possible cause of meltdown? mrviper?


Like mrviper700 said. I remember reading about this in SnowTech, they had an article about it. I remember the pics of the heads and crank machining.
 
After looking very closely at your heads, it does not, in any possible way look like they would support the use of pump gas. There was way too much taken off, especially for a non-ported motor.
 
i meant to say squish was 42-43 thou. 9801srx said you shouldnt run pump gas with less than 55 thou. wish i had of known about these heads before running 800 miles of pump gas through it!
 
im gonna go with the SPI kit on ebay, ive talked to a few guys that have used them and have had nothing but good to say about them so im gonna give them a shot
 
Should get you back on the trails again. I would allow plenty of warm up time with them but I'm only assuming they are like wisecos. are they the coated pistons?
 
mattysmith440 said:
i meant to say squish was 42-43 thou. 9801srx said you shouldnt run pump gas with less than 55 thou. wish i had of known about these heads before running 800 miles of pump gas through it!
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Good advice!
 
mattysmith440 said:
ya they are coated, and yes lots of warm up time, wouldnt want a cold seizure
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I have had good luck with SPI pistons in many snowmobiles. The ones I used were not "coated" but did have the black something or other on the sides which wears off after 20 min of running. Also, they are cast like OEM not forged like Wiseco but always alow the sled to come up to temp before riding.
 
ya ive been told theyre a much better product than wiseco, so im gonna give them a shot. i mean what do i have to lose? another motor?! lol my luck yes
 
ALOT more then .017" was cut off those heads. You see back where the water rail bolts on, on the underside of head, how you dont have any paint there, theres blue paint there factory and a small edge, so youd need to cut at least .040" flat off to remove the paint. They were most likely cut flat and then rechambered, but set up with tighter squish as you have found out. I would suggest you just getting another set of heads to use as it wouldnt be worth it to have 1 head done with the turbo mod that doesnt really do anything. :o|

As for the pistons just remember 1 thing, you try and save a buck now it may cost you many more bucks later to repair. The spi pistons are a cast unit and they are cheap cost for a reason, they are no where near the same quality as stock is. The stock piston in a srx and viper is a powder forged unit. They dont expand rapidly like the wiseco but is very,very strong and durable. Wiseco is also a very high quality unit but you need to have the understanding they take longer to warm up thats all.

Its your money spend it as you wish but be warned that stuff is cheaper for a rerason!
 
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