,000 in parts, plus $175 to re-size rods plus I dont even know what else I would need or possible other costs. I don't mind the additional labor assuming I can follow Waynes book and not end up with a mistake or leaks, but without touching the case, the current estimate is a little over $12,000 which is close to my limit. I am thinking maybe I am a little more concerned with the 915 and possibly rebuilding that in order to reduce the chances of that big money shift. I know this thing won't shift like my G50 but I am afraid I am probably going to have to address it. I was really encouraged by rcecale "Can't shift into first" 915 rebuild thread. I am replacing all the shifter bushings and tranny fluid as Mede8er and I discussed to see if that doesn't improve things first. He has been a real help and inspiration to me to get this project underway.

Looks like the 3.2 heads will work just fine so the heads were sent off today to Cgarr and I need to select springs very soon. Currently looking for advise on the valve springs to use. I have looked at the EBS vmax set, the JB Racing set and the performance and racing sets from John Dougherty. Any thoughts on these or other selections?

I am also anticipating sticking with standard 9mm valves, maybe even regrind the existing if within spec. The rocker arms were also sent to Cgarr to rebush and resurface the faces in anticipation of new cams. I am not planning to do anything to the rocker arm shafts but i had two observations. First, they looked very clean but one or two of them had the slightest wear on the one side, opposite the cam and right at the oil hole. Visible and could be felt with the finger nail test. Is this typical or normal and more importantly, do I need to do anything about it?

Second, one of the cups (non-threaded one) for the shaft bolt remains in the shaft and I am not sure how or if I need to remove it. Any suggestions?

Does anyone ever use the rocker arm shaft o-rings? Saw our host carried them and was just wondering if they were cheap insurance.

Thanks all, I am hoping to get some of the great help I have seen in so many threads on this wonderful forum. This is my first top end job and it is a little nerving considering I am making modifications and not just replacing what was there, so to speak.

Tony

I'll throw in my opinion to not split the case. Very unlikely to find any problem there. For valve springs I'd use John Dougherty's upgraded springs (performance). You need a little more than stock if you are using an agressive cam and spinning it to 7K or more. The rocker arms will make a little noise if they are worn but won't cause any other problems. You should be able to knock the cup out from the other side with a thin drift. I use the RSR o-rings and they seem to help with the leaks. Sounds like a great project.

-Andy

Thanks Andy,

I probably won't split the case. I spoke with John Dougherty and decided on some DC40 cams and racing springs. Found some of Dougherty's unused racing springs w/ Ti retainers set for cheap, perhaps a little overkill, but the price was right.

Anyone have some input or experience with this cam selection or better yet, this cam selection and a similar set-up?

-Tony

Well, the DC40 cams are on the way from John. I have almost all the parts to begin the rebuild but the nerves are a little stressed. Hmmm, what am I missing.

I have an order just about to place for the RSR rocker shaft rings, Goetz piston rings, chain ramps, carrera pressure fed tensioner o-rings, locktite 574, and Curil-T. I already have the complete gasket/rebuild kit and the head studs. Anyone have any other ideas so I can get what I need with reducing all the shipping cost of multiple orders. Thats probably funny as I bet I will have ten more orders as I attempt the build.

Here is some pics of the Mahle P&C's, 10.5c/r, used but still in spec. and the 3.2 heads with the new valve job, valves and springs.http://forums.pelicanparts.com/uploa...1233206870.jpg
http://forums.pelicanparts.com/uploa...1233206884.jpg
http://forums.pelicanparts.com/uploa...1233206895.jpg
http://forums.pelicanparts.com/uploa...1233206908.jpg
http://forums.pelicanparts.com/uploa...1233206921.jpg

Those heads look great...beautiful work on the twin plug...you need to ****can that clutch disc, however....:D

Thanks Bro,

Yeah that clutch disc and pressure plate/tob will be replaced and the PMO's should be here next week! Oh, if I missed a deal yesterday, I definitely made up for it last night ;) Thanks.

-Tony

nice build, looking forward to reading more of your progress.

I also don't see any reason to split the case with a low mileage engine such as this, but I am no expert.

Now that I have your attention, any chance you might want to part with one head from the old 3.0L parts? I am looking for one head only.

thanksSmileWavy

engine removed - check
 

Well, progress on the 3.0 is slow but as a great motivation, a fellow Pelican came over this weekend and gave me a hand in removing the 2.7L from the '73 911. Wow, he made it easy, major thanks and Kudos to Mede8er. Here are the obligatory shots.

http://forums.pelicanparts.com/uploa...1237208092.jpg
http://forums.pelicanparts.com/uploa...1237208116.jpg

Tony's got the makings of a super sano ST backdate here....excellent tub and wait till you see his suspension upgrades!!!

I'm drooling here....

Well, the new Goetz rings are on and the p&c's are on. I am about to do a dry-fit and check the valve to piston clearance, but I see something that concerns me.

The headwork was done on a set of '84 3.2L heads. New valves and springs/ret. The pistons have the deep valve pockets and I suspect I will ok in the depth direction. But the width of the pockets is very close to the width of the valves. Looks like maybe 2 to 3 mm wider pocket than valve. I measured with calipers and will have to go back out and check again to get specific measurements. Assuming the alignment places the valves dead center in the pocket, is this too small a pocket????

http://forums.pelicanparts.com/uploa...1243100198.jpg

http://forums.pelicanparts.com/uploa...1243100219.jpg

The Intake valve is 49.19mm in dia and the exhaust is 41.65mm.

Compared that to measurement of the valve pocket; intake is 51.88mm and exhaust is 42.96mm.

Anyone? What is typical for clearance in this direction?

Thanks

Perhaps the answer is that since all 3.0 and 3.2L engines had 49mm intake valves and 41.5mm exhaust valves, then any piston valve pocket designed for a 3.0L should work. Just because I am using a 3.2 head, it shouldn't matter as it is still the same size valves.

Does that make sense or can somone confirm???

Is there a way I can or should check the valve to piston clearance between the valve and the SIDES of the valve pocket?

The standard piston-to-valve interference check will detect the point of interference between the valve and the piston.

The pockets on the RSR pistons are designed for the valve sizes you are using.

The key checks will be deck ht and compression ratio.

Hey, Thanks Tom,

The deck height was just around 1.2 to 1.25mm after many reverifying vernier checks. But why is the cc'ing to verify c/r so important. At this point, isn't it the proverbial "It is what it is". If I find it is say 10.2:1 instead of 10.5:1, What could I do about it?

Tony

The RSR type pistons you are using are designed to run at around 10.5 CR. If your combustion chambers are the correct volume, you'll achieve that.

Your stock combustion chambers may be too big. If so, the CR will be lower and you will not realize the performance benefit of the increased CR due to the RSR style pistons.

After you do the cc volume checks and the CR math, you can make adjustments by changing base gasket thickness and/or by machining the heads. You'll want to get as close as possible to the 10.5 CR. Too high and you'll need race gas. Too low and you will not enjoy the performance benefit.

I have a very similar motor running with early SC heads that have been cut to produce the 10.5 CR. It is a great running street/track motor making around 285 HP and runs great on pump gas.

Others more experienced than me can jump in to help, but if you do a search on CR checks, you'll find that many of us have found surprises when doing them.

Hey cool, you bought Dave's old 73. That was such a fun little car with the 2.7. the PO is a good friend and used to live in Austin.

What are you doing with the 2.7?

What your final compression ratio measures is really up to you and how much time it takes to build the motor or do machine work. You may get to a point where you are high enough to be acceptable. If too low that is a problem. If too high that is worse of a problem. I was targeting 10.3:1 and ended up at 9.98:1. I don't think I would feel the difference except with dyno numbers.

You mention a deckheight of 1.2-1.5mm. Was this with or without base gaskets? Using some base numbers for a 3.0 build (stock head volume, and a piston crown volume of 48cc you get 10.1:1. If you drop the deckheight down to .9 or so (removal of 0.25mm base gasket) you get 10.5:1.

The lower compression will help your ability to maintain timing with the FL heat and humidity. The slightly lower compression will also mitigate the octane requirements. The higher compression will increase torque a few percent.

Hey Jamie,

I was hoping you might chime in on this thread. Yeah, this is his old car. His 2.7 was removed for this 3.0 project. It is for sale in another thread.

The deck heights are around 1.2mm. This was with the .25 base gasket. I am about to cc the heads and cylinders and I am trying to search for the best method possibly without removing the p&c's. Any good threads?

With the 3.2 twin plug heads, no fly cut, 10.5 Mahles, base gasket and no machining of the case I hope to achieve between 10.3 and 10.5:1. I suspect it will be on the lower end and maybe even as low as 10.1:1. I would like it as high as possible, but would be happy in that 10.3 to 10.5 range. Anything else to consider to help with the FL heat and humidity?

A quick way to check would be to bolt up one head, roll the engine up on its side, set it up to TDC and CC the chamber thru the spark plug hole, this gives you a very accurate measurement of the combustion chamber then you will know exactly what the CR will be.

Heya Craig,

The heads you did for me are a thing of beauty. How'd the mirrors turn out?

Is there a little more description I can find on the method? Like what to use for fluid (ATF or isoproply?) and what to measure with? I assume I would intall one of the two twin plugs. Do I need to seal up the piston/rings with anything? Any other tips? I've been doing searches but haven't found that idea cc'ing post for this method. Thanks all.

I got a 50ml which is (50 cubic centimeters) burette off ebay for about 16 bucks, I did install at least the top ring along with a bit of grease, I used fuel oil in mine but ATF or any light oil would work, install the lower plug and turn the engine so the top plug is level and see how many cc's it take to fill the chamber. Here is the program I used to calculate the CR using mm. You only fill in the Cylinder Bore Size, Stroke Length and the Combustion Chamber Volume In CCs, Zero out every thing else and hit calculate and it will give you the CR.

http://www.csgnetwork.com/compcalc.html

I have the mirrors on the car and they look great but still need to figure out the wiring to work with my 86

Here's some data from my trails and tribulations of determining the CR on my 3.0 RSR build.

Everything turned out fine in the end.

http://forums.pelicanparts.com/showthread.php?s=&threadid=213504&perpage=20&highl ight=head%20volume&pagenumber=1

Craig,

I know what you mean on the wiring.. I tried everything but could not get it right. Then I took apart my old flags enough to see what wire had gone where. Once I did that and realized two wires were actually tied together and coodinated the wiring to what WAS in the flags, wala!

With respect to your method on the cc'ing. How can I be absolutely sure I am at TDC if I do not have a dial indicator? Also, can I wipe a film of assemble lube on the cylinder wall then take the piston up to TDC to get that "seal" at the top ring, then place the head?

Tom,

Yes I had remembered reading that post, but couldn't find it again. Thanks and sounds like we are following similar paths except for my heads are 3.2's. It is my understanding that the 3.0 and 3.2 heads are the same volumns and in the stock range of 89 to 91. My heads were not fly-cut so I have not picked up some c/r in the way that Auto Associates coordinated for you. I am using the .25mm standard base gasket and have a deck height of 1.2 to 1.25mm. I will cc my volumn as soon as I get my burette.

Maybe a potential solution for my situation would be to reduce or eliminate the base gaskets as opposed to fly cutting at this point?

Tony

The stock heads are in the range of 90 cc.

Try using some of my numbers for piston dome volume and and the stock head volume in the CR calculator to see what your CR will be and what your options are.

The cylinders can be shortened to raise compression using the thin .25 mm base gasket. This will come at the expense of reduced deck ht.

Keep us posted on your results.

The lower compression will help your ability to maintain timing with the FL heat and humidity. The slightly lower compression will also mitigate the octane requirements. The higher compression will increase torque a few percent.

Hey Tony...can't argue with this logic....

Can't wait to fire this badboy up....