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Thread: Help me diagnose a VET with blown headgasket

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Posts: 21-30 of 38
2009-11-17 17:50:18
Did you re-use the stock head bolts? if so that is the prob, measure all the head bolts bagato... another thing if you use water meth make SURE you do not have any missfire...We have using water meth injections over 5 years 0 prob placing the nozzle at about 10 cm from the TB when I lift the head it was the same cilinder . Does the AEM kit have a check valve? if so what spring does its has? even if its leak a little its almost impocible to produce this prob.HOw safe is the timing? the best place to mount the nozzles are in the ports of the intake manifold like the injectors.
2009-11-17 17:59:11
Nop, I used brand new OEM studs, I already got some mazworx ARP's for when I put it back together...

I was using 70% drugstore alcohol and 30% water. What do you think about what my boys say about drops on the combustion chamber, possible?
2009-11-17 18:04:28
Pocible yes ..likely no... that is why I ask you if the kit does have the cheak valve and if you know the spring rate on that., what size of nozzle? are you sure its was not knocking????? please take a look into that piston(4) con una lupa man.

2009-11-17 18:15:58
Yes, it does have a check valve, I have it installed 2" from the nozzle, I dont know the spring rate on it though, here is the nozzle placement if that helps, it is on horizontal position:

There was no cylinder knock, since I have a very conservative timing map on the calum, and the MSD knock alert never went past the green light, I have checked the combustion chamber already and its perfect. I was using the smallest jet (130cc/min) just to try it out, since I was only running 12psi that day, and planning to run 15 but didn't make it.
2009-11-17 19:41:06
Then is has nothing to do with the meth water kit.

did you measure the head bolts espetially on the 4 cilinder? did you resurface the head and block before?
2009-11-17 20:15:14
Head and block were checked before assembling the engine, they were perfect. The problem started since that big backfire, after being parked for a while, when I left, shifted into second and BOOM! Reasons to get such a big backfire while having the engine under very very light load?
2009-11-17 20:18:35
Originally Posted by Bagato
Reasons to get such a big backfire while having the engine under very very light load?
Extremely advanced timing (or retarded if you're talking about it coming out of the tailpipe). Also tons of unburnt fuel (because of late timing or rich condition or no spark) will cause explosions out of the tailpipe.
2009-11-17 20:20:53
From the pocition of the nozzle I find hard top belive that the meth water was leaking to the combustion chamber... the car start right away when it pop-out?if so I dont see a meth prob .. do a test cheak if the nozzle is leaking under maf vol or boost ( do not know how the AEM works) AND AGAIN please post the timing map.

saludos man y mucha suerte1
2009-11-17 20:35:59
The car didn't shut down after the backfire. The AEM kit has a test button to trigger it. Here is the timing map:

2009-11-17 21:02:02
I meant before you start the car... and boom! its looks ok the map.
can you pot pics of the sparkplugs?
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