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By '49 bomb! - 5 Years Ago
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hi all! I just rebuilt my 272 over winter, it only has
some limited miles. what is going on is, it's puffing
blue smoke upon start, and using some oil. ( I had
this issue prior to rebuild). I had the heads recondt.
at a reputable shop?. they said they put new guides
as needed?. I know there are no valve stem seals
on the exhaust valves. I took the headers off, found
some oil on some exhaust valves. I really don't want
to have to take these heads off again. does anybody
have any suggestions how to stop this oil burn?
thanks!
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By Ted - 5 Years Ago
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You do need seals on all the valves. A positive type of seal is more effective than the umbrella seals when it comes to oil control down the guides. I’m surprised that the person(s) doing the head work did not install seals on all the valves. With all that being said, umbrella seals can be put on the valves that are missing them without pulling the heads. If the heads have been machined for positive seals on all the guides, then use positive seals instead of the umbrella style. Doing this operation with the heads on the engine will require pressurizing the cylinders while using the appropriate tools to remove and replace the springs while the valves are being held in place with air pressure.
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By oldcarmark - 5 Years Ago
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Ted beat Me to it! Great Minds think alike as the saying goes. LOL. I am almost Positive there should be Seals on all Valves. Why would there not be Seals on the Exhaust Valves???
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By '49 bomb! - 5 Years Ago
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Something else just came to mind? This is a heavy duty truck engine. Which means it has bigger diameter exhaust valves. Does anyone know what size umbrella seal I need, for exhaust valves?
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By 2721955meteor - 5 Years Ago
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heads are most likely from industrial ,or truck engine ,and sodium filled stems,you will need to find a ind. dealer for the bigger seals.also on intakes i use 289/ early 302 vave seals,just trim the umbrella 1/8th ,so it has more umbrella than correct yb seals
you may want to remove the heads and get have stem bushings from 54scrub 6cyl have them iinstalledin exhaust discard the sodium valves.and retainers.ther are usually hardened seats in ind. cases in ths1s idid the stock y ext. where same head size. hear in canada those engines where in lumber cariers and fork lifts. good luck
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By darrell - 5 Years Ago
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these heads dont use seals on exhaust.the odd time an engine will use oil after the heads have been of.
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By 2721955meteor - 5 Years Ago
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not saying they did use seals,suggesting how they can be be modified to be useful on the street,as sodium vaves do not belong on a light duty engine
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By darrell - 5 Years Ago
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i ran a 292 heavy engine in my last 56.all truck parts and sodium valves.ran as nice as any i ever drove.
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By darrell - 5 Years Ago
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i know sodium valves are not for the street as you say but they dont cause any amount of oil burning without seals mine gave about 1000 to quart.it was a rebuild out of a cabover so i didnt want to take it apart had 471 heads.a real nice engine.
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By DryLakesRacer - 5 Years Ago
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If you don't have air, take out the plugs (you are anyway) and put in some clothes line rope and rotate the piston around until it stops hold the valves, then compress the springs removing the keepers/retainers and put the seals on and reverse the procedure. I always put seals on all the valves done it too many times to count, Even an O-ring will help...
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By '49 bomb! - 5 Years Ago
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Great answers from all you guys!!!
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By '49 bomb! - 5 Years Ago
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I appreciate your reply ted, coming from a man with your knowledge... So, the heads were not machine for positive Seals. I only have umbrella Seals on the intakes. What do you recommend I put on the exhaust valves? Your help is greatly appreciated!!!
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By Ted - 5 Years Ago
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'49 bomb! (6/23/2019)
I appreciate your reply ted, coming from a man with your knowledge... So, the heads were not machine for positive Seals. I only have umbrella Seals on the intakes. What do you recommend I put on the exhaust valves? Your help is greatly appreciated!!!
Contrary to popular belief, the sodium filled exhaust valves did come from the factory with umbrella seals installed. Not running any seals on the exhausts in the long term will slowly create a build up on the valve undersides and eventually create other issues. I don’t stock those particular seals simply due to not restoring those heads with the original large stemmed valves in them. A shop that works on truck engines should have some of those seals floating loose. You could also try slipping some 3/8” stemmed umbrella seals over your current valves in lieu of finding the 7/16" seals and see if that works for the short term.
And here’s the reasoning behind why not to use those 7/16” stemmed valves in a street engine. In the truck engines, sodium filled exhaust valves have a life expectancy of ten years as the sodium does corrode or eat away at the interior of the valve stem and makes the valve prone to coming apart. It’s obviously not a good thing for an exhaust valve head to be bouncing around on top of moving piston. For what you are doing, a good cylinder head man would have simply recommended installing a new set of 11/32” guides and the appropriate new valves for the exhausts to get rid of the sodium filled exhaust valves.
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By '49 bomb! - 5 Years Ago
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What a great reply ted! Thank you for taking the time to write back.. I know you are quite busy....
Richard
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