Leakdown Testing

[junior barns]

Back off all rockers and do one at a time. Little time comsuming but at least you will know the valves are closed

[Ben Kallies]

Thanks to all for the responses. I think that I may not have been at TDC. I'll give it another try tonight.

-Ben

[69Cobra]

Originally Posted by junior barns

Back off all rockers and do one at a time. Little time comsuming but at least you will know the valves are closed

X2 We always back the rockers off as well. Also you set the incoming pressure to 100 and then what the cylinder is holding out of 100 is the percentage. For example if you have 100psi coming into your gauge but the cylinder side is only showing 92psi. Then you have 8% leakage on that cylinder. At least thats how we've done it.

[buzzinhalfdozen]

As stated previously, start with number 1 cyl. put pointer dead on TDC of balancer, if engine turns over, you may have an issue with the pointer not being set correctly. Typically an engine will not turn if the piston is on TDC. Of course you have the option of removing the valve train also.I would caution against using a bar and socket to try and hold it unless you have someone who wouldn't mind getting their knuckles busted. Joe

[Harry 6674]

Have you been able to verify your TDC is correct. If it would have slipped that would throw off your timing which could possibly be your miss. Not sure just taking a WAG.

[motohead1]

I have a related question that has been keeping me up at night for years, LOL. When using a twin gauge setup, do you set the incomming gauge to 100psi before connecting the cylinder hose, or do you adjust after connecting? The reason I ask is, if you set it before connecting, the reading on the incoming gauge drops slighty when connected. Chuck

[Mike Taylor 3601]

Mine is supposed to be connected and then adjusted to 100psi then backed down to 60 psi before disconnected so then when connected to next cylinder it starts @ 60 psi
Mike Taylor 3601