21 Stud 37mod

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Hey Guys

First I would like to say, what an awesome site with so much knowledge on these old engines. Way to to guys

I have got a 1937 221 Flathead that I bought from a guy that had salvaged it out of a quarrey in the mountains. I have no history on it but gave it a shot.
So far I have managed to figure out that it must be an UK built engine. It had a Lucas distributor and the amount of teeth on the ring gear and starter gear tells me it is not a US built engene. It has been bored 30 thou. over.
I have the block gutted and I'm getting ready to take it to the machine shop.
I have had a bit of problems finding main bearings and pistons for it.
The valve train seems to be easy to find. I will upgrade to the straight stem valves and adjustable lifters. The plan is to set it up with Sharp heads and a dual carb Sharp intake.
Not building a race engine. Just a mild street engine.
I have heard and read a lot on this Forum about the L100 cam. However I haven't been able to find out how I can get one!
So guys, where can I find main bearings, rod bearings, pistons and a L100 cam?

Any other pointers to aid me in the right direction is very much appreciated.

Eddie

[Brian]

L100 cam is NOT a good choice for such a small displacement engine.
There is some .030 pistons currently on eBay [no affiliation to me]. Bearings are around, be prepared to spend $$$$

[[email protected]]

Hi Brian

Thanks for your input. Can you recommend another cam that will give me a lumpy idle and is still streetworthy.
I'm afraid the 030 pistons wont cut it! The block is already bored 030over so I'm going to need a 060 or maybe more over.

Eddie

[Brian]

I like an isky 88 cam in a 21 stud.

[Charlie ny]

Eddie,
Fast track to Van Pelt 513 724 9486 or
3rd Gen Auto....Michael Driskell.........844 327 5988


Get the block sonic checked for wall thickness before the boring bar goes to work. Core shift can cause big heart aches.
Hook up with KIWI Tony here he is the L 100 guy.

Charlie ny

[Jack E/NJ]

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Agree to check on VanPelt for piston set. http://www.vanpeltsales.com/FH_web/e...prices-pg1.htm. Try to not to bore more if possible or as little as possible. Stock cam lope in mine sounds good enough to me. And I kept the mushrooms and split guides just because I could, and really don't expect I'll have to do them again anytime soon. 8^) Jack E/NJ

[frnkeore]

More goodys;
https://egge.com/product/kits.php?ac...engine=221+CID

If you can wait a while, Ebay will usually give you what you need, in NOS items. I got most of the stuff I needed for my 221 stud, '37 block but, I went back to FT pistons and aluminum '35 heads. Your engine should have domed pistons.

[deuce lover]

Welcome to FordBarn.The rod bearings seem to be the hardest to find or at least it was for me.The main bearings I got from C&G in Escondido,CA. Pistons and rings and rod bearings I found on EBAY.Chuck Kuntz who is a member here I heard has some of that stuff.Flathead Murre ,a member here,who is in Sweden has that stuff also.Good luck.

[tubman]

Since you are in Norway, I second the recommendation of "flatheadmurre" (that is his Ford Barn user name). He is in Sweden, and on top of that, a real good guy.

[KiWinUS]

G’day Eddie & welcome. PM sent.
Cheers
Tony

[G.M.]

Chuck Kurts in Penna. has lots of pistons and
bearings. G.M.

[[email protected]]

Nice to know, might be an option to find some parts in Sweden

[[email protected]]

So much good information, seems like it's going to be a matter of choosing where to buy.
I'm already more optimistic about this build
Any advice for upgrades is also very welcome.

Eddie

[Ol' Ron]

I put an 8BA crankand piston assy in a 37 block. This can be dome but is expensive. However you could bore it too 3 3/16 use 8BA pistons. angle mill the stock heads about .070" and use a isky 1007b cam check for piston and valve clearance. This Maked 2399ci and aprox 8:1 cr You'll need a good machinest to do this and sonic testing the bore is a good idea.
AS for the L-100 cam. I did use onr in the 37 I built, however the engine went into a Modeal A roadster that was vERY light.
god luck\Gramps

[[email protected]]

Wow Ron, you have tried it all. Did you ever dyno that build? Did you go for larger valves too? 8:1 in compression is good Would have been very interesting to see some numbers on that build especially torque
I’m going to use the stock crank and rods. Upgrade the valvetrain and make it a mild street engine. I’m not into racing but I love the way the Flathead sounds, hence the reason for wanting “the Smiley” cam
We are not blessed here in Scandinavia with easy access to parts unfortunately so I will reuse as much as I can. Valves and pistons were way beyond salvaging so that’s not even an option
She seems quite congested so some porting will be done too.
An honor to have you reply on my thread Sir
I’ll take my hat off to guys like you any time

[flatford8]

Post #11.... his name is Chuck Kuntz...he’s a member here and very good to deal with....I’ve bought a lot from him and his replies are quick, realistic prices and good descriptions on his parts. Vanpelt Sales and Third Gen Auto are your other best choices for what you need.......Mark

[[email protected]]

Thanks guys

I dropped the block off at the machine shop yesterday. Waiting to have it hot tanked and Magna fluxed, Get a report of the condition and see how much, or little rather, we will have to bore it to clean the cylinders. It was already bored 0.030 over. Most of the valve seats looked refurbish able, might have to replace a couple of them.
Any of you guys, had any experience in putting in larger valves?

[JSeery]

Flathead blocks really need to be pressure tested, mag doesn't always catch all of the crack issues.

[[email protected]]

Thanks
I will notify the machine shop

[JSeery]

Nothing on the blocks is more irritating (and expensive) than putting a lot of effort into machine work and ending up with a hidden crack!

[bobH]

Originally Posted by JSeery

Nothing on the blocks is more irritating (and expensive) than putting a lot of effort into machine work and ending up with a hidden crack!

This cost me the price of a complete engine job. My machinist (and engine builder) did the magnaflux, but not the pressure test. He is a very experienced flathead guy, and I trusted his call, and at the time, never thought of the pressure test. Anyway, it cost me. There were hidden leaks, causing water to exit via the RF exhaust port. Found this out after the engine was 100% complete, and on his engine run stand, for final checkout run. I paid the bill, and came home with nothing. Point is, I agree with above post that suggests a pressure test.
We speculated (engine builder and I) that my block was stored with the right front being lowest, and it was eaten out from inside rust. Besides the hidden leaks, it also leaked through numerous holes that put water into the timing gear area. The block material looked quite thin, where we could see. And, the decision was, even if we could fix the holes (at least the visible ones), we couldn't trust the block because it looked so thin in that area. (This was on a 59A block)

[Rodrelic]

I don’t know how much the lumpy cam maybe smoothed out by a heavy flywheel but I have a Weber aluminum with a Harmon Collins cam, sound is fantastic with tube headers, iron probably muffles a bit.
IMO

[Yoyodyne]

Here's my thread about finding a crack in a 37 block in a dumb place after the block was magnafluxed and cleaned and declared good. Not fatal in this case but still would have been a pain if found after installing it in the car.
https://www.fordbarn.com/forum/showp...10&postcount=1


I'm starting on a 36 block that has been magnafluxed and want to pressure test it before I go any farther. How do you guys plug the core plug holes in the pan rail to withstand pressure testing without leaking?

[hop up]

@rodrelic what cam are you using in your 21 studder , I am also using a aluminum flywheel and HC distributor but its a pancake type so cam maybe a issue

[Rodrelic]

I will have to look at the end and confirm just know its3/4
Same lifters were run together so we’re matched
Not an ignition wizard but had good results with the crab dist and used 12v worked good Firestone spark plugs

[[email protected]]

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Hi Tony
Messaged you but don't know if you got them. Please email me at [email protected]

[KiWinUS]

No pm today Eddie. I sent an email about an hour ago did you receive it.

[[email protected]]

Anybody here with any experience on the Allard heads?

[hop up]

Thanks for the info rodrelic on the crab and have one of them as well just have to figure cam out.

[whizzernick]

how do you do a presser test ?

[JSeery]

There are plates that block off the water passages in the head and the water pump areas of the block. The block water-jacket is then pressurized to see if there is any leakage. A flathead block has two separate water coolant systems/pathways in the block, so each side is checked separately.

[Zeke3]

I was thinking you should also cover the expansion plugs on the oil pan rail on the early engines that had them. The expansion plugs should be replaced anyway it you are pressure testing and cleaning out the block prior to machining.

[flatjack9]

Replace the plugs, then pressure test to be sure they are sealing.

[Ol' Ron]

This may be alittle off topic, but, I've only worked on a very few 21 stud engines, including the 37. I don't recommend presuming any modification on these engine, as the internal rotating assy was used for two years in the 36 LB and early 38 21 stud engines. Best left to the people that want to restore the original cars. Late 38 24 stud engines can use all the late cranks and a 4: crank will fit, most of these blocks can be bore to 3 3/16 with some sonic testing, and all the " pieces parts" are available.
Gramps

[38 coupe]

One thing to clarify to what Ron said, the 38 24 stud blocks have the smaller diameter mains and short snout crank like the late 21 stud motors. The 39 engines got the larger mains.

[Ol' Ron]

The 38 91A crank has a 2.498 crank and is the same as the later cranks. It's also the lightest stock crank and was used in the early stock cars in the later blocks with bigger bores and the 91/21A rods. built quite a few of these back then in 8BA blocks.

[38 coupe]

Ron, we are agreeing except for the year the crankshaft was introduced. The 91A part number is explicitly a 1939 part number. The 2.4 main crank carried through 1938 including the 24 stud motors. I have a 1938 24 stud motor with the earlier shorter crank, it is an oddball engine that is basically a 21 stud engine with three additional fasteners per head.


Also, from the Green Book (please pardon the formatting, I had to use ___ to show the different columns):

68 6303-A___Crankshaft assy-2.40" dia. main bearing-24.47" overall length-used with 78-6335 & 78-6336___Pass, Comm & Truck 90 HP (8 cyl)___36-38

91 6303-A___Crankshaft assy-2.50" diam. main bearing-26" overall length-slinger type rear main bearing seal-used with 78-6335 & 78-6336-replaced by 91A6303-B, 91A-6335, 19B-6336 & 19A-6347___Pass, Comm & Truck 90 HP (8 cyl)___39-42

91 6303-B___Crankshaft assy-2.50" diam. main bearing-26" overall length-bus type rear main bearing oil seal having oil grovves-used with 91A-6335, 19B-6336 & 91A-6347___Pass, Comm & Truck 90 HP (8 cyl)___39-42

[Ol' Ron]

Well you learn sumpin every day, till they throw dirt on ya. So your saying that early 91a blocks were small bearing ones. Did they have a different prefix number?? interesting.
Thanks Gramps

[JSeery]

I had an earlier 38 block that the machine shop lost the crankshaft to (this was back in the 60's). Had a difficult time trying to find a replacement.

[Ol' Ron]

I wonder if it has the slinger rear seal as well. Just a 37 crank. One thing about Ford, he didn't waste much.

[38 coupe]

Originally Posted by Ol' Ron

Well you learn sumpin every day, till they throw dirt on ya. So your saying that early 91a blocks were small bearing ones. Did they have a different prefix number?? interesting.
Thanks Gramps

Annoyingly Ford called both 81A blocks. The Green Book lists the 2.4 inch main version as 81A-6010-A for 1938 only and the 2.5 inch main version as 81A-6010-B for 39-42*.

*really annoyingly Ford apparently didn't change part numbers when the following three changes were made around the 40-41 model year change over to the blocks: "raised" intake surface (actually shrunk outside the gasket area), elimination of the core plugs in the oil pan rail, and sides of the block curved up to the exhaust ports.

I only know this stuff since I really like 38 Fords and trying to figure out how to make a correct looking 24 stud motor takes a bit of reading. I appreciate your experience and willingness to share, please don't take my clarifications as anything bad or mean.

[Ol' Ron]

Well it's hard to teach an old dog new tricks, but i've been known to have a very hi "stupid factor". Don't worry about correcting me or anyone else here if they make a mistake, Facts are facts. I don't know very much about all the models of early ford parts as I seldom use them. as for the early 91a crank, it was popular back in the day when we thought things like that were important. The only people that don't make mistakes , are people that don't do anything.
Gramps

[hop up]

How does one tell a 1938 block with out tearing into it.

[Brian]

How does one tell a 1938 block with out tearing into it.

Look at the length of the crankshaft snout

[Mart]

Originally Posted by 38 coupe

Annoyingly Ford called both 81A blocks. The Green Book lists the 2.4 inch main version as 81A-6010-A for 1938 only and the 2.5 inch main version as 81A-6010-B for 39-42*.

*really annoyingly Ford apparently didn't change part numbers when the following three changes were made around the 40-41 model year change over to the blocks: "raised" intake surface (actually shrunk outside the gasket area), elimination of the core plugs in the oil pan rail, and sides of the block curved up to the exhaust ports.

I only know this stuff since I really like 38 Fords and trying to figure out how to make a correct looking 24 stud motor takes a bit of reading. I appreciate your experience and willingness to share, please don't take my clarifications as anything bad or mean.

Just a hunch, but the three changes listed do not alter compatibility with any other parts, so there is no need to make the distinction.

Mart.