Reply With QuoteI'd never run them...for exactly the reason you just posted. If you have stuck valves, they're probably bent. Bet you wish you'd have spent the extra $ on the forged pistons now! :coffeycup
Has anyone had a problem with Speed Pro hypereutectic pistons?
I just recently rebuilt to 454s with 0.100" domes (8.6:1 compression with 119cc heads)..one motor grenaded a piston after 5 hours at a brief jaunt at 4500 RPM. It spread debris through the rest of the motor. From the best I can tell, the cylinder wall received a hole from a clanking rod and debris spread through out causing a few valves to be stuck partially open. No bent valves and valves do not appear to be the cause of failure.
The second motor seems to run fine, but I've got to wonder if it is ok with these pistons. In retrospect, I would have gone forged, but has anyone else heard of or experienced the same problems with speed pro hypereutectics? :cry:
I'd never run them...for exactly the reason you just posted. If you have stuck valves, they're probably bent. Bet you wish you'd have spent the extra $ on the forged pistons now! :coffeycup
With that brand (the old TRW) depending on dish, dome, part #, the forged can be less of more by only a few bucks. I just go with the forged, and put minimum piston to wall clearance. My work trucks have run them (forged) for decades.
Are you saying rip the second motor apart before I "have to" rip the second motor apart and replace with forged?
I thought Mercruiser motors came with cast pistons and the hypereutectics were an upgrade (??)... Or is the problem China can't make a good hypereutectic piston?
Are you saying rip the second motor apart before I "have to" rip the second motor apart and replace with forged?
Depends on how well you want to sleep at night. :wink:
Something is definitly wrong with certain Speed Pro hypereutectic pistons. We built two motors with them and had both motors break pistons. One grenaded so bad we lost almost every internal. Save up the extra dollars and go forged! :220v:
Ray @ Raylar
Ive been running the KB domed Hyper pistons for 5 seasons with no problems. My max RPM is 5300 but I usually cruise at 32-4000RPM and I dont beat the crap outa it except on occation for short burst's. Next time im running forged regardless. You know they say theres some places not to scimp, I got a brand new steel crank and good rods and should've got the good pistons the first time while I was at it!!!!!
The hypereutectic pistons are very brittle and don't absorb any shock, detonate once and it's all over with, that stuff is only good for street stuff, forged is the only way to go!..
those pistons require additional ring gap on the top ring. read the instructions. it is critical..........MP
You must mean Hyper-U-Cracked-It Pistons...
They can be fine in a properly suited application...I'd pass in a sustained high rpm jet boat...
LO
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