VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Rebuilding '30 block

My '31 Coach has a '30 engine and tranny, and a '29 head, everything worked good this summer (put about 500 miles on her). Car starts easily, runs smoothly, has good oil pressure (6-10lbs running warm), charges at about 10 amps on gauge, etc. Had head off 3 years ago for a rebuild (some new valves, rocker arm shafts/bushings, and seats ground/fitted, wicks, new exhaust system, new carb, etc).

However, the lower half of the engine has not been touched for perhaps 50 years or more (car had not been driven between 1967-2013). Engine seems very loud, especially if speed gets over 25 MPH. Old hands around here suggest likely piston slap and maybe excess play in crank/connecting rods etc.

So I am contemplating pulling engine out and sending to local specialists who would do 2 primary things;
1. machine the cylinders to eliminate "out of roundness", and machine crank to smooth out any imperfections.
2. refit crank bearings and replace pistons and rings, oversized to suit new cylinder dia. They have experiance with babbitt etc, and have done many Model A engines.

Does this seem routine for these old engines? Are oversized pistons generally available or am I likely to run into a supply problem for anything in this sort of job? Should I find new O/S pistons before I start?

Pistons and rings are available in both Cast Iron and Aluminum. Many of us continue to use cast iron despite many engine rebuilders that advise switching to aluminum. I have several sets of pistons in several oversizes if you need some.

Cast iron pistons seem to be readily available in most sizes so you shouldn't have a problem locating a set.

I purchased mine from Chipper's Auto Emporium. Parts were of good quality with very helpful, friendly people on hand...Joe

That's good to know Chipper. I will hold off on purchasing pistons until the block is disassembled and the machine shop guy knows just what condition the cylinders are in and how much "oversizing" is necesary. So I may be in touch with you later on. My inclination is to go with cast pistons as per original, is there much difference in price? How much is a set with appropriate rings likely to cost, and do they come complete with rods, wrist pins etc? just trying to ballpark what my costs may be.

The items you mention can be checked without first removing the engine. If it were mine I would do a compression test, drop the pan and check the bearings and I believe the piston clearance can also be checked. If its not smoking or burning oil, has good power and runs smooth rebuilding may not give you the results you are looking for. I think it would be good to verify you have a definite problem before trying to cure one that may not exist.

Thanks for added advice. If I decide to pull engine out, I will drop pan as you suggest and see what I find beforehand. Not sure just what to look for or how to verify condition, but once I do drop the pan, I will come back here for particulars. If a bit of adjustment to shims helps cure the engine noise, or if everything looks Ok, I may stop there. The car has sufficient power, and does not burn oil generally, although there is a few small puffs usually when started after sitting a few days (likely oil from valve guides?). Cheers.

Pistons come only with wrist pins. Rings are separately priced. Will send you a PM with pricing.

If you do decide that your 1930 engine with the 1929 cylinder head needs rebuilding have you considered possibly putting your money into a correct 1931 engine and cylinder head and rebuilding that unit instead?

Good thought JYD. I will see what is around, may take a couple of months, but what else is a winter in Atlantic Canada good for!

The block you have is for a 1930 car or it's cast in 1930? It is possible to have an engine cast in 1930 built for a 1931 car depending on casting dates & engine serial number...Joe

That is a good question Joe. If the engine block was cast late in 1930 (like in November for example) it would have the 1931 block casting number and a 1931 engine serial number. However, Gunsmoke has probably already checked that I would guess.

By the way, the 1930 and 1931 cylinder heads are one in the same, whereas the 1929 cylinder head is a one year only application.

Block is stamped mid-August 1930, so it is most likely a 1930 block. I'm not sure when they switched to casting '31 blocks. I could provide serial number if that would certify one way or the other?

The serial number and the casting date would help, but most likely the block is a 1930 issue.

In this case the casting number trumps either the casting date or serial number in determining if the block is a 1930 or 1931. Casting number for 1930 (and also 1929 BTW) is 835501 for a 1931 is 836409.

You didn't ask how to tell a '29 from a '30 block since the casting number for both is the same 835501. Those need the casting date and/or serial number. Also need the serial number or specific differences in the actual casting to determine an early from late '29 blocks. Cornfused? Me two.

There's also a 886273 used in Canada...Joe

Ok Chipper here are the details. The block is casting 835501, and cast date was H 16 0, suggesting a late 1930 block. Serial number is T293779(truck). The transmission is also '30 as it has the earlier bell housing and mounting shaft for brakes/clutch.
Head has casting date of C 30 9, suggesting March 30 '29.

One problem I would have if I find a '31 engine is mating up the '30 tranny I have, do they mate easily or would I also need a '31 transmission? or are bell housing thingy's (covers/supports?) interchangeable '30-'31?

You would need a 1931 transmission and a 1931 bell housing thingy. But to keep your car all original '31 besides finding a 1931 engine I would suggest locating a 1931 transmission.