In the first installment of this project car series, hardcore track enthusiast and project car owner Steven Tory found the source of the “bits in his oil,” but only after a complete engine teardown on his 1995 993 C2.
As it turned out, the “bits” were pieces of the engine’s intermediate shaft (IMS) thrust bearing that had literally just started to break up inside his engine prior to his “well-timed” oil draining. Only four small pieces of shrapnel were found, and the main pieces of the IMS thrust bearing were still in place. Fortunately the rest of his engine was completely unscathed by the ordeal, judging by a thorough inspection after the teardown. The IMS thrust bearing is not an identified trouble issue on air-cooled flat sixes, unlike the IMS issues on Porsche M96 water pumpers, which are well known, so Steven definitely had the good car Gods looking out for him that day.
Now the real fun can begin—with engine rebuild planning and full clean-up at the top of Steven’s “To-Do” list.
Steven was up to the technical task himself (with a little assistance and encouragement from yours truly), and really had four choices on how to go about the repair of his fully disassembled 3.6L Porsche flat six. The first choice was the simplest: He could do an extremely thorough clean-up, renew the two IMS thrust bearing halves, swap out all “known must replace” parts, and put everything back as he found it. His engine was strong and performing perfectly prior to the “incident,” but the process and man hours of disassembly and assembly would be the same as the option number two.
The second choice was he could undertake a complete OEM rebuild, which would include the measurement of all technical clearances (bearings, pistons, rings, etc.), and replacement of any out-of-spec or damaged parts as necessary with the OEM pieces. Several hours of extra time is required for such measurements and determining what else should be replaced. However, the advantage of this could be time and money very well spent, because the engine was already fully opened for such an evaluation and may very likely reveal another inexpensive (or expensive, it does not really matter which) part that might be ready to let go.
The third option was a mild performance rebuild along with additional head work to RS spec and an increase in displacement.
The fourth and final option was the “enthusiast’s choice”: He could fully rebuild and refresh his engine to custom specifications with something very special in mind, and end up with a lot more performance than he had in the first place. Also, he could sell off all of the excellent condition OEM parts that would not be used in the rebuild to partially offset the cost of the new performance parts (at the very least, a great story to tell the spouse, anyway!). As this is a project involving an enthusiast’s car in an enthusiast’s magazine, of course option four was absolutely the only way forward. Yeah baby, yeah!