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Oil pressure problem. Should I worry?

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vping

vping

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Fire it up to go to work and she starts fine. The OP creeps up to about 45 psi and then dips to 20 and I hear a slight ticking. (Never did this before - oil changed last summer and only driven about 200-300 miles) She idles and the OP increases. back to 45-50. I start to drive. OP is a steady 50 at speed. Stop at a light OP dips to about 48. Put it in gear and take off. OP drops to 20 and almost to 0 but springs back up to 50. Ticking stopped after about 10 seconds.

What gives? Not sure if this is normal for these cars or not so I post to make sure.

If my Oil pump is going, what does the swap entail? Engine pull?
 
Only time you should see "0" is when switched off. If the pump pickup sucks air this can happen, but usually that'd only be if you were over a quart low and in a hard turn. To do a proper inspection you should pull the unit. It can be done in the car but AFAIC it's easier and safer to just pull it.
What you describe would suggest doing it soon. /bcforum/images/%%GRAEMLIN_URL%%/shocked.gif
 
Interesting... My MGB just after changing the oil this weekend start me thinking about oil pressure. It runs @ 70PSI consistantly when under load and idle is around 50psi - is that ok? I seem to remember 50 to 60PSI under load and around 40PSI @ idle. What are good numbers?
 
Yes, I would worry. I would suspect very low oil or a bad pump. I suppose it's possibly in the relief valve too. Probably not but worth checking first.
 
Yes, I was responding to the first post. Your numbers sound good to me. If you changed oil filter brands, that could easily account for the pressure change. Always use a good filter! /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
 
DrEntropy said:
Only time you should see "0" is when switched off. If the pump pickup sucks air this can happen, but usually that'd only be if you were over a quart low and in a hard turn. To do a proper inspection you should pull the unit. It can be done in the car but AFAIC it's easier and safer to just pull it.
What you describe would suggest doing it soon. /bcforum/images/%%GRAEMLIN_URL%%/shocked.gif
Click to expand...

Pull the pump to inspect or pull the engine to take out the pump to inspect the pump.

I did notice that it was a bit low and it is only on takeoff. It really only goes to 20 but kinda bounces around a bit. It does not hit zero and stay there by any means. If it did that. I would have turned around and gone home to get me truck.

I just bought the stuff to change oil. Fram I think, and am scheduled to do it on Saturday.
 
Throw the Fram away quickly! Change the filter & see if that solves the problem.

If it doesn't, pull the oil pressure relief spring & put something small & round in the hole in front of it to see if that solves the problem.

If it doesn't...........
 
...time to pull the engine... (just finishing Tony's post) /bcforum/images/%%GRAEMLIN_URL%%/devilgrin.gif


And I meant the engine/tranny unit above.
 
Just wondering ............ does this engine have an electrical oil pressure sending unit? IF it does, you might check the wireing connection to ensure that it is affixed tightly to the unit. Before going to the legnths of pulling the engine I myself would try another sending unit if checking the connection doesnt fix it. OF COURSE instaling a premium oil filter would be a good idea too! IF none of the above cures the problem the next step woould be to dissasemble the oil pressure relief valve and check for blockages. IF none of these options cure the low oil pressure readings then I would look into replacing the oil pump.
One other option is to go to your local parts store and purchase an aftermarket oil pressure guage, NON electrical. Hook it up and check the reading with it.
It could be your guage has gone bonkers too!
Pulling the engine would be a LAST RESORT for me!
Just some thoughts.
I hope it is something simple and can be redily repaired
Kerry
 
He's got a '67 MGB-GT. Hard gauge. Putting another hard gauge on it just to check the on-board one would be prudent, tho.
 
My thoughts exactly Doc. After market Hard guages are cheap enough as to not kill ones budget either.
My thinking is a fluxuation in pressures doesnt mean a bad bearing usualy. The symptomes of low oil pressure due to worn bearings is good high pressure on cold start then falling off as temp comes up. I cant say to my thinking an oil pump would be intermittent. The only other thing that comes to mind is a low crankcase oil level starving the pump on acceleration.
Or as stated previously by someone other than me, the oil pressure bypass valve is sticking. Possibly it could be the line from the engine to the guage is blocked or partially blocked {my reasoning for wanting to try another line and guage.} Last but not least the guage is bonkers.
 
Yep Steve, Spam stinks and so do Fram oil filters.---Keoke
 
OK. I'm back to finish and reply. I get in it last night after practice and she starts fine. OP is up. I take off and the ticking is more like clacking. but only in first and when I accelerate hard than normal. Oil level is a little low.

First off, return the Fram.

Second get a better filter and change the oil. Recommendations on type/brand of 20/50 I should be using? 80k ona clock.

What and where is this relief valve? Pics?

I have a few midget Gauges will they be usefull or not depending on what happens when I change the oil?

I have an OP from the '72 block I'm stripping. Just bu looking at it how can I tell it's condition - I'll know what I am looking at when and If I need to pull the '67.

When all else fails, pull the motor and oh perfect time for the OD to go in :smile:

Answers if you could and don't be gentle. I want the reality of it all. I did not spend all those hours, dollars and days resurrecting this sucka to have it splode on me.
 
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