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Spitfire Oil pressure in a 1500 Spitfire

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78Z

78Z

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Ok so I finally got my Spitfire put back together, insured, lisenced, etc. Took it for a quick little test drive tonight. When I fire it up oil pressure is about 40 at idle and 60 under load. Then after about 10 mins it went to 40 under load and 20 at idle. As I quickly drove back to the garage it even dropped a bit more. This seems low to me. I don't remember it doing this when I bought it but I've never really got to drive it. The tempature guage says its not over heating. Anyone know what is normal and why it should drop like this? Any ideas/suggestions? Thanks.

oh the headlights stopped working pretty quick too. haha - Lucas strikes again!
 
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by 78Z:
When I fire it up oil pressure is about 40 at idle and 60 under load. Then after about 10 mins it went to 40 under load and 20 at idle. Anyone know what is normal and why it should drop like this? Any ideas/suggestions? Thanks.
<hr></blockquote>
The oil pressure will drop some from cold to hot. A typical 20W-50 oil will be about three times thicker when it is cold than when hot. 40 psi hot is a bit low but not a disaster. Try putting in fresh 20W-50 & a new filter, if you haven't already done so. Since it is showing 60 psi when cold, jacking up the regulator won't help much.

For reference, a straight 30 oil viscosity would vary by almost 7 to one from cold to hot.
D
 
hmmm ... I think there is 10W30 in there right now. Could be the problem then?

I meant to change but forgot. I'll try out some fresh 20W-50. Thanks
cheers.gif
 
Last season my 1500 Spit motor (in a Spridget) survived on 35 psi at 5500 RPM and under 10 psi at idle. This is all fully warmed up and under the most harsh racing conditions. The car clocked almost 2500 miles last year , most of it racing (11 two-day events). When I drove it on the street, I had oil pressure similar to your's. I'm using Castrol 20W-50 oil.
This winter, I checked the crank and it was well within specs (I had it cut to minimum -.030" a few years ago, so I have no more metal left). I replaced rod bearing and mains and I reduced the oil pump rotor side clearance by sanding down the oil pump side plate on a piece of glass (using 240 and then 600 paper).
I ran the car yesterday at Pocono Raceway and the oil pressure made a huge jump. Now I'm racing at 60 psi and post-race idle is about 30 psi. If you're really concerned, you could change the rod bearing and clean up the oil pump without removing the engine. I bet it would make a useful difference....but as I've said, I was racing on oil pressure lower than your's and was OK.
I realize than in Canada, you need the lighter oil, but I'd switch to 20W-50 in this season. You may want to check your gauge too.
 
I run straight 30 and I get about 15 at hot idle and about 40 at driving speed.

Cheers,
thirsty.gif
driving.gif

Walter
 
Now it doesn't start. I opened the valve cover and found this white gooey stuff ... any ideas. All I've done lately is change the water pump housing.

valvecover1-sml.jpg
 
Looks like "mayonnaise", an indication that there is water getting into the engine. Could be a dodgy head gasket, but as the car has been standing for a while it may be that it is just accumulated moisture. I would recommend changing oil and filter, using 20W50. The oil viscosity may be the reason for low oil pressure. I don't think that this is related to the non-starting of the car, it sounds like an unrelated problem, but I'm just a shade-tree mechanic.
 
It looks like a bit of water condensation. It happens sometimes when short runs don't get the oil hot enough to boil the moisture off.

On the other hand, How does the crankcase oil look. Is it clean & clear. You didn't say if you changed the oil or not. Did the old oil look like it might have coolant in it? If the oil looks cloudy it could have coolant in it. This could explain the previous low oil pressure. If the oil looks ok, I wouldn't worry.

Don't see how it could be related to starting problems.
D

It looks like I "doubled" with Steve. We both seem to be saying the same thing, so I'll leave it up.
D Shade tree #2.

[ 05-09-2004: Message edited by: Dave Russell ]</p>
 
Well I haven't yet changed the oil as I need to get some filters but I noticed that there is a slight tear in the charcoal canister and some of the charcoal got through. I don't see any reminants of in the the visible part of the head though.
 
the change to 20W50 seemed to do the trick - took it for a drive tonight and no issues. I think that white/grey stuff in the above picture was a little bit of oversprayed paint on the valve cover that melted.
 
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