Mr_bob

I would personally try to lean idle to at least 14.7, lean cruise in the low 15s, and not touch power unless you can datalog or dyno.

Squirt to the thrust side (oil filter and spark plugs) and piston mark to the front of the motor (timing chain).

Haha yeah those turbo porsches especially love their oil consumption; i knew of people who would just do periodic filter replacement and oil analysis as they were effectively adding a whole new sump full of oil just "topping up" between the suggested intervals. I have been pondering and could ask the same question about the mains and ring gaps and all the other engine specs as well as I have been perusing all these sources. So, given the relative longevity of the L6 and lower mileage these might accrue as secondary/fun/weekend/whatever cars, is this a general endorsement of the "how to modify" specs even if I am not building a race motor? I understand it is ultimately my decision and depends on my application, but this is the collective experience I am trying to gather that I just don't see in reading all the numbers.

Haha. Well, when you put it that way it seems pretty clear cut. Thanks for all the assistance.

Tony D, Thanks for the informative reply. I was tangentially aware of those other issues (side clearance, oil flow/pressure capacity) as well, but not well enough versed to incorporate it into my question; it did lead me to infer that the rod bearings are dealing with different issues than the mains. I was just concerned that the engines being built in "how to modify" are seeing much more severe service than mine (and thus those larger clearances aren't for me) and that I would be better off near the tighter side of the other sources. I definitely believe that 0.0005 can make a difference, and I don't want to be too tight like that either given what the oil needs to do in the rod bearings as you mentioned.

TimZ, Thanks for the suggestion. I did peruse the thread and it is a good read. PMC has some great tips but his section on clearances is from "how to modify" as well (just covering the mains); that definitely counts as a vote toward the larger clearances suggested by that book. I am definitely within that spec but that is on the high side of all the rest of the sources.

I have searched and read a reasonable amount, but I am curious as to the consensus regarding rod bearing oil clearance on the L6. I have encountered various different ranges from the different sources: "rule of thumb" 0.001 per inch diameter FSM materials (1972 = 0.0006 - 0.0022, 1982 = 0.0009 - 0.0026) "how to modify" book 0.0023 - 0.0028 an engine builder to whom I have spoken said 0.0015 (regardless of diameter) I was looking to target 0.002, and I currently have 0.0023 - 0.0027. I am concerned that I am potentially too loose. This is for an l28et rebuild with stock rods targeting ~300whp. So, for the L6, what is a recommended rod bearing oil clearance for such an application? *Edited after checking the numbers in the various sources