TR6 TR6 Oil Pressure

[TR3driver]

Hope and ignorance says to do the small, easy and inexpensive stuff prior to ripping
into the bearings and the like. Wouldn't I feel beyond ignorant...

Years ago, while I was overseas, the wife called to say the oil pressure gauge in the family grocery-getter would rise just a little when the engine started, then fall back to zero. Had her take it to a local shop, who told her the engine had to be replaced immediately and likely wouldn't even make it home otherwise. He also said the car wasn't worth even a used engine (which was probably true at his rates).

Couldn't afford a new car at that point, so when I got home I promptly dropped the pan (which on that car meant also disassembling part of the frame and front suspension). Oil pump pickup fell out in my hands, so I assumed that was the problem, stuffed new bearings in and buttoned it up.

Imagine my surprise when the oil gauge did exactly the same thing! Sure enough, bad OP sender; the diaphragm was leaking oil into the chamber where the variable resistor lived. At startup it would take a few seconds for the oil pressure to equalize, so the diaphragm would deflect and cause the gauge to rise, but once the pressure equalized across the diaphragm, the gauge would read 0. And the ONLY external indication of the problem was a ring of oil around the terminal.

So I'm a real believer in checking the easy stuff first, even if it is unlikely. (Not to mention not trusting "professionals" to know a bad engine from a bad OP sender.)

 

[TheSearcherMan]

I would not do anything until I hooked up another aftermarket gauge, if you already haven't.

 

[2wrench]

Placed a second washer into the relief valve piston stem. Drove it. Higher
pressure for longer period; oil pressure reduced but not as low as before.
Still not quite right.

Pulled the valve. Check out what the piston looks like now. It's
scored. Maybe it hung up on the washers??? Funny, because the ultimate
end result was the same as before the washers were placed. This thing
acts like it builds the pressure; opens and never fully closes allowing
pressure to be bled off.

Parts were supposed to be in today but didn't come. Just ordered the
piston and spring. Now thinking maybe shoulda gone whole hog and got
the valve housing as well. We'll see after I try the new parts.
This valve piston certainly creates question, doesn't it?

This thing looks like if it wasn't hanging before I "washered," it, that
it certainly is now, doesn't it? I dunno. We'll see. Saga to continue.....

 

[poolboy]

Is that an illusion or is the shaft showing scoring from the spring's coils ?

 

[emmett1010]

hello;
a week ago I suggested that you have the oil pressure checked by a shop with an accurate guage to verify pressure.
Dave is right. you'll jump through hoops trying to figure out problems that may or may not exist.
emmett

 

[2wrench]

Is that an illusion or is the shaft showing scoring from the spring's coils ?

Poolboy: That is definitely scoring. It does look very much like it follows the
pattern of the spring coils, doesn't it? I don't know exactly what is going on.
I suspected it could be possible that one of the washers I had to "custom fab"
on my grinder may have slid down the piston stem and caused the thing to hang and
score.

Thing is, the symptoms the car shown after the washer placement were the same or
similar to the symptoms shown prior to washer placement. I keep coming back to the
nagging feeling (or not so nagging....hope springs eternal.....) that the seminal
issue presently at hand stems from this relief valve.

So replace it already???? Yeah. I'm waiting for the parts....and the washer
thing was an interim look at things and it made me all the more suspect.

That piston sure looks weird, doesn't it? Hope the valve body itself is not
playing into this...I only ordered the piston and spring. I figured, what the
heck could go wrong with the body? But, then, you never know.

 

[2wrench]

hello;
a week ago I suggested that you have the oil pressure checked by a shop with an accurate guage to verify pressure.
Dave is right. you'll jump through hoops trying to figure out problems that may or may not exist.
emmett

Not ignoring your advice, Emmett. Getting to a respectable shop will involve
driving beyond my comfort zone and/or trailering. I just need to get past this
haunting pressure relief valve thing.

Seems rather obvious something about that valve piston looks bad from the pictures I've posted, wouldn't you agree?

Also, it occurs to me that with the placement of the washer in the relief valve, I see an overall increase in pressure...both pounds and duration....therefore suggesting that it's quite likely that my pressure gauge in the car is working fine, it reflected, as expected,
the increase in oil pressure.

I want to take this thing one thing at a time. If I'm wrong on the valve thing, I'll
be reviewing all threads on oil pressure and mapping a plan of attack from least to most
at that time. Thanks for your suggestion. It is a very good idea.

 

[vettedog72]

Since your oil pressure regulator piston is damaged or at least warn, get a new one and spring for less than $20 overnight. At least you can eliminate the up down pressure is being caused by the piston and spring. I suspect a PO worked the piston and that is why it has those marks; nothing but oil under pressure is around it under normal use.

 

[dklawson]

I have not looked at the insides of a Triumph oil pressure relief valve before so please don't flame me. I'm sure there's a reason what I'm about to suggest isn't done with the TR engines but I want to mention bring it up anyway.

As I mentioned previously, the oil pressure relief valve in the A-series engine is a problem particularly on the transverse engine applications. A common upgrade is to remove the standard, bullet shaped, valve plunger and replace it with a ball bearing from a CV joint. The spring is modified by cutting off 2-3 coils to compensate for the additional shape and size of the ball bearing and the pressure is fine-tuned by placing washers as shims between the spring and the nut that retains it. A further modification drills/taps through the nut and the screw that's inserted pushes against the spring to allow real-time adjustment of the relief valve setting by pushing on the spring.

Obviously the TR valve is a bit more sophisticated in that it has the stem to guide it as is shown in the pictures above. However, has no one made or tried to make an adjustable oil pressure valve with a different sealing member?

 

[poolboy]

Doug L. While the valve is not officially adjustable, I believe it was designed to be. I know that might sound strange, but if you see how fine the threads are on the housing, it would make you wonder too.
The housing contains the spring loaded plunger valve and of course the more you turn it clockwise the more you compress the spring.
The threads are so fine it just lends itself to adjustment. A compressible sealing washer like on spark plugs or oil drain plugs would make a good seal, if any oil should make it's way through the fine threads.
I've had mine backed off of "full tight" since last winter, with a nylon washer as a spacer.

 

[2wrench]

The thing that annoys me most about learning from experience is that it
comes at a cost, both dollars and sense.

So I quote from a TR6 owner's manual (1975) re: Oil Pressure Gauge

"Oil pressure at 2000 rpm under normal operating conditions should be
45-65 lbs./sq. in. Severe operating conditions, such as competition
work, may cause the oil pressure to drop below 25 lb./sq. in., indicating
that the oil temperature is excessive. Under these circumstances, fitment
of an oil cooler may be necessary."

Wow. Okay. Overly-tight bearing tolerances (in lieu of 'competition work') equals hot oil equals low oil pressure??? Hmmmmmm.........

Hey, long as I only drive five miles at a time........

 

[DNK]

Since your oil pressure regulator piston is damaged or at least warn, get a new one and spring for less than $20 overnight. At least you can eliminate the up down pressure is being caused by the piston and spring. I suspect a PO worked the piston and that is why it has those marks; nothing but oil under pressure is around it under normal use.

BPNW

For both parts $6.37 +$12.10 for shipping to you tomorrow.

 

[poolboy]

The spring marks around the shaft are puzzling, but the pitting or wear around the seating surface might have been caused by debris floating around in the oil. Stuff like bearing material, metal shavings, whatever, who knows.

 

[AweMan]

F.W.I.W. When I purchased my used M.H. when cold it showed 60 lbs O.P. BUT @ normal op temp it showed 0 oil pressure, NONE NADA!
Being greatly concerned as you might imagine. I changed the oil filter {No change}
tore into and replaced the Oil Pump, {No change} Plasitguaged the bearings both main and rods which showed a little wear but not excessive!
Replaced them with one under bearings {no change in O.P.}. getting pretty frustrated at this point and nearly in the poorhouse from the expense. I decided and aftermarket guage was in order. Installed it and wah lah a solid 60 lbs of O.P. @ idle cold, so far so good. Warm it up to 180 degrese, @ idle 40lbs O.P yessssssssssssssssss.
Do yourself a favor after you replace the O.P.R.V. instal an aftermarket MAUNAL O.P. guage and see what you have.
Things may not be as bleek as you think.
Just my Pennys worth

 

[Tinster]

https://images.bpnorthwest.com/www.bpnorthwest.com/OPS312_sm.jpg[/img]

For both parts $6.37 +$12.10 for shipping to you tomorrow.

<span style="color: #990000">Wow Don, a good thing I don't need those parts.
BPNW wants $62.00 to ship them to me here in PR 00961 zip.
I was thinking about replacing them to lay safe but at this
$62. profiteering shipping charge - I'll take a pass.

d</span>

 

[DNK]

I'll send them to you. PM me your address.

 

[Andrew Mace]

<span style="color: #990000">Wow Don, a good thing I don't need those parts.
BPNW wants $62.00 to ship them to me here in PR 00961 zip.
I was thinking about replacing them to lay safe but at this
$62. profiteering shipping charge - I'll take a pass.

d</span>

Did they really quote you that price? Seems a bit odd, since -- according to the USPS web site -- "Joe LBC Enthusiast," living in Oregon, could ship 8 oz. to your Zip Code for between $2.23 (media mail) and $19.50 (Express Mail). Nothing against any vendor, but that's a pretty good markup!? :shocked:

 

[Brosky]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Overly-tight bearing tolerances (in lieu of 'competition work') equals hot oil equals low oil pressure??? Hmmmmmm.........[/QUOTE]

2W,

Do your self and your sanity a favor and get a gauge reading by removing the OP switch and get it direct from there.

I personally think that you may be chasing a rainbow.

 

[AweMan]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Overly-tight bearing tolerances (in lieu of 'competition work') equals hot oil equals low oil pressure??? Hmmmmmm.........

2W,

Do your self and your sanity a favor and get a gauge reading by removing the OP switch and get it direct from there.

I personally think that you may be chasing a rainbow. [/QUOTE]

Exactly what I did on my M.H. what a difference too!
I have a feeling if I had done it before chasing all of the possibilitys I could/would have saved a bunch of $ in the process.
None of the parts I replaced warrented replacement due to excessive wear but once the pan was off I figured why not "Freshen" it up { O.P. rod & main bearings }
Even with the new bearings and oil pump if I use the O.E.M. O.P. switch and Guage I get the same readings as before the replacement of parts. The Maunal guage is a peice of mind to say the least.

 

[2wrench]

My parts came in. They've been installed. The jury is still out.
I'm optimistic. I anticipate clocking some miles tommorrow in order
to confirm what I think is good. Don't want to jump to any conclusions.

I will be reporting more specifics by tommorrow afternoon or tomorrow
night.

Look for the dancing bananas and you'll know that sometimes ignorance
is bliss.

Bought an after-market oil pressure gauge. I expect to return it and use
the money to buy a cheap stethoscope to tune my carbs. If it's a little
pricey, maybe I'll just go straight to the synchrometer. Numbers will
tell.