Steel sleeve leakdown %

[Ted Stryker]

With a steel motor, forged pistons, and the necessary ring gap what is considered a healthy leakdown %... I know a nic engine with .016" ring gap and straight bores can yield a leak of around 2-4%, but how much is expected to be lost with the increased ring gap of a Hi-Po steel motor build... Any estimates of how much power is lost compared to a .016" gap engine... Thanks...

[T-REX]

Tha steel bore drag on back ov tha yeller bote started life wit 8%....:thumbsup:

[Euroski]

When I re-rings my 300pm leakdown was 5-6% I had one bad hole and did a leakdown test on the other 5 which was also 5-6%. Does that help?

[Ted Stryker]

Tha steel bore drag on back ov tha yeller bote started life wit 8%....:thumbsup:

I figured that was about pretty good with .023"-.025" ring gap, but I'm only assuming what Your gap was...


Euroski, I'm thinking Your 300pm has hypereutectic cast pistons...? If so then it is probably factory built with something comparable to .016" ring gap...

[Euroski]

Euroski, I'm thinking Your 300pm has hypereutectic cast pistons...? If so then it is probably factory built with something comparable to .016" ring gap...


I just used a factory piston since one cylinder was sleeved along with factory rings. From memory I think my ring gap was slightly more since the pistons had .009 clearance.

[Ted Stryker]

Hmm, .009" is quite a bit and that falls in line with a forged in steel bore buildup... Thanks for the reply...

[T-REX]

Tha mota haz .010" clearances and .030" ring gap...It's very loose, but loose runz good...I tried sumpth'in differnt wit tha cyls, and it increased tha clearances a lil...but it work'd!!:thumbsup:

I had a steel bore 200 that ran reely strong...ran a leekdown and it wuz 34%!!!!....Rerung it and it then leekdown wuz around 10% (8%-11% varied)...Tha differnce in tha low end wuz noticable, but top end performance wuzn't much...maybe 200rpm!!...:rolleyes: