Low Comnpression Issue

[Deleted User]

Any thoughts on how to approach: Low compression in one cylinder (45# dry, 75# oil-aided) on an otherwise solid 308? Engine is installed in a '55 Hornet.



Also - anyone have problems welding up a crack in a cast iron TwinH exhaust header?



Thanks!

J Cronk

[Deleted User]

hudman51 wrote:

Any thoughts on how to approach: Low compression in one cylinder (45# dry, 75# oil-aided) on an otherwise solid 308? Engine is installed in a '55 Hornet.



Also - anyone have problems welding up a crack in a cast iron TwinH exhaust header?



Thanks!

J Cronk

Sorry to say but that cylinder has bad rings or rings are frozen in the piston. Put Marvel Mystery Oil in crankcase and in gas tank and drive it for awhile, then recheck compression again to see if it came up a few pounds, if yes, keep driving it. If not, new rings are a must. If you have a place that weld cast iron, as it must be put in an oven to preheat, then welded, back into the oven to reheat and then let set till it cools down in the oven. This way it will not crack where welded. Walt.

[Deleted User]

Thanks Walt!! re: Mystery Oil - how much to blend with regular lube oil?



JC

[Deleted User]

hudman51 wrote:

Thanks Walt!! re: Mystery Oil - how much to blend with regular lube oil?



JC

Comes in a RED SPOUT container, 32 ounce, 1 quart. Have at least 12 gallons of gas in your tank and put in 8 ounces. Change your oil and add 16 ounces to the new oil. Now you must drive the car to get the engine hot at least 5 times. After it sets overnight, check compression and see what the readings are now. If it stays the same, rings, if improved a little, keep driving it. Walt.

Chris Smith

Should your low compression be caused by cylinder wall wear rather than stuck rings, I have used a product called RESTORE with good results. It claims to fill in the cylinder wall imperfections to aid the ring seal. I can say it stopped the rapid oil consumption of a Ford 460 truck I put it in. You have to add it at every oil change.

[Deleted User]

walt's garage-53 wrote:

Sorry to say but that cylinder has bad rings or rings are frozen in the piston. Put Marvel Mystery Oil in crankcase and in gas tank and drive it for awhile, then recheck compression again to see if it came up a few pounds, if yes, keep driving it. If not, new rings are a must. If you have a place that weld cast iron, as it must be put in an oven to preheat, then welded, back into the oven to reheat and then let set till it cools down in the oven. This way it will not crack where welded. Walt.

To each his own, but I say stay away from that add on stuff. Walt.