From Archive: Valve Spring Compressor by Hot2360

[Club Archivist]

Club Archivist Note: It is unclear what the original question posed on this post was...I cannot trace the thread back to the beginning. There may me some useful info here for someone, however.

Original Post:
I APPRECIATE THE INFO BUT THIS IS A HERCULES ENGINE NOT A SMALL BLOCK CHEVY. THE VAVLE SPRINGS ARE UNDER THE LIFTER COVERS ON THE SIDE OF THE ENGINE. THE VALVES GO DOWN THROUGH THE TOP OF THE BLOCK NOT IN THE CYLINDER HEAD. IT'S A FLAT HEAD MOTOR. VALVES ARE IN THE BLOCK NOT THE CYLINDER HEAD.

[Club Archivist]

I have the type same engine (mine is an M). An old style valve spring compressor is what you need. They are sold at auto parts stores. If you can find one large enough you may be able to get the springs off without removing the manifolds. The compressors are C shaped and of the offset is great enough it will span the manifolds.

Removing the head is most likely necessary although you may be able to hold the top of the valve down enough with a big screwdriver so that the spring can still be compressed without removing the head. This depends on the cylinder being worked on. If all valve springs need to be removed the head will have to be removed.

Stuff a shop rag into the oil drain passages under the valve springs so that you don't loose the keepers into the oil pan.

Its not too bad a job if the manifolds and head are removed. If you are not replacing the springs and keepers, put them back on the same valve and keep the valves in their original position.

If you are doing a full disassembly and replacement, consider stainless valves. Definitely replace valves with new ones that do not require lead lubrication. Also replace all valve guides.

[Club Archivist]

Removing the head and the manifolds is not a big deal. The biggest feature to removing the fixtures is that you can mill the head and the faces of the manifold, as well as replacing the gaskets. If you are going far enough to do the valves, you are only looking a couple more hours to do a complete "upper end overhaul." I did this with my MBL's two years ago and got dramatic results.

I also had the valve seats ground. It took some work to find a fellow who had the skill and the equipment to do the job with the engine in the boat, but boy was it ever well worth it. The drawback was that the compression was so enhanced that I began to draw some oil up past the rings.. but it was a small price to pay for the great increase in compression and performance.

Taking the valves out? My mechanic used a common yard stick with holes drilled (and numbered) to hold the valves while out of the engine to insure they were able to be placed back in the correct position. (One for the intake and one for the exhaust.) This also helps in inspecting the valves, one next to each other to see unusual heating or wear patterns. Also we used a cheap partitioned craft box to hold the keepers and springs for each identified cylinder.

And by the way JAY ARMSTRONG on this list was of great help in walking me through this job.

Please drop the list a note on your progress and successes!

SkiperBob

[Club Archivist]

All good points, Bob. It took me while also to find someone to regrind the valve seats with the engine in the boat. It also takes someone who know what they are doing. If they do it on a badly worn valve guide, the seat may not be true. The best way is to replace all the guides first, regrind the seats and put in all new valves. Alternatively, reface all the valves on a refacing machine and true up the end of the valve stem.

It's amazing how smooth these big 6-cylinder engines will run with good, equal cylinder compression and equal cylinder vacuum.

The valve tappet clearances should be rechecked (cold) several times after doing a valve job and running the engine to operating temperature on several outings. The head bolt torque needs to be checked, too.

Frank