I have a 1995 Blazer that I am going to buy for a song and dance if I can get it running. I have changed the plugs and one plug (#2 on passenger) had an electrode broke off. Maybe a fluke, maybe running way to lean. It has recently had a tune up i.e. plugs, wires, cap, button, and such. The same cylinder that had the broke plug also has little to no compression. I put another plug in it and it didn't break that plug. It has some compression and the piston is functioning I can tell by placing my finger over the plug hole. I either have a hole in the piston or bent valve, I think. The car will run but it is a pain to get it started and will run great over 1500rpm's. I took the valve cover off and from a basic visual standpoint it mechanically seems to be cycling.

Any help would be great b/c I need this car, my household is down to one car we really need the transportation.

Can I check things out without taking the head off? Can I maybe use a plumbers camera, or should I just take the head off?

Please help guys and gals

 

You can put air pressure to the #2 cylinder and listen for air flowing into the intake (intake valve problem), exhaust (exhaust valve problem), or crankcase (piston/ring problem).

You may be able to use a fiber optic camera to have a look inside the cylinder, but you may not be able to see a bent valve too well from that angle.

 

Brilliant, I should have thought of that. Easy way to tell. Thanks for the fast response. How can I get the motor to the combustion cycle. Bump the key or turn manually by harmonic balancer?

 

If you have someone bump the starter while you hold your finger over the empty plug hole, you should be able to get it.

 

Instead of posting a new post I am going to update my status. I took the head off with the thought I had a bad valve. Turns out the intake valve has a big chunk missing out of the corner. I took it out and the seat looks fine as does everything else from a visual inspection. I mic'ed the old valve and do not see that size anywhere on the net. I believe what I mic'ed was .320" and the closest I see it a .375". Maybe my mic is off but I will use another and check

My real question is, can I just order a new valve from Advance, Rockauto or anywhere and be able to put it and go or does it have to be taken to a machine shop to be seated? I have never had to replace a valve.

Any help would be great again.
(p.s. Cylinder looks fine as does piston)

 

You should be able to order a new valve to just drop in. There should not be anything special about it.

At the very least, you should lap the valve and check the seat pattern.

I would pop both heads off and have them checked for flatness and a full valve job done, checking the valve guides for wear and replacing the valve seals.