3.2 rebuild vs 3.6?

[gliding_serpent]

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: Budget 3.2 head stud replacement project

[Reiver]

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.

[Charles Freeborn]

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

[gliding_serpent]

Originally Posted by Reiver

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.

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: Diesel engine oils, good for aircooled Porsche?

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?

[gliding_serpent]

Originally Posted by Charles Freeborn

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

Freight will be 20,000$

[Bleedsblue]

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

I would suspect improper warm up, not bad oil.

[safe]

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.

[OffCamber00]

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!

[gliding_serpent]

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.

[Bill Verburg]

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

[gliding_serpent]

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

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.

[Josh D]

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......

[safe]

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.

[gliding_serpent]

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......

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.

[Bird911]

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 !

[gtc]

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.

[gliding_serpent]

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.

[michael lang]

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.

[gliding_serpent]

Originally Posted by michael lang

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.

[Kemo]

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