3.2 rebuild vs 3.6?
 

Long and the short of it... my new to me 1984 3.2 with 58k (documented) miles has a missing head stud (someone left the washer behind however...), and pitted cams.

My thought is dirty oil at some point as far as the cams go. This makes me wonder about what the rest of the engine looks like. Compression was 155-165, leakdown 4-8%. No smoke telling of bad valve guides.

I am thinking of 964 cam regrind or webcam 20/21. Of note I will have SSI's, M+K 2:1, SW chip, cut airbox (cup style). Plan is for street/HPDE compromise so the SSIs were chosen with midrange and heat in mind, I am not out for max high RPM gains. I am also ordering the engine rebuild book by Dempsey (although I will not be doing this myself).

So my questions:
1. Beyond the cam and rockers, anything else to look out for? (I am expecting to do exhaust guides at least, resurface head, APR or equiv upgraded head studs)
2. Crack the bottom end? new rod bearings? (scope creep!!! getting into 3.6 territory when you factor selling the 3.2)
3. Swap to a 3.6? (~20K cost, plus scope creep like bigger brakes)

Thanks for any thoughts. A good discussion of the same type can be found here: http://forums.pelicanparts.com/911-engine-rebuilding-forum/753883-budget-3-2-head-stud-replacement-project.html

The pitted cams/rockers are more than likely from the wrong oil not dirty oil...a guess would be a non zddp type oil. That's where you see the damage if the oil lacked zddp.
The lack of zddp will not cause an issue elsewhere...it's a cam/rocker specific ingredient for flat tappets.
With 58k on the motor I would not crack the case if in fact you find no other wear items in the heads (oil issues you mentioned).
Do you know any history as that helps with the decision on upper or total.
The crank/bearings/bottom on the 3.0/3.2 are known for their longevity....I'd only crack it if a known issue existed.

Definitely go the 3.6 route and give me the 3.2.... I'll pay freight.

The PO did a claimed 4 autocrosses and 2 HPDE's. I changed all fluids and then I did one HPDE. I am thinking over-rev risk.

The oil residue in the lines post engine removal was classic for water in the oil... i.e. not heating the engine up properly. Likely part of why it had so few miles.

PO swore by Rotella T diesel oil (15W40). He was sold on that based on a reputable west coast shop that did a lot of work on PCA race cars and swore by it also. PO only owned it for 6K miles and maybe two oil changes. I used the same oil for 2k miles (changed the oil after getting the car). Good discussion here: http://forums.pelicanparts.com/porsche-911-technical-forum/290009-diesel-engine-oils-good-aircooled-porsche.html

Not trying to start an oil war here, but how long do you think it would take bad oil to do this kind of damage?

http://i1168.photobucket.com/albums/...ps9doytneg.jpg

Freight will be 20,000$

Some S14/S38 guys also swear by that diesel oil, it's full of zddp.

I would suspect improper warm up, not bad oil.

Change the head studs, I recommend Supertec, change cams and chip.
Leave the bottom end and set a side a budget for exhaust valve guides if they are needed. The valve guides are easy to check when you have the heads of.

I just went through this. I had cam tower leaks at the rocker shafts and pitted cams resulting from blocked spray bars. This was due to a poor top end done by the PO.

I decided to rebuild vs swap. I did not crack the case but did everything down to and including rod bearings. Added 964 cams, Supertec head studs, ARP rod bolts, etc etc. I've paired it w/ custom SW chip, George's headers and a Dansk 2 in / 2 out. Its not got the torque of a 3.6L but its new and it is strong!

I think i saw a thread you made. I will likely go your route. My mind has been directed to external mods to date, but i will now adjust my focus to internal options.

Did you do any intake mods? I am doing the stage 2 wong chip now with my 964 cam plans.

Here's a comparison of a very hot very well built 3.2 vs a stock 3.6 in the same chassis and w/ the same gearing

guess which is going to be a more enjoyable drive most of the time
http://forums.pelicanparts.com/uploa...1423666188.gif

I love those graphs. "There is no replacement for displacement".

But the costs just don't favor the 3.6 for me. I slso like the idea of keeping the original 3.2, and knowing what went into it. My mind is not yet made. Time for armchair math.

Most engines are in the us. The 3.6 could be done for about 20k. A bit less with my engine as a core. Add bigger brakes (around 2.5k for 964). Then you start wondering about extra oil cooling needs. Same for tranny cooling in the 915. Work would be farmed out. Plus i have new ssi's and a m+k and sw chip. I could sell at a loss. Add 25-30% to the prices for the weak canadian dollar. Add 15% sales tax on that. Add transportation costs from the us to eastern/atlantic canada for an engine.

The engine and car are in a trusted workshop. Three feet of snow outside. My 915 is also in pieces and will need routine parts.

Lets be optomistic with a cost of 25k with brakes and all labour in... That is north of 36k canadian, taxes in. More than the cost of my car. Minus 6-7k for my 3.2 and exhaust. 30k canadian or so at the end of the day, if all goes well. Reality is, labour is probably 20 hours on top of that.

I am leaning to rebuild locally as planned... The engine work will just likely extend beyond fixing oil leaks.

I personally think the pitted cam issue isn't oil type related. There are way too many pitted cams out there, but the rest of the lobe and rocker face intact, for this to be a lack of ZDDP. If you've ever seen a flattened cam before, it looks nothing like a pitted cam. I think the pitted cam issue is due to the surface hardening of the cams not being deep enough. JMHO.

As far as the rebuild, get some JE 98mm 9.5:1 pistons and have your cylinders bored and plated. That will run you about $2K and gets you 3.4L and a good jump in torque. Add 964 cams and a tuned chip and I bet you'd be close to a stock 3.6.

Buying a used 3.6L is like a box of chocolates......

The 3.6 is the best bang for the buck, but have to be picky getting the right engine, otherwise you might need to rebuild that too. A 3.6 is an old engine to today.
But with a little tweaking a 3.6 will give you around 300 hp, that's a lot more difficult in a 3.2.

Its a hard choice, it depends on the car. The prices are rising and its very likely that rebuilding the original engine makes more economic sense.

Interesting on the pistons. My understanding was that the 3.4 or 3.5's did best with a twin plug conversion, but a good thought. I did not realize the lower cost, so i might check it out.

I avoided thinking hard about oversized pistons as i thought the dogma was that a really hot 3.2 borders on 3.6 conversion costs.

Slippery slope, but i will digest for sure.

As it stands, with chip, ssi, open airbox, and 964 cam, 250hp is a resl possibility, especially with a fresh top end. With my car targeted at 2500lbs, that would be plenty fun. 10lbs per hp was my original goal... 964 cams may allow me to reach it.

All the projects will cost way more on this side of the border as we get hit by the duty and the higher freight cost.

If you want to keep cost at a minimal, I would recommend the APR rod bolts and head studs, you can buy them at local ARP dealers. That's what I did and it was cheaper than thru internet suppliers. (the guy at my local muscle car shop was amazed at the quality of the Porsche ARP head studs package!)

For the cams, John Dougherty is also a good source. I was able to buy a set of his 993ss cams here on Pelican for $600. That is exactly what he recommend for my upgrade.

If you want to go the 3.4 route without twin plugs, you can buy a set of 9.5:1 JE Pistons and have your cylinder bored to 98mm. This will cost you about $2000.

If you don't have anymore issues (valves guides, bearings...) and want to stuck to this, you should be able to keep the cost down. After that, it really get slippery if you go with heads porting, intake mod, better headers, etc...

One last thing, just remember that most of the time you have to consider ''the big picture'' as just changing one or two parts will not give you optimal result.

Good luck !

With the price of SSIs these days, I just don't think they make a lot of sense on a 3.2. After the muffler, oil lines, heater backdate tin, etc, you're probably talking about close to $3k if you buy new parts, plus installation.
That money would be better spent on pistons, cylinders, and cams, IMO.

I already have the ssi's and m+k and everything fir the heat backdate. The worn cams and missing head stud was a surprise... But that is another story.

G_S, we're both at about the same point. I now have everything I need, I have cleaned as much as I am going to but probably will be wiping things down one more time as I go back together. I never gave rebuild vs. replacement any serious thought, I always knew I was keeping my engine, if for any reason for authenticity. All the things you have, I have for my engine. Except, I have not decided how I want the DME chip to be programmed. I'm waiting on that until I get closer to being finished with the reassembly. Although I can say that the money I have saved on doing the disassembly has been spent on other services and custom work that I have really thought long and hard about with regards to what I want out of this engine when I'm done. The grinding and polishing of the 964 cams, the head work and who did it, the exhaust...all those things I carefully thought about and waited until I got exactly what I wanted. I'm sure that I will have/already have spent far more than I wanted to or budgeted for but in the end when the car is on the track and I am now pulling far enough ahead in the twisties of the Boxster and 996 guys that they will not be able to run me down on the straight aways the smile on my face inside my helmet will be far greater than the money I spent putting this thing back together. Best of luck on whatever you end up deciding to do, either way, you will end up on the winning end of the stick.

I lose as I paid a price for my car that assumed it did not need a top end, but I agree, this will be positive in the end. I panned to do the top end in the next 5 or so years, but I am just advancing my timeline. The good news is that I will have a top end 915 and fresh 3.2 when this is done. My forcast weight loss will bring me to 2500lbs, and with 250hp, I am hitting my target 10lbs per hp.

First world problems.

if you put in a hotter cam, should we be worried about the rod bolts? I hear all the stories of weak bolts in the 3.2s

I think the dogma is that a rod bolt of unknown history should be replaced as it is a known weak point with terrible consequences. They can be replaced without cracking the bottom end. Another dogma is replace them if your engine is open anyway.

A 964 cam should add 5-6hp above 4.5k according to an expert in the matter if my memory recalls. Probably will not cause much of a change from stock in the stress department.

my best recommendation, (i am nobody), rebuild the 3.2 matching numbers are king. unless you can afford to save the 3.2 and convert to 3.6.

[QUOTE=gliding_serpent;8481335]The PO did a claimed 4 autocrosses and 2 HPDE's. I changed all fluids and then I did one HPDE. I am thinking over-rev risk.

The oil residue in the lines post engine removal was classic for water in the oil... i.e. not heating the engine up properly. Likely part of why it had so few miles.

PO swore by Rotella T diesel oil (15W40). He was sold on that based on a reputable west coast shop that did a lot of work on PCA race cars and swore by it also. PO only owned it for 6K miles and maybe two oil changes. I used the same oil for 2k miles (changed the oil after getting the car). Good discussion here: http://forums.pelicanparts.com/porsche-911-technical-forum/290009-diesel-engine-oils-good-aircooled-porsche.html

Not trying to start an oil war here, but how long do you think it would take bad oil to do this kind of damage?

The Rotella should be good and the broken stud is a classic on a low mileage motor that's not properly brought to temp then sits.
That lobe looks pretty bad for that kind of mileage tho...who knows? As noted improper hardening...I didn't know that to be a common Porsche issue especially at that mileage.
I wouldn't split the cases myself....I've a full top end on a 3.0 euro that had 67k on it (same deal as yours driven little not warmed up ...head studs) when rebuilt and swapped out my US spec for it. I suspect it'll need another head rebuild before the bottom end has any issues.

You may not want to hear this but.....if the engine is out and apart down to the cylinder head studs I would split the case to inspect. You will then be able to replace the rod bolts correctly with a stretch gauge. It's a good bet your intermediate shaft bearings will be showing copper as most do. If your cams are pitted it may be indicative of hard use, dirty/wrong oil or incorrectly stated mileage. All these things could cause wear in the bottom end. You will also be able to correctly reseal the front pulley seal and number 8 bearing. If you split the case and all is well, you are only out the cost of sealants and a few more hours of labor. The peace of mind will be priceless. Most of the labor involves engine removal/installation and top end disassembly/assembly. I debated splitting my 3.2 case when doing a top overhaul and I was glad I decided to go the full distance. My 100k engine had worn intermediate shaft bearings and gears/chains, and the rod bearings were pretty bad. The mains also showed some wear. This was, I believe, the result of poor maintenance, oil contamination, and neglect. You seem like the type of person who will not be happy with a half assed job. Do it right and enjoy the car for decades to come.

is 3.6 motor price getting that expensive?
I chose the 3.6 route because rebuilding 3.2...ummm, with 3.4 twin plug high compression was more expensive at the time...circa 2008...

Market for engines is going crazy just like the classic 911 market. If i lived in the us near a big time shop it would be a different story. My quick math says 35k csnadian for a proper used 3.6 install all in (including essential brakes upgrade). Plus labour. The swap alone is more than the price i paid for my car.

I very much agree with you.

You are working with a 56K (right?) mile 3.2 here!! Just pull the heads and have them sent out out. for a valve job, replace the studs with new steel ones or a set from Supertec or ARP. This is a known failure and not the end of the world. LOTS has been written about it and many fixes have been documented right here and if you need inspiration, I can find the posts.

I just pulled the full top end off of an '87 3.2 with 100K miles and everything looks like brandy new. I have the rods out for new bolts just as a precaution. This is also a known weakness, and easy to replace. We are replacing the rod bearings because 1 had a polished area where the oil gallery comes out of the crank. The crank measure up perfect and new bearings will be fine.

We are building a 3.4 as a DD for my daughter and expect another 100K out if it before opening the cases.

Doing the top end is kind of easy and new cams are a nice upgrade for your base engine.

Jcdlocum... I totally agree with you, but the 90's were a bit of a dark ages in my cars documentation a couple of owners ago). Car fax records only start in 2004 or so. I figure is was either in storage, or off the grid (racetrack?).

Signs seem to sugest accelerated wear due to any combo of bad oil, improper warmup, possibly even the jets to lube the cam needing cleaning.

The 915 has had a hard life. The body of the car shows a hard life (red white rub marks on the rubber smile when i got it... You know where those came from...).

The 915 has been opened. 58k and one rebuild already and needing a second. The ring and pinion shows signs of being replaced. I will do a tooth count to see if it is 3.88:1

Something does not add up. Based on how things look when the top end is off, i will have a low threshold to open the bottom.

The rod bolts are only weak if you're going to rev it above 6500 for extended periods or have over revved it significantly. I take my stock bottom 3.2 to 6800 on regular basis.
You might not know if it has been over revved in the past, but since it still lives, then probably not, it would have shown...

56k is nothing for the bottom end. If you plan on living above 6500, then go ahead and change the rod bolts, otherwise you can leave it alone.

If you have major unknowns and suspect some abuse then Id go for the full monty.
The rebuilt 3.0 I picked up had a known history one owner deal so was confident with not splitting.
You won't feel right unless you do from the sound of your posts.

I concur with jcslocum. While the lower end (main bearings) of 3.2 engines seem to have good longevity (esp. at 58K mi.), the rod bearings don't necessarily follow that path. Easy enough to yank and take a look. Take your cue from the rod bearings as to your next move. At a minimum, I suggest having the rods rebuilt (big/small end, balance) and add the more reassuring ARP con rod fasteners.

And since there's evidence that a cylinder may have bounced around (missing crankcase nut - damn!), I would thoroughly inspect the crankcase spigot(s) and cyl. head(s) for signs of cylinder abuse, then confirm each bank's stack height during fit up (cylinder + cyl. head + cam housing). BTW, the engine internals in the photo don't look particularly clean. May be just the lighting. That typically depends on normal operating conditions and oil change intervals. For example, did the PO install the period-correct, factory race-like air filter delete option? You sure about the documented eng. mileage? Check piston and cylinder wear as well.

Yes, there's no substitute for cubic centimeters. However, you must add the cost of a good or rebuildable 3.6 if you go that route. But then, you might be tempted to continue along that slippery slope.

Sherwood

It always depends on your goals for the money. If you rebuild the 3.2 You'll still have a very fun classic to enjoy for another few decades for less money than you can get into another one. For the rebuild/swap price difference, I think you could get a (much faster) E46 M3 on the side.

I have a 3.6 in an M491 coupe. The power is nice, but it still spins the sticky 275 rear tires in a straight line. There have been a few annoying gotchas with the swapped motor, but I knew this would be the case going in. 993 prices are through the roof, and so is the price of parts. The bang/buck is gone.

I have a bone-stock 3.2 coupe. It's wonderful to drive and it's rare that I think "If only I had more power". Damn thing has appreciated like $10k since I bought it with no end in sight. Ride the wave.

Which is not to say that the 3.6 isn't particularly wonderful to drive, I just wouldn't build one from a 3.2 anymore.

As was said, the 3.6 bang/buck is gone. Engine prices have rocketed with the market, making rebuilds the more cost effective option

I've done both - and rebuilt both. If I'm spending the money to rebuild an engine - I'll go ahead and do the 3.6. Tough not to like a 3.6 in an earlier car. Creates a nice hooligan machine. (although I have to say that my 3.4 993ss single plug was a screamer of an engine)

That is probably the number one reason why I decided to stop teardown at the heads. My car only has 64,000 and definitely does not live north of 6500. Don't get me wrong, it goes there and I would get everything out of that engine that I could but it didn't live at 6500 and above and I never treated it like a rented mule.

I recently went through this same issue. My 3.2 has more miles, 114k, and indeed had 2 broken head studs which were discovered 6 months after purchasing the car. I live right near a great porsche shop and that influenced my decision to rebuild the 3.2 with some upgrades. While we were in there I upgraded the head studs, rod bolts, and rod bearings, along with 20/21 cams. The upgrades were of course not necessary, but the added cost at that stage was minimal compared to the piece of mind it gave me.

I'm happy I kept the 3.2 and hope to enjoy it for many miles to come.

Forgot to mention the bottom end, ok actually the middle, was not touched.

I will add to the 3.2 vs 3.6 debate that goes beyond cost or 3.6 availability:

Bill V's performance graph should be consitered, but at the end of the day, with some light mods, 250hp is quite accessable with a 3.2. The 3.6 964 is 247hp. Now, if you are starting with a 2.2, 2.7, or 3.0, the 3.6 might be an easier choice.

I doubt that any 3.6 dynos as low as 247, light mods on a 3.6 and you are pushing 290-300 hp...