LT1 Help

[masterfab]

sounds like a possible bent or stick valve. the head of the valce cold be slightly bent and the warmer it gets the more prominent the miss fire would be. do a cylinder leak down test. its pretty easy to do and can save you alot of time. right down all the percentages you get per cylinder and if one percentage is standing out more than the other you will know that you problem cylinder. listen to see if the air is escaping out of the exhuast or the intake.

[ryanwarby01]

sounds like a possible bent or stick valve. the head of the valce cold be slightly bent and the warm it get the more prominent the miss fire could be. so a cylinder leak down test. its pretty easy to do and can save you alot of time.

How do you do this test?

[masterfab]

first off you need to buy or borrow a leak down tester.

1. you remove the spark plugs from the engine. screw the threaded end of the leak down test into the spark plug hole.( make sure it has a good seal)


2. then u plug a air compressor into the leak down gauge without the hose pluged into that it that you screw'd into the spark plug hole. adjust the regulater on the leak down gauge. (it should have a knob on it) to about 100psi or till the persentage side reads 0%. ( some leak down testers have a pressure gauge and a leak down percentage gauge and some have just the leak down percentage gauge)



3. next you make sure both valves for the cylinder your testing are closed.( you may want to have a friend hold the crank bolt from rotating while testing) the added pressure in the cylinder likes to rotate the motor. or you cam removed the valve cover and back the lash off the 2 valves to the cylinders you working on.

4. then you plug the hose coming from the spark plu hole into the leak down tester and read the percentage side. any higher than 22% i start to worry. on a used motor. if its a new engine anything over 12% is bad in my book.

hope this helps

[ryanwarby01]

Checked my TPS voltage and it was fine. Drove it again and notice at half throttle or less it will rev to 6200 rpm with no miss at all. It only has a misfire at WOT. Does this mean anything?

[masterfab]

Checked my TPS voltage and it was fine. Drove it again and notice at half throttle or less it will rev to 6200 rpm with no miss at all. It only has a misfire at WOT. Does this mean anything?

has this car over been over rev'd, it could be as little as a spark plug, or as major as a bent valve or weak valve spring. its a stick so im thinking it possible that someone maybe got into it and missed a shift, and over rev'd it. seen it happen ounce or twice.

[ryanwarby01]

has this car over been over rev'd, it could be as little as a spark plug, or as major as a bent valve or weak valve spring. its a stick so im thinking it possible that someone maybe got into it and missed a shift, and over rev'd it. seen it happen ounce or twice.

Plugs are new. It has Comp Cams Beehive springs. I really don't drive it that hard, rarely gets over 5500 rpm. Do you work on LT1s? I'm not too far from Lennon.

[masterfab]

Plugs are new. It has Comp Cams Beehive springs. I really don't drive it that hard, rarely gets over 5500 rpm. Do you work on LT1s? I'm not too far from Lennon.

yes, i work on anything that makes power your welcome to call me 810-620-5097 my name is ken

[98blackbeauty]

Didn't comp cams have problems with their springs breaking? Seems I remember hearing something about this. Just throwing it out there for a possiblity also.

[ryanwarby01]

Didn't comp cams have problems with their springs breaking? Seems I remember hearing something about this. Just throwing it out there for a possiblity also.

I didn't know that at the time, but did some checking and found out they had some issues back in 2007/2008 when they switched suppliers. I am taking my car to Ken @ sniperperformance in 2 weeks for a LE Cam and some new springs & lifters, hopefully he will find the problem.