I am in the process of building a ZZ430 clone motor. For those who haven't seen this, it is a ZZ4 crate motor with fast burn heads and lt4 hotcam. Anyhow, I have just installed the fast burn heads. I have not installed the pushrods or rocker arms yet. However, before installing the motor in the vehicle, is there a way to check that the headgasket sealed properly, i.e. via compression or something of that nature? This is my first time bolting heads on and while I am confident about the procedure I followed, I would also like to play it safe. I'd hate to button it up, install everything in the car, only to find out it didn't seal properly. I ended up using ARP head bolts torqued at 70ft lbs per the instructions. I went in three passes at 25, 50, and then 70.
Just installed heads on 350, is there a way to check seal?
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Re: Just installed heads on 350, is there a way to check sea
Don't think you can do a compression test cause you have to crank the engine over to build compression. You could probably do a leakdown test with an air compressor in each cylinder. Do this test before you put the rockers and pushrods on to make sure the valves aren't open. Good luck.
Don't think you can do a compression test cause you have to crank the engine over to build compression. You could probably do a leakdown test with an air compressor in each cylinder. Do this test before you put the rockers and pushrods on to make sure the valves aren't open. Good luck.
Re: Just installed heads on 350, is there a way to check sea
Put a vacuum gauge in the spark plug hole with each cylinder on TDC. If it holds vacuum, your good. Then just go down the line.
Put a vacuum gauge in the spark plug hole with each cylinder on TDC. If it holds vacuum, your good. Then just go down the line.
Re: Just installed heads on 350, is there a way to check sea
I agree about doing a leakdown test. Otherwise, it sounds like you did everything to the letter. You gotta have confidence...
I agree about doing a leakdown test. Otherwise, it sounds like you did everything to the letter. You gotta have confidence...
Re: Just installed heads on 350, is there a way to check sea
x2
what part number are the fast burn heads...I've been looking for the 19300955 heads
Longroof79 said:it sounds like you did everything to the letter. You gotta have confidence...
x2
what part number are the fast burn heads...I've been looking for the 19300955 heads
Re: Just installed heads on 350, is there a way to check sea
Yes, those are the heads I went with. The original Lt4 hotcam kit comes with springs that are rated to .525 lift as well as the old fast burn 298 heads. I didn't like that the springs were rated exactly what the lift would be(with 1.6:1 rockers). The new 955(new fast burn part number) heads use the ls6 valve springs now which are rated to max lift of .550, which gives me a little peace of mind.
pontiacgp said:Longroof79 said:it sounds like you did everything to the letter. You gotta have confidence...
x2
what part number are the fast burn heads...I've been looking for the 19300955 heads
Yes, those are the heads I went with. The original Lt4 hotcam kit comes with springs that are rated to .525 lift as well as the old fast burn 298 heads. I didn't like that the springs were rated exactly what the lift would be(with 1.6:1 rockers). The new 955(new fast burn part number) heads use the ls6 valve springs now which are rated to max lift of .550, which gives me a little peace of mind.
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