I can answer the question on the pistons. On one of my BSR U20 rebuilds,
they used +.040 R16 pistons to raise the compression and needed to fly cut
reliefs for the valves. The stock pistons did not have any reliefs. This was
how they built their own engines too. BTW, in the late 60's the pistons were
$5 each, still have the bill!
Jerry Krakauer
SRL311 00099
-----Original Message-----
From: datsun-roadsters-bounces@autox.team.net
[mailto:datsun-roadsters-bounces@autox.team.net] On Behalf Of Marty
Escarcega
Sent: Monday, March 28, 2011 3:24 PM
To: datsun-roadsters@autox.team.net
Subject: [Roadsters] 1600 Cylinder Head height
Does anyone know the factory thickness of the Cylinder head? Ours reads
about 3.160". Reason I ask is that we had noise in our engine (1967 1600)
that sounded like valves. We pulled the head and it was apparent someone
removed the head before. Pistons have been hitting the bottom of the head,
nice shiny spots on the pistons and the head. Also pistons in Cylinders #1&4
have damage indentations from the valves hitting them at one time (don't
look fresh)
Do the factory domed pistons have reliefs for valves or no?
I am contemplating milling the area where the pistons are hitting the
combustion chambers to gain the clearance back.
I surmise that perhaps someone did not adjust the valves correctly and
damaged them when pistons hit them. They were bent, head was removed for a
valve job and someone milled the head too much. (or a poor man's performance
upgrade)
The other option I'm told is doubling the head gasket or I was told there
was a copper shim made at one time for this problem.
Neither strike me too well. The downside to milling is I don't know how much
meat is in that area of the head. I think removing .050" should be fine.
Any thoughts comments appreciated.
Marty
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