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**tbirdtbird** · 04-30-2017, 07:39 PM

Piston to Wall Clearance! Do not go by the piston manufactures recommended clearances.

Original Thread

Another failed motor from lack of clearance

Thread Link

Many Model A owners will need their engine overhauled at some point. There are great many questions that come up when this occurs. We strongly encourage owners to do careful research, as there seems to be a lot of shops that claim they know engine building, but few that really do. Questions such as, babbitt or inserts, ring gaps, piston-to-cyl wall clearance, piston choices, camshaft choices, proper cleaning of the water jacket, valve clearances (lash), bearing clearances, and such need to be addressed. Word of mouth from the pros on this board will usually steer you right. Several of us have extensive engine building experience and would be happy to entertain questions and suggestions. It is important to note that in many respects, engine building is not something you want to skimp on. Clearly owners are looking for reliability and longevity. We can help you find that. But, of course, you get what you pay for.

We recently knew of a guy who bought a "freshly rebuilt motor" from a third party, "for a good price", and his complaint was, "I can't turn it over with the crank" RUN away, do not buy that motor. It has been built WRONG. Once he got it running, it quickly locked up, having spun the rear main bearing. I have seen line-boring done off-center. I have seen timing gears beat to hell because of improper assembly. I have seen piston-to-wall clearance done very wrong. The list is endless.

Be aware that any engine, and particularly the Model A engine, has peculiarities that MUST be taken into account for a proper build. For example, in most Model As, cylinders 3 and 4 run 10-20° hotter than 1 and 2. Your IR temp gun tells you so. As soon as the water returning from the radiator enters the block via the inlet on the driver's side of the block, between cyls 2 & 3, it is immediately sucked forward by the water pump. Little cooled water is left to circulate around the water jackets of 3 and 4. If this is not taken into account, you can have major problems. Those that are used to building a Chevy or Ford modern small block, for example, will be out in left field on an A motor.

Engine overheats can lead to shrunk (collapsed) pistons, a topic for another time, but we have seen it many times. In the meantime, make sure your newly rebuilt engine is timed properly, and had the water jacket properly cleaned during rebuilding, and get yourself a good radiator.

**George Miller** · 06-03-2017, 09:16 AM

Oil Pump Bushing Replacement

If you ever need to replace the bushings in your oil pump. Do not drive them out, you might break the pump housing.
Take a small hack saw blade and cut the bushing into lengthwise, being careful to not saw into the housing. When done take a pice of thread all and put it through the housing hole.Then put a bushing on the thread all, put a big flat washer and nut on each end. then tighten the nut, make sure the bushing is starting straight. Now do the same with the other bushing. Now try the shaft with a little grease on it ,if just a little sung chuck it in your drill press and spin the shaft. Be carefull it does not grab and hurt you. Most of the time this works for me, if to tight you will have to ream the bushing.

**Mitch** · 06-11-2017, 01:25 PM

A really good article on installing an oil pan gasket:

9611ECB1-2DF5-4608-8D9E-1AA710F470E0.png B355D4D9-6145-4351-89BB-6A2357665258.png B1A4009B-1547-49D7-A0FB-5EDAE7BEB38D.png

**Guest** · 06-17-2017, 03:58 PM

Cylinder Head info and Compression Ratio

The following images are screen shots from Ford Garage showing a variety of cast iron cylinder heads made for Model A and B Fords and their corresponding compression ratios.

Also included is a chart which can be used to approximate the CR of a head based on a measurement of it's combustion chamber volume.

This page covers a variety of heads produced over the years by both Ford and outside suppliers.

See the link on Ford Garage for more info.

http://www.fordgarage.com/pages/headcompressionratio.htm

**Mitch** · 07-05-2017, 12:52 PM

Water inlet baffle casting change prior to June 1929 (Marcos Barnyard)

inlet-1.jpg

**Tom Wesenberg** · 07-19-2017, 09:45 PM

Timing Gears Index Marks

When you install timing gears, be sure they are lined up exactly as in my picture. The cam gear dimple lines up with the right side of the keyway as you face the gears from the front. Some books have mistakenly pictured the dimple lined up on the left side, instead of the correct right side. Don't forget the oil slinger, or the crank pulley may not tighten like it should.

When aligning the the cam and crank gears dot to dot, this is NOT top dead center (TDC). What this does is it times the mechanical's (cam, valves to the pistons, crank) so that when the timing pin is located in the cam gear divot that is TDC. At this point your rotor gets positioned as shown below with the backlash removed.

Timing Gear Marks.jpg

Attached Files

Timing Gear Marks.jpg (77.2 KB, 1820 views)

**BNCHIEF** · 07-26-2017, 04:11 AM

New Engine Break in Procedure

After a engine is rebuilt how long does it take to break it in 100 miles or more vary the rpm up and down drive slower do not over rev the engine, drain oil and refill after 100 miles. Anything to add to this and also do you use an air filter? Thought this might be a good question to ask. Marvel mystery oil in the gas for upper cylinder lubrication. Also non ethanol premium gasoline.

**Mitch** · 08-03-2017, 07:04 AM

Schwalms cutaway engine / trans!

**Tom Wesenberg** · 08-11-2017, 10:02 PM

Oil pan gasket installation and sealing tips

I also like the cork pan gasket, and I like to use a stick-um to hold it to the engine block, then a light coat of grease on the pan lip. This way the gasket stays in place and the pan should easily come off to check bearings. These pictures are from a customer's house and he had white lithium grease on hand. I usually like to use Mystik JT-6 red high temp grease for assembly, but this engine was started within a few days, so the white lithium didn't get a chance to separate or dry out.

I cut a U shape in the front of the side gaskets to fit around the rope seal. Most times I have to trim a little of the rope, but leave enough to compress when the pan is bolted on. I also never soak rope seals, but tuck them into the groove, then form them with a socket, then oil and grease them. Notice I seal the rear main cap and bolts also.

**Mitch** · 09-05-2017, 12:33 PM

Oil pan showing the dipper tray

8CA9807C-C14B-4F9C-9CBC-2A0D574AD1B8L0001.jpg

D7A32CA7-4A75-41AE-9C60-73A5335E658E.jpg

**Mitch** · 09-17-2017, 09:19 PM

'What's are the differences in the Ford A, B and C engines?'

The 1932 V-8 was introduced as the 'Ford Model 18.' The four cylinder model was designated the 'Model B.' Although the V-8 was a national sensation and sold very well, there were many four cylinder Model B's produced. Compression of the Model B engine was 4.8; the A was 4.2. The Model B engine produced 50 hp at 2800 rpm; the A produced 40 hp at 2200 rpm. The Model 'B' mains were 2" diameter; mains in the 'A' were 1-5/8". 'B' rods were 1-7/8"; A rods were 1-1/2". The 'B' camshaft provided an increase in valve timing duration which contributed to the 50 hp at 2800 rpm. A diaphragm type fuel pump was mounted to the lower right side of the engine block. The water pump mounted with three bolts instead of four. The oil pump forced oil directly to the main bearings under mild pressure. Along with other valve chamber modifications, the oil return pipe was eliminated. Model 'C;' The 1933-34 Ford four cylinder engine has been unofficially dubbed the Model 'C.' photo of C head here This designation cannot be found in Ford literature or correspondence. It is strictly a user connotation. Changes from the 'B' to the 'C' engine included: a crank shaft employing integrally forged counterbalances, a shortened three bolt water water pump housing and a 39 pound flywheel compared to a 62-1/2 pound flywheel provided with the Model 'A.' (The counterbalances make up the difference.) There were 263,765 Model 'B' (and 'C') engines produced between March 9, 1932 and late 1934.

Ford produced the Model 'B' 4 cylinder engine from 1932 - 1934, concurrently with the V-8.

Some noticeable differences between the A and B engines.

The Model "A" engine has a oil return tube on the right side of the engine, that extends

from the lower left corner of the valve cover to the lower right corner of the block. The

"B" engine has no external oil return tube.

The Model "B" engine has a small port on the right side just below the valve chamber

cover for a cam driven fuel pump. This port will either have a fuel pump attached or

have a triangular shaped plate covering the hole.

Both engines use the same manifold gasket. The "A" and "B" manifolds are

interchangeable for either engine. The differences in exhaust manifolds is the angle of

the exhaust tube at the end of the manifold. The "A" is at about 90 degrees (drops

almost straight down) and the "B" manifold drops off at about a 45 degree angle.

Answer above by John Hargrave, Technical Director, MAFCA

-----------------------------------------------------------------------

Modifications to the B engine included "pressure" feed to the main and cam bearings ; hence there was no need to partially fill the valve chamber with oil so that it could feed by gravity through tubes or holes to these bearings. Rather, oil was pumped directly into a gallery below the chamber and through holes which fed the main and cam bearings. The oil return pipe on the A engine carried away the overage and also cooled the oil as it was returned to the pan.

To understand why this was done, one must consider the engineering of the time. With respect to the main bearings of the crankshaft, Favary (see "Motor Vehicle Engineering - Engines" McGraw-Hill Book Company, Inc.) had this to say in 1926: "When the linear speed of the bearings exceeds 1000 feet per minute, it is most important to maintain a film of oil between the bearing surfaces, hence pressure feed for such bearings in high-speed engines is essential." It should also be noted that a certain volume of oil must also circulate through the bearings to cool them.

Since the main bearing journal size on the B engine was increased to 2" from the 1 5/8" diameter of the Model A, and the engine was rated 50 hp at 2800 rpm instead of the previous 40 at 2250, this linear speed of the crankshaft was thus likely to exceed that which was considered "safe" for adequate lubrication using just gravity feed. At these rated speeds, the A crank linear speed is about 957 ft. per minute; the B is a touch over 1465 ft. per minute.

The above article by Phil Mino

---------------------------------------------------------------------

The B Engine has bigger bearing surfaces on the crank, which means tougher bearings that can take higher speeds and compression. The later couonterweighted ones can be balanced very nicely, although a balanced non-counterweighted one is also smooth. The main bearings are pressurized, meaning they will be cooled and lubed better. Its not a difficult thing to have the crank drilled out to pressurize the rod bearings as well. The weakness in the B block is that they tend to crack between the #4 exhaust valve and the cylinder, sometimes in other cylinders too. These cracks can be repaired sometimes. The block should always be magnafluxed before rebuilding it, to insure it is sound. The exhaust and intake ports are shaped for better breathing and ported to allow more air in and out. You can put a B carb on there with a B manifold and get the original higher 50 horsepower, but with a high compression head, you can really get a boost out of the engine.

The Difference, Ford A,B & C En

**Tom Wesenberg** · 09-17-2017, 11:52 PM

Here's a few cutaway displays in the Model A museum at Gilmore.

**George Miller** · 10-20-2017, 01:02 PM

Tightening the Cam Gear / Timing Gear

The best way to hold the timing gear when tightening the timing gear nut to 100 ft lbs, is take the side cover off and put a good clamp across the gear below the teeth. That will take all the strain off the gear teeth.

**George Miller** · 10-21-2017, 11:32 AM

Tapping Blocks with a Standard Hardware Tap

You should not re tap your block with a standard tap. The factory used a tighter class tap. If you tap it with a standard tap the stud will be looser in the block than it should be. Which will weaken the threads in the block.

**George Miller** · 10-26-2017, 04:28 PM

Cheap and easy test to check for bad valves

To check for burnt valves, turn you ignition off and turn the engine over with the starter. If it speeds up on compression stroke, you probably need a valve job. this is just a quick check, you still need to check with a gauge to be sure.

Years ago a Guy came in with a 56 chev V8 it had less than 50,000 miles. He was a mechanic at the county garage. He said he wanted a valve job. Next day I check it because chev V8's do not need a valve job with those low miles. I checked it with out the ignition on. It checked fine. It was a bad plug wire. When he came back to get it with his wife, she gave him a hard time because he was wrong. I think he would have been happier if I would have done a valve job.

**Mitch** · 11-06-2017, 09:34 PM

Cylinder Head Torque Info

C51B318B-D4CC-4338-8D75-AD093097A4F9L0001.jpg

**George Miller** · 11-15-2017, 08:59 PM

Getting out head studs:

I have been helping a couple of friends build a hill climb engine. It had 8 studs that would not come out. Bill DeVore and Steven Grace are the two guys. They came up with a neat idea how to get them out. They took some 1/2 inch plastic conduit cut it about 3/4 long and glued it to the block around the stud. Then filled it with penetrating oil. Then let it set for a few days. It worked.

**Mitch** · 11-29-2017, 09:52 PM

AER’s Rear Main Oil Leak Diagnosis:

PROVERBIAL REAR MAIN LEAK

After 30 plus years of experience with the Model A & B engines, the most common problem is a rear main oil leak. This problem can be very simple to correct or it can turn into costly time consuming job. What is important is a correct diagnoses. You do not want to rebuild engine if you have a bad oil filler cap. Do not assume the worst until you have checked out the problem thoroughly.

1. After wiping clean flywheel housing. Check that oil is leaking from out of cotter pin hole at bottom of flywheel housing. If oil does not leak out of cotter pin hole you have a leak some place else, suggestions oil pan, timing case cover, front seal, valve cover, oil pipe to mention a few. Most oil leaks drip off of the cotter pin. You need to determine that oil is leaking out of cotter pin hole not off of the cotter pin to be a rear main leak. If oil is leaking out of cotter pin hole go to step 2.

2. Remove oil filler cap check to see that oil filler pipe is not restricted or plugged. With oil filler cap removed from car take car for a drive. If leak stopped the oil filler cap is bad. There are tabs bent over under top of cap to stop cap from seating all the way down. The stops could be bent or missing on your cap. This will seal crankcase pressures in and will force oil out. Replace oil filler cap. This is a common problem, overlooked and easy to fix.

3. Hold a plastic food storage bag around oil filler pipe and bring engine to high idle. Bag should flutter if does not and fills up with air, you have excessive blow by in crankcase. This can be caused by bad rings, pistons, cylinders or possibly valves and guides. Excessive pressures in crankcase will cause oil to leak out rear main and any other place not sealed.

4. If above is all good now remove half moon inspection cover on flywheel housing, three hex head screws. Chock wheels. Check to see if inside of flywheel is wet with oil. If flywheel is wet inside this means oil is leaking out rear main cap and or cap to block. Start engine, with flash light look for oil leak. EXHAUST IS HOT AND MUST BE VENTED.

POSSIBLE PLACES FOR OIL LEAK.
Checking inside flywheel housing with half moon cover removed.
Engine running

A. Dripping or running down right side of engine around outside of rear main cap. Probably gasket between engine and flywheel housing. Remove engine and replace gasket. We seal around camshaft hole with RTV no longer use a gasket.

B. Dripping between rear main cap and block at shims. Cap must fit flat to engine block. Rear seal part A6335 must be filed flat with block. I use a thin film of RTV on both sides of shim to prevent leakage.

C. Dripping out side of rear main block could be oil running up rear main bolts, I use RTV under heads of the rear main bolts and on threads of the two upper bolts that secure flywheel housing to block. These leaks are generally slow drips and are not common.

D. Dripping or running out of back of rear main cap into flywheel is common. This is a rear main leak. If you have not seen oil leak at this time take car for a drive, immediately chock wheels and check again. If rear main leaks. Remove oil pan.

E. Check oil tube on rear main cap that it is not missing, broken or cut off. The end of this pipe must be in oil in bottom of sump. If pipe is not in oil, pressures in crankcase will blow oil out rear main. If pipe is screwed into cap too far this will restrict oil flow back to sump and cause rear main leak. The oil galley plug in rear main should be installed again to stop crankcase pressures from pushing oil out rear main. Next remove rear main cap, oil galley in cap must be open and clean so oil can flow back to sump. With cap removed from engine you can now inspect Babbitt for wear, cracks chips, ECT. The last quarter inch of the bearing must be full diameter of Babbitt no cuts, grooves or chips. Shims must fit tight to crankshaft . Plastigage can be used to check bearing clearance at this time with engine still in car. I suggest a jack be used to apply pressure upward on crankshaft. This will seat crankshaft up into bearings in block to give you an accurate measurement. Desired clearance is .001 to .0015.

By now you should have diagnosed the problem. I hope that your problem was easy to fix. I have seen newly rebuilt engines leak and many times it was just the oil filler cap. Do not assume the worst till you have checked out the problem thoroughly

http://www.antiqueenginerebuilding.c...RMAINLEAK.html

Excessive crankshaft end play will also cause a leak. This is easily checked in the car

Crankshaft end play

.004

excessive blowby will cause a leak

**George Miller** · 12-18-2017, 12:13 PM

Bolt hole next to the camshaft on the rear of the engine. Poss source of oil leak

To day while tearing a engine apart that got flood water in it some time ago. I remembered the cause of some rear main leaks that gets over looked. On some engines one of the bolt holes next to the cam shaft on the rear of the engine goes all the way into the inside of the engine. This engine is one of them, in this case it leaked so much oil it helped save the out side of the engine.
Check any engine that you have apart. If the hole goes inside, seal the bolt with RTV.

**George Miller** · 01-07-2018, 12:08 PM

Tip on grinding A valves

When grinding valves and using the old parts. I made a wood box that has 8 compartments and 8 holes drilled in back of the compartments. to hold the valves, and parts for each cylinder. They are numbered for the cylinders. It is important to keep all the parts for each cylinder to gather. And time you reuse old parts they should be put back just like they were.

When you grind the valves and using the split guides make sure you keep the pairs to gather, mark them when you grind the valve seat so you can put them back the same when you put the valve back in. It is important because the bore some times runs out with the od. Also put the valves back in the same hole they came from.

The difference between a ok engine and a great engine is attention to detail.

**WayneT** · 01-20-2018, 10:43 AM

Shim Information thread 1:

Original Thread:
https://www.vintagefordforum.com/for...ng-brass-shims

Does anyone know a way to separate (delaminate) the many layers of brass main bearing shims that come laminated together when you buy them?

**Tom Wesenberg** · 01-29-2018, 03:22 AM

Main Bearing Oil Feed Holes in Valve Chamber

Below are 3 pictures showing the main bearing oil feed hole locations in the valve chamber, and also a 4th picture showing the front opening where the oil overflows onto the cam gear. If you are cleaning sludge from the oil pan and valve chamber, be sure to run pipe cleaners up and down each of the oil feed tubes to the main bearings to be sure they are open.

**Mitch** · 02-27-2018, 10:05 PM

Oil Pump Specifications

Type Pump, splash, gravity feed

Crankshaft Bearings Gravity feed

Connecting Rods Splash

Camshaft Bearings Gravity feed

Oil Pump Type Gear

Oil Pump Capacity 9 pints, minimum at 1300 rpm

Oil Pump Pressure 80-100 pounds

Oil Pump Shaft 1/2" diameter (in 5/8" bore), except 1928 with 9/16" bore & undercut shaft (Model B used 5/8" bore with undercut shaft)

Oil Pump Gear Teeth to Housing Clearance .001" to .002"

Housing Cover to Face of Gears Clearance .001" to .002"

Drive Gear to Camshaft Gear Clearance .003" to .005"

**Mitch** · 02-27-2018, 10:16 PM

Cylinder Block Specifications

Length 19-5/16"

Width 7-13/16"

Height 11-1/2"

Bore 3.875" to 3.876"

Bottom of Block to Camshaft Centerline 2.876" to 2.878"

Top of Block to Camshaft Bore Centerline 8.624" to 8.627"

Valve Lifter & Guide Bore .594" to .5945" diameter

Distributor Drive Gear Bore .9365" to .9375" diameter

Cylinder Outside Diameter 4-3/8" outside diameter

Flatness of Top of Block .003" to .005"

Cylinder Bore Perpendicular
to the Top of the Block .001" to .002

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