Hey guys, picked up my first flathead (8BA) on an impulse buy. Knowing it needed a rebuild and machine work I’ve started doing some research. I called my local machine shop and gave me a price of $240 for bore/honing plus another $90 to hot tank all the parts. I don’t have rods or pistons, but I do have a crank (which needs to be resurfaced) and have a line on a Merc crank for $300. Cam, lifters and valves all need to be replaced and I assume the timing gears. Knowing all this, after I get the machine shop I’d like to assemble it all myself. I’ve never put an entire engine together, but with the use of technology and numerous books I don’t see any major issues. I’d like to keep it on a budget, mild performer, if I wanted a go fast motor I wouldn’t be building a flat head. Any suggestions on parts, books, threads etc. is welcome. -Jarrod
I’ll catch hell for this, but I’d just go with an entire new Scat rotating assembly. They come in numerous bore/ stroke configurations.
Around every head bolt and the bad ones will be between the cylinder and valve. Bad because usually means junk.
Usually between cylinder & valves, do a search for cracked flathead blocks and you will find a bunch of information. Not always detected by the naked eye. Have it magnafluxed.
Would having the block magnafluxed show any cracks? Sent from my iPhone using The H.A.M.B. mobile app
What advantages am I looking at to have this thing bored .030, .040 or even .060 over? Would I gain much with a Merc crank? Sent from my iPhone using The H.A.M.B. mobile app
Bore as little as possible to save for future rebuilds, the Merc crank is preferable but not necessary. You will never spend as much money for such little performance but there's nothing that sounds or looks like a Flathead. If done properly it will outlive you by a longshot.
Sayings like budget and flathead have nothing in common. Awful lot of money for not a lot of performance. Mine is 0.30 over Potvin 3/8 cam with adjustable lifters Edelbrock heads Twin 97 Stromberg
1. Make sure the guy doing the machine work is experienced in flatheads. 2. You may need to pressure test the block in addition to magnafluxing. I didn't do it on the 8ba I built based on my machinist opinion but some will say always pressure test but its your and your machinist's decision. 3. Depending on how much you plan on boring the block you may need to sonic test it to make sure it can handle whatever over bore you are planning on. 4. After the block is disassembled, take some time cleaning all the rust and casting sand out of the water passages. Use Long probes, screw drivers, etc. and a good pressure wash and you'll be surprised how much crap will come out of the block. There are several good books about flatheads available and I'm sure others will recommend the ones they like best. IMO on a budget and flathead don't usually go together. I bought NOS rods from I believe SoCal Speed Shop in Sacramento for just about the price to redo my old rods. Good luck.
I think budget was the wrong word I was trying to use. I understand the expense behind a Flathead, just not trying to throw money at it either ♂️ Sent from my iPhone using The H.A.M.B. mobile app
If you think all this is confusing go to the Flathead Oil thread or What Oil to use in a Hot Rod! Lol
Everything about a flathead is brand new to me. Always ran SB and BB, just trying to do it the correct way. Sent from my iPhone using The H.A.M.B. mobile app
If I come across a set of original ford rods, used but still in decent condition is it unheard of to use them? Sent from my iPhone using The H.A.M.B. mobile app
I'm not machinist but from what I understand, resizing/refurbishing flathead rods is not quite the same as other rods such as for instance a SBC. Your machinist may feel differently.
Good for you! There is a lot of good information here and I will add my 2 cents. I built an 8BA for my A roadster. Actually I paid a guy to build it and he screwed it up. I had to tear it all apart and redo everything he did except the bare machining of the block. Given I paid somewhere close to $3k for the honor of correcting it myself I could see spending the money to have someone like H+H do one for me. The bonus is they do the break in as well and you essentially get a motor that is ready to run. I had mine bored 1/8", had a Merc 4" crank, relieved, Schnieder custom ground cam, full flow oil set up, Bubba's distributor, and so on. It runs pretty nicely now and is a fun motor.
I am rebuilding my motor. I got a set of sharp heads for free, merc crank for $150 then I had it cut and that costs $295. Pistons and rings were 300. Bearings were 200 and gaskets were 60. I work at a machine shop so I get machining done for free and can sandblast everything. Then $30 on paint to make it look nice. Mine is bored .040 over Sent from my iPhone using H.A.M.B.
The Ford and Mercury connecting rods are the same the difference in the engines is the pin to top of the piston height or compression height. If the Mercury crank is used then use Mercury pistons or pistons for a Ford 4" stroker. Post 23 here. https://www.fordbarn.com/forum/showthread.php?t=113466&showall=1
First have it checked for cracks no matter what it cost. Pressure test is the best in my opinion. If your on a budget get a SBC.
Since cracks seem to come up when ever a flathead is mentioned. What causes a flathead to crack ? I would hate to spend $3-4,000 on a flathead to have it crack after running it a short time.
They ran hot back in the days before coolant and pressureized cooling systems.The exhaust runs past the cooling jacket in the block.If you got stuck in heavy traffic on a summer day they could run hot.They aren't the best engine for a 4th of july parade car.
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