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Old 08-27-2013, 02:11 PM   #1
cuzncletus
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Default torquing Offenhauser heads

A friend just pulled an 8ba from a 49 truck. The owner complained it was running hot; indeed there was water in the oil and center exhaust port. My thought is this is caused by one of two things. First is the dread crack from ex. valve seat to cylinder wall. If so, it's toast. The other thought I had was my friend, who had recently redone the truck before selling it to the current owner, had installed new Offy aluminum heads. Being new to flatheads, I hadn't known to torque aluminum heads from back to front, not in the conventional pattern. An old(er) timer told me this. When I checked with several sources they confirmed he was right.

I asked my friend how he had torqued the alum. heads. He said he had torqued them in the conventional flathead pattern as recommended by Ford. Is this correct?

If the Offy heads did warp, will pulling torque on them flatten them out or do they need to be milled? The engine is not going back into the truck as the new owner wants it swapped for a small block Ford. The new owner complained of reliability and the truck running hot. My flathead stash is getting full after only a couple of years but I hate to let a potentially good motor get away. This motor ran well in the truck when it was stock for years in the community as the old 49 was an actual working vehicle.

Either way, my interest in the engine is casual until I can pull the heads.
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Old 08-27-2013, 02:25 PM   #2
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Default Re: torquing Offenhauser heads

pull the plugs till you find one that is snow white, no carbon on it at all, then pressurize that cylinder with one of the sttachments used to change valve springs with out pulling head, after pressurized cylinder check to see if there are bubbles in radiator, of course that could mean a blown head gasket
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Old 08-27-2013, 02:46 PM   #3
cuzncletus
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Default Re: torquing Offenhauser heads

The engine is already out of the truck.
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Old 08-27-2013, 06:29 PM   #4
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Default Re: torquing Offenhauser heads

I'd like to learn more of the theory for the tightening sequence for alum. heads vs cast iron heads.
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Old 08-27-2013, 07:18 PM   #5
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Default Re: torquing Offenhauser heads

Wouldn't recommend that front-to-rear sequence, not sure where it started??

It's best to follow the gasket mfr/head vendor for the sequence, and it's also best to follow the fastener mfr for the torque.

We use ONLY the ARP fastener line on our builds, and most get Fel-Pro gaskets. Some get bolts and some get studs, usually customer dictates here!

We use 60#/65# (nominal) for "iron" and 50#/55# (nominal) for aluminum! Have never lost a gasket or pulled a thread so far. But we do get to pre-check the holes when we install the block-plate for honing.

(Add) If the heads are "warped" it's best to mill them flat. You may get by with a couple "thou", but we would mill, even just a "skim" cut!

Thanks, Gary in N.Y.

P.S. Here's a shot of Fel-Pro's recommended torque sequence on the left and Edelbrocks with the their sequence and amount of torque also. Pattern #33 in the left photo is the 8BA Flathead unit.
Attached Images
File Type: jpg Flathead Torque Sequence-32.JPG (77.9 KB, 129 views)
File Type: jpg Flathead Torque-Edel.JPG (76.2 KB, 143 views)

Last edited by GOSFAST; 08-27-2013 at 07:20 PM. Reason: Add info
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Old 08-27-2013, 10:53 PM   #6
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Default Re: torquing Offenhauser heads

I've been torquing the heads the Ford method to 45 ft/lbs, Over toquring will cause warpage.
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Old 08-28-2013, 05:52 AM   #7
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Default Re: torquing Offenhauser heads

Ron is absolutely correct.

The torque sequence is not as important as being certain to tighten in relatively small, equal, increments up to the final level. Keep everything as flat as possible during the process. At least 3 cycles around all the fasteners to get up to the final.

The strength of the fastener or fastener manufacturers torque recommendations are completely worthless statistics for Flathead cylinder head clamping torque.

The heads should be checked for flatness with the appropriate, precision, straight edge and placed on the granite inspection table to determine whether or not they are flat.
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Old 08-28-2013, 08:39 AM   #8
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Default Re: torquing Offenhauser heads

Quote:
Originally Posted by GOSFAST View Post
Wouldn't recommend that front-to-rear sequence, not sure where it started??
It's Offenhauser's directions. If interested, click the "instructions PDF" link at the bottom of the description paragraph here: http://www.speedwaymotors.com/Flathe...-Kit,1785.html
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Old 08-28-2013, 11:41 AM   #9
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Default Re: torquing Offenhauser heads

Quote:
Originally Posted by Uncle Bob View Post
It's Offenhauser's directions. If interested, click the "instructions PDF" link at the bottom of the description paragraph here: http://www.speedwaymotors.com/Flathe...-Kit,1785.html
Hi Bob, we aren't in this for a hobby, we do it 100% for a living, CNC, flow bench, dyno, etc.

You may want to give the guys at Offenhauser a call, they DO NOT recommend the procedure explained above here, the same one that Speedway is showing.

That's Fel-Pro, Edelbrock, and even Offenhauser saying it isn't the correct way. Speedway is entitled to their own opinion.

I had the opportunity to meet Ron a while back and he sort of knows now what we're about!

When we do these builds I need to know they will NOT come back for any "follow-up-maintenance" so to speak! I have some of these units out for over 15 years now and not a single issue still! No bolt/stud leaks, no head gasket leaks, no oil leaks, nothing. Having the dyno however is huge "plus".

I would never consider a "Grade 5" fastener on any head bolts/studs, not saying it's wrong, just saying "this is our policy here"! There hasn't been a single issue so far with ARP's components!

This is some of the reasoning that makes us choose components like "coated" cam brgs, bronze-lined guides, dowel-pinned heads/block, oil-filtration system, etc. The unit's life is extended greatly! I've had numerous contacts on the head-pinning deal by some of the builders across the country. We keep doing our best to improve on most situations.

Thanks, Gary in N.Y.

P.S. I absolutely do agree with torquing the fasteners in 3 steps, with us that is a "given". I also would be somewhat comfortable with the 45# number on the aluminum heads, depending on the torque wrench accuracy.
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Old 08-28-2013, 12:40 PM   #10
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Default Re: torquing Offenhauser heads

Not trying to start a whizzing contest, nor have an axe to grind, just responding to your "not sure where it started" remark. That same form also comes in the Offenhauser labeled and sealed (presumably factory?) box of those studs and nuts. Is this only Speedway's opinion and are they an authorized packager under the Offenhauser brand name? I have no idea, let the reader who's interested do their own research.
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Old 08-28-2013, 05:48 PM   #11
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Default Re: torquing Offenhauser heads

Quote:
Originally Posted by Uncle Bob View Post
Not trying to start a whizzing contest, nor have an axe to grind, just responding to your "not sure where it started" remark. That same form also comes in the Offenhauser labeled and sealed (presumably factory?) box of those studs and nuts. Is this only Speedway's opinion and are they an authorized packager under the Offenhauser brand name? I have no idea, let the reader who's interested do their own research.
Hi Bob, wasn't meant to be a "harsh" response, but sometimes in this business logic dictates with respect to the some of the questions!

I apologize if I came across wrong?

When you build these for a living you simply cannot afford ANY "comeback". It's one thing when an owner does the labor and ends up with some sort of failure, but it's quite another when you take a customer's hard-earned money and problems arise. No matter who's to blame, we are responsible 99.9% of the time. This comes with the territory of being in business.

This is the reason we do our best to try to avoid even a single issue, sometimes it's near impossible, especially today when you have no idea of who is making what anymore, or even where they are making it.

Back in the mid/latter '80's and into the early '90's we were averaging about 8 Flathead builds per year, not all were fully assembled, but we did all the machining. We had one single customer/friend in the area who did nothing but Flatheads. Between us we learned much at that time how to improve some on them!

Thanks, Gary in N.Y.

P.S. You are also correct, the O.P. should make the calls for verification. We try to pass along what we learn from building AND testing all these units! The Flathead's are not like building a SBC or BBC, they warrant more attention to detail.
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Old 08-28-2013, 07:47 PM   #12
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Default Re: torquing Offenhauser heads

Some of you might like to consider this thought.
Does anyone know of any manufacturer that does NOT recommend working from the center of the head out, when either fitting or removing a cylinder head? (I can't think of one)

I like a lot of speedways recommendations, in those instructions, but that bit about the tightening sequence seems like a lemon to me.
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Old 08-29-2013, 11:21 AM   #13
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Default Re: torquing Offenhauser heads

I have torqued hundreds (if not more) racing heads over 35 years of fairly competative racing. I have never had a torque related head gasket failure...never! I have never ever torqued a head from front to back even though; none other than Brad Anderson recommends it. This includes SBC, Rats, "W", and late hemi's. I take issue with someone above suggesting that a flattie takes more "attention to detail" than others. Try making an error with a nitro hemi, they are completely totally unforgiving! You suddenly have 35K worth of junk often you can't save anything except the intake and the headers!
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