VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 1932 engine overhaul

My 1932 did run pretty ok, but began to loose water at each trip, so I did some testing including compression test, which showed lower values on cylinder 4 & 5.
I then did a leakdown test, and could see bubbles in radiator when testing cylinder 4 & 5.
I decided to overhaul engine, so I removed engine from the car.
I removed the head, and could see there were blow through from cylinder 4 & 5 to waterchannel, and also beginning around cylinder 2 & 3.
Head is now at engine shop and will have a crack repaired, machined flat including manifold surfaces, and exhaust seats will be machined or replaced.

I now want to check my main and rod bearings.
When I look through old threads and in manuals, I can see that best way to check bearings are by removing shims until engine is binding, and then reinstall shims.
I only have shims in 1 rod, what is then the best way to check bearings?
For the mains I plan to use Plastigage to get an indication of clearance, is this the best way, or can I for the test put a shim behind the bearing shell?
Rods can be slightly moved sideways by hand, but can`t feel any slap when I lift in the rods, any good ways to check clearance?

I didn`t have any knocking sounds when driving, so think bearings are ok, but at the very end of their lifetime.
For now I hope just to do an overhaul and get the last miles out of it, and then do an rebuild in some years.

you can check the rod clearance with plastigage. .001" would be OK. Years ago when no shims emained we filed the rod cap clearance. If babbitt lookk OK that is wh I would do.
To check the mains with Plastigage turn block up side down and remove cap. would suggest .002" on mains.

Hi Morten

Gene gives very good advice.
I filed the caps on my 1929 Chev many years ago.

Take care doing it though.
Use the widest, sharpest and best file you can find.
Hold the cap in a vise and file across both mating surfaces of the cap at the same time.
File a bit from one direction, the turn around and file from the other direction to make sure you don't file the surface off square.
And don't file too much before trying your clearance again.

You will want new shims so you have something to add when you get to the point where the bearing begins to bind.
They can be found here for example:
https://store.fillingstation.com/detail/FS-88/Chevrolet_192953_CONNECTING_ROD_SHIMSSET_OF_12.html

As for rod clearance, Gene is right again.
You can also file until you can't move the rod back and forth on the journal, then add 1 shim on 1 side, then an additional 1 on the other side (alternating side to side) until you can move it.
The shims are .002", so you will end up with .001" clearance either way.
Even if the rod seems slightly "sticky" on the journal... as long as you can "snap" it back and forth by hand... you have enough clearance.

Good luck!

Also if tou file too much from the rod cap you can insert the required amount of shims - which you can purchase from the Filling Station.

If the mains require shims , shim material can be inserted under the insert - in the cap. The center main babbitt could be poundud out, check the lower half as it takes all the pounding.
Reove the engine mounting plate as the passage for timing gear oil is usually plugged up.
Make sure the oil return passage in the rear main cap is free of sludge.
Do have new wrist pins fitted as they are always loose in the pistopn and make noise at idle.

Thanks both for your advice, I`ll do some checking and filing, and come back with the result.

Are there any way to check this?
Pistons were replaced at some point, as they are not original, so don`t know how many miles they have been running, but doesn`t feel worn out.

If the pistons are aluminum they should be OK. If cast iron it is difficult to determine. When new they were often loose by 25,000 miles.While loose pins do not hurt anything it makes the engine sound crappy at idle.

Engine shop called me with bad news.
There are 2 or 3 minor cracks, see picture.
While waiting for me to come by, they tried to mount a new exhaust valve seat, but as they cut, they went trough to waterchannel, and cut in picture is not even deep enough for the new seat ring.
Should they have used a smaller valve seat ring, or is this just what happen when head is corroded from inside?

I had a second 32 head I hoped was in better condition, but in presure test, it leaked between sparkplug holes, they tried to fix it, but the material is so corroded from inside, so the can`t get it clean enough for a clean weld.

A good friend of our family used to run a cast iron repair shop in Saskatoon (sadly he's gone now).
He would have fusion welded your first head.
He would make a carbon core to put into the port, heat the whole head red hot in an insulated oven, and weld the area full with a cast iron rod.
The head was then fully covered while still in the oven and left to cool very slowly.
When he was done machining, there was a brand new port of the same material as the rest of the head.
He of course planed the head, and unless otherwise requested, he installed all new guides before doing a complete valve job to finish.

Kansje du kan finne noen slik i Danmark? (Not Danish, but I'm sure you understand.)
Surely there is a shop that can do it somewhere, but the cost may be pretty high.

Most repairs to cylinder heads that i am aware off are done by pinning. I sent a head with four cracks to a member and it was repaired that way. You might want to check with another shop to see if they give the same advise. I don't think welding is a good option . Lots of info on this site: https://southeastcylinderhead.com/cylinder-head-services/

Pinning can't be done through a valve seat.
The head pictured must be welded.

Probably will need to be welded now that it has been cut. I think possibly it could have been pinned previously. The shop I use said they do use stitch pinning even in valve seat area but depends on the amount of metal in the area and no two jobs are the same. Their site also has some good info on head repair much better presented than i could do. https://www.rlengines.com Click on services and select Cylinder Head Crack Repair

You can pin in the valve seat area.
But... you can't pin THROUGH the valve seat itself and into the port where the original crack was.

general question, do they put valve seats in the 1929-32 ? though they were machined in the cast stock, and not recommended to machine and put in seats ?

when i was having overheating problems, this was a concern, a cracked head, but lucked out with a warped head .008" out. machined .010" off the deck and then had it completely rebuild with new valve guides, cleaned up valves, valve seats, and then pressure tested and all that jazz. also had the manifold face machined flat :)

MY 32 head had all new seats installed and luckily it had zero cracks. Should have said my SECOND head as the first one had many cracks.

I`m no expert on this, but I beleive my original head (pictured) would need welding.
My second head (crack between sparkplug holes) could maybe have been pinned, but I didn`t see the crack before they tried welding it.
I`ve found a lot of info on pinning on the Internet, but not sure if it`s common in Denmark, can`t find any information from Denmark, but will ask engine shop at next visit.

The reason for cutting out for valve seat rings is, that the head had already been cut a least one time before, so some seats were already cut low in the head.

Good news is that I have found a third head, and seller will pressure test it, and do the machining before we do the deal.

You may not think yourself to be an expert, but you are obviously very knowledgeable on the subject!

If the machining on the 3rd head includes installing new seats (it sounds like that is the case)...
The new seats should be installed slightly below the edge of the surrounding surface if possible, and that edge should be slightly peened over in a few places.
Some shops don't do this, but good shops will, as it ensures that the seat won't work loose and drop out in the future.

Lykke til!

This 3`rd head I buy from a guy who have had Chevrolet for >50 years, so I have full confidence to his judgement of need work.

Tak

My rod journals on the crank have no marks or defects in the surface, but there is a slight indication of what more looks like dirt after engine has been standing still in same position for a long time, although I have driven the car some miles the last 3 years.
Is it a good idea to polish the journals with 800 grit sand paper, or will it be the same as adding extra "wear"?

Hei Morten

I wouldn't use a grit that course.
The surface left by an 800 grit would be a little hard on soft babbit.
I use a very fine paper used for polishing called "crocus cloth".
The grit on that is around 2000 I believe.
Examples can be found here:
https://www.mcmaster.com/crocus-cloth/

Use crocus cloth, sand paper is too rough.
If you send it out to rebuilder they use a leather belt and it looks as if it is chrome plated....

Thanks, crocus cloth was also was I meant, just didn`t know the correct word.

See if I can source something around 2000 grit here locally.

The crocuses will not be up til Spring.

I got some 0,002 brass that I will test under the insert, but what is the most gentle way to remove the insert without damaging it?

In Deans great thread "Resurrecting a 28 4 banger" he only put the shim in the middelpart of the cap, it`s of course this part taking the most beating, but is this small shim enough or should I make it longer, so it goes higher up on the sides?

Make shims the full width of the insert and make two, one about an 1 1/2" wide and one 2". Bolt it up with two and see if the crank shaft turns with no resistance. If it takes a lot of effort to turn remove the short shim.
To remove the insert carefully tap the bearing flange in the side of the cap (in the center).

I should add the insert is positioned by a raised head on the insert so it must come straight up from the cap.