Losing oil pressure

[sparkydave]

My 1500 engine has had a strange problem ever since resurrecting it 2 years ago. Whenever I make a hard stop, the oil pressure drops almost to zero. I replaced the oil pan last year since it was rusting badly and had a dent in the bottom, but when I looked inside, the oil pump pickup is not bent or damaged, and the full mark on the dipstick seems to be a ways up from the bottom of the pickup. My guess is the oil is sloshing forward and uncovering the intake, but does anyone else's 1500 do this? I'm reluctant to just put more oil in since I don't want the crank to splash in it, but the oil pressure is fine otherwise. It gets 50 PSI at speed and never gets below 20 at idle. Just curious, since it is a little unnerving to see it going way down and then jumping back up when I'm stopped. I keep the oil at the upper mark on the dipstick, and as far as I know the dipstick isn't bent, damaged or the wrong one. It takes 4 quarts to fill it up that far when I do an oil change.
-Dave

 

[fmichaels]

Dave,
I felt compelled to post a response without actually having the answer. I am rebuilding a 67 sprite. Twenty years ago when I actually drove the car it did the same thing. As I came to a stop (hard stop especially) the oil pressure would drop to zero. I never found out why this occurred but I am sure the guys on this forum ( and girls) will know this. I am as curious as you are on this one. I know there is a pressure relief valve on the engine that might have something to do with this but don't count on that response as any more than a guess.
Fred

 

[SilentUnicorn]

Just a shot in the Dark here fellas but ...there were two styles of oil pump pick-up. a curved one and a straight one. and possiblly two types of pan?? i had a post similar to this a while back , but cant seem to find it. one of the racing crew here will know about the pans. and there was something about spitfire pans being different?

mark

 

[Keoke]

Dave, I have no experience with that engine.However, if there are no baffels in the oil pan I would expect that type of response upon a sudden stop.FWIW---Keoke

 

[wolfman]

Dave, I had that experience all the time on my 76. Yes, the oil would sloosh forward and depending on how fast I stopped depended on how low the oilpressure actually went. I looked at it this way, seeing as the 76 liked to mark it's territory all the time, I figured the manufacturer installed this optional feature to inform the driver when the oil was 1/2 quart low. Invariably whenever the oil pressure dropped to zero on a sudden stop, the engine was 1/2 quart low. You gotta use all the indications your car is telling you.

 

[Keoke]

Wolfman, /ubbthreads/images/graemlins/lol.gif---Keoke

 

[sparkydave]

Thanks for all the info. The replacment pan actually came from a Spitfire, but it was identical to the one that came out, and there are no baffles in either one. So, I'll just make sure I keep the oil up, and I will concur that as the oil gets lower it doesn't take as much braking effort to lose pressure. Guess this is another little quirk of this engine, along with the infamous thrust bearings!
-Dave

 

[Dave Russell]

Has anyone considered adding baffles to the pan. It would certainly seem preferable to putting up with this design oversight. Attached is a pic of a properly baffled pan. There are small return slots in the bottom part of the baffles.
D

 

[jcatnite]

Dave,
Is that a pan you did yourself or did you find in on the web somewhere. I'm not tearing into mine till after this summer (hopefully) but would certainly like to add baffles when I have the engine out.
JC

 

[Dave Russell]

Jc,
It is a cast aluminum pan from Denis Welch - UK. The same ideas apply to any pan & baffles can be added. Even common old Chevies had pan baffles. There are likely aftermarket pans available for your car also.
D

 

[Tullamore]

FYI - The stock MOWAG pan I have on my 1275 Sprite has a baffle in the middle of it.

 

[jcatnite]

Thanks, When I used to build Fords V8's for fun I would always get a deep sump pan with a high volume oil pump. Those pans would come with baffles but I never really thought about adding them to a stock pan. Perhaps these little pans aren't deep enough to give the oil that "slosh volume" that it needs.
Thanks again,
JC

 

[aeronca65t]

I've seen this before: when a 1500 Spitfire oil pump and pickup was installed in a 1500 Midget.
It sounds like the exact same problem. Mark mentioned the fact that they have different pickups...he's correct.
If your oil pump pickup goes straight down and is fairly short, you have the right pickup.
If the pickup goes out from the pump on an angle (about 45 degrees) then you have the wrong oil pump pickup.
By the way, though I'm sure the oil pans will interchange, I thought that they were different on 1500 Midgets and Spits...are you sure that your car didn't already have a Spit oil pan and you've put on another one?

FYI: here's a picture of the incorrect (Spitfire) oil pump pickup (#69):

 

[sparkydave]

I'm a little confused by the picture; both pickups are labeled #69. Are you sure the angled one is the wrong one? My Midget 1500 Factory Workshop manual shows a picture that has the angled pickup, as do the pictures on Moss' website. The previous owner never had anyone do engine work on it, and it only has 30,000 miles, so I'm pretty sure the oil pump and pan are what came from the factory. I'm just guessing the pan is from a Spitfire, since I got it from a place that mostly recycled Triumphs. I just asked if he had a pan for a 1500 engine and that it was for a Midget. My pickup is the angled one.

-Dave

 

[aeronca65t]

The angled #69 is the incorrect unit.

The shorter straight-down #69 unit is the correct one for a 1500 Midget.