It worked! This evening I got the TR-250's engine all put back together
(surprise! no extra pieces), filled it up with oil, and cranked it. No oil
pressure. Hmmm. Look underneath to see where the oil must be spilling out.
Crank it some more. Look underneath again. Crank it some more. Finally, the
oil pressure shot up and engine revs tailed off. Now, stop and put the plugs
in, roll it out of the garage, and fire it up.
Wow! Oil pressure! Lots of oil pressure! No valve noise! Quiet as a mouse!
My previous wrenching experience was always on air-cooled Porsches and VWs.
They're supposed to be relatively noisy. (Germans like to know the engine is
running.) I never dreamed the valves were supposed to be as quiet as they
are now.
The numbers: 70 psi cold idle. 50+ psi hot idle. 75+ psi hot @ 3000 rpm. I'm
a happy camper.
Thanks go to Bob Bownes, Kim Graff and Dave Furiani (the latter two of Kim's
Imports - virtual SOLers, so to speak), and especially to Roger Bolick for
his fine instructions. I repost them here, with some embellishment of my own
thrown in.
1. Drop oil pan. Roger said the bolts take some torque to remove. Mine
practically let themselves out. Note that the four center bolts (two
front and two rear) are longer than the other 19. They attach to the
front and rear sealing blocks. (More on that later.)
2. Remove and replace rod bearings one at a time. Remember all must be
returned to their original positions and orientations. On my engine the
part numbers on the conn rod caps all faced the same way (top of the
letters/numbers pointed toward the front of the car). Push out the
bearing with something soft, like a plastic stick, wooden popsicle
stick, or the thin end of a wooden clothespin. Don't use anything metal,
as you will scar the journal. Use plenty of assembly lube. (Actually, I
just used clean oil, applied with a small paint brush.) Insert the new
bearing shells, making sure they stay properly aligned so the tang
nestles into its little slot. Plastigauge at least one. Mine was .003
before, .001+ after. Roger recalled his figures being about the same.
3. Mains are the same, except you do all of them at once. Even with all
four main bearing shells removed, the crank doesn't really go anywhere,
but don't stop now, because you don't want the extra weight on the front
and rear seals any longer than necessary. Be careful when you remove the
front sealing block, as it mates with the bottom edge of the gasket
between the front engine plate and the block. That chunk of gasket
stayed attached the the sealing block when I removed it.
I found the upper bearing shells a bit tricky to remove and insert. You
just have to fiddle with them and turn the crank to remove the old
ones. Oil both sides of the new shells. That seemed to help for me. I
plastigauged one main before and after. Same numbers as the rod
bearing. Again, make sure to retain the original position and
orientation of the bearing caps.
4. Before replacing the cap for the #4 bearing, remove the old thrust
washers. Both are above the crank, one in front and one behind the
bearing. I went in thinking the two halves somehow fit together into a
circle like the shell bearings. The oil slots face away from the
bearing.
5. Replace the front sealing block and the oil pan. In my case, I left
the piece of torn gasket attached to the sealing block, and made sure I
used plenty of gasket compound on all mating surfaces.
Replacing the oil pan is no place to get in a rush. I applied gasket
compound to both sides of the gasket then let it air dry for 10-15
minutes before putting everything together. I also cleaned the 23 pan
bolts. Still, some of them were a bit tricky to get started. I recommend
you also clean out the threads in the block before lifting the pan into
place. Remember the four longer bolts that attach to the sealing blocks?
Well, don't try and impress them with your Arnold Schwarzenegger act,
since their being threaded into aluminum.
I cranked the engine initially with the plugs removed to avoid any undue
stress on the new bearings while the pump was busy trying to get oil to
them. Before the bearings get any oil, the pump must fill up the oil filter
and the passages in the crank. It takes a lot longer than I expected. (A
spin-on oil filter would be useful here, as you could fill it with oil
before installing it. I think I will add one when I replace the oil.)
I broke for the evening after steps 1 and 4, and wound up spending 2-4 hours
on each of three consecutive evenings doing the job. Much of the first
night's time was spent getting set up and cleaning the oil pan. (I might
well reconsider and have it hot tanked in the future.) Some things that
slowed me down a bit: Over the years of working on German cars, my supply of
English dimensioned tools has dwindled, to the point where I don't even have
a 1/2" ratchet any more. Also, my engine was absolutely filthy. Most all of
the bolts on the oil pan were quite loose, as was the one I had to remove
from the bottom of the timing cover. When I get the chance and a bit of
daylight, I will revisit the timing cover.
My torque wrench is too big (both in length - over 20" long - and
measurement range 20-200 ft. lbs.) to work comfortably under the car. I
recommend a smaller one, certainly with a handle that is no longer than 15",
with a range that goes down to around 10-15 ft. lbs. at the lower end.
The other thing that was quite annoying was the lack of a 6" extension when
tightening up the oil pan bolts. I have a shorter extension for my 3/8"
ratchet, but a 6" extension would have really helped.
Finally, if I was to repeat this job, I'd get the underside of the car steam
cleaned beforehand. It would have saved a lot of clean up time. I just
didn't realize how dirty it was.
I'm happy with the results. Perhaps the repost of Roger's instructions will
be useful to someone else contemplating this job.
Ladies and gentlemen, start your engines!
Skip (montanaro@crd.ge.com)
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