wunfstgsr

closed

pimpwagon

Don't drive it.

doood

iTrader: (1)

how did you confirm it was the rings? did you do a wet compression test? was the head pressure tested after being rebuilt? did you do a leakdown?

wunfstgsr

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mouab18c1

iTrader: (5)

Only way you could have washed out the rings is if it ran extremely rich. Meaning AFR were below 11's or even lower.

racebum

more likely you have fractured ringlands and or ring damage. at any rate you may need one new single piston and you might as well re ring the bottom end. remember to use a fine ball hone for the re ring. no cutting hones. if one of those is required for cylinder scarring you have to overbore and run .25's

wunfstgsr

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wunfstgsr

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doood

iTrader: (1)

did you re-hone the cylinder that piston came out of? with damage like that i'd be afraid there would be scoring on the walls.

have you done another leakdown and compression test?

racebum

if the hone was done with a 3 prong cutting hone that absolutely could be your problem. these engines like 400 grit or so ball hones for the final hone. cylinders have to be very smooth and straight. i only learned this by chatting with endyn and researching how the factory hone was done. many many machine shops seem to not realize this and use a cutting hone for the final pass. rings will never seat

a cutting hone like you would use to seal a 1970 SBC with cast iron rings will burn oil on a b18c. oil will just follow the grooves.

also did you check your oil ring tension? i remember one set of pistons i received had something like 8lbs on the wall. i ordered the next size up, cut to fit and got 13lbs on the wall. much better

another bit of information comes from GM. the LSx motors use a similar cylinder liner and ring pack to the b18c. unless the top ring is replaced GM specifically says NOT to alter the oem hone and it's for just this reason. the secondary and oil rings are designed for a smooth surface

wunfstgsr

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racebum

the honing method is critical. if there are no deep scratches you can use a fine flex hone on a drill and get decent results, BUT it has to be clean and you have to use a lot of oil.

machine shops like to use those 3 prong cutting hones and they just do not seal. tried it before. rings never seated. you can of course use one but the finish has to be done with a fine ball hone. honda rings are tool steel and just too hard to seat on a rough surface

i can't remember the exact recommended grit but it was either 360 or 420

so many mistakes get made with these i think a person is almost better off mailing their shortblocks to endyn or golden eagle etc. some place that has extensive experience with the rebuilds

wunfstgsr

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B_Swapped93

easier fix than rings ! still a pita my car slippied timing(at idle) no clue how but one of my "up arrows" was down while the other was up . comp is still even within 5 psi.

racebum

seals have no effect on leakdown as they are not designed to hold pressure only keep oil from running down the valve

you either have bad ring seal or a leaking valve seat

wunfstgsr

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racebum

pressure testing the head would be step one.

worst case you may need to ball hone and install new rings in one cylinder.

compression shows what the engine can compress, your problem is that one cylinder isn't really holding that number so the question is where's it leaking?

if you leave your leakdown gauge on with 100psi and that cylinder closed you should hear hissing one place or the other.

wunfstgsr

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