MTFCA Forum

New owner to a '16 touring car. It has a 10,9xx,xxx engine. I am going to do a compression check and I would like to learn what is considered a healthy number.
Under the rear seat there is storage. Should that area have a metal lid like over the fuel tank?
Thanks for the help.
Campbell Tellman II
Beaufort,NC

60 # is top stock piston compression.

Campbell, in fairness to you, you are not going to have an easy time hand cranking a valid compression test, particularly without a setup specifically designed for 1/2" pipe plugs and you certainly are not going to get 60# in any event. 14.7 PSI at sea level and a 4:1 compression ratio in a perfectly sealed container will fall short...your engine most assuredly is not sealed to that extent. The 60# figure is a general/rough approximation of perfection and one shouldn't use that number too literally for gauging engine health (or not). 50# on a used T engine would be wonderful, and even lower would not be surprising, and still run just fine.

After you're done with the exercise, tell the forum WHY you wanted to do a compression test. Curiosity? Rough running?

If you get 60 psi you're in hog heaven. If you get 50 you're doing better than most. The important thing is for compression on all four cylinders to be pretty close together. A Model T will run with compression as low as 30 psi, but don't expect it to produce 20 HP.

I thought a compression test was an indicator of engine health. I have not started this engine but with the plugs removed it turns over with the crank. It has not run since 1990. I am going to remove the engine to clean up the frame. At that time I will get some professional help with the mechanicals.
With a ratio of 4:1 I didn't know what to expect.
Thanks,
Campbell

I would put a tablespoon full of Marvel Mystery oil into each cylinder and then hand crank the engine with the plugs out. Then I'd replace the plugs in the engine and, after making sure there is clean oil in the crankcase and water in the radiator and fresh gasoline available, fire it up. Be sure there is no old gasoline remaining in the tank before adding a couple of gallons of fresh gas. I would not fill it up, since it might leak. As for compression pressure, you will get a more accurate reading after the engine has run for a while and everything is loosened up and oiled up. 35-45 lbs at cranking speed with the throttle open is around average. As pointed out, the closer each cylinder's reading to the others is, the better. If one or two cylinders is very low, it could indicate stuck valves. They can usually be freed-up without taking anything apart.

Most of today's compression testers are made for today's higher compression engines and have a 300 psi scale. For a Model T a 100 psi gauge is better.

You will also need an adapter with ½" pipe thread. I used a valve stem on this one, but for a compression tester I soldered in a bit of tubing that would clamp into the tester hose.

With all spark plugs out maybe you will be able to "spin" the engine fast enough to get a valid test.

Whatever the compression readings are...they will get better after a few hundred miles once the old oxidized oil is flushed out of the ring grooves and the rings start to work again. With respect to rings, new oil has very aggressive solvent qualities. Pat's suggestion of some Marvel Mystery Oil into the plug holes is a good suggestion as that will start the freeing-up of the rings as it soaks. Assuming the engine will: 1. Start, and 2. not make disturbing noises, just drive it a bit

Additionally, you want to start/drive it NOW and determine the health of the engine and transmission. Pulling it right away to work on cleaning up the frame, reinstalling it and then finding it has to come right back out is not a sequence that I'd allow in my shop.

Finally, in my experience, hand-cranked Ts are more often in surprising and quite serviceable condition even after lengthy storage, (I believe) due to the effort of hand cranking, they are/were not driven nearly as much as starter equipped cars through the years (once they passed their utility life and became hobby cars).

I wouldn't be in a big hurry to clean up the running gear beyond rinsing off loose dirt. I would want to get a lubrication chart and go over the entire car and oil/grease everything, front to back, including the springs. Running the car will tend to re-oil old greasy deposits and soften them somewhat. Remember that the car has no idea how long it has been sitting, and it wouldn't care if it did. I'd want to clean out any mud and heavy dust and rodent filth that may have accumulated in nooks and crannies, under seats, and other places that trap such crud. Compressed air can be a great help in doing this. Hardened grease and oil caked on the undercarriage can be very difficult to remove, and pulling the engine is a big job and it won't help much as far as cleaning things up. Running the car and keeping everything lubed will help some.

I would recommend that you get the engine running and driving like it is now to see how it runs, how the transmission shifts and etc then work on what you find and any issues that you may have. You will learn more doing it that way in the long run. Read the T service book and any other T repair and driving manuals that are available.
It’s wise to remember that Model T’s are pretty much 100 year old technology and not to compare a T to modern cars and trucks.

You can sweep out or use air to blow out or use a vacume to clean it up. You can clean up the grease later. Make sure it has oil water and gas.
Then try to start it up and run it. You’ll be glad later you did it that way.

Just beause I can't help thinking outside the box, has anyone tried testing the compression with the engine running? pull one plug install the gauge in one cylinder & start the engine, check the gauge at idle & then do the other cylinders one at a time. This would only help a hand crank only engine. From what I have found compression testing with the hand crank the cylinders get progressively weaker from the first to the last as you get worn out. A modern plug adapter will make adapting the gauge easyer & jacking the rear wheels up also helps.
Craig.

Hand crank test procedure: Test #1, beer. Test #2, beer. Test #3, beer. Test # 4, beer.

TXGOAT2 wrote: ↑

Mon Mar 14, 2022 4:28 pm

Hand crank test procedure: Test #1, beer. Test #2, beer. Test #3, beer. Test # 4, beer.

Yes but test reliability may suffer. #3 reading questionable. #4 what was I doing?

More proof of Ford economy: Test complete, and you still have 2 more beers...

TXGOAT2 wrote: ↑

Mon Mar 14, 2022 4:28 pm

Hand crank test procedure: Test #1, beer. Test #2, beer. Test #3, beer. Test # 4, beer.

I tried that. Then I realized I forgot to record the results. Test #1, beer record beer. Test #2, beer record beer. Test #3, beer record 550 beerr, Test # 4 &$#&* out of beer

Campbell, our Canadian sourced cars had a wooden cover under the rear seat, made of random width 1/4" thick boards nailed to two cross pieces on the underside. When I rebuilt mine the hardest thing was duplicating one of the broken hinges which allowed the cover to be lifted up from the front. If nothing else, the wooden lid was good support for the seat spring frame.
Hope this helps, Allan from down under, where the responsible use of alcohol is encouraged.

October 1915 unrestored US touring sports a stamped steel cover under the springs/over the storage compartment

Allan
always interesting to note the differences in our cars...as Trent Boggess used to say: "all the same, huh?"