Rebuilt Sportjet - Compression way off?

[hckrphil]

I rebuilt the engine completely (sportjet 90). Bored 2 over, new pistons, rings, bearings, etc.

Never could get it to tune properly........ although when I did have it running, it had lots of get up and go, no problem.

Finally broke down and took the engine to the mechanic, he did a compression test......... 130 - 119 - 95

What the heck did I do wrong on the rebuild? Those numbers are way outta wack!

Do you think a warped head or bad head gasket woudl cause that?

Its only got about 6 hours on it.

Thanks!

 

[JB]

Re: Rebuilt Sportjet - Compression way off?

Break it in, then worry about compression.

 

[hckrphil]

Re: Rebuilt Sportjet - Compression way off?

How many hours are we talking to break it in?? Thanks!

Phil

 

[CharlieB]

Re: Rebuilt Sportjet - Compression way off?

Remove the exhaust cover to inspect the piston rings. Use a VERY small screwdriver (the little pocket type) to carefully reach in and 'push' on each ring to feel for the tension.

If a rings is broken during assembly then there will be no tension, the ring will not be pushing out against the cylinder walls to form a good seal.