More 302 Questions

[Two greens]

Two more questions for you Ford experts out there.

Firstly, can anyone tell me what the red line RPM is for a standard Ford 302?

Secondly, when my car idles the red low oil pressure light will come even though the oil pressure guage still registers lots of PSI. Is this likely to indicate a problem or can I afford to ignore the red light?

Regards
Two Greens

[wilf]

Not sure about the rev limit, but normally I would keep below 6000rpm for non-forged pistons etc. A std engine won't be breathing well at those revs anyway.

Oil light - could be you have a oil warning light switch set to higher psi than normal? Or a blocked oil filter?
The fact that the guage is indicating pressure does not necessarily mean the crank bearings etc. are receiving that pressure - it depends where the oil pressure guage is plumbed in.
If it is sensing "high" pressure, but this is before the oil filter, then the bolocked oil filter theory would hold - and it would mean that your engine is not receiving enough pressure.

Out of interest, do you have a remote oil filter?? If so, double check (and triple check) that it is plumbed properly - oil should flow into the outside of the oil filter and out to the engine from the centre.
The other way around means that the non-drain valve in the filter is stopping oil flow to the engine, and it won't last long. In this condition you could still see healthy readings on the guage.

Wilf

[Two greens]

Hi Wilf,
I do have a remote oil filter. How can I tell if it is plumbed the right way around?

Regards
Two Greens

[wilf]

Two Greens - the only way to do it is to trace it out.

From the block, the oil comes from the pump out of the small hole "outboard" of the central oilway in the oil filter mounting pad, where you now have your sandwich takeoff plate. The central oilway probably has the threaded tube in it onto which the sandwich plate is secured.

The oil should then be routed to the filter, entering the filter via the outermost ring of holes, coming out of the filter by the central single hole (again with the thread for the filter to screw onto).

From there it should go back to the sandwich plate, going into the engine through the central hole.

You will probably have to drop off the sandwich take off plate to check this out. If you are at all unsure that it is correct, I would advise against running the engine until you are.

Chap in the 'states has blown up two new and expensive engines one after the other because of this misrouting to the remote oil filter head. The engines ran OK whilst under light loads, blew up, (broken conrods etc) one on the track, the other on the rolling road, when pushed. At all times his oil pressure guage showed healthy oil pressure, because it was sensing the pressure before the filter, not after it, which I think is how yours would be plumbed as well.

HTH

WIlf

[Two greens]

Wilf,
I just had a quick look at the "sandwich take off plates". Both the one mounted on the block and the one connected to the remote filter appear indentical. They both have the words "in" and "out" cast into the pipe work connectors.

At present the "out" from the block plate is connected to the "in" on the remote filter plate. Presumably this is correct (?).

Regards
Two Greens

PS Looking at the sensor take off points it does look as though the oil guage is connected to one side of the filter and the warning light the other.

[wilf]

That sounds OK, but if it were my car I would have the system to bits to check it out!!

If the oil pressure guage and oil warning light sensor are connected as you say then the blocked filter theory takes on more credence. Which side of the filter is which?

Wilf

[Two greens]

The warning light sensor is connected to the "out" line of the crankcase sandwich plate (before the filter); the gauge sender is screwed into the crankcase.

When the engine is started, the gauge quickly rises to 50 psi and pretty much stays there regardless of engine speed. The warning light will remain on until the engine speed is raised above idle.

Regards
Two Greens

[wilf]

Hmm - I believe the guage sender screwed into the crankcase (just behind the fuel pump or fuel pump blocking plate right?, but at the front of the block in any case) and your warning light sensor should be "seeing" the same pressure - i.e. before the filter.

Is the pressure guage elec or mech? Not that I think this should make much difference, looks as though you might have a "high pressure" warning light sensor. Sometimes these are adjustable, sometimes not.

For complete peace of mind, you need to rig up an accurate mechanical oil pressure guage, just to check which of the two (light & guage) is tellng the truth.
Has it always been like this, or just started to do it?

Wilf

[Two greens]

I have only just bought the car so not sure how long it has been going on.

I think I am going to adopt the "Wilf approach", strip the thing down and start from first principles. I'll let you know the outcome!

Thanks for taking the time.

Regards
Two Greens

[Two greens]

Wilf,
Replaced the warning light sensor with a new mechanical oil pressure gauge and, guess what, 50psi just like the installed gauge!

Guess who is off to buy a new warning light switch tomorrow!

Thanks for the help Wilf.

Regards
Two Greens