The Payen head gasket last used was compressed to 0.055 at the fire ring. So,
with the 0.010 pop-up that I have from the all efforts to deck the block, I
will have 0.045 clearance. I have Carrillo rods and we try to stay to under
6000 RPM for engine ?longevity?. (Not sure ?longevity? is a term that can be
used with a race engine!) At the most we?ll hit 6200 or 6300 RPM briefly
before upshifting. Therefore, I should be within the 0.030 clearance that you
recommended. It will be interesting to see what the top of the pistons looks
like on the next rebuild with regard to carbon build up in the squish area.
Thanks for the advice and all the other comments on this subject. All much
appreciated. Still a lot to learn?
Tim
P.S. Finally got everything together on the engine and about ready to mate up
to the transmission and put back in the car. Looking forward to ELVF next
month. That will be the test.
From: fubog1 [mailto:fubog1 at aol.com]
Sent: Wednesday, August 16, 2017 5:27 PM
To: timmmurphh at gmail.com; fot at autox.team.net
Subject: Re: [Fot] FW: Grattan VSCDA next weekend?
Check the gasket thickness, it depends on what piston/wall clearance, rods, and
RPM you use.
You generally need around .030 piston/head with stock rods, so add that to your
pop-up of .010 for minimum gasket thickness.
If you run good rods you can run a little less before the pistons smack the
head.
It's perfect when there isn't any carbon build up on the piston tops under the
squish area.
When it's not right, it goes BRRRRRRRRRRRRR...
HTH
Glen
After all the machining to get the stick out
right I now have the pistons sticking up about 0.010 above the tops of the
liners. No problem with the composite Payen head gasket.
-----Original Message-----
Sent: Wed, Aug 16, 2017 5:48 pm
Subject: [Fot] FW: Grattan VSCDA next weekend?
-----Original Message-----
Sent: Monday, August 14, 2017 12:20 PM
Subject: RE: [Fot] Grattan VSCDA next weekend?
Sadly, we won't be able to make it.
I just got the block back from the machine shop last Tuesday. Not enough
time to get everything together and in the car and ready to go by Thursday.
The good news is the liner stick out is the 0.004 the machine shop said they
machined the liner seats and deck to. It's still a bitch to measure, as the
liners "wobble" on the seats and when you're looking for 0.004 it's a
problem. I finally have a decent dial indicator gage setup to at least give
repeatable readings. The figure 8's used was a set of copper ones I had
that measured 0.016. The machining was done on a single setup on a Rottler
floor type vertical 4-inch spindle milling/boring machine. These are
special purpose machine tools built specifically to machine engine parts,
such as blocks and heads. After all the machining to get the stick out
right I now have the pistons sticking up about 0.010 above the tops of the
liners. No problem with the composite Payen head gasket.
Thanks for all the responses to the Figure 8 gasket question. I did
eventually hear back from Moss UK. They said their steel fig. 8's are 0.016
and their copper fig. 8's were 0.018. No explanation regarding the
different thickness other that they have not had reported problems with the
gaskets. I'm not sure where the 0.020 thick copper ones that I measured
came from or for that matter, the 0.016 thick copper ones I'm using.
Tim & Ryan Murphy
1961 ('61, it is Comm. No. 511 and was built in 1961 per British Heritage)
TR4 #317 BRG
-----Original Message-----
Fot
Sent: Saturday, August 12, 2017 6:21 PM
Subject: [Fot] Grattan VSCDA next weekend?
Anyone else going to Grattan next weekend?
Vroom, vroom, Tony Drews
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