I'm having a similar problem, never seen it before. I'm on a fresh built motor
from the off season, top to bottom.
I'm on my third top end tear down and can't find the compression leak. I've had
all the liners out,
Started out with .003 - .004 liner projection. Cold, pre-start compression was
210 +/- 3 lbs across
all cylinders. After start and cam run in #'s 1 & 2 cylinders are 90lbs
exactly. I've done this three times
the first time with solid copper gasket, the second two times with Cometic
composite gaskets.
After the second time all liners were removed, and re-elevated to .004-.005
with thicker base gaskets.
All the pistons out and re-ringed. It wasn't the rings, I was really hoping I
got a couple compression rings
in upside down but no.
I use a torque plate every time a liner is removed to seat it squarely in the
bore. Before that I used to
use the head to seat them. Trying to cinch down a liner with a head stud was
always futile because
they will rock in their bores.
The compression never returns to 210, after the first heat cycle on a new head
gasket 1 & 2 drop to 90
and stay that way. A cracked head is highly unlikely as it seems # 1 & 2 are
sharing the same compression leak
since both are consistently 90 lbs. On a leakdown all I can hear is air in the
crankcase. My best guess at the moment is
it's getting past at the pushrod gallery. No compression getting into the
cooling system or I/E ports.The gaskets do not show
leaks like you would see after a common head gasket failure with either
evidence of coolant passing through or
hot gasses getting by. I have a total of about 65 minutes run time on the
motor.
All I can think of is some sort of block deformation going on. I bought a
couple precision straight edges, the head is
perfect, with the block in the car it's difficult to tell.
I pretty much tabled my season before it ever started in May, ran out of time
for it. I'm getting damn good at tearing the top
end off of it though.
jim g
----- Original Message -----
From: "timmmurphh--- via Fot" <fot at autox.team.net>
To: "fot" <fot at autox.team.net>
Sent: Wednesday, August 16, 2017 10:27:04 AM
Subject: [Fot] FW: Grattan VSCDA next weekend?
-----Original Message-----
From: timmmurphh at gmail.com [mailto:timmmurphh at gmail.com]
Sent: Monday, August 14, 2017 12:20 PM
To: 'Tony Drews' <tony at tonydrews.com>
Cc: ryan.murphy at fdlco.wi.gov; Steve Yott <tr4 at wi.rr.com>
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-----
From: Fot [mailto:fot-bounces at autox.team.net] On Behalf Of Tony Drews via
Fot
Sent: Saturday, August 12, 2017 6:21 PM
To: fot at autox.team.net
Subject: [Fot] Grattan VSCDA next weekend?
Anyone else going to Grattan next weekend?
Vroom, vroom, Tony Drews
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