I need serious experienced help with an engine problem

[Ray Horton]

This engine, with only 4000 miles on it since rebuild, has always overheated and locked up when shut down after overheating, which is usually when driven at 45 or less for 30 minutes or more. (This did not and does not happen when driven under 35 and/or just around town for less than 45 minutes). I thought I had this problem fixed. But apparently not.

Here is the history: On 3/16/14 I installed an engine which had been boiled out, sleeved back to standard, new pistons and rings from Snyder's, new valves, exhaust valve seats, new lifters, and new babbit by Bill Barlow. It was tight, but I figured it would loosen up during breakin, which I did very carefully, as I have done with all my previous engines.

After 2000 miles it was still overheating and locking up on shutdown. I took it apart to check measurements. Ring gap, rod bearings, and piston clearance were just where they should be, according tbirdtbird, Bill Barlow, Tom Godish, and several other commenters on the Barn. But when reassembled it had the same troubles.

At 3500 miles I went through the disassembly again and rechecked the clearances, just to make sure I had done it right before. I had (so I thought). So I put it back together, timed it to a gnat's eyebrow, thinking that might be the issue, drove it with the spark rod exactly where everyone agrees it should be in a stock engine. It still overheated and locked up.

Today I took it apart again, and again checked my piston clearances. I checked with my engine guru, Tom Gosish. He informed me I had been checking the piston clearance incorrectly. I had done it front and back. I was getting .004 that way. But side to side, the correct way, today I got .012 on all four pistons, except the driver's side #4, which was .016. These all seem excessive, so I don't see how too tight a fit resulting in expansion could be the situation causing the lockup.

Other notes: all spark plugs (Champion 3X) have perfect tan coloring.
There is very slight partial accumulation of carbon on the tops of 2 & 3.
This engine has always had a knock on deceleration, but after this last overheating, it is present in both acceleration and deceleration, but not a cruise speed. It's not like a rod knock; more like a loose wrist pin.
The cylinder walls show no signs of scoring or damage from the pistons. They are clean and shiny, though the crosshatching is gone.
It is not burning oil; the rings seem to have seated properly, though there is some minor blowby when under heavy load, like going up a steep hill.
There were no metal flakes or pieces or other metal indications present in the oil when drained.
I noticed today, which I hadn't noticed before, that I have a '28 head with no center hole in the middle between 2 & 3 for water circulation. This might affect the overheating issue, but to the point of causing it to lock up when shut off seems unlikely.

Tomorrow I am pulling the pistons and having the rods checked for trueness and balance. That is the only thing I have not done, even from the beginning, because Bill Barlow provided those rods and assures me they were trued and balanced, and he is a reputable engine rebuilder.

So, if anything occurs to any of you much more experienced engine guys that might be the cause of this, I am ready to try anything. I have run out of my shade tree ideas. I flat don't know what else to do, and neither do any of my local engine guys.

Thanks for indulging my long post.

[DaWizard]

I would ask a couple of questions.

First, what carburetor are you running?
Second, where is the GAV set at? I have found mine wanted to warm up with the GAV set at ¼ turn, AND at ½ turn, but at ¾ turn runs cooler.

As for a possible fix, have you taken it apart at the time of seizure and determined exactly what parts are seizing up?

If it were my engine, knowing what I know now, I would install a Nu-Rex centrifugal advance and remove the need for self timing advancement. (Just my working opinion) This could be a possible overheating problem cause.

Since you have enough clearance in the pistons, and if you checked the rods and mains and had .0015 there, the only other thing that could cause friction enough to seize the engine is the cam. You might be able to determine what is seizing the engine on an engine stand, but I really think you should pull the engine right after the seizure and find out which part is causing it. You could also be off a tooth on the cam timing. I bet you are running aluminum timing gears. Are you running a stock cam?

[Ray Horton]

Checked my cam gear. It's right where it should be.

[Beauford]

Sounds like the combination of heat expanding something to shut it down. If you have a thermostat, take it out and see what it does.

[Mitch]

Ray
First off i admire your perseverance working through this very strange issue. I remember your postings about this from a previous thread or two but i didn't think it was that long ago being 2014, boy how time fly's. You say that the engine locks up so i am assuming you cannot turn it with the hand crank after it overheats and shuts down. Being you had this engine apart so many times and have not found zilch which i would have thought some sort of cancer would have surfaced, what about something not internal to the engine at all. Thinking outside the box a little could it be an accessory issue? Something that as it heats up is putting a drag on the motor causing it to work harder and overheat, then get tight expands until it cools off. When the engine is locked have you tried removing the fan belt and spinning everything? What about a starter bolt or something on that order expanding hot against the fly wheel. I'm just throwing this dumb shit out there as you have had your back against the wall for a long time. Another thing that throws a wrench it this theory is the noise you have on accell and decell that you think might be a pin. My thinking is after overheating it this many times and having this baby lock up that you would have saw some sort of visual indicator inside on tear-down. Please keep us posted on this mystery

[DaWizard]

Ya know Mitch, that long starter bolt against the flywheel could give both the noise AND the lockup, but I doubt it would rub enough to make the motor overheat. *taps chin thinking*

[Mitch]

Yo Wiz i hear ya, i just through that out there as an example more or less.. Maybe there is something else other than the engine itself creating this issue. I would think that if the motor locked up internally all these times that something would have been found on the exploratory surgery especially after all these overheats to boot etc. Maybe there are two issues a cooling problem as Vince mentioned and then something else. At this point i think Ray is open to hearing anything at all that may give even the slightest clue to resolving this.

[Tom Wesenberg]

With that much piston clearance the engine should rattle from piston slap. I'd use a temp gun to shoot cylinder temps front to rear on the left side. Also shoot the radiator in several places.

Have you tried to hand crank the engine when you say it locks up?
I'm just wondering if it could be a battery or starter issue with heat?

Post pictures of the piston skirts when you get them out. I'm surprised the crosshatching is gone already.

[pAAt]

Sounds like a two stroke when you don't add oil to the gas. Try adding 2 stroke oil to your gas one time, it will smoke some, but won't hurt anything. See if anything changes, it could be an oiling problem ?

[tbirdtbird]

Ray check your PMs
dave

[mshmodela]

I cannot add any help but hope your car's issue is once and for all resolved...

[Rowdy]

Ray, I assume you have ruled out a sticking bendix. Had one bendix fail that overheated the engine, then starter locked up. After it sat a while the bendix snapped back, things cooled and all worked good, including the starter. This repeated several times until I caught the problem. Rod

[tbirdtbird]

the scuffing is not always noticeable on the cyl walls. The pistons scuff up waay faster/easier than the walls, since the aluminum is so soft.and of course you can't see the pistons until they are out

[Ray Horton]

There is scuffing on all the pistons on the driver's side. See pix. No noticeable scratches, and nothing on the cylinder walls.

[George Miller]

If the clearance you say you have is right. it is not the pistons. Are you sure the engines is locking up, or is the starter just not turning the engine. Some times starters lock up from heat. It normally is not a problem on a motel A, but it might be. If it locked up that many times it should have left some kind of marks on the cylinder walls. After all this time I would think the bearings would be ok. I think you need to look further. What are you using for a thrust bearing, could it be to tight, or not getting enough oil. How about your dist drive could it be to tight. You need to start fresh and check every thing on the engine, do not assume anything.
Like Tom said check it with a heat gun.

[DaWizard]

Hey Ray, After doing a bit more thinking about this, I would suggest before removing the engine again, find yourself a FLIR and take it out for a drive that you think will make it seize, at this point no more harm can come of the drive, and as soon as you park it, look at it with the FLIR (forward looking infrared) and see where the "hot spot" is, because to make it seize, you almost have to have a hot spot or three.

[Ray Horton]

First, thank you for all the suggestions. Let me respond as I am able by post number.

#2: DaWiz: I run this car with GAV at 1/2 to start, 1/4 at warmup. It runs smoothest at 1/4. It is too hot to even consider disassembly when it seizes up. I am running all stock, including a fiber cam gear and a stock cam. I “may” have installed the timing gear one tooth off, but that would be a newby mistake, and I don’t think I would have done it. But I am going to check that this afternoon anyway.

#4: Mitch: I don’t have any accessories that would affect the way the engine runs. It’s all stock. I have had the starter checked at it is fine, and I am always extra careful about that long bolt issue on the starter, so I have eliminated that possibility.

#5: Tom W: Yes, I would expect that I would have had piston slap and rattle also, but I am not hearing that. I have done the laser temp check several times. During lockup the temps are elevated, particularly on 3 and 4, as we would expect. I don’t remember what the temps were last time I checked these, but I think they were in the 400 degree plus range on the driver’s side. The radiator was rodded out by the last radiator guy in Portland who knew how to do this. This was done back in 2013 when the engine was first rebuilt. The water runs clean at all times, no oil or grease indications. I have tried to hand crank it when it locks up, to the extent of even standing on the crank to get it to move. It absolutely will not move until it cools off. The battery is brand new, and the starter was checked out and deemed good at rebuild. I am surprised at the crosshatch issue too. The sleeving, honing, and fitting pistons was done by Portland Engine Rebuilders. They are one of the most highly regarded shops in the area; they primarily rebuild racing engines for professional and amateur competition, but have done many Model A engines, employing insert bearings. Their service report states that the pistons were fitted with .004 clearance.

#9: Rowdy: Nice to hear from you again. I am ready to consider anything, but the behavior of the starter when it is cold would indicate it is functioning correctly.

#10: *****: I think you’re actually one year ahead of me on Model Aing. I’ve only owned my first A for 56 years. I have considered giving up on this block, as you suggest. But I want to think this is something I am overlooking and can be resolved. I am measuring the piston clearance with the bottom of the piston even at bottom of the cylinder; I am using a standard flat feeler gauge to measure and measuring at the bottom of the piston. I am considering getting some kind of laser digital gauge to measure the cylinders, and a large micrometer to measure the pistons. My distributor has virtually no backlash; I set my points at .018. I use a small light on alligator clips to determine exactly when the points open when timing, and otherwise follow the Ford spec procedure. The spark lever can be confusing. I run mine at different positions depending on the car, and the position is determined by what sounds best and runs smoothest under any given driving conditions (steep hill, flat long distance above 40, around town puttering). Back when I got my first Model A (1961), my dad said start it with the lever all the way up, run it with the lever all the way down. I ruined the rear mains on a couple good engines running it all the way down all the time. Now I pay careful attention to the sound and the road conditions

#11: tbirdtbird: see photos.

#13: George M: At this point, I am not sure of anything, though the starter does get pretty hot in this situation. But I would expect the engine to still be able to be turned by had if the problem was the starter. I am not seeing any marks on the cylinder wall, and I can’t take a good picture of them. I can describe them as being shiny down to the oil ring, and not so shiny below that. They are smooth, with no scoring that can be felt by fingernail, and really no other marks indication potential scoring. The bearings all look good (see photos). The thrust bearing was cast and set, along with the crank and mains, by Bill Barlow. There’s no excessive endplay; I think I’m safe in assuming he set it up correctly. The distributor drive is a good point; I did replace it when the engine was rebuilt, but I did not replace the cam, as it looked to be in good shape. I’ll pull the drive and see what that indicates. I may pull the cam as well.

Vince Foster::Ford Garage: I was going to respond to your post, but is has been removed, and can't remember your comment. If you would care to email me or send a PM. I'd like to hear what you have to say.

I hope Mitch doesn’t have some kind of limit on post length!

[Mitch]

From reading this new information i have lost some trust in the cooling ability of your radiator.
I would seriously consider looking into a new one

[Greynomad]

Would a quick temperature reading with an infra red gun be helpful in deciding whether the cooling system was working well enough? It has been suggested above that some readings be taken while it is locked. Sounds like that could yield something useful. Maybe check top and bottom tanks at the same time.

[DaWizard]

Ray, while you have the head off, take a gun cleaning wire bore brush along with a magnet and run it around and between the 3rd and 4th cylinders and behind the 4th. It is very possible that you are not getting enough coolant flow around those two jugs. Also, somewhere I saw a photo of the water inlet having a web built in that could be seen by looking into the water inlet that, in my estimation, would limit the amount of water delivered to the rear of the block. Check and see IF your block has that web, and if it were me, I would try to remove as much of that web as possible since you are obviously getting poor circulation back there.

[tbirdtbird]

the web was put in later to try to direct some more water back to 3 & 4. Did not do much, tho.....I would vote against removing it

[Ray Horton]

The engine is a '29, I didn't see any web or crud or rust in the block, but I didn't expect to, because the block had been hot tanked at rebuild.

[tbirdtbird]

yep, cyls 3 &4 still run 20° hotter than 1 & 2 on any A motor I have ever worked on which is quite a few, web or not. I would still not remove it

[tbirdtbird]

Ray, sent you a PM
I have a laundry list of stuff to discuss with you but by landline, too much to type

[Ray Horton]

Thanks Dave. I'll call tomorrow.

[Tom Wesenberg]

I also would not remove the web in the inlet that directs coolant towards the rear of the block. The Service Bulletins mention when the web was trimmed back a little bit, but I don't recall the date of the change. Anyway, I'd leave that alone. Have the rod and main bearings been checked for clearance. One of the rods looked like the babbit had something in it, but a closer picture would help.

If you measured 400*, then all the coolant should have been turned to steam.
I could see 400* on the exhaust manifold, but not on the left side of the block.

[Ray Horton]

Tom, I just accidentally flagged your post when I meant to click on comment. Please ignore that flag. What my message said was, I may be remembering the manifold temp. I took that reading that day too. The coolant was down about a gallon after the overheat.

[1931 Flamingo]

400* ::: Wow !
Paul in CT

[DaWizard]

Hey, you guys looking for " ° " to make it 400° ?

Hold down the Left ALT button, and with the Num Lock locked, type 0176 then let up off the ALT button. Simply magic

[Ray Horton]

Yeah! I thought so too! But I may have remembered that wrong...

[George Miller]

Number 3 is rubbing bad. If you have -004 clearance the cylinders are running to hot. Number 4 is to tight also. Plus the block from here looks like it is running hot. Maybe you could put a temperature gauge on it to check the running temp. But the problem does look like the pistons are expanding to much, and rubbing hard. You may have to hone the cylinders more.

[Ray Horton]

George, the .004 measurement was taken front and back; the side measurements are all .012 except #4 which is .016 on the DS, as noted in my OP. Why would scuffing occur on this side?

[Tom Wesenberg]

Hey, you guys looking for " ° " to make it 400° ?

Hold down the Left ALT button, and with the Num Lock locked, type 0176 then let up off the ALT button. Simply magic

That's why you are the "wizard", but how do computer dummies like me know about these tricks?

There must be some instructions somewhere for all the magic buttons to push.

[DaWizard]

There is Tom, it's called the "Character Map". Now, to find that you click Start--Accessories--System Tools--Character Map. Now, once you have that opened, if you click on the character you want to use, in the lower right corner it will give you the keystroke for that character. Give it a shot, what ya got to loose?

[Tom Wesenberg]

There is scuffing on all the pistons on the driver's side. See pix. No noticeable scratches, and nothing on the cylinder walls.

You mention reply numbers, but no numbers show up on my screen. Anyway, in the last picture (number 5) are you showing the cam side of the pistons, or the driver's side?

The combustion pressure should make the cam side show more wear and scuffing.
Some pistons have more contact area on the thrust side, but your's look even on both sides of the pistons.

[Ray Horton]

Tom, the number references should appear in the text of my response with the pictures on page one. The scuff marks in picture 5 are on the driver's side on all four pistons.

[tbirdtbird]

you cannot properly measure piston-wall clearance with the engine assembled.
The top of the piston from the rings up is a smaller diameter than below the rings. Below the rings is where the numbers need to come from.
The pistons are cam ground and the widest diameter is 90° to the pin. That is the number you want to determine piston-wall clearance
The pistons have to be out of the motor, and measured with a 4" micrometer. The bore needs to be measured with a dial bore gauge. [my avatar]. Other attempts at measuring will yield inaccurate results. Inside micrometers are available but not as accurate. You also have to know how to properly use micrometers.
The clearance is crucial.

There is also a mountain of offshore pistons out there which are shared by many of the vendors. The quality is just not there. I would only use SilvoLite pistons.

In accordance with my engine building thread here in the very beginning, in this shop we clearance #1 and 2 at .0035. # 3 we set at .004. # 4 we set at .0045. These numbers seem to give a lot of people heartburn, and many cry PISTON SLAP. Not so. It is extremely important to remember that an engine is a living thing, and when it is at operating temp, those clearances are way tighter, because the aluminum expands more than the bore. For what it is worth, some other builders on here that I have a lot of respect for, such as George Miller, agree with my numbers. Too many do not appreciate that an engine is NOT a static pile of parts. Many relationships change when at operating temp

Those using tighter clearances, proceed at your own risk.

[Tom Wesenberg]

I too was wondering about the ring gaps, but with the numbers you posted, they should be plenty good. If you use a thermostat, be sure it's as close to the head as possible and has at least two 1/8" holes drilled in it, so the hot coolant can flow past the wax pellet to open the stat.

Now I'm wondering about your timing. With a stock 4.2 head I never go past about 2/3rds. down. A higher compression head should take a bit less advance. Too late or too much advance will overheat an engine.

[tbirdtbird]

Use these machinist tools if you want to properly measure piston-wall clearance

Dial bore gauge:
https://goodson.com/products/bore-ga...nt=33471454470
4" outside micrometer:
https://www.amazon.com/dp/B01548KD5O/ref=biss_dp_t_asn

the bore gauge is supplied by Goodson, which supplies the entire machine shop industry
The use of feeler gauges, inside micrometers, etc is very inadequate.
The bore gauge is what a pro machine shop uses.You can determine ID at any point, determine if there is any taper to the bore, determine trueness of the bore meaning lack or presence of ovality, etc. They are quick and very accurate

If you use other methods, proceed at your own risk

[BILL WILLIAMSON]

DON'T forget the ROOFING NAIL thingy----Loss of water from "splash" over, "might" be a player in this problem????
Bill W.

[DaWizard]

Hey Bill, I have found that a drywall screw also works well with those over flow pipes.

[mshmodela]

Ray, given you have more years Model A'ing than my nearly 54 years breathing, you surely would have discovered non-engine rebuilding issues that might cause your issue. I would assume your engine was not properly rebuilt sadly. I hope your engine rebuilder considers the your torment and the fact their work has never properly performed.

Best wishes,

Mike