Quote:
Originally Posted by kamaro
I have decided to refresh my '87 Carrera 3.2 engine, just a typical rebuild, nothing fancy, and after 180,000 miles it must be due for that anyway. I bought a set of main/rod Glyco bearings from design911 in UK (just because of faster delivery time) but I was surprised when I saw between 0.004 and 0.005 of clearance in the mains which is excessive, I tried the old ones and they went back to 0.002 consistently on all of the main bearings, I happen to have another set of Glyco main bearings on the shelf so I tried them and sure enough it gave me the same excessive clearance. also I happen to have another old used Porsche 3.2 main bearings which are almost scratch free and I tried them as well and they were all OK @ 0.002 .. Whats wrong with all the Glyco main bearings being way out of spec like that? .. I know they had a similar issue few years ago with the con rod bearings but now I see the same issue again with the mains. and BTW the con rod bearings are fine with 0.002" clearance among all 6 rods. I used both plastigauge method and mic/boregauge method just to be %100 sure. I have decided just to use the used genuine Porsche set and call it a day.
|
um
wow.
That is a massive difference!
woud be interesting to measure the thickness of the glyco bearinngs with a quality micrometer and ball (for the concave side).
Do you have the packet they came in? Where were they manufactured and the date?
They will obviously be replaced as an extra 2 to 3 thou means they are junk!
On the topic of splitting the case; I have ONLY done a top end once since the owner had receipts for proof of a full rebuilt not that long before (in terms of miles, not time).
The engine I am working on now, is being rebuilt mainly for oil leaks and a clean bill of health. It was running and made good oil pressure...
Every rod bearing showed wear.
Every main bearing showed minor wear.
Without pulling it apart, how do you know? I would say that MORESO for diyers, they should pull it apart.. I don't know too many diyers who would want to go through the whole process again at a later stage. Most want to do it once, and once only.
