Considering it only costs around another 15% to replace the big-end bearings when doing a rebuild (and therefore effectively having a completely rebuilt engine rather than a 'top-end') I would consider it false economy not to do it.

 

Low oil pressure at idle is, i thought, symptomatic of a dry-sump oil system.

 

That would mean that the people who have twice the pressure that mine does have an even bigger problem then - their cars have become wet sump!

 

For bushing type bearings I remember using plastiguage, I'm not sure how it's done when there's an actual roller type bearing, which I assume is used throughout the 964 engine. Unless maybe it is all measured with a dial guage?
To check the bearings one can use what is called plastiguage in which a small plastic fiber is placed on the bearing surface of the bearing journal then the bearing and cap are put on top of it and torqued to specification. The plastic fiber is squished and the bearing/cap are removed and the resulting squished fiber which sticks to the journal is measured by how much it is deformed or flattened out. The more it flattens out the tighter the bearing and there are certain tolerances it should be within. Another measurment is the bearing end play in which a dial guage is used to measure how much the bearing moves side to side - it should also be within a certain specification to be considered in good condition.

Hope this helps
Bill
90C2

 

This is more forum paranoia.

It seems that you have a big fear specifically of your bottom end going and costing you another 7 grand, Dave, and that from where I'm sitting seemed to come from the time last year when a few people on the board had their big ends go? This and some personal life changes seemed to lead you to conclude to sell the car, even though its driving completely fine (apart from the 'maintenance' needed)

You've been around rennlist as long as me, and you will have seen the 'whats a normal oil pressure?' posts that come up from time to time, and as far as I remember most people always report sitting at 1-2 at idle, or less.

We probably ALL have some wear to our big ends, and if you're rebuilding the motor then a bit of demonstrable wear mean its probably worth doing them too - as Christer says. But that is poles apart from the catastrophic failure that blows the engine, and that seems to happen to a tiny majority of unlucky people (who will always post on forums about it...) - isn't it? Darth's post seems to concur.

So - Dude, stop fretting! You'll get us all doing it..

 

Well, not exactly. I've seen the past posts on low oil pressure, and I know there is variation. I also saw the stuff in 911 & P World that mentioned the oil squirters, and I know it was mentioned on here recently.

My question to JZ was more curiosity than anything else. I'm not planning a rebuild, and I don't expect my engine to suddenly blow up. To be honest - if it did, then I'm not convinced I would be willing to spend £7K to get it fixed. I'm glad I kept the car, I enjoy driving it - but I'm not sure I would want a £7K drop in my bank account to continue driving it.

I was simply interested in what JZ's view was, and I thought people here might be interested as well.

 

And thanks for sharing, I do seem to remember though that 9M said he'd not seen any oil squirters go, so that being the case, big ends would be the logical answer....

My way of dealing with that is.












































Never let the damn thing idle.....


kevin

 

I like the idea of not letting it idle.But when it must its around 1 1/2 bar.Pretty much anything over 2500 rpm and its close to 5 bar.