Cylinder head crack
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Burning Brakes
Joined: Sep 2010
Posts: 799
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From: Lexington Park Maryland
Cylinder head crack
I am helping a friend to eliminate the leaks on his 72 automatic; I thought I would start with replacing the valve cover gasket with rubber set. Replaced both side, then I started the car to warm up the rubber gasket and tighten the bolts more while it is soft to get a better seal. As the engine warmed up I started to see oil dripping on the exhaust manifold on cylinder 4 and 6 exhaust manifold. so I tighten the mount bolts more; but the oil kept leaking out, by now the valve cover mount bolts are tight and no more movement on them. So I sprayed some cleaner on the area to make sure it is coming from the valve cover, it was not. The cylinder head wall that retains the oil and funnels it back is crack, that's my initial assessment. If it is crack, has anyone experience this and can it be welded to seal it and call it good. The heads are after market aluminum heads the previous owner installed. The car runs great; I am thinking the crack is not affecting the functionality of the head vise,the oil leaking on the side.
Le Mans Master
Joined: Aug 2017
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From: Cool Northern Michigan
You can't really build up any type of material there on the inside such as JB Weld, brazing or RTV. That area has to remain smooth so as not to block the natural gravity flow of oil from the front of the head to the drain in the back. Any high spot along the oil return route could cause some starvation in the oil pan.
Maybe some type of seal on the outside only, but not on the inside.
But I m afraid the head is toast. It will be a constant battle to keep from leaking on the exhaust.
Maybe some type of seal on the outside only, but not on the inside.
But I m afraid the head is toast. It will be a constant battle to keep from leaking on the exhaust.
Last edited by HeadsU.P.; Jan 18, 2019 at 08:20 PM.
Race Director
Joined: Jul 2015
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From: SW Florida.
you have nothing to lose but a little epoxy by trying. do the inside and outside at the leak. and aluminum is weldable. there is also locknstitch. google it. drill hole. tap. thread in pin with anerobic sealer. grind smooth. they make aluminum repair pins. not cheap but effective.
Last edited by derekderek; Jan 19, 2019 at 07:13 AM.
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I would weld then smooth it out. Can you post pics of the crack.
