[L28 4bbl EFI build - help/input wanted!]

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.

[L28ET Rod Oil Squirters and Piston Alignment]

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

[Rod Bearing Oil Clearance]

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.

[Rod Bearing Oil Clearance]

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

[Rod Bearing Oil Clearance]

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.

[Rod Bearing Oil Clearance]

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.

[Rod Bearing Oil Clearance]

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