VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 rebuilding my 29 engine

I NEED TO RERING MY ENGINE,IT HAS 60-62 PRE.ON ALL 6 CYL.I DO NOT KNOW WHAT IT SHOULD BE,CAN ANYONE TELL ME? WHERE CAN I BUY RINGS? ROD&MAINS GOOD,JUST SMOKES,"NEED HELP"

I don't understand what you mean by 60-62 pre. It depends on which pistons you have. Original or replacement. They use different width rings. The rods are poured babbitt and the mains are babbitted inserts. There are many people who can rebabbit the mains and rods but you will need to send them the exact dimensions of the crank. An the mains will need to be lined bored to be properly fitted.

I'll bet its Compression pressure..gave that some thought also :confused:

YES I DID MEAN 60 LBS. COMPRESSION ON EACH CYL.BABBITT RODS & MAINS ARE GOOD.SHOULD CYL. COMPRESSION BE MORE LIKE 100-125 LBS?

With the low compression 1929 engine I would say compression would be more in the 80 to 90 lb. range.Also should be fairly consistant for all cylinders.If your gauge is accurate 60 sounds low.Could be rings or valves or both.

If you were to overhaul the engine rather than rebuild it The following would be necessary..If rod and main bearing babbit is good they can be adjusted by removing shims to adjust the bearings to proper clearence.If cylinder wall wear is slight a new set of rings will help.Replacing the wrist (piston) pins is also necessary as well as grinding the valves.Would consider replacing the timing gear also.If one or two rod bearings have poor babbit the rods can be replaced and adjusted.

Important to know-
Is crank shaft standard size
Cylinder bore standard or oversize
Original or newer replacement pistons.
Pistons are the same from 1929-36 but ring width was changed a few times thru the years.To get correct rings , width would need to be measured.


for limited driving, for which most cars that old are used, an overhaul could be sufficent if crank , bearings, and cylinder walls permit.
It is most common to find, due to old age and neglect thru the years,a complete rebuild will be necessary (and expensive) as there is no way to do a cheap rebuild on these engines.

THANK YOU,I GUESS I NEED TO PULL PISTONS & CHECK CRANK CLEARENCE.I CANNOT DO A COMPLETE OVERHAUL AT THIS TIME,JUST GET RID OF BLOWBY& SMOKE.MOTOR SOUNDS GOOD OTHERWISE.IT HAS 7LBS.OIL PRESSURE AT IDLE & 12LBS RUNNING DOWN THE ROAD.THANKS AGAIN

ENGINE ALSO LEAKS OIL FROM REAR,DOES NOT APPEAR TO BE PAN GASKET.DOES REAR MAIN HAVE SEAL.OR CAN ANYTHING ELSE CAUSE THIS.ONLY LEAKS WHEN RUNNING AND RIGHT AFTER SHUTDOWN.

There is no rear main seal on that engine, only an oil slinger on the rear portion of the crankshaft. Check behind the cylinder head next to the cowl to see if your valve cover gasket is leaking. A valve cover gasket leak in that area will give the same appearance as a rear main leak since the oil drip off of the bottom rear portion of the engine.

By the way, in your first posting, what did you mean by "60-62 Pre."??

I just had engine shop rebuild a 207, I found all nos from many places, :confused: took some time to hunt. Harts machine shop in Ohio had a good price on repouring mains.

JYD, check posts #3,4 above for the answer to your question. :)

THANKS EVERYBODY FOR YOUR HELP,I WILL CHECK THAT VALVE COVER.

The compression chart for the 1929-31 engines shows that the compression should be 76 pounds, and for 1932 the compression should be 80 pounds.

Perhaps the rings are stuck on your '29.Remove the plugs, dump in about 2 ounces of Marvel Mystery Oil in each cylinder and let soak for a day....you need only another 14 pounds

The leak from the rear is likely too wide a tolerance on the rear main. Anything greater than 0.003 will result in a leak. Also if the oil return passage is plugged then it will leak. So checking the rear main and cap is in order.

You can also see if the ball check valve in the rear main bearing cap is working correctly. If it is frozen in the up (back) position, then oil cannot return to the pan and it will run out behind the rear main bearing. :eek: :eek:

GREETINGS;I MADE A COPY OF ALL THIS INFO.AND WILL CHECK ALL BEFORE PULLING PISTONS.REAR MAIN PROBLEM MAY BE SOLVED BECAUSE I BELIEVE IT HAS SOMETHING TO DO WITH THE OIL NOT DRAINING BACK INTO PAN FREELY.ALSO I LIKE MARVEL MYSTERY OIL, WILL TRY.HEY DONT FIX IF NOT BROKE.THANKS

I PULLED REAR MAIN AND FOUND BOLTS WERE FINGER TIGHT.IT HAS INSERT,IS THIS FACTORY? ON BACK OF INSERT HAS CHEVY BOTIE&JB CO.STAMPED ON.WHERE CAN I GET ANOTHER ONE.ALSO DRAIN HOLE IN CAP IS CLEAR.

The insert is "factory"....One main insert can not be replaced on these.All need to be done and line bored to have all bearings on the same ....level....with each other.Some mechanics would replace just the lower insert if the babbit was in bad shape.The lower took all the pounding.If babbit looks OK shims could be removed for proper adjustment if needed.The loose bolts would have caused a leak...not a common thing to find.

And, the rear main bearing cap bolts should have a factory bolt lock on them as well so that they don't become loose.

Would check the other two mains-for bearing condition and clearence also.Often the babbit in the lower half of the center main is pounded out.

Typically the center main goes first then the rear and finally the front. Also check the run-out on the crank. The flanges on the center main control front to back movement which should be 0.006 - 0.010". Each main bearing is different size largest in back, smallest in front. As Chevygene wrote line boring is the best (only) way to really fit the crank if taking out shims does not give correct fit. And the dog-face is right about the locks. Rear and middle have triangular tabs that bend up against the bolt flats. Front has 12 notched ring retainers that are tied together and secured by bolt.

Why are the mains different sizes?

The 1937 Engineering Books states "At the main bearings,the increase of diameter is approximently 5/8 inch (varying because the journals and bearings are stepped very slightly in size for manufacturing purposes)"

Actually the size of each beaing increased from rear to front to faciliate the line boring process.First the block with main bearing caps attached was bored.Then the main bearing inserts were installed and line bored.The boring bar would have been inserted from the rear (largest opening)...the smaller front portion of the boring bar could pass thru the larger rear openings with out contacting their surface.

Modern methods eleminated this problem.The newer 7 main bearing 6 (1962 and up) had all bearings of the same size except the rear-as it also took the end thrust.

I FOUND A 1940 REBUILT 6 CYL. WILL THIS FIT INTO MY 1929? BOLT TO MY TRANSMISSION ETC.