Has anyone broken a 95-96 hyper piston?

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86f250straight6
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Has anyone broken a 95-96 hyper piston?

Post #1 by 86f250straight6 » Sat Apr 21, 2018 7:21 pm

I recently bought a ‘96 300 to replace my worn out ‘91 300 in my 86 f250. I got this motor/harness (besides that it was a steal of a price) for the reasons that it has hypereutectic pistons, a cps and sequential injection, obd2 blah blah blah. so while im refreshing this motor to install, I was wondering, how strong are the stock hyper pistons? The motor has 82k miles and the bores look like new. Tolerances are good, compression is good, so i am going to replace as little as possible as it is only an interim motor to test with while I build the engine its replacing for boost.

Has anyone ever broken or cracked one? This 91 engine has some severe damage to #5 based on the sounds im hearing. With the mild tuning and mods im utilizing now, will the 96 handle it any better? Im looking to find the weak points in the stock combo as I wrap up this build.
I'm trying to build a truck that I can't break :bang:

Wesman07
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Re: Has anyone broken a 95-96 hyper piston?

Post #2 by Wesman07 » Sat Apr 21, 2018 9:07 pm

The standard cast pistons were a weak link. Skirts tend to beak, but the motor often continues to run.

The hypers are much stronger. Breakage is not common unless the motor sees heavy detonation. When they do beak, I’m told the shrapnel is hard and sharp. Usual this will take out other parts.
In-lines we trust

86 f150 300 efi with advanced stock cam. Np435, Dana 60/ 10.25, 35" BFG's, four link front suspension with 12" travel fox coil overs, custom deaver leaf pack in the rear.

pmuller9
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Location: Columbus, Indiana

Re: Has anyone broken a 95-96 hyper piston?

Post #3 by pmuller9 » Sat Apr 21, 2018 9:42 pm

A cast or hyper piston under detonation typically will break the top ring land leaving the top ring exposed.

A piston that is designed for boost or nitrous has a wider top ring land.

86f250straight6
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Re: Has anyone broken a 95-96 hyper piston?

Post #4 by 86f250straight6 » Sun Apr 22, 2018 5:07 pm

No forced induction or nitrous for this motor . Im even gonna keep the stock injectors this time, I think they supply enough fuel for what im doing, since the goal is low rpm torque and it will probably never see 3500 rpms the way I drive it.

So i feel alot better that I can depend on this motor for a while. The truck it powers is probably close to 8000 lb on alot of steep backroads between quarries so any kind of detonation is dangerous considering the load on the engine. I have to be careful with the timing since alot of the gas around here is junk even the premium is garbage in my opinion.
I'm trying to build a truck that I can't break :bang:

Stonebreaker
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Re: Has anyone broken a 95-96 hyper piston?

Post #5 by Stonebreaker » Wed May 09, 2018 3:50 pm

86f250straight6 wrote:No forced induction or nitrous for this motor . Im even gonna keep the stock injectors this time, I think they supply enough fuel for what im doing, since the goal is low rpm torque and it will probably never see 3500 rpms the way I drive it.

So i feel alot better that I can depend on this motor for a while. The truck it powers is probably close to 8000 lb on alot of steep backroads between quarries so any kind of detonation is dangerous considering the load on the engine. I have to be careful with the timing since alot of the gas around here is junk even the premium is garbage in my opinion.


As insurance, you might consider applying some thermal control. What I mean by that is working to keep the intake charge cooler. There are several strategies we use for drag racing that would help prevent detonation in a heavy load/low speed situation.

1) put a cooler thermostat in the engine. The factory usually puts a thermostat in the engine that minimizes emissions, but isn't necessarily best for the engine. Look for a 180 or 160 degree thermostat. If you have electric fans, it would also help to have the ECU reprogrammed to have them come on at a lower temp.
2) Wrap the exhaust or have it ceramic coated to keep it from heating the intake runners.
3) Get some high temp epoxy and coat the inside of the intake runners. This will reduce heat transfer from the aluminum intake to the intake air, just like that paper ring on coffee cups.
4) Route the intake to pull cold air in from outside instead of hot under hood air.

Any of these will help reduce detonation under high load.

Hope this helps,

Stonebreaker

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