Traded for a French Flathead Block

[Krylon32]

Just traded for a new French block with the French crank, rods, pistons, bearings and rings all from Halibrand. Other than machining off the governor casting on the back which I've done before. What are the short comings of the French parts? I'm just trying to build a reliable street FH. What problems can I look forward to?

[Ronnieroadster]

From my experience with one NOS French block the ports directly below the valves were extremely small in diameter it appears no secondary operation was performed to open up that area compared to the stock Ford blocks. Also the internal diameter of the oil passage the pipe located in the valley is a much smaller diameter than the Ford oil passage. Now these two issues may not effect the original application for these engines that being placed in military vehicles. However in my opinion a reliable street Flathead would mean its at least similar to the Ford production design for some performance and of course economy. The French block is certainly an excellent platform to work from the above listed items can be improved upon i know since I did improve on those areas when i ran one in my car to a speed of just over 180 MPH many years ago. But the Ford blocks I run are now over 200 MPH.
Ronnieroadster

[Ol' Ron]

If it has the cra
snk, rods and pistons in it. you don't have to do much. Does it have the 4" crank (Merc)/?

[deuce lover]

All the French blocks here I have seen do not have hardened valve seats.

[Brian]

If running a standard 59A style oil pan, you'll need to close up the cast hole behind the timing gear, and fit stand pipe in valley, otherwise you'll have major oil leak out the breather at front of pan

[flatheadmurre]

Sponsored Links (Register now to hide all advertisements)

I´m not in the crowd promoting them as the golden flathead...they are industrials to me...runners was made for torq.
If you´re used to porting 59ab´s and try to remove the hump in the intake you hit water...
Then machining away the part on back plugging the port going up and welding the hole into the valley...

[Krylon32]

Ron: It's the 3 3/4 crank. I was thinking of using it and keeping the stock bore since I got all the parts with it but I might chose to go 4 inch with 3 5/16th? It''s a bare block with all the parts in separate crates.

[TomT/Williamsburg]

I didn’t grind off anything, Gary - I just got some plugs to plug the holes in that area and anything else that was not useful. Brian has it right regarding the 59ab oil pan but I ground a relief in the block for any oil in the breather pipe to drain back into the oil pan along with a small relief in the oil pan in the same spot to assist flow.

I can provide pics if you like of the relief and electronic copies of the literature Halibrand sent out when I purchased my block and main caps when they first came out .... just PM me your email address and give me a couple days to dig them up ...

[Mart]

Most points covered above.
I have a French motor in my roadster. Just from memory here are my take-homes on French motors.

Blocks are 59A/8BA hybrids with features from both.
Front area is an oil drain and the vent in the pan must be closed off. (PCV system may be required)
4" crank in the SUMB version. Rods are 6-7/8 so common pistons can be used.
7" rods same as 8BA in 3-3/4" versions. Common pistons with 4".
If you use Ford pistons the skirts need trimming in a 4" motor and you leave out the bottom ring.
The exhaust fixings use studs because the holes are drilled into the water jacket. The studs are 10mm x 1.25 pitch. I have run a 3/8 UNF die down them successfully including holding on an engine stand. I believe block side of studs are SAE.
You need 59A style main bearings.
You need a matching oil pan, starter and flywheel from a 59A as donors. The oil pan will need clearancing near the front main.
Valve bowls are restricted. These can be hogged out, I don't know how far. I didn't hit water on mine, but was pretty conservative.
59A cam can be used with a 2 bolt cover and a crab dizzy.
Ring gear on flywheel MAY have the teeth chamfered the wrong way round for an non inertia starter. 4" SUMB are all 11" clutches.
4" crank plugs are deep drawn sheet metal 5/8" diameter.
All core parts are imperial same as USA. Some peripheral parts are metric but these are normally discarded, with the exception of the exhaust studs.

There's probably more but that is all I can think of for now.

Mart.

[Zeke3]

George McNicholl documented the build of a blown French flathead in his book, "How To Build Ford Flathead V-8 Horsepower", if that would be of any help.

[Flathead]

Interesting that these more modern versions of Ford's flathead would have restricted ports. You would think it would be a no brainer to make some improvements or at least leave them alone.

[Tim Ayers]

Originally Posted by Flathead

Interesting that these more modern versions of Ford's flathead would have restricted ports. You would think it would be a no brainer to make some improvements or at least leave them alone.

Just a guess, but I would think it was by actual design. That boss on the back of the bell housing top 1/2 was for a governor, so maybe the restrictive ports helped to achieve the desired effect of limiting rev's and speed along with the governor.

[Mart]

It is thought that the restrictive ports were by design along with very soft valve springs. These were built for military vehicles where being dependable and not breaking down could be a matter of life and death.

Mart.

[bob miller]

I know 4 differents block foundries, in the 90's we bought 10 blocks from a military junkyard. After the mission we note the differences between blocks !

[Flathead]

Just seems like giving up some power, unless that governor was set very low. Thanks for the replies.

[Mart]

I've got a French block in my engine stand right now so thought I would bump this back up.
It would appear some French blocks do have valve seat inserts.
The motor in my roadster with a casting date of 1964 has inserts in the inlet and exhaust.
The block on my stand has no inserts on the inlets but does have them on the exhausts.
Deuce Lover above says he has seen them with no inserts at all.

So all 3 combinations seem to have been in production at various times.

The only minor difference I noticed on this one is that the oil pump is retained with a stud and nut. The stud is drilled and a castellated nut used with a splitpin (cotter pin if you prefer).

I also noticed an O ring used to help prevent leaks at the oil pump/block interface. Seems like a good idea to me.

Mart.