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.

Finally got my "new" head a few weeks ago.
It looks good, and has been pressure tested with success.

I got it with valves installed, and some could easily be removed, other needed a few days with WD40 and light knock with hammer.
But I have 4 valves I can`t get to loosen up, I have on daily basis sprayed with WD40 and other light oil for 2-3 weeks, but they are still completely stuck.
What is the best way to get these valves out?

As it`s been almost impossible to find a good head, I don`t want to risk damaging it.

I have had good luck separating rusted knee shock absorber pistons and other parts using "PB Blaster" and a little heat and tapping gently with a hammer and a light touch. I would be careful not to overheat the part. Repeat the process, it may take a few times. Be patient and it might loosen up for you. Good luck

If the valves are rusted to the guides you may need to press out the guides and install new guides and valves. In fact it looks like all the guides will need to be replaced and possibly the valves also due to rust to prevent future problems.

agree with Gene, when i had my head done a local shop replaced all the guides, and replaced a few valves. the guides were cheap !! and well worth it. i had them tear it down magnaflux it, they did a complete rebuild and machined all mating surfaces, re seated al the valves, and then put it all back together like new. then pressure testes and validated all valves worked and were set the same the total cost was cheap and well worth it.

I`ll replace all valves and guides, so not trying to save them.

Guides would normally be pressed out from the underside, because wide end is in top, and here guides small end can`t be put under pressure from the underside, because of the valve head.
Do you cut the wide end of the guide just above collar/washer, and press it the "wrong" way out?

I know I could leave all this to machineshop, but I better understand and remember things by doing them myself.

once you remove the valves the valve guides can be easily pressed out from underneath. clean clear shot :) tool & press

Few shots of spare head sitting on my shelf.

Yes, valve guides are easy to press out from underneath once valve is removed.
My problem I can`t get the last 4 valves free, even after 3 weeks of daily oiling with WD40 and other light oilproducts.

I`ll replace valves and guides, so it`s just a matter of not damaging my hard to find 1932 head, so don`t want to use to high pressure or hard tapping with hammer.

Have you tried rotating the valves to help free them up?

if you are going to replace valves and guides anyways, cut the stem off at the guide and drill it out, then press out the guide. other option is use an annular cutter and remove the valve head and then punch stem through with the guide.

worst case, have a local shop knock em out.

Hi Morten

Why not just put the head in a press, valve stem side up (as it is on the engine),
support the bottom side of the head as close to the valve you are working on as possible,
then press directly on the end of the valve stem?

Make sure you have completely cleaned the exposed part of the valve stem with emery cloth.

You should be able to press with as much force as would be needed to press the guide out of the head, without hurting anything.
That's a lot of force, but it is after all the same force that any shop will use if and when they actually replace the guides.
And that force will be taken on the guide (just as it will when removing the guide) until the valve breaks loose.

If the valve still doesn't want to move,
maintain as much press force as you dare on the end of the valve,
then use a large torch to rapidly heat the exposed part of the guide and the valve should pop loose.

Once the valve is broken loose,
make sure there is no "mushrooming" on the end of the valve stem from pressing or hammering.
If there is,
grind it off before trying to complete the removal of the valve so it won't stick in the guide on the way through.

Hope this helps!

PS
If your valve heads are recessed below the bottom face of the head as I think they are,
you can support the full face of the head until the valve breaks loose.
That should help insure that no damage is done to the head during the process.

I should add that constant force, even if it is a LOT of force, will be much safer for your head than sharp hammer blows.
Also, if you are really lucky, you may not destroy the guide in the process, and actually be able to clean it up and use it as is.

Thanks for all your inputs, I tried a little of everything.

First tried to rotate the valves, it was impossible.
Then I cut the wide end of one guides, tried to press out the valve in my 20 ton press, didn`t move.
I drilled out the valve stem about half way trough guide length.
As I don`t have a stand, I had to do it in free hand, so was not sure enough of angel to drill all way through so stopped halfway.
Still couldn`t press valve out.
Turned head around, and grinded the head off the valve, pressed on the remaining stem, still no succes.
Turned head back to normal position, drilled hole a bit wider, and finnally I could press the short stem part out, but only because it at the same time broke a bit of the guide of.
On the next 3 valves I cut the stem, so it was only slightly over the guide, and they all gave up a lot easier in the press.

So I just started with the hardest valve to get out, if I had started with one of the other, I might not have been so concerned about damaging the head.

that is all good news....

so it is completely torn down ? minus the valve guides. regardless i would have all new valve guides put in especially if you are doing new valves !!
also if you plan to reuse springs have them tested to make sure they are all good

2 of the guides cracked and went into several parts when I removed valves, so them seem fragile, and will all be replaced.
I expect all guides to come out pretty easy, but will see in the next few days.

Didn`t you make a thread some time ago, about spring load and length?

After 3 months at the machine shop I could finally pick up my machined head (+ rebored block, new pistons and other extra parts), so I was very happy, until I unpacked all the machined parts.

The head has got a lot of work done, including new seats at all exhaust valves.
At least 3 of the new seats have caused cracks in chambers, see pictures.

I didn`t notice it at the shop, so haven`t talked with them yet, but when I picked up the parts, they claimed head was pressure tested.
I`m not sure at which state this pressure test was done, but is it possible to have these cracks without getting lots of bubbles at pressure test?
All cracks run from exhaust seats and down towards the chamber in front of sparkplug.

This is my 3 cracked 1932 head, so I`m not very happy right now, and it doesn`t help that this one head has already cost me more than 1500$, and as most of you know it`s so hard to find 1932 heads.

are the cracks surface cracks ? or cracked through ?

my head was pressure tested was when it was completed

I would call them/go up there and just ask them about the cracks, and express your concerns. see what they have to say before jumping

what did they do for $1500

I beleive also it was tested after they finished the work, but have to ask.

Cracks might be in surface now, but hard to tell what will happen when engine is all put together, so not to happy about using it, even if it`s tight now.

see if they have a warranty/guarantee ??

tell them your concerns, my shop that did mine said if any issues bring it back no questions. so far no issues on mine. they guarantee their work

Had the same problem with my '32 head. "hairline" cracks around valve seats. Engine was completely rebuilt and water drained to oil pan just sitting. Fortunately the shop stood behind their work. Found a local gentleman with a ton of old Chevy parts and he had a new unused head (really) which is on the car now and it runs perfect. The cracks on yours appear bigger than what I had and mine leaked.

I first called the shop and talked with them, and they claimed the cracks were no problem, as the material in that area is over 1 inch thick, and they had done a pressure test without leaks.
I couldn`t beleive there should be so thick walls, so I took a 1929 head which was already scrapped and cut it in 2.
In picture you can see the cracked area marked red, and the black/white is the part you can`t see, but must expect to have cracks as well.

I then took my 1932 head and the cut head to the shop, and they accepted to do a new pressure test while I was still there, and it showed that all 3 cracks are all the way through the material, so can`t be used as it is now.
Shop will check if it can be fixed in any way, but i`m not to possitive, as they might succed to repair cracks for now, but what will happen when head is exposed to pressure and heat when in use.

There are a few methods to repair a cracked cylinder head. Do a goggle search for the info. I would advise to have it done by a shop that is experienced in doing so and it appears that the shop you have now is not competent for the repair. It really needs to be done by an experienced shop and not all heads can be repaired. The process I am most familiar with is pinning or some call it stitching. If done properly and on a repairable head it should give work as good as any rebuilt head.

also note they must be knowledgable and experienced in dealing with cast iron !!

This is also what they are looking at, but problem is to find some with the knowledge, and i`m concerned about the area i`ve marked with black/white, as you can`t access it for stitching.

From the pictures of the cut cylinder head there doesn't seem to be much "Meat" to cut away for the new valve seat install before hitting the water jacket. I would think one would have to be careful when installing a new seat, was told of this by several automotive machinists in years past.

Correct, that was exactly what happend to the original head.

Next problem (not the last) with the parts I received back is piston deck height/clearance.
As you can see in pictures piston is slightly over block surface, measurement is in mm.

What is minimum deck height/clearance?
Can I get that by machining pistons lower, or is that a nogo?

If it we mine I would leave the pistos as -is, The head gasket will take care of that problem.

I agree with Gene.
The head gasket is thick enough to provide the clearance you need.

Thanks, that`s good news.
I was aware that gasket would give clearance, but thought I would risk some kind of performance issues, because of change in compression ratio.

The higher compression would be a plus.

Boring out the cylinder walls also will raise the compression ratio.

Agreed.
Valve and seat grinding (without installing new seats) will set the valves a little lower in the head and reduce the compression ratio slightly.
So, you are probably actually just gaining back what was lost.

You'll be fine. :-)

Block is newly bored for +.060 pistons, and if above head with cracks can`t be saved, next head will only get seats grinded, and not replaced.

That would be the course of action I would choose as well.

In fact, I DID choose to do the same thing.

The shop I took my head to tried to talk me into installing hardened seats. I refused, and I'm glad I did.

The hard seats are unnecessary and grinding the seats into the head can weaken the area and encourage cracking.
Valve spring shims (under the springs) should be used to make up forrthe increse of the deeper valve seats.

I agree that installing hardened seats can create more problems than it solves. One thing that I have learned from this forum is that we are not building 50,000+ mile vehicles. I doubt if valve seat recession due to the lack of lead in the gas will ever be an issue for you.

Gene's suggestion to install shims under the valve springs is a good one. You also might want to have the shop grind a small amount of material off the tip if the valve stem. Then is will be at the original height where it contacts the rocker arm.

Now might be a good time to have the rocker arms faced if there are grooves worn in the tip.

Regular grade of gas did not have lead in the 1930s1940s and 1950s.
Lead wAS ADDED TO PREMIUM GRade at that time to raise the octane
which makes the gas burn slower and prevent pre-ignition knocking.

I`m now in the process of adjusting the connecting rod bearings.
Engine shop made my used crank and bearings fit, and checked the were not out of round.
I felt a few were a tad to loose, as I could move bearing sideways by hand.
I have then adjusted the bearings with some 0,002 shims instaed of their thicker shims.
I feel they are now adjusted correctly according to manual, but when all 6 is adjusted this close, I can`t turn engine by hand, but if I use a short wrench on harmonic balancer I can turn it pretty easily.

I have only crank, connecting rods, pistons mounted, so no lifters or head (compression).
Cylinders are also rebored, so new pistons.
What is best to an overhault engine, a little loose connecting rods, or an engine that is a bit hard to turn?

The new pistons and rings on honed cylinders present more resistance than when the engine is broken in. It should be a bit hard to turn. Will get harder when the valve train is installed. Once the pistons smooth out the walls and seat the rings it will get easier to turn.

If you can lightly tap the rods side to side they are good. Pushing by hand is too loose prior to break-in.

I wonder if you have the main bearings a little tight. I would loosen the main bearing caps slightly and try to turn the engine. Then start tightening one at a time and try to turn the crank each time.

Chipper is correct that the method to check rod clearances is a light tap side to side.

I agree on the rods, they will loosen with a little running.
With the mains the crank shaft should turn freely with the rods disconnected as the mains take forever to loosen with just running. Thats where you get the turning over difficult when hot problem.

The main bearings are adjusted correctly, it`s when I adjust the connecting rods it gets a little harder to turn for each bearing I adjust.

You have confirmed what I expected (hoped), but I got a little worried when I thought about the parts not yet installed, that will also make it a little harder to turn.
When I turn it with the wrench, it feels correct and even all way around, so I`ll continue the assamble.

Sounds exactly right to me!

I agree. Having rebuilt several early 6 cyl engines they are very difficult to get to turn over by hand or hand crank. The starters will often turn them over fast enough to fire even on 6 volts. Occasionally I have used a 12 volt battery on initial starts. After a few starts they loosen enough to start fairly readily.

I once had Dad step on the starter while I helped out with the crank. :-)
It Worked!

I had to resort to pulling one with another vehicle. Put in high gear was enough to get the engine rotating. After less than 1/4 mile it was running at a high idle speed. Think getting enough gas to carburetor was part of the delay in it running.

lol i just went through this scenario less than a year ago, pretty much same discussion as this on here.
ended up using my riding mower 12v in parallel with my 6v optima to get it to spin enough to start. after a few start cycles it would spin up on its own with just the 6v and the more i run it and drive it the better it gets :)

Thanks all, I can see I`m in good position to just carry on.

It takes a while before I can do the first startup, but I have planned to prime entire oilsystem by rotating oilpump with my electric drill until I have a nice flow.
But regarding the binding at first startup, which option is the best?

1. Assemble complete engine, start it up and let it loosen up by running. This will give best oilflow, but hard to turnover until it starts.

2. Assemble complete engine, remove spark plugs (to reduse compression), turnover engine with starter, until starter gets hot, and repeat process. Reduced oilflow so engine might get hot and poorly oiled.

I would spin it over with the stsrter with the plugs removed for about 30 seconds and then install the plugs and get it running AT A FAST IDLE.... DO NOT idle at a low speed. You want a higher speed yo get the oil sllnging around.
f it turns over too slow you can jump it with a 12 volt battery or booster for a short time.

Do not use the starter method (method #2)

First, it won't significantly loosen up your new engine.

Second, if you do it enough to actually loosen up your engine, you will have worn out your starter.

Third, you won't be throwing ANY oil up on the cylinder walls or the camshaft lobes and lifters.

Also, sliding surfaces require some speed to actually float on a film of lubricating oil.
(Think about even water being thick enough to lubricate your slipping foot in the shower... once it gets moving.)

PS
Obviously I agree fully with Gene.
I was still typing when he beat me to it. :-)

PPS
Also, the first fill of oil should be a light oil.
Something like a 0w-20 would be nearly ideal.
And watch your temperature gauge!

The heat riser on manifold was frozen by rust, I`ve now got it loose, but want to lock it in closed position, as I will only use my car in the summer, and I previosly had problems with boiling petrol in carburator.
I don`t have the outside arm, so can`t check position on the arm.

Is position in picture the closed position, where I can lock it, to get the least heat to carburator?

Picture is borrowed from here: Heat riser overhaul kit

I forgot to take picture before taking heat riser apart, but from my logic, the above picture from kit homepage must be wrong.

I beleive open/closed positions in these pictures are correct, can anyone confirm?

As pictured above the "closed" position will do as you prefer.

Thanks, will lock it in this position.

Back on the road again

Engine not in exact correct color, but the best I could get locally, and still some external parts to paint or replace, but it`s running, and running very well, and only a single oil leak to solve.
Also passed the technical test today, so it`s road legal for the next 8 years.

A big THANKS to all who have given tips and advice in this thread, but also for this fantastic forum where I`ve spend endless hours (says the wife) reading old threads