A bad valve job?

[Local2ED]

I have been putting together a 230cu.in. for my 1958 Dodge Coronet.

Put the engine in the car and it would not start no way, no how.

Run a compression test, compression low. Pull engine back out, take off oil pan and manifolds. I connect a airline to pressurize the cylinders, NOT a leakdown tester but just a fitting and airline. Compressor set to turn off at 100 PSI. Pump up the cylinders and almost every single valve leaks, some much worse than others. I made sure the tappets were loose so their was no chance the valves were held open.

I had a machine shop install new exhaust seats, grind the intake seats, install new valve guides, I confirmed there at the correct depth, and I installed all new valves. I assembled the engine my self, not the first one I ever done.

Is there any reason OTHER than a botched valve job that would make the valves leak? I did not lap the valves after the valve job because the shop said it was not necessary.

Anyway the shop wants me to bring the motor to them to see whats wrong.

Can a machine shop that says they are familiar with our flatheads screw up a valve job that bad or am I missing some other problem I am not aware off.

Thanks.

[Plymouthy Adams]

inattention to details of any component could lead to failure..I have seen worse than you have described from high end builders..could be some rookie was given the task on your engine as it being a simple flathead learning platform..

[RobertKB]

Intake and exhaust valve guides go in a certain way but end for end. Intake goes one way, the exhaust the other. Do a search as there are some threads on this issue. This could be your problem if your rebuilder was not "familiar" enough with your engine.

[Local2ED]

Intake and exhaust valve guides go in a certain way but end for end. Intake goes one way, the exhaust the other. Do a search as there are some threads on this issue. This could be your problem if your rebuilder was not "familiar" enough with your engine.

Rebuilder said he was familiar with how they go, I also supplied him with the information when he originally did the valve job and I confirmed that they were correct when I picked up the engine before leaving the shop.

It is unbelievable the frustrations I've encountered with this engine from dropping a piston and breaking the top land to being told it would be ready in two weeks that turned out to be five weeks to ordering and waiting four days for plug wires from NAPA only to find they don't fit to ordering points and condenser from Napa, not checking the boxes, and come to find out there was no points in the points box, just the grease and the little instruction paper rattling around in it, and having to wait another day, to getting a carb kit from,you geessed it, only to find it not complete, another couple day wait.

[sorensen_dk]

Rebuilder said.....

I've been there, nothing more frustrating. Time to find another shop. How were you referred?

Hope it's only a valve issue and that you get it sorted out.

Tom

[Local2ED]

Rebuilder said.....

I've been there, nothing more frustrating. Time to find another shop. How were you referred?

Hope it's only a valve issue and that you get it sorted out.

Tom

Found the rebuilder from a flyer at a car show and hung on to it for a couple years. The last machinest who did the engine in my "38 Dodge pick up was 82 years old when he did it several years ago and I didn't have the heart to call his home for fear he may have passed on. I called a few shops in my area and inquired about the work I wanted done and recieved reply's from "What's a flathead?" to "Bring it in I'll have to look at it".

I spoke to this shop on the phone including the owner and felt comfortable with their answers.

[james curl]

I had to hand lap mine about four time each to stop any leakage, I filled the ports with paint thinner with the ports up and the engine on its side and could just watch the seep start on the bottom of each valve. This was with springs and keepers in place which is a pain because you have to compress the spring to remove the keeper each time before you can re lap the valves. I used a drill on the valve steam to rotate the valve and a rounded 1/2" dowel rod to push down on the center of the valve while rotating with the drill, used both the course then the fine compound before I finally got them to seal.

Edited September 1, 2012 by james curl
spelling

[40P10touring sedan]

When I took auto shop, we use the stalk type lappers- they used the valve guide as a guide for grinding the angles...if the valve guide was worn or loose you'd get off center grinding...even alittle is enough to cause a problem.

Mind you, I have no idea what he used or how he did them....I'd pull the head and valves, take a permanent marker and mark the valve seats, then slap the valves a few times to see how they mark the seats. It'd be a good time to hike the valves up and look for play in the guides...if he didn't replace them and maybe knurled them you'll be looking for new ones to be installed.

Once again, I have no idea what he did to the motor, this is just random guessing..

[Don Coatney]

When you did the compressed air test how did you calculate when each cylinder was at top dead center on the compression stroke?

Also what were your original compression readings? What kind of compression gauge did you use for the test? The kind that screws into the sparkplug holes? If it was this type what was the length of the probe that screws into the plug hole?

[Guest P15-D24]

When you did the compressed air test how did you calculate when each cylinder was at top dead center on the compression stroke?

Also what were your original compression readings? What kind of compression gauge did you use for the test? The kind that screws into the sparkplug holes? If it was this type what was the length of the probe that screws into the plug hole?

To Don's point I would question the diagnosis. What was the compression with the plugs pulled, proper compression tester installed for each cylinder?

[Local2ED]

When I took auto shop, we use the stalk type lappers- they used the valve guide as a guide for grinding the angles...if the valve guide was worn or loose you'd get off center grinding...even alittle is enough to cause a problem.

Mind you, I have no idea what he used or how he did them....I'd pull the head and valves, take a permanent marker and mark the valve seats, then slap the valves a few times to see how they mark the seats. It'd be a good time to hike the valves up and look for play in the guides...if he didn't replace them and maybe knurled them you'll be looking for new ones to be installed.

Once again, I have no idea what he did to the motor, this is just random guessing..

All new valve guides,exhaust seat inserts, intake seats recut, all new valves installed.

[Local2ED]

To Don's point I would question the diagnosis. What was the compression with the plugs pulled, proper compression tester installed for each cylinder?

To answer Don and p15-d24's question.

Don't have the compression numbers in front of me right now.

The compression test was done with all plugs removed, throttle held wide open, with the type of tester that you hold in the spark plug hole by hand, also wiped a thin coat of oil on the rubber part goes in the plug hole.

Don when I applied the compressed air to the cylinder, the piston rotated to the bottom of the cylinder but I loosened all the tappets as far as they would go and verified nothing touched the valve stems that could hold the valves open. I understand what your asking, but with both valves closed I don't know if the position of the piston matters. Does it?

Not sure if I made myself clear but the engine now sits on a stand with the oil pan off and manifolds off. With the compressed air in the cylinder I can stick my thumb as far as it will go in the ports and hear and feel the air leaking out of the ports that lead to the manifolds.

I don't have the #'s in front of me but when I pumped the cylinders up with air the lowest ones would pump up to BUT NOT HOLD 60 PSI. while the higher ones would pump up but to BUT NOT HOLD 80psi to 100psi.

I don't think putting that much air pressure in the cylinder would cause a GOOD valve seal to leak, would it?

The machine shop wants the engine back next week so maybe they could check their work.

Thank you for letting me pick your brains. Ed.

[Local2ED]

Finally got it back and put together and installed and running nicely.

The machine shop told me they think the 30 degree angle was not cut correctly and was holding the valves open.

Anyhow, thanks for the brainstorming session, Ed.

[greg g]

glad you got it up and running. Thanks for the follow up. Most folks here really appreciate a thread that comes to an informed end rather than dangling with no conclussion. Good luck withthe rest of the project. Too bad it needed to start with an engine R and R.