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Oil pressure ???s

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Moonie527

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Okay, the purists over at mgexperience have already chastised me for my treatment of this poor car but after some searching around here it looks like I could actually get some advice as opposed to opinions. I'll try to give you all the info I can, '73 Mgb with unknown mileage, new head, weber setup, and plenty of oil leaks. At start up it clatters a little but settles down once warm. Oil pressure is around 5 to 10 psi cold and shows between 0 and 5 when hot. Running down the highway at 3500 rpm it stays right around 25 psi hot and cold. I've driven this thing roughly 200 miles this way and it seems to get no better or worse. The pressure results above are after an oil change. Testing with a known good external mechanical gauge verified the results. Sitting in the driveway holding a steady 3000 rpm the needle goes up and down in a roughly 5 psi sweep. Is there any other tests to perform or do I need to go into this thing? Also, is brit-tek the best deal going on engine kits or does someone else have a better deal?
 
You need to get it apart. Sorry, but thats the best answer. fresh engine will be alot more enjoyable too and to continue driving it is risking doing damage to what may still be a salvagable crank and other expensive bits.
 
Alright, i,ll give a thought. If you are getting a sweep of 5 psi at the guage the oil pressure release valve could be opening and closing. And at a very low pressure. I would change the Valve and spring and see what happens. Its a cheap and easy start. The next step would be to remove the oil pan and check the clearances in the oil pump and install a new set of rod bearings.(and maybe a oil pump).In a perfect world the engine would come out and a full rebuild would happen. If you are just going to tool around town and stay within your 100 mile free tow thru AAA then start with the release valve.Just remember if you are doing 60 and spin a bearing it will lock the engine down and that will also lock the rear wheels down till you put the clutch pedel down. Could be a real bad situation! How long before winter hits Iowa? With the head already done the bottom end could be a great winter project. Start looking for sales on pistons,gaskets, cam, lifters etc. Or give Tony a crack at pricing the parts for you. We'll help you thru it. And no chastising. Bob
 
Until you do get the pan dropped and rod bearings replaced I would change the oil to straight 40 weight and add a can of STP. This is NOT the preferred option to rebuilding but may keep the engine turning until you do a more proper fix.
Bill
 
I had similar problems but slightly better pressure - the flutuating freaked me out though. I changed to a Bosch filer from Fram and changed my oil over to Rotella. I have decent, steady pressure around 70psi at speed and about 50 at idle. Prior to that I had 25-50 with bigger sweeps. Not sure which made the difference but I feel better looking at the guage now.

I'm planning a total rebuild and have already purchased block, Crank and Head but need to source out the balance.
 
Thanks for all the ideas. I'm still gonna drive it, just gently and not too far. The oil leak has gotten pretty bad as well so I don't want to be an environmental ne're-do-well depositing puddles of 20w50 everywhere I stop.
 
:iagree: All of the above comments regarding imminent rebuild and a photo for illustration purposes:
 

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I also hav changed the oil more time than I normally would. Either from leaks or burning oil, when I notice it's a bit low, I change it and it's usually black. Since I don't have all the history on the car, I don't know how well it's been kept. Who knows what kind of gunk lurks in there.
 
Not very well I guess. Still hanging in there at 25 psi when hot down the highway. Looks like its time to pull the motor. Back to the engine kit question. I like the idea of buying something in kit form, maybe add main bearings to the brit-tek minor engine kit or something. Would it be cheaper to source everything seperately? There are a lot of weird little incidental parts that I am not familiar with on this engine, any suggestions on other items that may be required? I've only got around $1k in the budget for all this so I'd rather not pay for parts that I don't need. I come from the land of the small block chevy so this motor is foreign to me (bad pun intended).
 
How extensive of a rebuild do you want to do? Timing Chair and the bearings? Are you looking to replace the cam, pistons and rings or go further?
 
Probably rod and main bearings, rings, timing set, gaskets, and a mild cam while I'm in there. If it absolutely needs machine work I'll do it. I'm trying to go cheap here, hence the ?s about the brit-tek kit.
 
I would really avoid any (power) cam in that engine until you do a complete rebuild (ie turned/polished crank, new pistons , etc). Remember that a new cam is a bad idea without new lifters too.
A new (or well reshimmed) oilpump sounds critical at this point too.
Bill
 
Machine work is mandatory. Boil block and head, grind valves, look at guides, hone bores, polish crank, etc.
 
My other option is a local parts car. Its a '75 with around 50k on it that is supposed to run good. I figure to swap over the Weber from my car to that motor and go, are the distributors different as well?
 
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