MTFCA Forum

Seeing a very fine line in the manifold, I suspected a crack and proceeded to wire brush and paint anyway. Crack seemed to go away. After running it, I now see that the crack is in fact, a crack.

Question 1: Can I should I drive it this way?

Question two: If I shouldn't, what are the chances of repair?.

Question C: If question A and 2 are off the table, how good are the new manifolds?

Throw it in the scrap bin & purchase a new one - they're good ! Save yourself some grief !

Run the engine and check for noise... If it's acceptable, that's your choice

I can't help but think that the crack will get worse. Replace it.

Been looking at the Langs manifolds since I got noticed the crack, so I'm adding it to my list.
Thanks everyone.

You might find a good original at Luray, Hershey, Bakersfield, etc. But going there is likely to cost more than a new manifold.

I have two or three good or NOS originals, but I have not decide to part with them.

The 'value' answer is to purchase new. It's the best value for buck to be found...sooo much gets resolved in and of itself just by going in that direction.

Before I close my comment...one more thought for 'youngin' and 'newbies'. There was a time stuff like this was discussed, even debated, openly on forum...not so much these days as us old guys move onward

You can almost always stop a crack in cast iron! If it is due to torsion of flex...not really...as the answer is a crapshoot If it's just the release of old internal stress from the original shrinkage after a billion heat cycles?

1- Drill a 1/8" hole at each end of the found crack with a sharp bit. Normally, end of crack propagation by this step alone.

2- so what about the remaining opening? The best old school is to take a 1/4" copper rod and thread it, even to 1/4-20 if you don't have a 1/4-28 available. Sink a 1/4-whatever tap at the first relief hole. Thread in the rod and cut off slightly proud. Stitch along with a line of overlapping taps and inserted threaded copper rod cut off proud. All done the daisy chain? 'peen' without too much attention, then grind copper off flush. Good as new and you might not even have to take the part off!

Actually a better old school hole fixer is what is called a 'rust joint'. I'll leave it to anyone who wants to know to do a lookup but some easily available things, mixed into a putty. Drill the relief holes at cracks end, work the 'putty' like you might JB...ALL DONE, by tomorrow as strong if not stronger than the original material.

Here's a post I did 15 or so years ago, was for a head backbone crack at the time, but same stuff...which explains the home made putty better. Every head backbone crack that I've done for the last 40 years I believe is still holding strong...at least I know the first and second have no issues to this day. Old school stuff is fun to chat about. I know, new world, new order, and if I had to work to live...then time is precious and the cost of a new is dirt cheap. For an old timer swatting gnats? I have all week to do old school things



Top of pagePrevious messageNext messageBottom of page Link to this message By George...Cherry Hill, NJ on Sunday, December 05, 2010 - 11:39 pm:

A hairline crack can develop for a couple of reasons, the most notable being run without water and that extra thermal expansion causes internal original stress in the back to try and move too quickly on cooling.

Actually, you are on the right track, it is a non-pressurized head, so...just stop the crack from spreading by drilling a hole at each end, not too big but do use a sharp drill. Some plug the ends by press fitting a chunk of copper rod and filing smooth to contour.

The crack itself will eventually rust itself shut provided it is a real hairline and not an open crack...but you probably don't want a weeper on your rebuild until it seals. In that case dremel or die grind it out a bit, and you can try a filler....but...the best would be what is called a rust joint where you can make that rust seal in about 24 hours.

Get a sal amoniac block at a solder supply store...lifetime and then some supply for about 3 bucks.....buy some near pure sulphur tablets at a health food store for about 2 bucks...also a lifetime and then some supply.

The proper mix is 80 parts iron filing, 1 part Sal amoniac, 1 part Sulphur. That works out to be a nice pile of iron, a pinch of Sal Amoniac, and a pinch of Sulphur :-) Mix it up, wet it enough to be a putty, and then pretend it is bondo! In about a day it will be as solid as a rock and water tight! Grind/Sand it out smooth to profile and good to go!

Sound crazy? You'll be amazed at how well it works!

it would have been interesting to see a photo of the whole manifold. I wonder if it is warped as well? When replacing it, be sure to use gaskets with glands that center the manifold into the block.

All about budget and your talent if you don't have alot then fox it ibmve had very good results with might welding the cash manifolds if you don't have the talent then buy a new or good used one

Thanks to George Mills for a wonderful description of how Granddad would have solved the problem. Knowledge of these older techniques needs to be preserved, an essential part of the antique car hobby.

That crack goes more than halfway around.

The manifold is trash!