Instead of spending $1400 for a kit or $950 for just pistons I grabbed an old block and decided to take the low road on this build.
I’m going to use an old crank and block with minimal machining. Maybe a balance only. E85 pump fuel.
Which ones are strongest?
I like the design of the kb but it has a high ring placement and no skirt coating. The speed pros have coating on the skirt and lower ring placement but not sure about material and also gives lower compression. I know nothing about the Wiseco.
2 reasons. That piston would put my compression into the 8’s. Also, The more I steer away from factory 4” bore the more I risk water spitting out into the cyclinder through rusted coolant passages near the cylinder walls. This happen to Dulcich on roadkill in his 360. I’m hoping to maintain stock bore size.
I’m also assuming you think that piston is better than the $400 Wisecos I listed above. Now just need stock bore size and max 5cc valve reliefs.
"Old" member Registered: Sep 2001 Lost my credentials, I'm Back!! LOL 71 Ply Satellite Procharged 73 Dodge Dart Swinger 73 Ford F-100 390/Sniper efi/back to carb 01 Town and Country Limited 08 Dodge 2500 6.7 5" Deleted 02 Mercedes C230K 19 Camry
Re: Which pistons for Moderate boost 360
[Re: Porter67]
#2444241 01/31/1809:20 PM01/31/1809:20 PM
How much boost do plan to run? Hypers do not like detonaton. and will need a HUGE end gap. Standard thin top forged may sag with higher boost levels (over 14-15). Doug
Re: Which pistons for Moderate boost 360
[Re: dvw]
#2444395 02/01/1812:49 AM02/01/1812:49 AM
How much boost do plan to run? Hypers do not like detonaton. and will need a HUGE end gap. Standard thin top forged may sag with higher boost levels (over 14-15). Doug
I’d like to say 10-12 max but with my heads that would be a LOT of power which is what really matters.
Some fishy info being given on the interwebs. This piston is weaker than a stock 5.3L piston? Stock 5.3s can handle over 1k hp for hundreds of pulls according to Richard Holdener on the Westec Dyno.
It's a pretty well documented fact that hyper pistons are more sensitive to detonation, especially at high horsepower levels. They tend to fracture while forged pistons tend to just deform.
Pretty sure the tune on a 1000hp engine is pretty conservative and designed to not rattle the pistons regardless.
But go ahead, run cheap pistons in a cheap build and be sure to share the results.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
My brother has a new set of Mopar Performance forged pistons made by Wiseco for a 360 (Mopar # P4876976) which are 4.020" (+.020"). Still in the boxes. $350 PM me here.
- EM
Re: Which pistons for Moderate boost 360
[Re: Supercuda]
#2444710 02/01/1804:06 PM02/01/1804:06 PM
It's a pretty well documented fact that hyper pistons are more sensitive to detonation, especially at high horsepower levels. They tend to fracture while forged pistons tend to just deform.
Pretty sure the tune on a 1000hp engine is pretty conservative and designed to not rattle the pistons regardless.
But go ahead, run cheap pistons in a cheap build and be sure to share the results.
Ok, I just might. Harder also means more brittle in most cases.
Still doesn’t answer my question. Are the speed pro performance pistons weaker than a stock LS Hyper?
If not, many somebody’s are throwing away money and increasing cylinder wear on their street cars.
"Old" member Registered: Sep 2001 Lost my credentials, I'm Back!! LOL 71 Ply Satellite Procharged 73 Dodge Dart Swinger 73 Ford F-100 390/Sniper efi/back to carb 01 Town and Country Limited 08 Dodge 2500 6.7 5" Deleted 02 Mercedes C230K 19 Camry
1. Keith Black hypereutectic pistons require a larger top ring end gap and KB is very helpful in telling you how much, assuming you can read and have a calculator (or do multiplication in your head). NO OTHER hypereutectic pistons have that requirement.
2. Federal-Mogul is huge and there's a real good chance that the hypereutectic pistons in a 5.3 were made by them with the same material they use for aftermarket pistons.
3. Will the piston live is nearly totally dependent on the tune-up. That was said above and I agree.
4. Given the choice between a forged piston and a hypereutectic piston in a power adder application I would always pick forged. Always. Pistons can be machined or custom built to give the compression ratio you desire.
Now one of my own: Even in a boosted application, squish makes the combustion chamber to have a lower octane requirement. So plan your piston around that.
Another: Moly rings are in actuality moly-coated or moly-filled rings. Engineers select the ring material according to the engine requirements, then the moly is added to the outer surface of the ring. The ring material can be cast iron or cast ductile iron or steel, could even be tool steel if that was necessary, as long as what touches the cylinder wall is molybdenum.
Pick the best piston you can afford. It's a bummer when a piston breaks and the wristpin gouges a groove in the cylinder wall.
Let me share my iffy info backed by years of experience.
I ran the TT440 HARD on el cheapo Speed Pro forgings. I never had a piston related failure.
My first build ran through so much detonation that upon disassembly the rings fell out in pieces. The pistons survived. Some of those adventures included 17 psi boost with an injector spraying water, rubbing alcohol, race fuel, and most any other type fuel I could think of. The majority of the time I ran it at 8 psi with no injector and the car never had an intercooler. At one point I surged the turbos over 20 psi and 6,000 rpm without failure. The cylinder temps had to be slightly higher than the surface of the sun but it didn't kill it.
Now that I know better I would never recommend subjecting a set of cheap forged pistons to that kind of abuse but my engine never went to pieces. I did manage to kill a head gasket or two in my time.
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon
Let me share my iffy info backed by years of experience.
I ran the TT440 HARD on el cheapo Speed Pro forgings. I never had a piston related failure.
My first build ran through so much detonation that upon disassembly the rings fell out in pieces. The pistons survived. Some of those adventures included 17 psi boost with an injector spraying water, rubbing alcohol, race fuel, and most any other type fuel I could think of. The majority of the time I ran it at 8 psi with no injector and the car never had an intercooler. At one point I surged the turbos over 20 psi and 6,000 rpm without failure. The cylinder temps had to be slightly higher than the surface of the sun but it didn't kill it.
Now that I know better I would never recommend subjecting a set of cheap forged pistons to that kind of abuse but my engine never went to pieces. I did manage to kill a head gasket or two in my time.
Running "hard" at 8psi is a lot different than making full 1/4 mile or longer passes at the original posters desired 12psi. Doug
Starting from a 360 V8 If it was me The moderate cost of 408 ci stroker parts with high compression ratio and now wide availabilty of E85 fuel would lead me in that direction over the option of 14psi boost without an intercooler and electronic controls.
