VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1940 216 Question

I am dissembling my 1940 216 because I am going to get the block bored. I see the mount for the oil pump is secured with machine bolts through the wall of the block. In later motors those those bolts were replaced with ones with round heads. The explanation I have read is that the pump mount was secured and then bored so that it was located precisely. The idea was never to disturb the mounting. So I am thinking that I should leave it in place when I take it to the shop. Is this correct?

That is what I learned when doing my 54 235-leave the oil pump mounting flange in place and do not disturb.

If it is bolted that means it was removed at one time, possibly for rebuilding. I would suggest leaving well enough alone and make sure the shop working on the engine does the same.
Are you going to bore it out and install 226 pistons?

Oh that is interesting! Last year I had it out and all apart. I ignored some scoring in the back cylinder from a previous build. Unfortunately that soring allowed the copious blowby to continue. So I am going with the least bore size that will correct the problem. It is interesting to note that it is a 1940 motor in my 38 Chev, nice motor. It doesn't have a lot of wear on the block and the coolant passages didn't have much rust, just some leftover casting sand! I would guess that early in it's life there was a piston failure in #6. Someone probably tossed the motor and years later someone else decided to rebuild it.

Here is another question. there is a little plumbing sleeve that sticks out of the bottom of the block. This is where the pump output tube fits in. Is there a was if removing that sleeve? I am worried about it getting damaged.

Another thing I would/t touch.

Thanks, I will note that. Here is another interesting detail. I did a compression test during the summer and got the following results: from Cylinder one to six, 120 95 95 100 100 110. Now looking at the copper head gasket that I installed, there is carbon between 2 and 3 and then again between 4 and 5. That carbon is on the head too. Looking at the copper gasket that I removed last year, it was very similar. The head was completely redone including surfacing. I am intending to go with a modern style of gasket this time but I don't know why this turned out this way.

Check the top surface of the block with straight edge and feeler gauge. The block surface may need to be machined.

Yes that seems to be the only suspect left. It will definitely be machined but I like to gain as much information from the teardown as possible.

The low reading between 2 and 3 and the carbon track indicates just blown head gasket but the higher reading between 4 and 5 doesnt ring the alarm bells with me though the carbon track does.
The only way I know of CORRECTLY repairing this is machining both head and block to flat and a new gasket, but I have often got away with only machining the head and new gasket. You say the head was machined recently so doing both now is probably the way to go.
While it is apart thoroughly inspect everything and do whatever repairs are indicated while it is apart, as you know it is a lot of work to remove and refit so much easier to do it once only.
Tony

Everything will be checked for sure because it is all coming apart. I was wondering if there would be comments regarding the use of a copper head gasket as apposed to a composite one. I think I will go with the composite this time.

I used to use the copper gasket back in the day because that was all you could get. I used to reuse the copper gaskets at least once, usually when I ground the valves between overhauls. Can't reuse a fiber gasket. I have used the fiber gasket in recent years without any problems. Neither gasket has ever leaked. I have always checked the head and block deck to make sure they are true. During 420,000 miles the block has been "decked" twice and the head has been "milled" numerous times. Be sure to check the head intake and exhaust ports for being warped. I've had more exhaust leaks because of exhaust port warps and corrosion over the years than head gasket leaks.

Use either gasket. I don't think it makes any difference as long as it is installed correctly.

If you use a composite head gasket make sure it has a metal insert around the cylinder hole. If not the gasket will eventually erode between the cylinders. Typically that is between 2&3 and 4&5 as those are not as directly held by a head bolt.

mike,

Excellent advice about getting the exhaust and intake manifolds and head ports machined, as well. Exhaust and intake leaks are a pain.

Best,
Charlie

I have another questing regarding my rebuild of the 216. The timing gears had only a very small amount of oil on them. I have only put a couple of thousand mile on this motor since I put it together. Now the plate gasket was correct, the screw in nozzel was clear and aimed correctly but it appears that not a lot of oil comes out of the front camshaft bearing and so that source is inadequate. The bearing itself is in good condition so it is not being starved. In any case the cam bearings will be replace because the block is being reconditioned. I am thinking of adding some clearance to the front main crankshaft bearing in an effort to supply some more oil. Any suggestions would be welcome.

The oil is more or less of a drip, drip, deal.It is fed by gravity from the overflow from the front cam bearing on a 1940 engine. If you wish to get more flow I would do what they did in 1949. That was enlarge the opening in the nozzel from 1/16" to 1/8". In the later years if you purchased a new nozzel for and earlier model it would be the 1/8" version.
When starting a cold engine no oil will pas through the small opening until the oil gets hot and thined out. Another good reason not to use straight #30 oil.

Thank you Gene for your advice, again. I had thought of enlarging the hole and I will do that. I see your point about the oil thickness.

The other possible thing is the front mounting plate to block gasket. Chevrolet made two different gaskets. One covered 1937-1948 and one 1949-1962. Chevrolet used to put both in a gasket set. I believe modern gaskets sets come with just the 1949 gasket. If your set comes with one gasket only place the gasket against the block and the mounting plate and make sure the shape does not restrict the oil flow.
In 1949 the pressured the oil to the passage and changed the shape of he oil reservoir for better flow.

Note we have a reply under engine ID thread.

Yes, I don't know how that happened. I am sure I was in this thread when I posted.

Gene,
I was incorrect about the oil pump mount. It still has the factory rounded bolt heads. I guess I was looking through the wrong part of my bifocals, if you know what I mean!