3.2 rebuild thread

dave7320 · 01:28 AM

I’m rebuilding my 1987 3.2. It will be a stock rebuild. I have a couple questions for you seasoned rebuilders.
1) should I replace the exhaust side head studs. Are they a problem like the 3.0 liters?
2) I’m planning on using the Cohline brand oil lines available here on Pelican. The cam and tensioner feed lines. Has anyone had issues with them?
TIA

Flat6pac · 01-25-2018, 10:28 AM

Replace the bottom row of studs with factory steel.
Oil lines will be good, sometimes they need a smidge of adjusting
Lest you forget, the oil scavenge line goes to the inside on the thermostat.
If you can’t get the connector off the thermostat, cut diagonally the nut to relieve the threads of aluminum on the thermostat.
Bruce

P3lico · 02-01-2018, 09:24 PM

How's the progress of your rebuild?

dave7320 · 02-02-2018, 01:27 AM

Disassembly is done. Found problems with #4 cylinder. It was leaking oil around the base of the cylinder and looked like the combustion chamber seal was leaking too. The oil control ring was 2 pieces and the intermediate shaft bearings were showing some copper. The crankshaft is straight and in spec. The rods are being rebushed and resized. Cams and rockers show minimal wear.
My head guy found a problem with head #4. It was machined wrong at the factory. It was .006” deeper pocket than the other heads. Effectively making it shorter when torqued. No wonder they head leaked. Intakes guides were toast in the whole motor. Everything else showed low wear.

cgarr · cgarr's Garage

with one head off that much I'm surprised the cam even turned?

dave7320 · 07:07 AM

It wasn’t .006” across. It’s was deeper at one end like there was a chip or something under the one sidewhen they machined it at the factory. There are no signs that the motor had been opened before. I will check the cam bores for elongation.

Trackrash · Trackrash's Garage

Kudos to your motor guy for finding that problem with the head. Amazing.

Sounds like the rest of the motor just needs a freshen-up. Good luck.

dave7320 · 02-04-2018, 03:20 AM

Picked up the heads yesterday. The intake guide were Were severely worn. Stems on the valves were shot. Three sets of valve springs were weak. So all new valves guides and springs. Today is cleaning parts at work. Then check the cam bores and the new cylinder heights/bores and piston diameters. Ring gaps and ring groove clearances. Not even trusting Mahle’s quality control after finding my head issue. Hehe

dave7320 · 02-11-2018, 12:33 PM

After spending 4 hours in the parts cleaning tank. Found some wear issues with the cam and rockers. Rockers are heading to cgarr and the cam is going to camgrinder for a regrind. Here are some cam lobe pics.

KTL · 02-12-2018, 06:16 AM

Mahle didn't make the heads so don't blame them?

I gots a spark plug like that too!

What Craig is saying about the cam housings isn't about the bore dimensions. It's about one head being the wrong height and then when you bolt the housing to the head, it potentially distorts the housing such that the four cam bearing bores are not co-linear. That would make the cam difficult to turn.

These cam housings seem to be somewhat of a dimensionally unstable casting. You can check the flatness of the housing's head sealing surface and the valve cover surfaces and you'll rarely find them to be anywhere near flat. Seems a lot of them are slightly "twisted" when they're not mounted on the heads. I suspect when they are mounted to the heads, they straighten out a bit.

88911coupe · 02-12-2018, 10:25 AM

One thing I learned in my rebuild, and in later attempts to address the issue, is the cam oil lines have an issue. The problem is the tube part that inserts into the hollow bolt on the case is about 1/8" too long. This keeps the ferrule from snugging down and actually making a good seal. The simple solution is to grind off about 1/8", making sure to clean it up, then installing as normal. I replaced this 3 times before I finally figured out what the problem was. IIRC John Walker may have noticed this as well. Another, expensive, solution is to order the "Porsche" part that does not have the ferrule pre installed, Its much more expensive and the solution I used solved the problem perfectly.

bickyd · bickyd's Garage

Quote:

Originally Posted by dave7320

After spending 4 hours in the parts cleaning tank. Found some wear issues with the cam and rockers. Rockers are heading to cgarr and the cam is going to camgrinder for a regrind. Here are some cam lobe pics.

May I ask how many miles were on this engine? I am in the process of doing similar on my 88 with 101K in the coming months and would like to use this as a baseline for what I may encounter inside. looking forward to your progress. Dan.

dave7320 · 02-17-2018, 04:26 PM

About 65k as far as I know. Bought it used of a guy who did a 3.2 conversation. Hopefully you won’t find this any issues.

bickyd · bickyd's Garage

Quote:

Originally Posted by dave7320

About 65k as far as I know. Bought it used of a guy who did a 3.2 conversation. Hopefully you won’t find this any issues.

Wow. That is surprising and worrying all at the same time. I wonder why the cams are so marked up and the guides were so worn. Maybe an extreme lack of oil changes. I expected you to say 150 plus miles. I wish you successful wrenching sir! Subscribed.

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dave7320 · 02-18-2018, 02:29 AM

My guess is quality control slipped up on this motor. The exhaust guides were only worn minimal. So there must have been a quality problem with the intakes being so bad at such low mileage. The cam looks like poor oil condition. The bottom end looks like a low mileage motor.

bickyd · bickyd's Garage

Quote:

Originally Posted by dave7320

My guess is quality control slipped up on this motor. The exhaust guides were only worn minimal. So there must have been a quality problem with the intakes being so bad at such low mileage. The cam looks like poor oil condition. The bottom end looks like a low mileage motor.

Good timing on your part. I hate to think some kissing of valve and pistons was in the near future on your motor. I would like to keep to the top end of mine. I know the bottom end of these motors is very sound except for the pump shaft bearings more than likely showing copper which bothers me. 3:29 am....

dave7320 · 02-18-2018, 08:19 AM

Intermediate shaft bearings were showing copper on this motor.

Flat6pac · 02-18-2018, 02:42 PM

They all show copper. The tensioners put out lots of running pressure and intermediate shaft bearings suffer but do their job.
Bruce

bickyd · bickyd's Garage

Quote:

Originally Posted by Flat6pac

They all show copper. The tensioners put out lots of running pressure and intermediate shaft bearings suffer but do their job.
Bruce

A question. We all know about the slick slope money wise. Will they "suffer" adequately for 200k miles? Have you ever heard of this bearing resulting in a catastrophe? I am sorry if I am treading on the OP's thread.

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KTL · 02-19-2018, 05:44 AM

Premature valve guide wear on the 3.2L engines is very common. Nothing out of the ordinary to see an engine that needs them as early as high 50K miles. I have had two engines that needed them. Both were 60K mile engines when the signs were there- oil consumption and noisy valvetrain.

Intermediate shaft bearing shells seem to hit copper and then level off there. They don't continue to get worse and cause a major failure. It's enough to make you wonder, why bother replacing them since the new shells will suffer the same fate.