pistons failing

has anyone had troble with pistons failing.
so far i have had 3 race series pistons fail in the ring lands between no1 and 2 piston on 2 different engine's.
previous to that had the sae thing happen with duralite's
so what ones dont fail.
and do 4Lohc engines have the same troble.

Have you asked ACL what might be the cause?

If you made it clear this was not a claim for compensation, but your desire to avoid another mistake, they might help out.

so far i have had 3 race series pistons fail in the ring lands between no1 and 2 piston on 2 different engine's

Click to expand...

Don't tell me that, I just forked out for a set of them to go in my new motor! Are you running the custom 250 with 200 rod pistons? What kind of loads is the motor under? Mine is only a hot street build so it will be being driven sanely about 95% of the time. Is it possible that they just made a bad batch?

Need some pics. It sounds like ring gap, or lack of ring gap.
You need to look at the ends of the rings, and see if they look like they are butting together at temp. If they have been butting, they will ilkely have some galling or chafing or shiny area on the ends where they have touched.
I have seen some goofy things with inline fours, I would suspect that some sixes are prone to the same problems.
The problem seems to stem from the water pump dumping water around the front cylinders. Since these cylinders get water first, the cylinder walls don't expand as much as the others and can result in clearence problems.

no as far as can be traced the rings havent been touching at all.
problem as far as ive managed to find is high speed detanation from changing atmospheric presures and density's from when tuned to when raced causing a lean out.
how ever with out posing an atmosphear pressure and density sensor and also changing from day to night with little time to change jets.
if i must run acl ill will probly use the 2 ring pistons for the 200 rods.
i doubt you will have any problems with these on the street only place ive herd them fail is speedway racing so 100% load for 98% of time run.
also ones that failed where no5 on one and no5/6 on the second so farest away from the water pump.

acl has been contacted and dident blow me off might even get a set of pistons
supose to be getting a call tomorra
so ill what happens.

We all want to know why they broke - that's really the core issue! Will ACL examine the old ones for you?

i think ill be droping them off on tuesday from the sound of it

Good luck with getting to the bottom of this.
My engine man has strongly suggested forged pistons if i want to see 7K rpm regularly in a tarmac rally role.

let us know how you get on...the machinist I was talking to today is telling me to go with the 2 ring 250 short skirt piston with the 200 conrods.......

well they traced it back to det and dident end up getting a set of pistons but dident expect to gether.

i think the det is due to bad fuel as the old log engine broke the ring lands out as welland did this the only time i raced with out and octane booster
so anyone have this drama at all as ive asked around a lot of people running xflows and log engines and only 1 has had the same drama.

Sounds more like you have fuel distribution issues with your carb and manifold.
My motor used to run horribly rich on 1-4, whilst being dangerously lean on 5 and 6.
To find out if you have distribution problems, stick it on a dyno with a 4 gas analyzer. Unless you have a separate oxy sensor in each exhaust runner, you are not going to know if it is running lean on any one cyl.

The advantage to using a multiple gas analyzer, is that when a cyl runs rich it pumps out higher concentrations of co2(?) and when they run lean, you will get higher concentrations of HC. When you get both, you know you have a problem.

What manifold were you running. What Carby. What do the plugs look like.
How much total timing were you running?

allways was dynoed but do tend to run on the leaner side then richer to pick up an extra 5-10rwkw
broken them with standerd manifold + carby
redline manifold + autolight
2v with with 350 holley
can be any cyl from 2 to 6

total advance is around 28 i think
starting at around 12
no vac advance
hell last one was a points dizzy lol