mikew968

Hi all:

I am doing some off season work to the 968 and was thinking of replacing rod and main bearings and other misc things. The car has about 90k on it I am having 2nd thoughts as all is well at this point. Any thoughts on when this maintenance should be done would be great. As an alternative the rob bearings could be done without removing the engine so that is an option as well.

Thanks, Mike

flash968

now that is a loaded question for sure

rods are probably not a bad idea, but mains may not yet be necessary - how do you drive the car? what is the oil pressure like? how is the compression? (not bearing related, but if you're doing those, and it's low, then it would be convenient to address that too)

i myself am rebuilding whatever necessary when my compression gets down around 180-185 - that will likely be at about 60k - definitely not necessary yet, but the 20 plus hp that would be costing me is unacceptable - at that time i may well punch it out to 3.2 and do a number of other things

this is the never ending spiral of "while you are in there"

Dave in Chicago

I'm a fan of doing a PM on the rod bearings, though they do not seem to be as problematic on the 968's as they were on my 944. I'm kinda subscribing to a 40-50 hour rod bearing interval. The pistons/rods/cylinder walls all looked very good.

RajDatta

Mike, if you track, yes do them. If you don't track, you don't need to. Your mileage is relatively low for a street car.
Raj

Lemming

I did my rod bearings on the track car last summer, engine had around 70K miles and a little over a year of tracking. The bearings were fine, but I'm still glad that I changed them out. I have another set sitting in the garage and plan to put them in my spare 968 engine during the rebuild.

GeorgeNZ

unless you are going to do the rings as well (shouldn't need to on a road car at that mileage), I wouldn't unless you're goin to track it hard.

mikew968

Thanks for the imput guys!

I am going to replace rod bearings and the p/u tube, replace motor mounts, front and rear crank seals and do a general reseal. This way I don't have to pull the engine and that definately saves some money. BTW the car is a strictly track car at this point racing in NASA and PCA.

Thanks, Mike

GeorgeNZ

I really need to find some time to pull the old engine down to see why it failed.

JivenJim

Could Not agree more about changing Rod Bearings! After Big time Track Failure on a 94 Engine with 30K! Ok I ran it kinda hard and oil blow by got a little low#$%. But do that. Also at 90K you should do your Cam Tensioner pads and Chain. Old ones can Crack and then your head is done. Rear Seals on Balance shaft covers. (Probably all seals on a 13 year old Engine) My Oil Intake to return tube tab was snapped in middle too, but the Intake tube held solid.

Seriously consider Knife edge the Crank and Isharra Johnson Crank Scaper / windage tray if you do a full engine pull. You'll be faster and safer.

RajDatta

Mike, if its a 100% race car, definitely do it. The oil pickup tube cracking is primarily from a misaligned lower balance shaft housing. Usual symptoms are lower oil pressure and noisy variocam operation from lack of oil pressure.
To do everything right, you are looking at atleast suspending the engine on a hoist or removing it. The balance shaft housings are a pain to do from within the car unless you remove a bunch of stuff.
As stated, do you chain and pads while in there. I would also send the injectors out for balance and blueprint. Marren Injection in CT does an excellent job.
Good luck.
Raj

Jason Judd

I'm doing my rod bearings as we speak...well, I've asked my shop to do them.

I've decided to go with the 3 piece member to make it easier when we do them next time,too.

Jason

RajDatta

Jason, you might want to post on the turbo boards regarding the 3 piece cross member. Looks like a few individuals had issues with them from a quality control standpoint.
Raj

Jason Judd

Thanks Raj...I'll ask around!

Jason

mikew968

I did the vario cam pads a couple of thousand miles ago and they were pitted pretty bad. The cam sprockets were good as well as the chain. One thing my mechanic did mention was the engine was running a little lean at the top of the rpm range so that is something he will address. One thing he will do before actually beginning any of this is do a compression check and leak down to make sure everything is sealing up ok. My main goal in this whole process is to avoid a major failure in the lower part of the engine.

Mike