VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Valve timing

On Bill Barkers 31 web page it states that 'inlet valve opens 4" after TDC. Does the 4" represent 4 degrees after TDC? Flywheel is marked for No1 Cylinder' A few days ago I posted the 'vapor lock' question regarding my 31 Phaeton in conjunction with car boiling over on uphill. However, I failed to mention that the Phaeton motor seems to run 'stiff' and not as smooth as the one in my 31 Spcl Sedan. Phaeton motor was rebuilt about 4,500 miles ago, using cast iron pistons, new rods, valves valve guides, rocker shaft, bushings, and new camshaft fiber gear. The spcl sedan motor is all original (only 42,300 miles) except someone put aluminum pistons in it, and I replaced the head. That motor runs smooth, like a six should. I wonder when reassembling the Phaeton engine that I may have 'missed' the camshaft gear to crank gear mesh by perhaps one tooth, causing the 'stiff' running engine? How can I check the accuracy of valve timing without having to 'open up' the front of the engine for a visual inspection of the two gears? I am afraid to remove and reinstall the harmonic balancer since the only way to get the balancer back onto the crank is by 'pounding' it back on. As always appreciate the help. VCCA #18184

Hello 31Phaeton,
That is a difficult question to answer. What you are suggesting is that your valve timing may be off. Without removing the timing cover to verify, I think the only other option would be to experiment with the distributor timing. If the suggested 18 degrees BTDC is your current setting, (as per the mark at the flywheel), try varying a few degrees each way to obtain smoother performance, if possible. This is not how the engines were manufactured to operate, so performance/mileage may be affected. Remember, only you will know this secret. If another mechanic works on the engine, they won't have a clue, if the timing gears are not in sync.

I would say the only accurate way would be to remove the front cover. The valve timing and distributor timing are two different things. The valve timing times the camshaft with the crankshaft.

Gene is completely right ,as usual, if the timing gear on the camshaft isn't correctly mounted on the camshaft and the cam gear isn't meshed with the crankshaft gear exactly in time you will never be able to "tweek" the distributor and get the vehicle engine to run at it's potential. The valve train will always be out of time with the pistons, the only way to correct this is to make sure the valves and pistons are in sync. You will need to source a shop manual for your engine for the correct timing procedure.

If you want to fiddle a bit, you might give this a try. Remove the valve cover and all the spark plugs. Position the engine such that the TDC mark is aligned with the pointer in the timing opening and is set such that Number one is ready to fire. Place a mark on the fan pulley at some natural or artificial pointer. Now take a look at NUMBER SIX VALVES. Both valves should be closed. I.E. the exhaust valve has just closed and the intake valve should just be ready to open. Have a helper slowly turn the engine backward just a few degrees until you see the exhaust valve just start to move and place another mark on the fan pulley at the pointer. Now turn the engine forward until the intake valve just starts to move. Place another mark on the fan pulley at your pointer. Now take a close look at the marks. TDC should be the center mark and the other two marks should be equal distance from that center mark. If they are not, your camshaft is not in time with the crankshaft.

There isn't an 18 degree mark on the flywheel, only a U/C mark and a 12 degree mark.

Does anyone remember my problem that I posted on here for over a year with my uncles 31 phaeton? I'll get the instructions on how to check this. Also how do you have it timed currently? By the book or how everyone does these cars with gap .040 and 18 degrees?

Back in a minute with what you need....and this is in a book most of us have.

OK....on my uncle's 31 phaeton which we had for 2 or 3 years before I found the problem with the timing gear being off one tooth....it ran great but would pop out the carb now and then.

Vale Timing:
1931 Models AE Independence (ONLY)
Set the intake valve tappet clearance for timing to 0.010". The intake valve should just start to open 1 1/2 flywheel teeth after top dead center.

EDIT: I just talked to Bruce and he asked me to post this within his original posting. The position where the intake valve opens isn't at TDC on the POWER stroke, but rather at TDC on the INTAKE stroke. That is 180 degrees from Top Dead Center as you usually think of it. Remember that a four-stroke engine goes around TWICE for each time that it fires. So you want to check the intake valve opening on the "third" stroke. -- Bill B

This works and you don't need to take the car apart to check it....and that was the problem with our phaeton. When I took it apart the timing gear was not marked at all and was one tooth off.....fixed the problem! Call me if you would like to talk about how to do it. I didn't think it would work, but it did.

I can attest that the '31 Phaeton runs well!!! Was on the recently completed SW Fall Tour in Canon City, CO. First day we climbed and climbed to Cripple Creek. Could hardly keep up with it in my '51. Maybe cause your uncle was not behind the wheel.

Bill, you are exactly right about the four stroke engine. That is why my instructions said to check the intake/exhaust valve setting on cylinder NUMBER SIX, which would be at TDC Exhaust when Number one is at TDC Fire.
Ron

To 32 Confederate and others! Thank you indeed, exactly what I was looking for. I do have the 31 repair manual, but 'forgot' that the answer may be hidden therein. I have been to Cripple Creek, and to get there you definitely have some long uphill climbs. I'll let you know what I find out regarding my valve timing. Prior to rebuilding the engine, it seems I never had any heat issues, but I had 'lots of noises' from the engine (loose pistons, worn bearings, etc. but it ran great. I even towed a big old Chrysler up a one kilometer long hill without issues back in 1965 when we were putting the car in storage. Again, thank you - hope the valve timing is OK so I don't have to pull the front cover, etc. to reposition the gear. 18184

Roneyres - You're right. That probably is an easier way to tell folks what to look for (ie. Number six at TDC). Good suggestion.

I'm thinking that I should add another page to my http://1931chevrolet.com timing instructions . It seems a shame not to document this kind of good information.

--bb