kiwifarmer

ive got two questions-I removed the heads on my 1955 olds as the inlet valve on no.1 cyl was getting no oil so I have had the machine shop fit new valve guide and seat ,I cant see any reason why the oil wasn't getting to it is this common and is there any way of fixing this? I took both heads off and had some other valve guides and seats replaced and fitted new hydraulic lifters I now have no compression on no. 4 cyl I have refitted the old lifters on that cyl but made no difference ,I pumped oil in that cyl and still no compression do you think the machine shop may have cut the angle on the seat or valve wrong and that is why no compession?

olds 307 and 403

If it had compression, before, yes that is possible. They may have to redo the valve grind. A crooked valve guide is also possible.

Ozzie

The oil for the valves feeds from the cylinder head into the rocker arm shaft assembly and through holes in the shaft to the individual rocker arms. With age, the rockers and the shaft can "polish" each other together to such a condition that oil will not flow. This has happened to many. You can replace the assembly or modify the existing one. On mine I cut circumferential grooves in the rocker arm shaft to coincide with the existing oil holes. This allowed oil to flow again to all rockers. This was done many years ago. So far, all is working well with oil to all rockers.
As has been said, if you had compression before the work, it is likely that the work caused the shortfall. It is probably not the lifters, barring something catastrophic. Look closely at the valve seats and the depth of the guide placement. Probably something was done incorrectly. If the guides were placed at the wrong depth, they will hold the valves from closing. The valve guides should extend 47/64" above the face of the valve spring seat. Use of tool J-5158-2 will provide exact placement of the guide. However, a careful worker should be able to properly set the guides without the tool.

kiwifarmer

thanks-ive taken head off and had it re-checked and all appears ok ive poured thinners in the combustion chamber to see if valves are sealed and they are ok ,ive found if I rev the motor up and pull plug wire off it misses but if it idles and I do the same thing it does not miss I have no compression when I do the compression test when I put oil in the chamber I get compression none of this makes since to me

Ozzie

It sounds like the valves and seats are correct, which makes me think that unless something else in the valve train is holding a valve open, the problem is elsewhere. I am assuming that the compression problem is still only on #4 cylinder. If you have one cylinder which has no compression at all (without added oil) there should be a bit of unsmooth running. When adding oil to the cylinder during a compression test and getting significant more compression indicates a problem with the cylinder, piston and/or piston rings. It is difficult to understand how the machine shop work could have caused such a problem. Your first post said that the addition of oil to the cylinder resulted in no additional compression. So now I'm wondering how much the compression now changes with the addition of the oil. If you have the results of the compression test perhaps you could post them. Was the compression normal before the work on the engine started? The compression test should be done as follows:
Remove all spark plugs.
Have the throttle open.
Conduct the test with a screw in type gauge and record the values.
On the cylinders with low values, add the oil and do the test again and record the values.
Perhaps the compression is so low at idle speed that eliminating the spark does not affect the way the engine runs. It would seem that the engine would already not be running smooth due to the lack of compression.

kiwifarmer

thanks, it is the same cylinder. when I put oil in the cylinder the first time the compression didn't change ,thinking back maybe I didn't put enough oil in it which is why I thought valves,with no oil there is zero compression all other cylinders read 130-140 ,there is a obvious miss when motor is revved up and plug removed but no difference when idling,im thinking im going to leave it as seems to go just fine on the open road-frustrating!

kiwifarmer

forgot to mention -with oil, compression almost same as others ,ive never heard another olds running -very few in new Zealand so I didn't know if it was missing before the head work only picked it up checking I had the plug wires on correctly after head job as to my ear it seemed it was running ok !

Ozzie

Surely it is important about the plug wires being correct, but if you are getting 130-140 on all other cylinders and zero on #4, then there is a problem on that cylinder. I have a 1955 Olds. It has uniform compression on all cylinders and runs smoothly, so I hope that you will be able to find the shortfall and correct the problem. If the cylinder and piston looked good on #4 when you had the head off, and the gasket was "normal" (not blown), then there must be something wrong with the rings (assuming that a valve was not being held open). To check them, removal of the oil pan would be required, which would be a "substantial" job. If the rings are broken, continuing to run the engine could result in damage to the cylinder wall. Best wishes!