advice on 3.2 rebuild
 

Not sure how far I should go so asking advice from the group.

89 Carrera 3.2 with 120k miles.

Burns no oil and has good oil pressure. Leakdown test indicated #4 cylinder has a bad valve. Original clutch (G50 trans) so that will get replaced.

It idles a little lumpy because of the #4 cylinder (I assume) but not terrible. Not sure if this would effect any of the bearings (question 1).

Definitely going to have all the heads rebuilt with new chains / ramps. Should I stop there or do any of the following (in order of difficulty)?

New rings?
New, upgraded rod bolts?
New main bearings?
New rod bearings?
Anything I am missing while in there?

I would be doing the disassembly and reassembly myself in a small garage. Prob send the heads to Ollies. Not sure about the other stuff. With increased to do list increases my chances of screw ups. I did rebuild my 2.4 E motor 10 years ago.

Advice is greatly appreciated.

Chris

89 Carrera

Hi Chris,
The 3.2 most likely had alusil cylinders so I would have reservations trying to throw rings in it.
I would definitely upgrade those rod bolts to ARP.
Be mindful of the pressure fed tensioners, they do have a service life and the replacements have been known to fail. A friend of mine built a motor with new tensioners and had a failure 2 weeks after delivery to the client. The parts from the tensioner got between the intermediate sprocket and the case and generated a nice hole.

Lastly, I have had issues with old ECU's, wiring and sensors. That system was in production when the Commodore64 was the preferred PC...

Thanks Aaron,

To do the bolts, have to remove the cylinders (believe it can be done w/o splitting the case). At that point I would need to replace the rings (no point reinstalling the old ones). Should I have the Cylinders Nickacel plated? or just de gloss them with scotch-brite and install new rings?

Going to leave the tensioners alone. They can be replaced anytime with the engine installed....project for another day.

Have the SW chip in in the Commodore64 so slight upgrade there.

Many Thanks,

Chris

Assessing the viability of used cylinders is always a challenge.
Alusil: have them coated.
Nikasil is good/great shape, de-glaze and re-ring.
If the budget allows, bore to 98 and buy new pistons that meet your performance criteria.
Or of course, new stock Ps&Cs are available. Quite often the higher compression Euro Carrera sets are priced fairly reasonably.

Hi Chris, I don't care to replace rod bolts with the crank in the case. You loose the ability to see what you are doing. A rod bearing can unseat and overlap during install and you have some damage to address.
You also do not have room to use the stretch method on the rod bolts. I go by Stretch while noting the amount of torque required to get there. Its torque numbers are usually higher than what ARP calls out. EX I usually see about 50-52 ft lbs on a 10mm bolt. I believe the spec is 45.
Lastly, it's easier to measure for bearing clearance with the crank out.

Rod bearing clearance and Bolt stretch are the most critical points for me on the bottom end.

Leakdown numbers and not using oil, why mess with the cylinders. 1988 is going to be Nikisil, will last another 100k. As we all know, they don’t make bearings like they used too. Do the heads, replace the cams and refinish the rockers if worn. Drive it like you stole it!

Application determines longevity.
Nikasil can last 200K+ under the right conditions but will the rings.
The ridiculous rod length to stroke ratio of the 3.2 creates excessive side loads on the piston. This causes rings to wear more quickly vs say 911SC . I would be amazed to hear that a 3.2 with 120K would be stingy with oil.
Now my Tundra with 350K doesn't use oil but an air-cooled 3.2 with 120K....I'm skeptical.

My 3.2 does not burn or leak at all. After a year of driving, redline at least once a drive. it has 3/4 a qt less then when the oil was changed in the spring. Around 5k miles. Prob burns 1 qt per 10k miles. Not to say it could not use new rings at 120k miles (also has original clutch and has been to several DE's). Go figure, think I got a good one (burnt valve is the PO's fault for not doing valve adjustments last 10 years).

Assuming the cylinders are Nikisil, will deglaze and new rings. If Aluisis, will likely bore, plate and install 98 mm pistons.

Car is heavy and can use all the HP I can find.

Chris