Cylinder leakage test - Page 2

340Cuda · Yesterday, 03:25 PM

Quote:

Originally Posted by Kirk Morgan

Will a gas ported piston and ring package leak the same as a conventional piston and ring package?

That has been my experience over they years even though the engines could be very different.

I could have very good or not so good readings on any piston configurations.

Terry Drinkwater · Yesterday, 04:03 PM

I was fortunate to travel with Johnny Pilcher and his family to a lot of Pro Mod races, including ADRL and many local events. There was a lot of teardown in between rounds at the larger events due to excessive cylinder leakage. In all of our mid-race repairs, the problem seemed to be detonation and/or excessive cylinder temps, which would lock up the top ring.

Adger Smith · Today, 08:15 AM

As with most instrumentation the end user is usually looking for a specific number rather than using the instrument as a diagnostic tool.
I have always used a leakdown to diagnose conditions. As said earlier Valve leakage, ring leakage and even head gasket condition.
All engines are not the same due to various clearance diffenences in cylinder wall and ring lands and end gaps for the specific aplication.
I remember when EGT gauges became the vogue.
I had customers telling me that EGT "Had to Be" XXXX number because the instructions sais so.
Put the engine on our dyno and tune it and the number didn't match what they said. Do a re tune to try to achieve their numbers and the power was way off...
I always leaked a fresh engine as I built it.. then re leak after a short run on the Dyno...
For the question about gas ports. I have never done a back to back, but it would seem they might leak a little more. However with ring seal being aided by the air pressure pressing the ring out against the cylinder wall and down against the ring land it might help static ring seal.

Yesterday, 04:03 PM	#12
Terry Drinkwater Junior Member Join Date: Mar 2014 Location: Alabama Posts: 74 Likes: 1 Liked 16 Times in 6 Posts	Re: Cylinder leakage test I was fortunate to travel with Johnny Pilcher and his family to a lot of Pro Mod races, including ADRL and many local events. There was a lot of teardown in between rounds at the larger events due to excessive cylinder leakage. In all of our mid-race repairs, the problem seemed to be detonation and/or excessive cylinder temps, which would lock up the top ring.

Today, 08:15 AM	#13
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,417 Likes: 518 Liked 765 Times in 292 Posts	Re: Cylinder leakage test As with most instrumentation the end user is usually looking for a specific number rather than using the instrument as a diagnostic tool. I have always used a leakdown to diagnose conditions. As said earlier Valve leakage, ring leakage and even head gasket condition. All engines are not the same due to various clearance diffenences in cylinder wall and ring lands and end gaps for the specific aplication. I remember when EGT gauges became the vogue. I had customers telling me that EGT "Had to Be" XXXX number because the instructions sais so. Put the engine on our dyno and tune it and the number didn't match what they said. Do a re tune to try to achieve their numbers and the power was way off... I always leaked a fresh engine as I built it.. then re leak after a short run on the Dyno... For the question about gas ports. I have never done a back to back, but it would seem they might leak a little more. However with ring seal being aided by the air pressure pressing the ring out against the cylinder wall and down against the ring land it might help static ring seal. __________________ Adger Smith (Former SS)