PDA

View Full Version : head gasket


SLSD400exGUY
07-24-2006, 12:51 PM
i put in my 440 kit in FEB since then i rode my quad maybe like 8 times? im puttin in the 3rd head gasket.. can anyone tell me why i keep blowin them?
ohsobad_chevy
07-24-2006, 12:59 PM
Head studs are prolly causing it. Make sure they are torqued to specs and are not pulling out. ;)
400exrules
07-24-2006, 01:20 PM
12.5 compression, i wouldnt even run that without HD studs
ohsobad_chevy
07-24-2006, 01:40 PM
oh chit!!! I just noticed that he had 12.5:1 compression...SLSD are you seriously using stock head studs???
F-16Guy
07-24-2006, 02:07 PM
Send your jug to GT Thunder and have their heavy duty studs installed. It's about $100 with parts and labor, and the best money you could spend on a high compression 400ex. Turn-around time is very quick, too. Unfortunately, this isn't an area that you can "cheap" your way out of unless you really like installing head gaskets.
cals400ex
07-24-2006, 10:45 PM
it is possible that the head and/or cylinder surface is warped too. i would get new head studs though as well.
ohsobad_chevy
07-25-2006, 07:35 AM
Originally posted by cals400ex
it is possible that the head and/or cylinder surface is warped too. i would get new head studs though as well.
Yes, causing your gasket not to seal up well.
400exrules
07-25-2006, 10:12 AM
do u have the stock rod on also? im not sure how long it will hold up with a 12.5:1
ohsobad_chevy
07-25-2006, 10:50 AM
Originally posted by 400exrules
do u have the stock rod on also? im not sure how long it will hold up with a 12.5:1
Stock rod will do fine with 12.5:1, but it couldnt hurt to replace it when you got it opened up. :D
400exrider707
07-25-2006, 11:32 AM
Originally posted by ohsobad_chevy
Stock rod will do fine with 12.5:1, but it couldnt hurt to replace it when you got it opened up. :D

I personally wouldn't run a stock 400ex rod with anything over 11:1 compression. Heavy duty head studs are almost a MUST with anything in the 12:1 region.
ohsobad_chevy
07-25-2006, 11:42 AM
Originally posted by 400exrider707
I personally wouldn't run a stock 400ex rod with anything over 11:1 compression. Heavy duty head studs are almost a MUST with anything in the 12:1 region.
Ive seen many 11:1 compression 400's ran on stock rods, they all did just fine. HD studs are smart to install no matter what.