About 8 years ago I bought a motor from GEX. The motor never ran well as it had low compression. I took the heads off of it this evening and I dont think the motor was built with the right crank.
The first picture is of the GEX piston, it is clear that the piston does not travel near the end of the cylinder, one can see the wear line. The second picture is of the piston from the 2.0 that spun a rod bearing ( http://i13.photobucket.com/albums/a276/tra.../DSCN4027-1.jpg ), it is clear the the piston travels very close to the end of the cylinder.
Any thoughts?

low compression bus pistons ...


just checked on my 2.0L jugs, the top of the piston travels to about 4mm below the top of the cylinder.

that's way higher than in your pic. looks like you got hosed ...
Andy

Those are not Bus pistons.. They are 914 pistons, more than likely an econo set..
It appears that the top ring is dropped down from the crown a long way... from the pics as it looks like the deck is tight, but the carbon ring goes a ways into the cylinder. Make sure if you rering that engine to remove that carbon ring or it'll break the new top rings..

jake i think he saying that pic one is of the gex engine with wrong piston for stroke of crank. the second pic is of a different engine.

messix, you got it right the top pic is of the GEX engine the bottom pic is the engine I am going to rebuild.
I took the heads off of the GEX engine (top pic) to compare them to the "factory" heads. I instantly noticed the large ring of carbon at the end of the piston travel (pic 1). I did not notice a ring of carbon on the other piston (pic 2) as the travel went very close to the end of the piston. I am not planning on pulling the rest of the gex engine apart at the time, I was hoping to get some club insight on what may be wrong w/o taking the engine apart. I am going to keep the GEX engine for some future use...
I was thinking that the engine has the wrong crank and that is why the travel stop so far from the head, and therefor giving the low compression. I suppose it could be the wrong pistons on the GEX motor, they have the number "80" stamped on them..
thanks for the replies
-Rob

1. Rotate suspect motor to TDC, you are just speculating with the current picture, it could be that the piston does not travel far enough or like Jake said, the rings could be further down the piston

2. It easy to measure the crank, just measure when the piston is at the top, then rotate to the bottom, use a flat edge across the cylinder top and a scale

Mueller, I'll measure them this afternoon... I did not even think of measuring them last night.
-Rob

only 2 stock stroke numbers....

66mm for 1.7/1.8 motors

71mm for 2.0 motors

looks like it's ready to turbo to me!

thanks for the measurements for the strok, I'll get to checking later and post back..
-Rob

Low compression = TURBO!!