Need Advice on Non running motor

[epatterson]

I am trying to get a 45 flathead that I believe was taken out of a Servi car (the numbers on the front cylinder included GE) running again. The gentleman I purchased it from said he had it running a few years ago and then just let it sit. I am very much a novice to all this, so any advice would be much appreciated.

So far I have cleaned out the gas tank, changed the oil, replaced the carb (Mukuni), and compression tested it. The compression test came out at 30psi per cylinder which I am told is low. My question is: Should I try to adjust the tappets and see if the compression changes or just try to turn it over and see what happens? Thank you to anyone that can help out.

[Sargehere]

It will start and run with 30 pounds per cylinder. Go ahead and get it running and run it in a little and see if that compression doesn't go up a little as the valves and rings get a chance to seat.
It's not rocket science to adjust the tappets, cold, by the book.

Take both of the sparkplugs out to be able to easily turn the engine. Also, raise all of the engine's four valve covers so you can watch the valves rise and fall.

With its opposite intake valve fully open, you can adjust (loosen the base nut and turn the tappet top, both with a 7/16" wrench, & tighten the locknut back down) on a seated intake valve to about .004 to .006-inch. Exhaust needs just a little more because the exhaust valves get hotter, and expand infinitesimally more when running, maybe .006 to.008-inch.

You do that using the "Go- No Go" method: like a specification of ".004 to .006 in." for an intake tappet means you can drag a flat .004 feeler gauge through the gap between the top of the tappet and bottom of the valve (under the spring) ("Go"), but can't push an .006 feeler in the same place ("No Go"). That tells you that you've hit the median, .005", and you'll be good to go.

Then turn the motor until the opposite Exhaust Valve rises all the way, and use .006 and .008 feelers, and get good .007" clearance on the closed Exhaust tappet you're working on. Then, do the other cylinders tappets by the same method. That will allow you to start and run the engine when you've done everything else necessary. Run in a little bit, the compression ratio may rise a little.

[exeric]

That is very nice of you to go to all that trouble, and typing Sarge, to help out a fellow member. . . Now where were you when I was having all that trouble with my '19 Hen

[epatterson]

Thank you so much for your help! I'll get to it.

[sirhrmechanic]

One thing that can be useful is to lift the cylinders off and make sure the rings are free.

Ferrous rings in aluminum pistons can seize solid. If they have a lot of old carbon and muck in them... it's almost a given. Lift the cylinders. Clean/free up rings. Put a quick hone in the cylinders and you will be glad you did. You can do this at home with common tools, a glaze breaker and a power drill.

Broken rings make good engines into bad engines really fast. The peace of mind from doing this will be well worth it.

Recommissioning engines takes time. Which is no fun when you want to hear it run. But it takes a lot less time and costs a lot less money than rebuilding an engine that otherwise would have been fine.

As Sarge says, most of the rest of it is simply measuring, checking and feeling how thing move through their cycles. But the rings... you can't judge those with out a good old fashioned Mk 1 Mod 0 eyeball.

Cheers,

Sirhr

[Sargehere]

Good advice if you want to take the 8 cylinder base nuts off and wiggle the cylinders free. You may need a 9/16 and 5/8" "starter wrench" available at your local auto parts store, to get a good hold on the cyl. base nuts behind the valve covers.

And once you get the cylinders up (with the pistons toward the top of the cylinders where you can see some daylight under them), stuff some clean rags under the cylinders in their crankcase holes. Reason for this is if you do have any broken rings, pieces of them don't end up in the bottom of your crankcase when you raise the cylinders all the way off the pistons (!) That can be a very very icky situation, requiring the lower end to be split, even if it doesn't need it.

Having the cylinders off completely also gives you a chance to feel very very gently, if your connecting rods' Big Ends are serviceable. You shouldn't be able to feel ANY "up & down" and only a little side-to-side rocking in good connecting rods.

Of course, that will require replacement of cyl. base gaskets, at least. If you take the cyl heads off, you'll need new 8-bolt 45 head gaskets (I recommend solid copper, metal head gaskets, but you can get arguments about that!) And buy a 2-1/2 to 3-inch hose clamp, to use as a spring compressor to replace the cylinders.

Two new sets of rings in the same size as stamped on top of your pistons would help, too, after you re-hone the cylinders. You can do that with an auto-store cylinder hone that will do 2 -1/2 inch cylinders and a drill press, just to re-cross hatch your cylinders.

Get the use of a regular automotive valve spring compressor, and you might as well take your four valves apart and re-lap them, keeping all the parts for each valve separate and in the order they come off. There are a couple of gaskets, top and bottom, to each of them, too. So, you spring for a 45" motor gasket set and use most of it, and you've pretty much done a top-end job on your 45 motor! Or you can do just as much as you feel comfortable with at once. Good luck! Hope some of this helps.

[epatterson]

Thank you guys for being so generous with your knowledge. I'm listening and I appreciate it!