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TR6 TR6 MANIFOLD GASKET QUESTION

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H

hkzimmer

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I HAVE A 71 TR6. ONCE AGAIN I AM HAVING PROBLEMS WITH THE MANIFOLD GASKET LEAKING W/ NOT THAT MANY MILES ON THE VEHICLE. I PUT ON NEW SPRING WASHERS WHEN I REPLACED THE GASKET THE LAST TIME AND TORQUED THE NUTS TO SPECIFICATION (RIGHT NOW I CAN'T RECALL HOW TIGHT). ANYONE HAVE ANY SUGGESTION ON HOW TO INSTALL THE MANIFOLD GASKET AND NOT HAVE PROBLEMS WITH IT? SHOULD I USE A GASKET SEALANT WHEN I INSTALL THE NEW GASKET AND IF SO WHAT BRAND? THANKS FOR ANY HELP.

HANS
 
Hans,
It's possible that your intake manifold is warped. Check the mounting face with a straight edge. If you don't have a long enough straight edge put the manifold on as straight a surface as you can find and see if it rocks. My brother's TR250 had a warped intake manifold. It cost around $50 to have a machine shop reface it.
 
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Other things to check :
Head surface is flat and not distorted.

That the stud threads are not distorted and are long enough that the nut clamps only onto the manifold (through the bridge pieces).

No burrs or other defects on either sealing surface.

Manifold isn't hitting anything else. (Not sure about a TR6, but TR3 manifolds sometimes foul on the edge of the cylinder block.)

Nuts are in good condition and spin easily all the way down the threads; spring washers still have their spring. I usually find the spring (lock) washers need replaced almost every time I have the manifolds off.

I've also found it helpful to check the nuts for tightness occasionally (I make it part of my major tune-up procedure).

Not sure if this would apply to a TR6, but on a TR3 there is no flat washer or bridge piece on the outermost studs. Adding a thick flat washer between the lockwasher and the manifold made a difference for me.

You shouldn't need any sealant on those gaskets, IMO. If everything is right, they'll seal fine. And if something is wrong, it should be fixed.
 
Perchance, are you talking about exhaust blowing out and are you running headers. Which manifold are you talking about, exhaust or intake. Explain.
 
I retorqued mine after 500 miles and was amazed at how loose they had become. And I have all new studs, lock washers and the proper nuts. 300 miles later and they are tight as a drum. I guess the initial will be the most critical.

If I did it over, or when I swap heads, I'll check them at 300 first, rather than 500.
 
I find TR6 manifold fasteners need attention about as much as the valves need to be checked. I think the heat must take a bit of the spring out of the washers; I just don't know why they really back off but the heat/spring helps with a plausible explination.
 
a retorque should be on everyones list of things to do after replaceing anything on the engine block, especily heads and manifolds. I always do it after the first warm up to full temperture and again in 3 to 5 hundred miles.
So don't bolt that valve cover gasket down tight the first time, just set it on and tighten it by hand, only put sealer on the cover side for the first 3 or 5 hundred miles, then retorque with sealer on the head side. Check for leaks often until you fully seal it, or buy two gaskets.

Wayne
 
For a rocker cover gasket, just buy one of Justin Wagner's magic silicone gaskets and be done with it. No leaks, no retorque and best of all, it's reusable.
 
OK, Randall, how about that link again for the silicone gasket?
 
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