Wayne, if your oil pressure was 20 when hot you are very nearly due for an
engine rebuild. Your oil pump clearances sound fine, but 20 psig when hot
indicates a LOT of wear. My only experience is with the TR3 engine, but
this will mainatain 60 psig when hot when new. I would imagine this is true
for the TR6 - 60 psig when hot is fairly standard for english cars. The
grey goop you saw is most likely an emulsion made up of water, old oil and
metal worn from your mains, big ends, rings, piston sides, valve guides,
timing chain, timing chain tensioner etc. Most of this is aluminum based.
One thing you should check, before you get into a full rebuild, is to make
sure the pressure relief valve is not hanging up. If it is not seating
correctly after the oil has warmed up. then you will get the low oil
pressure that you describe. I'm not sure where the relief valve is located
on the 6 - I'm sure that someone else on the list will know. Good luck!
BTW, my TR3 has had 30-40 psig when hot for the last ten years, so that
rebuild is not
something that needs to be done tomorrow, but remember, low oil pressure
will accelerate any wear that has already started. It's not going to get
any better!
-----Original Message-----
From: Rengrave@aol.com <Rengrave@aol.com>
To: Bud_Rolofson@nps.gov <Bud_Rolofson@nps.gov>
Cc: triumphs@autox.team.net <triumphs@autox.team.net>
Date: Thursday, November 05, 1998 11:53 PM
Subject: Re: Received Carb Info (Longish)
>
>Dear Bud and anyone else interested,
>
>After 15 years of owning my 1973 TR6, I have never had a problem starting
the
>car, in fact I would go so far as to say that the car was very reliable and
I
>was never afraid to drive her on any trips.
>This year, after a new paint job (Mallard Blue) and attending my first
season
>of car shows, I decided to spend time cleaning the engine compartment,
>renewing the engine to it's original clean state. When removing the carbs
top
>covers for polishing, I discovered a large tear in one air valve diaphragm.
>This made me commit to the dreaded CARB REBUILD. After rebuilding with TRF
>gasket kit and installing Grose jets and following the limited info that
came
>with the kit, I couldn't get the car started. The plugs were getting wet
(mix
>to rich). Even with the needles adjusted all the way down into the orifices
>(the leanest setting), I still have was getting wet plugs and the only way
I
>could start the car was to floor the gas pedal and leave the choke all the
way
>in.
>A fellow lister, Adrian from Canada, helped me out by suggesting various
>things to check on my carbs. He even mailed me some carb info which gives
very
>detailed info on my ZS carbs. (Thanks again Adrian)
>It seems that after dismantling the choke and adjusting the small screw (7
>turns out) in the small diaphragm on the cold start valve might have
helped. I
>still think my mix is rich, but it probably always was. I can start the car
>every time now :)
>My new problem is very low oil pressure after reaching operating
temperature.
>At cold start, I get 60 psi, when warmed up, I get near 0 psi. Even when I
rev
>the engine, the oil pressure does not rise like it use to? I think all the
raw
>gas that has been going into the cylinders after the carb rebuild has
>contaminated my oil in the base and from what I here, this makes the oil to
>thin to pump and thus, gives a low oil pressure reading.
>Is this true?
>I have drained the oil and dropped the oil pan. The oil pan hasn't been off
>the car in the 15 years I've owned the car. In the bottom of the oil pan,
>under all the very black oil, was a thick gray colored muck, I think this
is
>worn steel powder that has settled over the years.
>I pulled the oil pump off and cleaned and measured, the allowable clearance
>between mating parts is max. .010", I had between .006" and .008" but I
>noticed small scratches on all the outer services of the middle gear on the
>oil pump. How much affect do these scratches have on oil pressure using
20-50
>castrol oil?
>I think I will put everything back together and add fresh oil and filter
and
>see if I get my oil pressure back to the 70 cold and 20 hot readings that I
>use to have before the gas contamination.
>
>Wayne from Massachusetts
>1973 TR6
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