Had the same problem a while ago. sounds like you are on the right track as
far as the cause of the trouble. Repeated valve jobs will sink the valve
seating level deeper into the head, which in turn puts the valve stem up
too high for the adjusters to compensate. How much did they buzz off the
head during resurfacing? sometimes they stamp this figure into the head,
but many times they don't. You would be wise to bite the bullet and have
lead free gas tolerant valve seats put in the head in the interest of valve
life, and even more importantly, to keep the compression ratios even from
cylinder to cylinder. Sunken valves can make a fairly big difference in
compression ratios, which can be felt as a bit of engine roughness
especially under full throttle
Good
luck!
Bob Westerdale
-----Original Message-----
From: Jerry Oliver [mailto:slantws@home.com]
Sent: Wednesday, October 20, 1999 5:57 PM
To: triumphs@autox.team.net
Subject: TR4A Engine part problems
I'm having problems putting my engine back together, apparently due to
incompatible reproduction valve train parts. After blowing the head
gasket on my 66 TR4A, and even though the engine only has a few hundred
miles on it, I took the precaution of having the head redone. Since it
was the original head to the car, rather than get an exchange head, I
sent it to BPNW for rebuild. They welded a small corner that had been
damaged by the previous rebuilder, resurfaced it, replaced the guides
and ground the valves. I also bought their rocker arm kit, replacing
rockers and adjuster. During reassembly the last few days I noticed that
a couple of the push rods were less the perfect, so I ordered a new set
from BPNW. While I waited for parts, I installed the head and all the
various pieces back on the engine. Come to find out that the
reproduction putrid cups are to small for the ball on the reproduction
adjusters. Ok, I'll use my old adjusters. No, they're better, but not a
good fit (ball does not go all the way into the cup). Ok, I'll just use
my old push rods. Bolted the rocker arm set on, and began adjusting the
valves. All adjusters screwed "in" as far as possible, and I got .010
clearance with only a minuscule part of the threads of the adjuster
screwed out. And on valve 6 & 7, although the adjuster is screwed all
the way in, I can't get any clearance. Pulled the rockers, and compared
them to the originals, and they appear very much alike. So, pulled the
head (again) to check the valves. They appear to be setting just above
the seat, though 6 & 7 are less so. I wonder if the combination of two
surfacing and a rather deep cut in the valve grinds could cause this
much problem? I have another engine, and tomorrow I will pull that head.
Then bold it and the new rocker arms on to see if the problem persists.
If it does, then I will change the rocker new arms for the old ones. But
I'm afraid its in the head valve grind or worse that too much material
has been removed during resurfacing. Has anyone ever had to grind the
end of the valve stem for proper clearance? Bye the Bye, don't buy those
push rods and rockers with adjusters until they solve this problem.
Comments welcome. Jerry Oliver, Olympia, WA.
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