Flathead Ford V8 head retorquing?

frenchy dehoux

frenchy dehoux

Well-known member
How often do you need to retorque cast iron heads on a flathead V8. Do you need to do them when the engine is cold or warm. And the reason you have to retorque them so often. Could this be the reason why you see some water leaking around the heads at times because they were no retorque.

Thanks
Frenchy
 
Hi Frenchy,
With composite head gaskets and cast-iron heads I torque them in sequence up to the Ford specs. (do this when they are cold) after an initial running of the flathead (up to normal temp.), let the engine cool and re-torque. You should only have to do this three times, no more, that should do it, it works for me. Vic
 
With FelPro's comp gaskets I've never found it necessary to do it more than one re-torque. Even before the re-torque, they don't leak. They are excellent.
 
Thanks

I had re torque them last year and I had a small leak on the driver side head so I added a bottle of Bar's leak it stopped and now on the passenger side I have a small leak as well so decided to re torque the head on that side and I am going and add another bottle of Bar's leak this is on a V12 Lincoln engine on my 32.

Thanks
Frenchy
 
I don't like to over torque the head bolts and some specs call for higher torque settings that some of find excessive. For the 20 or so years I've been torquing to 45 ft/lbs and this may require several re-torques back to 45 ft/lbs for three hear cycles. I believe over torquing can distort the head/block connection. However the flathead is very forgiving in most cases, so other methods may work just as well.
 
On my NOS 81A motor the heads went on and I never retorqued in 20000+ miles without issues. On my latest 8BA rebuild (decked heads and block) I had issues with blowing gaskets which only stopped when I kept retorquing (felpro composite gaskets, cold , 551bs) until there was no more bolt movement - with the last bolt this was at least 6 heat cycles.
 
The last time with the Offy heads, I just rorqued the once while they were still warm. Haven't had a drop leak out yet. Also were the new felpro gaskets.
Butch
 
If you never re-torque, how do you know if they haven't loosened up? You should re-torque, just to make sure you don't have to re torque.
 
"You should re-torque, just to make sure you don't have to re torque." There is something remarkably funny about that statement...I like it!....Matt in Alameda
 
An old-timer once told me something interesting about applied torque versus break away:
Torque a head fastener to you spec, then reapply same wrench to same torque...of course there will be no movement. Now, mark the position of the nut with a pencil and back the fastener off very slightly, like 1/8 turn or so, and retorque...there will be a very perceptible movement of the fastener past the mark. He suggested doing this slight back-off on all the fasteners on the first retorque of a head.
 
Torque wrench readings are usually just a ballpark number. Very few people bother to keep their torque wrenches current on calibration.
If you can get a CONSISTENT reading somewhere between 45 and 50 ft. lb. you most likely will be ok for a street engine. It's not that critical.
For really accurate torque readings as required in race applications, measuring the stretch of the fastener is the preferred method.
 
Simple...re-torque as often as it takes. Keep checking until it doesn't move. I only use studs so this might not be advisable with 8BA style fasteners. I probably re-torqued my AB motor 6 seperate times. Aftermarket studs with aluminium heads and Felpro gaskets.
 
frenchy dehoux said:
Thanks

I had re torque them last year and I had a small leak on the driver side head so I added a bottle of Bar's leak it stopped and now on the passenger side I have a small leak as well so decided to re torque the head on that side and I am going and add another bottle of Bar's leak this is on a V12 Lincoln engine on my 32.

Thanks
Frenchy
Click to expand...

After I added a bottle of the Bar's leak ( Copper bottle ) I ran the engine for 5 minutes shut it down for a few hours and than started it up and drove about 5 miles and no leaks so far so good no problem that stuff really does work.

Frenchy
 
If you never re-torque, how do you know if they haven't loosened up? You should re-torque, just to make sure you don't have to re torque....Ol Ron...

That is a true Yogi Berra comment, awesome. Casey Stengel was talking with Yogi
about a pop up Yogi dropped in the previous night's ballgame. "How could you have missed it?" To which Yogi replied "the moon got in my eyes".
 
cast iron you retorque when engine is hot, use copper gaskets the best, always soak with copper gasket sealant, several good coats till dripping, make sure head studs are sealed with permetex white sealer or heads will leak, anything past that a little copper radiator stop leak will plug water jacket holes right up.
 
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