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Hello and Oil Pressure??

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wolfman

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Hello, I am new to this forum. Just found out about it. Looking through - it looks great.

My question - I have a 76 1500. Does anyone know what I should be specifically looking for to cause the oil pressure to be slow to increase when the car is slightly warm?

I am in the middle of a tear down now. Cause - After driving about 6 miles, stopped the car. REstarted 10 minutes later, Oil pressure was slow to increase to >20#. Got the double clack from the low end. When pressure inceased >20# (10 seconds)clacking went away. but she's coming apart anyway. This is the first time this has happened. Normal pressure is 65-70+# cold and driving and 20-25# at idle hot. (Note: this was also after a fresh oil change.)

TIA
wolfman
76 Midget - engine on rack
71 Midget - in pieces
 
Welcome, Wolfman!

Sorry, I don't have an answer for you... But somebody will!
Just wanted to say howdy to the board!

Kim de B
66 MGB
 
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by wolfman:
Hello, I am new to this forum. Just found out about it. Looking through - it looks great.

My question - I have a 76 1500. Does anyone know what I should be specifically looking for to cause the oil pressure to be slow to increase when the car is slightly warm?

I am in the middle of a tear down now. Cause - After driving about 6 miles, stopped the car. REstarted 10 minutes later, Oil pressure was slow to increase to >20#. Got the double clack from the low end. When pressure inceased >20# (10 seconds)clacking went away. but she's coming apart anyway. This is the first time this has happened. Normal pressure is 65-70+# cold and driving and 20-25# at idle hot. (Note: this was also after a fresh oil change.)

TIA
wolfman
76 Midget - engine on rack
71 Midget - in pieces<hr></blockquote>

I'll second Kim's welcome...
savewave.gif
this is a great forum and getting better every day!
On your oil pressure, assuming you have a clean filter and fresh oil, it is possible you have a stuck or dirty oil pressure releif valve. If that's not it, then (and based on the noise you heard), I'd suspect the main and rod bearings. If its coming apart anyway, definitely have your crank looked at and new bearings on the low end. Bad bearings can definitely cause oil pressure problems - If you have the motor out and tearing it down anyway, I'd just have the bottom end redone. Then, when you reassemble, be sure to install new front and rear seals.

Good luck!
George
wink.gif
 
Wow. I have been racking my brain trying to think of a cause. I never even thought of the relief stuck open. Kinda makes sense. Would account for the slow build up. The relief is always open when I am up in rpms. The trip was relatively short, probably didn't reach equilibrium temperatures yet.

Ya, the bearings are on their way out. the crank will be examined, etc. etc. new seals. Seems like I just did this about 1500 miles ago, hey I did. Bottom end, but not that relief. You can bet it will not be forgotten again.

Brent
 
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by wolfman:
Wow. I have been racking my brain trying to think of a cause. I never even thought of the relief stuck open. Kinda makes sense. Would account for the slow build up. The relief is always open when I am up in rpms. The trip was relatively short, probably didn't reach equilibrium temperatures yet.

Ya, the bearings are on their way out. the crank will be examined, etc. etc. new seals. Seems like I just did this about 1500 miles ago, hey I did. Bottom end, but not that relief. You can bet it will not be forgotten again.

Brent<hr></blockquote>

If you suspect the relief valve, I'd just slap a new one in...they're probably not too expensive.

Cheers,
George
 
Yeah--I was thinking lower end bearings too. If you are doing a rebuild, might be a good time to go ahead with a new pump and pressure relief valve as well.

--David
 
Brent: One word..."plastigage" (sorry guys, I couldn't resist).

Really though, plastigage is cheap insurance that everything is OK before you button it all up.

Also, I have a '78 1500 Spridget (with a '76 motor). When I rebuilt it, I planned on deleting the air pump (and I know in Fla, there's no emissions insp.) As a result, I also deleted the large cast aluminum oil filter adapter (that's used to clear the air pump). I figured it's one less thing to leak or slow down the oil flow. I can't remember exactly (did this 2 yrs ago) , but I *think* the threaded adapter (that the filter screws onto) will screw straight into the block. It's worth looking at, since you have it apart anyway.
Good luck and welcome!

Nial
 
Update... I finished the tear down today. Surprisingly the bearings all look very good. They will be replaced anyway. One thing I did find, the DPO had made a modification to the oil relief valve. He had ground down the spring so it was about 3/8" shorter than it should be (compared to a new one). Then he figure he messed up, so he installed a piece of copper tubing over the valve shaft about 1/4" long. When I removed the relief valve a piece fell off in my hand. It looked like 1/2 of a washer. It was the end of the spring that the DPO had ground off.

I figure as long as its down, I'll have everything gone through and renewed where required.
 
My old '76 Midget had a sticky gauge-right about 20 psi, too. I drove around with it going no higher than 20 until I had an oil change done and it shot up to 70 or 80, and upon shutting down, it stuck at 20 again. A sharp rap on the gauge glass popped it back to the peg. Turns out both sender and gauge were going south. Clutch was going anyway, and I had tuition to pay, so I never did anything else with the car until we got rid of it.
BTW-the bearings only last 1500 miles?
shocked.gif

-William
 
I went and looked it up-apparently standing on the clutch at stoplights, while also wrecking the release bearing, also played havoc with the shims for the crankshaft, causing the crank to move a bit and wreck the bearings, etc. To the best of my knowledge, my old Midget had never had an engine rebuild, so maybe I got lucky.
-William
 
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