Just for general interest, thought some of you might be interested in how
Scrappy's motor is holding up.
At Ken Gillander's suggestion, I pulled the head and the pan. The engine has
about 10,000 rallye miles (no odometer anymore so it's a guess). I know it
had lost a little power, it was dieseling really severely on shutdown, and is
having trouble accelerating smoothly below 165f operating temp. Other than
that oil consumption is low and power is good. It has also been run as hot as
a sustained 215f. The engine has used Mobil 1 since break in. Cranking
compression from cold was 165 high to 150 low, so I also suspected some valve
seating issues. The engine is 87mm with 9.5:1 compression.
The rod bearings are smooth and clean, no pits, but the white metal is
getting thin, so it will get a new set. Easily the cleanest bearings I have
seen out of a running engine. It's balanced, runs the harmonic balancer, and
the rods were sized. If I wasn't just seeing some steel in spots I'd leave
'em. This explains the loss of some oil pressure at hot temps at idle, I'm
guessing. It's not serious, just a change from when the motor was fresh. The
thrusts are fine. I left the mains alone since they aren't usually a problem.
The tappets likewise are perfect: no dishing, no pits, looks like I put them
in last week. They are stock, against stock valve springs. I don't normally
run high rpm's, but every once in a while it sees a 5000 rpm squirt. It has
an Erson 260 cam.
I suspected carbon was the dieseling problem, and I was right. Heavy carbon
deposits in the combustion chambers, but not so much on the pistons. The area
across from the plug had 'fingers' which were gray and obviously the ignition
source after the key was shut of. Took quite a while to chisel these out. I
attribute it to indifferent gas from all sorts of weird stations across the
country, and a lot of relatively low speed running. There were only normal
build ups on the backs of the valves, and I expected to see more there.
The steel guides were also as new, and the valve stems were perfect. I am
becoming convinced that bronze guides are too soft and wear faster than
steel.
There was no wear on the valve train: the tops of the valves were as new, and
the rockers nice and snug. I also use the overhead oiler conversion, which I
like a lot.
The exhaust valve surfaces were pitted, and some seats had some minor
recession starting. The intakes were likewise not perfectly clean, but not
pitted. The exhaust valves all cleaned up nicely. I have my own valve
grinder, and I do 2 angles plus hand lapping to assure perfect sealing. The
low cylinder had the most exhaust wear, so that's what I expected there. Once
reassembled all valves are tested for leaks by pouring gasoline in the ports.
No seepage.
The head is ready to go back on, and the rod bearings ready to pop back in.
Once she's refired and heat cycled, I'll run a compression test and see how
much difference it made. I'm going up 2 heat ranges to chase the cold running
problem. Otherwise, I'm real happy with how it's held up, easily the best TR
motor I've had so far. Thanks for the help, parts, and advice, Ken. It surely
worked!
Steve Hedke
British Pacific Ltd.
26007 Huntington Lane, Unit 2
Valencia, CA. 91355 USA
orders: 800 554 4133
tech: 661 257 8634
e-mail: britpac@aol.com
web: britishpacific.com
fax: 661 257-9765
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