Mustang and Ford Performance Forums banner
1 - 10 of 10 Posts

·
Registered
Joined
·
1,497 Posts
Discussion Starter · #1 ·
I got some high pressure in the system and its causing blowback. I am trying to eliminate all the small reasons for it before we open up the engine. Basically trying to avoid that, hoping its not a broken ring or something. So far we looked inside the cylinders with a bore scope, and didnt find any problems at all, the pistons were black, and no signs of lean condition. Cylinders 3,5,6 have low pressure in them, around 70-90psi, while the rest of cylinders are holding at 120psi. The pressure is forcing the oil out around spark plug gaskets, and if u get up to 9 psi and higher in the boost under load it completly blows the plug wire out of the hole. I can see where the little round gaskets are leacking. If you guys have anyideas on things that i can check without taking the engine appart i would really appreciate it.
Thanks.
Vlad
 

·
Registered
Joined
·
1,497 Posts
Discussion Starter · #3 ·
..do a leak down test to see were its hemeraging at.. that should answer ur question...
yeah i am trying to find the tester, as soon as i do, i will check it.
Thanks
 

·
Registered
Joined
·
572 Posts
there should be no way your having an leak down thru the spark plug holes unless you have a cracked head. did you have any piston to valve contact. low compression seems strange if the rings are in correct and they seated well it shouldnt be a prob but i would say just be prepared to tear that engine back down.
 

·
Registered
Joined
·
677 Posts
there are little gaskets on your valve covers for the spark plug holes right? i have heard of those going bad and oil getting into the spark plug holes.
but never heard of them blowing off your spark plug wires.< that doesnt seem right to me.
 

·
Registered
Joined
·
1,497 Posts
Discussion Starter · #6 ·
there are little gaskets on your valve covers for the spark plug holes right? i have heard of those going bad and oil getting into the spark plug holes.
but never heard of them blowing off your spark plug wires.< that doesnt seem right to me.
Yeah the little orings shifted and letting the oil in the spark plug holes. U can almost see the edge of one. When it blew the spark plug wire out it probably happened cause i got on it a little bit and went into about 10 to 12 psi of boost. Also at the time i didnt have the plug wire cover on it.
I am thinking that i might have bad or broken rings on the 3 cylinders with the low compression. Already determined that we are gonna have to tear it down, however we want to find what cause it so we can fix it and it wont happen again. The theory we are having right now is that the knock sensor was turned off during tuning and cause those pistons to overheat and burn the rings. I am taking my tune to the shop tmrw to make sure its turned on.
 

·
Registered
Joined
·
572 Posts
i wouldnt even trust the stock knock sensors i took mine out when i did my swap. are you still running stock pistons? as long as your iat's were not too high and your a/f was good and you didnt have too much timing in it you should have been fine what compression r/u running with that engine?
 

·
Registered
Joined
·
1,497 Posts
Discussion Starter · #8 ·
i wouldnt even trust the stock knock sensors i took mine out when i did my swap. are you still running stock pistons? as long as your iat's were not too high and your a/f was good and you didnt have too much timing in it you should have been fine what compression r/u running with that engine?
the engine is built with forged bottom end and low compression pistons. 8.5:1. I dont know about iat's, but A/f was good. Got a wide band O2 gage. And Timing is pretty low too.
 

·
Registered
Joined
·
572 Posts
well man let me know what u find out when u tear it down hopefully no broken ring lands.
 

·
Registered
Joined
·
1,497 Posts
Discussion Starter · #10 ·
well man let me know what u find out when u tear it down hopefully no broken ring lands.
yeah buddy will do......i am hoping that its just a bad valve or something.
 
1 - 10 of 10 Posts
Top