2g no compression

[Rmvr53]

Son in Law has a 2g 97 GSX. He did an engine swap back in the fall and left the timing cover off. Couple of months ago broke an alt belt on the freeway. Engine died and has yet to restart. We finally did a compression check and everything is 0 (zero) nada zilch

Our guess is the alt belt got into the timing belt but everything is still "timed" so the question begs...

Is this an interference motor and he has trashed the valve train or something else we're overlooking?

thanks

Bill

 

[Bender]

Yes, unfortunately the 4G63 is an interference type engine. The best bet is to pull the valve cover off first to see if the valvetrain is still intact. If damage isn't too bad, it could jsut be eight bent intake valves. Worse case scenario, the valve heads snapped off, and got embedded in the piston dish. Then the engine pushed the broken valves in the underside of the aluminum head. It all depends on if the belt broke or slipped, and how high the engine was revving when this happened. One way to tell is to try to turn the engine over by hand. It won't go all the way over if the valves are snapped. (For they will get jammed between the piston top and the bottom of the cylinder head) Be sure to take the spark plugs out, because they may interfere if there is compression in one cylinder.

 

[Rmvr53]

Yes, unfortunately the 4G63 is an interference type engine. The best bet is to pull the valve cover off first to see if the valvetrain is still intact. If damage isn't too bad, it could jsut be eight bent intake valves. Worse case scenario, the valve heads snapped off, and got embedded in the piston dish. Then the engine pushed the broken valves in the underside of the aluminum head. It all depends on if the belt broke or slipped, and how high the engine was revving when this happened. One way to tell is to try to turn the engine over by hand. It won't go all the way over if the valves are snapped. (For they will get jammed between the piston top and the bottom of the cylinder head) Be sure to take the spark plugs out, because they may interfere if there is compression in one cylinder.

it turns over fine so I guess its time to pull the cam cover and see if everything is moving else wise its time to pull the head and look at valves

Bill