My First Flathead

G

Grizlywinkleman

Junior Member
Greetings from Iraq!

I am new to the forum and have a few questions. At home (Wisconsin), I have a ‘50 or ’51 8BA (thin belt) from a F100. The awesome old timer I bought it from claims it was running about three years ago when he sold the ’39 f100 it was in (the guy who bought the truck did not want the motor, lucky me!).

Is there a way of telling exactly what year it is?

I removed each of the spark plugs to take a peek at the condition and carbon buildup on the block deck and valve faces. I found no evidence of water but a fair amount of carbon which I expected. The spark plugs were not stuck; they looked pretty good and actually still smelled of gas. The only issue I found was one of the valves had been slapping the spark plug. I was told the springs can break and the retainer can slip off the valve letting it loosely slap around as the cam spins. When I rotate the motor by hand the valve does not come up as the others do.

Any other diagnosis here?

I am planning on removing the heads and intake manifolds and confirming this is the case. I then plan on replacing all valve springs and retainers and cleaning anything I can get too, searching for cracks, and checking stroke & bore.

While I am at it, is there anything else I should look for, replace, or upgrade?

I am in hopes of being able to throw the motor (stock with header upgrade, water pump upgrade, and stock style oil filter added) into a T-bucket my brother is building for at least a while before I do a rebuild. It looks so cool just the way it is!

As for when I am ready to rebuild, I am hoping to get about 180 – 200 HP. Is this reasonable to do? What is a good method for picking out the correct parts?

I have built a 347 Stroker and took the approach of starting with the cam and matching the performance of the remaing parts to it in order to match performance level and maximize HP. Should I take the same approach with the flathead?

Thanks in advance for sharing your knowledge! I look forward to learning from the barn!

FYI, I may not be able to respond right away but I will hop back on as soon as I can.

Ryan
 
Couple of suggestions. First have the block pressure tested to assure it is crack free. On the preformance side, 180 to 200 hp is duable with a flathead but difficult and expensive for a street engine. A good start would be JWLs book and O' Ron's book as well.
 

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Some of the 8BA blocks have a stamp on the intake surface that contains a date code. It's kinda weird, but if it's there you can date the engine. If the stamp is there, you should be able to find the date code interpreter on the internet somewhere; I don't have it right now, but if you have trouble, I can probably find it. It's really not that important because last series Ford and Mercury blocks were very similar, the only major differences is starting in '51 (I think) they began losing the hardened seats and going with rotating valves. Probably the best thing to do is to open it up and see where (and if) you have seat inserts. There were also at least 4 different timing covers for them which were different enough so that some of the distributors won't interchange. I think that since you have the "thin" belts, the one-piece/two-piece crankshaft pulley problem doesn't come into play.

I'd be more worried about the valve that doesn't move. You may have gotten lucky and had a lifter top fail, but it's probably a flat cam.
 
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JFYI, '48-'53 flathead trucks used wide belts,(along with '50 Ford/Merc cars) while '50-'53 F/M cars used narrow belts.
Ford trucks were simply trucks until the first F-1 in '48. F-100s came out in '53.
Pictures of the engine would help, but it's probably a mixture of car and truck parts.
 
It would take a pretty wild cam to get over 180 HP; not something that would be fun for putting around town. Stick with a street cam and settle for the 160 to 170 HP you can get with headers, 2+ carbs, high compression heads, and bore/stroke for cubic inches.

I love the pretty bolt-on stuff, but there is no substitute for inches!

I put the 3x2 intake manifold on my rod knocking worn out flathead to get it the jets close and the linkage perfected, so that when it went on the rebuild test stand, we knew it was good.

Have fun!
 
It may or may not have a build date code stamped on the passenger side rear intake mount surface.
This example translates to 5/10/51.
 

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You might check to see what spark plugs are in there. I don't know if a valve even could hit an H10 type plug. Might be too much reach. It certainly won't hurt to check all the stuff on top end out and it won't cost but a set of top end gaskets if everything is OK. You can make sure all the valves & springs are good to go. It may or may not have adjustable tappets. They didn't come with them from the factory.

You might have been thinking F1 in the 50/51 range but the 53 F100 did change over to the car type belts and a different set of pumps. The 48 thru 52 all had the single belt setup. The Fords & Mercs only had a single belt in 1949 so the F1 pickup stuff is a way lot easier to find.

I think you would need a blower to get the horse power up as high as you mention. The old flat motors can be made to breathe well enough to get higher HP but Maybe not quite that high.
 
Check the spark plugs for reach because if they are too long you can bend valves. Been there, done that.
 
Thanks for the wealth of information!

I think I will aim for 150 to 160 HP when I do rebuild. Sounds more reasonable, streetable, and affordable after hearing the expert testimony.

As for the spark plugs, they are the H11's that screw into the head approx 1/2". The valve was definitely hitting the plug at one point though it was only hard enough to bend the ground electrode to touch the center electrode. There are dings in the valve face also.

JSeery, thanks for the heads up on the books. I while add those to the collection.

drolston, Thanks for valuable tip on the intake. I will be sure to run what ever configuration I go with prior to rebuild (if I can) to make my life easier after the build.

I do have the double thin belt set up on the motor. According to the link below, the dual thin belts started in 1950 for all 8BA's/EAB's. Either way, I will search for the goofy engine code on my block when I get home. I am just curious about the past life of my motor. Thanks for providing the date code interpreter!

http://www.vanpeltsales.com/FH_web/flathead_specs-90to125late.htm

Thanks again!
 
All of the trucks with flathead V8s were single belt till 1953. That statement is true for the passenger cars.

The heads may have been milled a bit much or busted spring as was mentioned. H11 is just a different heat range that the old H10 and the reach should be the same.
 
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