Discovered this crack in my intake manifold at #8 cylinder intake port. I believe I am now in the market for a S2MS intake manifold. Do not really want to buy a reproduction. Hopefully, someone has a good used one or NOS piece.
Thanks,
Greek
PM sent
.
Quote from: greekz on October 18, 2021, 04:09:36 PM
Discovered this crack in my intake manifold at #8 cylinder intake port. I believe I am now in the market for a S2MS intake manifold. Do not really want to buy a reproduction. Hopefully, someone has a good used one or NOS piece.
Thanks,
Greek
Could that just be a casting flaw? I've seen similar on other OE manifolds that looked more like flaws, plus yours seems "inward" from the "typical" location...
Does not look like a crack to me. Just sloppy casting.
Take it off and test it and see if it's actually cracked! Try either brake Kleen or solvent and see if it bleeds through. If it is, fix it!
~E
Yep looks like a casting mark not a crack.
Have you noticed a change in the the way the engine runs since discovering the image?
Thank you all for your replies and suggestions. Have been told it might be a casting flaw. While searching Ebay, I found a manifold for sale and it had a line/crack in the same place. I plan on getting tested, but will try the solvent test as well.
The engine was running great before I took the car(6S1134) apart for painting.
Greek
That manifold, unfortunately, is very susceptible to breaking off that ear. I don't know if there is anything that you can do about it?
That corner is also where the engine has a tendency to develop a water leak.
Maybe just use silicone back there on that corner and just drop the bolt in and make it just a little more then finger tight?
Under NO conditions ATTEMPT to use the cork "s" gaskets under it. Use ONLY silicone.
Quote from: shelbydoug on October 19, 2021, 10:06:32 AM
That manifold, unfortunately, is very susceptible to breaking off that ear. I don't know if there is anything that you can do about it?
The engineering of the unsupported flange in this area (260/289 cylinder heads) was based on the iron component which was fine; but with the substitution of the less rigid aluminum material for the intake manifold, and as a nonstandard production component probably didn't receive the engineering discover effort typically warranted, failures began to result. Later Ford changed the intake face casting profile of the cylinder heads to provide support, but I wonder if this was thru observation of the difficulties experienced with the aluminum intakes, or due to similar failures of even the cast iron units with the propensity of air impact wrenches in use in the assembling of such items at the dealership service departments? :o
Don't over torque the bolts (particularly the end ones') and you won't have any problems; but remember, the torque values listed in the repair manual is based on the cast iron component! ???
Scott.
Quote from: pbf777 on October 19, 2021, 11:39:32 AM
Quote from: shelbydoug on October 19, 2021, 10:06:32 AM
That manifold, unfortunately, is very susceptible to breaking off that ear. I don't know if there is anything that you can do about it?
The engineering of the unsupported flange in this area (260/289 cylinder heads) was based on the iron component which was fine; but with the substitution of the less rigid aluminum material for the intake manifold, and as a nonstandard production component probably didn't receive the engineering discover effort typically warranted, failures began to result. Later Ford changed the intake face casting profile of the cylinder heads to provide support, but I wonder if this was thru observation of the difficulties experienced with the aluminum intakes, or due to similar failures of even the cast iron units with the propensity of air impact wrenches in use in the assembling of such items at the dealership service departments? :o
Don't over torque the bolts (particularly the end ones') and you won't have any problems; but remember, the torque values listed in the repair manual is based on the cast iron component! ???
Scott.
It in fact may be an unfair statement from me but in all honesty I question the quality of the casting itself.
The close ups of the break to me show a lousy grain pattern and again, it's easy for me to criticize but exactly what alloy was Buddy Barr using?
Don't go ANYWHERE near these manifolds with any kind of an impact wrench or for that matter even a torque wrench. Use a 6" box wrench and just snug up the freakin' bolts otherwise...
The only thing I can think of that's worse is the likeliness of breaking the center on a Cragar on the old tire mounting machines. That HAS TO BE the worst but this is a close second?
Quote from: shelbydoug on October 19, 2021, 11:59:11 AM
.......................or for that matter even a torque wrench.
Well,...........maybe I would disagree here. That is, a properly used torque wrench! ;)
Scott.
One thing is for sure, you can't just go cranking down on those unsupported corners. Use a good torque wrench and creep up to the specified value in small increments. When you get to the nominal value, go around the torque sequence as many times as you need to until the readings are all the same.
I agree with others that you are probably looking at a casting anomaly and not a crack.
Torque wrench? OK. What are the recommended values for the aluminum manifold vs. iron?
Considering the replacement cost of the manifold I wouldn't torque anything on it more then 15-20 which is snug with a box wrench.
I would wager that more manifolds have been broken in attempting to use the cork s pieces, because you need to COMPRESS them, then anything else and I'd double or nothing that NO ONE exceeded the recommended torque when they broke.
Stay away from it. If you drop it, you can hurt your foot. ;)
Quote from: shelbydoug on October 19, 2021, 03:11:07 PM
Torque wrench? OK. What are the recommended values for the aluminum manifold vs. iron?
The use of a torque wrench does not dictate a torque value, just aids in executing and the consistency fastener to fastener of the torque value chosen! ;)
Scott.
Doug,
OK, point taken. However, the proper use of a torque wrench will allow for the equal application of clamping force on all the intake bolts. If done in small increments, any warping of the manifold will be non-existent or minimal and allow the manifold and heads to seal optimally (isn't that what we are looking for?). I don't think you can apply a consistent 15-20 ft-lb with a 6 inch box wrench unless you have a calibrated wrist. Looking at my copy of "Road Racing the Ford 289 High Performance Engine", "Special Components & Specifications, Group 2 Sedan & GT 40", the recommended torque is 12-15 ft-lb (read aluminum intake here). So, that's a bit lower than your 15-20. The cast iron manifold recommended torque is something like 23-25 ft-lb. If the torque wrench is set properly and used properly, the installer risks very little. Of course if you whale away on the intake bolts, you're going to break something for sure, especially at the corners which are essentially unsupported.
People disregarding the differences in material strength is why we see lots of helicoils in aluminum parts. They treat those parts as if they were cast iron, crank on the fasteners "just to make sure they are tight" and end up stripping out the threads. The lesson here is be careful and know what you are doing before you do it, get help if you need it.
Quote from: pbf777 on October 19, 2021, 04:01:10 PM
Quote from: shelbydoug on October 19, 2021, 03:11:07 PM
Torque wrench? OK. What are the recommended values for the aluminum manifold vs. iron?
The use of a torque wrench does not dictate a torque value, just aids in executing and the consistency fastener to fastener of the torque value chosen! ;)
Scott.
+1
Quote from: shelbydoug on October 19, 2021, 03:11:07 PM
What are the recommended values for the aluminum manifold vs. iron?
Published intake manifold torque limits:
Cobra aluminum intake: 14-16 ft-lb according to the 66 GT350 Owner's Manual, I assume 65 GT350 manual is the same.
Stock cast iron intake: 20-22 ft-lb, according to the 66 Shop Manual.
For the Cobra intake I've always followed the recommended limits on the inner bolts but only use 12-13 ft-lb on the LF, RF, and LR bolts, and 8 ft-lb on the RR bolt since it seems to be the most problematic
Just as equally important is the torque limit is the sequence, make sure you follow it and you will be okay.
Back to my original post, I checked another 66 manifold today and it has the same "crack" pattern as mine. I now believe this is a casting flaw as others have stated. Still going to check with liquid, and if no leaks, install.
Thanks again for all the input to my original question.
Greek