<VV> VirtualVairs Digest, Vol 128, Issue 18

[John Weigel]

Is there a chance the head gaskets are hitting the top of the piston?


  
Message: 1
Date: Thu, 10 Sep 2015 16:24:16 GMT
From: "Brian" <bmoneill at juno.com>
To: fastvair at yahoogroups.com,    VirtualVairs at corvair.org
Subject: <VV> Engine Assembly Mystery
Message-ID: <20150910.122416.18050.0 at webmail02.vgs.untd.com>
Content-Type: text/plain; charset=windows-1252

I have run into an issue I don't think I've ever seen before when assembling engines. What I'm about to describe happens on either side. That is either the drivers or passengers pistons and cylinders installed. With three pistons installed on a crank, using cylinder hold downs so the cylinders don't pop up as I rotate the engine; the assembly turns smoothly and easily. When I put a head on and the nuts and the rocker studs, the assembly still rotates smoothly and easily. When I torque the head down using the pattern in the old Richard Finch book, just 10 pounds of torque causes there to be binding as I rotate the crank. Looking down to the top of the engine, I can see this happens as the as anyone of the rods changes direction. In other words if that piston again any piston if that piston was coming down away from top dead center at that point where it turns to go back up to the top of the cylinder I feel this resistance. If I continue to the full 30 pounds of torque, this bi
 nding becomes much more noticeable. If I rapidly rotate the crank it smooths out almost to the point that I cannot feel any resistance. However if I go slowly and sometimes stop just at a certain point it is extremely hard to get the crank to turn again. In all these tests I have rotated the engine in its normal direction using a large screwdriver and two bolts threaded into the harmonic balancer.Some pertinent facts are, this is a replacement case which according to its numbers is from a 69 AIR engine. The crank and cam are the same that was used in the original case which is being replaced because it sprung a leak. That's a whole nother the story. The pistons and cylinders are also the ones that we used on the original engine. On this replacement engine I had to replace two missing head studs. One lower and one upper both on the passenger side. I also installed those special case studs from Clark's. Those are the ones that have nuts on both and this and require reaming out
  the casepassage. I bolted the case together using standard case bolts and then reamed down from one side but did not go all the way through. I made sure that the fatter part of this case study was centered on the case. In my mind the studs don't seem to contribute to the problem. However maybe they do.So now I'm looking for some comments. Any ideas? Should I continue to assemble the engine relying on the power of the slaughter and then the engine to rotate through this binding feeling. Any assistance would be appreciated at this point I am frustrated and be willed or. Thanks.

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