Oil -Temp/Pressure Gauge

[MichiganMike]

Does anyone have a gauge like this? I cant seem to find it anywhere online in photos. The 911 is close but not quite. Also I bring this up because I am having a hard time getting my oil pressure gauge to work right. It always springs towards the top no matter if car is running or not. Does this point to a groundin issue somewhere? I replaced the swith unit on the engine but nothing has changed. Any advice?



Thanks,
Mike

67 Porsche 912 - 5 gauge / 5 speed

[w6zo]

Well - I'll try to help, but I am not well versed in pre-69 cars.

It does look like an early 911 gauge - but I don't think that matters. I think the ones I have seen have 2 lights - one for oil and one for the generator. That would require two sensors. What you need to understand it that it is not an Oil Pressure Switch that is needed for a gauge (and is what normally would be found on a 912 engine) but an Oil Pressure Sender - the difference being that a switch is a binary device - on/off where a Sender is analog - it changes resistance to reflect the amount of pressure it is sensing. A switch is designed to turn a light on and off. So it sounds like the problem is that you are using the wrong sensor.

I would do a google for either Palo Alto Speedometer or North Hollywood Speedometer and email them a picture of your gauge and a description of the problem - they will likely be able to provide the proper sending unit.

Regarding your other post on your case being a "Marine Version"- I don't think there is anything "better" about it - but without researching the writings of Harry Pellow, I couldn't say for sure. As for the heads - I think the early engines only had a hole drilled in the right head. The place is there in the casting, but it isn't drilled on the left. Since I think that is the ONLY difference between a left and right head - and since you seem to have an "odd" case also - it is entirely possible you have 2 left heads - or it was built that way. In any event - probably not a good idea as there may be no where for the moisture in the oil to escape when warmed up and the crankcase pressure to be released.

[djdsc]

You need a double pole sender like the one in this photo (above the wrench with the 2 gold tipped knobs) to be able to hook up a pressure gauge and an idiot light.

[w6zo]

Yes - but the OIL idiot light is green, is it not? I don't see one on that gauge. The generator light is red.

I take that back - there does appear to be one at the top of the gauge in the shadow.

So - maybe he has the necessary senders - they are just hooked up backwards.

[MichiganMike]

Thanks for the help guys! I appreciate it tons. The current switch ? sender ? I have are two types:

1 VDO - 1 terminal switch? sender?
1 GP Sorenson cheapo - 1 terminal switch.

I believe I may need the two terminal VDO part instead so it can do both tasks. Also since I burned out the top GREEN bulb yesterday I am currently lookin for another one to replace it. Anyone have ideas? Advanced Auto does not carry this bulb of course.

w6zo - Yeah I havent got a good look at the backside of the left head to see if the hole is there. Maybe heads put on backwards? In any event, running the heads without that hole is bad? What kind of damage am I lookin at? Perhaps the boat didnt have this option which made it a bad candidate too?

mm.

[w6zo]

I would suspect the marine engine was vented differently, hence no hole. The possible issue I would think is that condensation would have a harder time escaping the crankcase and you would end up with an oil/moisture combination that resembles mayonaise. It is a fairly common issue to ge that in the oil filler can even with cars that have vented heads - particularly if they aren't driven often or only for short distances (say - less the 10 miles or so).

The bulb should be available at an auto parts store - they were pretty commonly used on a lot of cars.