Quote:
Originally Posted by Rob VN
(Post 503471)
Are your connecting rod piston pin bushings OK and are you going with better rod bolts?
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The rod bushings at the small end looked really good. Very little wear there compared to the big end. I am keeping them. I did look into replacing them though, out of curiosity. The bushings are about $120 for all 6, so not very costly, but I'm not sure how I'd install them myself. I do have a press, which I use for the motor mounts, but this seems like it would take a lot more precision. Also, it looked like the bushings come without the oiling hole and you would have to drill that after pressing in the bushings. After drilling it looked like they used a tiny sander to smoothen out the inside edge where the drill bit came out. Pretty amazing. I think it's doable at home, but I wasn't feeling it this time. I don't know, at that point you might as well upgrade the rods to a better spec anyway.
I'm not doing aftermarket rod bolts because it's not necessary in this application (no track = no stretching IMHO. I can tell you that I revved the crap out of it for street driving and had no issues in 187k miles so...yeah). The 996 rod bolts that came on my 986 were superseded by 997 rod bolts, so I guess it may be a tiny upgrade in that regard, but all stock.
BTW, as a general comment for folks interested in these things - when I opened this engine, I was of the mindset that for a track build, everything would have to be replaced with better, aftermarket components. Pistons, rods, rod bolts, crankshaft carrier bolts, IMS chain tensioner paddle, the list goes on and on and on. After taking this engine apart down to the last nut and bolt, I have changed my opinion slightly. It seems that a lot of the aftermarket products are complete overkill. They definitely are overkill for the road. My day job deals with statistics. Unfortunately I can't collect and don't have enough data on these engines, but I'm pretty sure that some of the failures that are now being avoided through costly aftermarket parts are so rare in occurrence, that they are well within the defect rate of parts in manufacturing. Essentially, I am attributing the failures to defective components (within normal defect rates) rather than poor design. Of course aftermarket companies would have you believe that you should replace all internals save for the engine cases (and that's because they don't make aftermarket versions of those).
Now, would I still upgrade everything on a track engine build? Hell yes. If I was building an upgraded 3.8 to drop in my Cayman track car, I would go all out and shell an extra $10 to $15k to have everything over designed and have peace of mind and be able to blueprint the engine, etc. etc. This engine though, simply isn't worth that kind of money. I think owners should really look at the use cases for their cars when deciding to do these very expensive rebuilds. If the use case involves some "spirited" driving on weekends, then I don't think any aftermarket components are necessary. Just one man's opinion, of course.
Martin and others on here, who have a lot more experience and knowledge with these engines can comment on this. I'm a very data driven person, and having looked at the parts and the failure modes I'm just not so convinced anymore that these engines were design disasters that we should spend the price of a very nice car to make right.
