hyperu crackticks

[oldgold]

i run in a class that says no performance parts and run flattop hypers i have 23 nites on it and it pulled the pin .2 weeks ago i told myself pull it out and rebuild so much for the gut feeling. speed-pro 618 i know you guys are gonna say stay away from those but we get checked thru the inspection hole every week for performance parts.never ever went above 6000 never hot always good oil pressure. anyone else deal with this?thats only about 15 miles per nite.thanks for input.355 30 over balanced

[stock car driver]

yep ive pulled the pins on speed pros

speed pro makes a forged piston also with 4 valve reliefs, you cant tell hyper from forged thru the hole, lol..

[carowner73]

cast or hypers, change every 20 races or your asking for trouble.

[oldgold]

cast or hypers, change every 20 races or your asking for trouble. that was the answer i was looking for.our season is about 18 weeks and i decided to run it 4 nites this year while telling our crew i needed to freshen the engine right away but its to late now so i will build a new one and follow your advice thanks guys

[rubbinsracin]

maybe im wrong, but arent the pistons that are in the crate motors hyperu? we have a guy at our track that that for 3 years has done nothing but change the valve springs and he turns his 602 6500rpm. am i missing something?

[Egoracing]

maybe im wrong, but arent the pistons that are in the crate motors hyperu? we have a guy at our track that that for 3 years has done nothing but change the valve springs and he turns his 602 6500rpm. am i missing something?

Yes you are right. Our first crate ran a TON of 50-100 lap races and ran about 2 times a week for about 1/2 of the weeks of the year, raced about 45 weeks a year and was running and racing when we sold it and it was 3 years old.

[SRXSRULE]

Compression, carb tuning, and spark plugs are the 3 main things that kill Hyper pistons. If you have more then 10:1, or run it too lean/hot, or detonate it they will break. If its tuned right and under 10:1 they will last a long time.

One of my 9:1 motors had 75+ nights on the same set of hyper pistons with no problems. Eric

[oldgold]

Compression, carb tuning, and spark plugs are the 3 main things that kill Hyper pistons. If you have more then 10:1, or run it too lean/hot, or detonate it they will break. If its tuned right and under 10:1 they will last a long time.

One of my 9:1 motors had 75+ nights on the same set of hyper pistons with no problems. Eric we are at 10-1 and 6000 rpm although one nite i put more gear to it and turned 6300 and we are on quadrajet and 110 fuel. always looks a tad rich when we pull plugs.any one of those 3 things will cause the pin to pull out? thanks guys.

[SRXSRULE]

The motors that I ran them in all turned 6800-7000 rpm. Mine were all pressed pin too.

Are you doing a true plug check? After a heat race hit the kill switch just after you lift off the gas on the last lap and let it coast to the pits (or get pushed in) Then pull a plug and check them? Eric

[oldgold]

The motors that I ran them in all turned 6800-7000 rpm. Mine were all pressed pin too.

Are you doing a true plug check? After a heat race hit the kill switch just after you lift off the gas on the last lap and let it coast to the pits (or get pushed in) Then pull a plug and check them? Eric no i idle it in and should do as you say or it wont be valid.floaters

[Egoracing]

no i idle it in and should do as you say or it wont be valid.floaters

No you are supposed to kill it a WOT and take your foot off the same time. If you idle it you are going to get the plug condition at idle NOT at WOT.

[500BOMBER]

In my own experience with hypers and cast pistons, the skirt clearance in a severe application such as, oval track use, needs to be at least .001" to 0015" more than what the specs normally say.
Problem solved for me anyway. No more skirt galling and pin pull thru.