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Tue Aug 12, 2008 6:40 pm

Read through all the posts on the VDO dual senders and gauges, light coming on at idle, etc. Here are my numbers..

New stock 1600 DP (no extras)
Startup oil pressure about 60
After engine is warmed up (hot) oil pressure between 10 and 15.
Idiot light comes on at idle (sometimes)
Idle set at 750 RPM
10-30W oil

Final questions:
1. If these numbers are normal, what should I do about the light?
2. I am hooking up a VDO temp sender at the fill plug. What is normal for max temps? When should I be concerned?

Tue Aug 12, 2008 7:08 pm

If the pressure really is 10 psi at idle, you're in good shape. The low pressure switch is supposed to close around 7 psi IIRC. You could have a bum switch. You could verify true pressure with a mechanical gauge.

Max

Tue Aug 12, 2008 7:10 pm

My completely stock 1600dp runs about 12psi @ idle and 45psi @ 3000rpm.
I run 10w30 oil.
I would remove and measure the relief springs. If it's a fresh engine, I would bet there is a collapsed spring.

Tue Aug 12, 2008 7:20 pm

lostinbaja wrote: I would remove and measure the relief springs. If it's a fresh engine, I would bet there is a collapsed spring.
If he already has 10 psi at idle, there isn't a problem.

Max

Tue Aug 12, 2008 7:22 pm

Why do you have your idle set so low? You should be in the 850-900 range. That might even get rid of the oil light flicker at idle. Everything else sounds good.

Tue Aug 12, 2008 10:26 pm

The 750 comes from the Myers book. 900 may make it better for sure. I will raise the idle RPM and see how that works for the light.

Wed Aug 13, 2008 8:38 am

Raising the idle to 800-900 will definitely help.

In general, low oil pressure at idle isn't a big deal if you're getting good pressure everywhere else.

IIRC the stock idiot light comes on at 5 psi, while the VDO pressure senders are set to 7-10 psi depending on the model, so the idiot light would come on sooner than normal.

Thu Aug 14, 2008 8:05 pm

Got the VDO temp hooked up today. Takes a while for it to register above 120, but after a good hard drive up a few hills, I was able to get it to about 205 degrees. The idle pressure is at about 10 when it is hot and the light stays off as long as the idle is set at around 900. When driving and RPM increases, it goes up to about 40 PSI (60 at cold start). So, all in all it seems that both the temp and the pressure are great. Thanks for the great advice!

Fri Aug 15, 2008 2:30 pm

Glad to hear it's working! Those little dash lights can be very demoralizing at times.

Fri Aug 15, 2008 9:26 pm

Torkman wrote: Got the VDO temp hooked up today. Takes a while for it to register above 120, but after a good hard drive up a few hills, I was able to get it to about 205 degrees. !

I got a question - where did you put your oil temp sender? I tried the kind that go on the oil drain plug and found that thing was way off in engine temperature. I was comparing it to my custom remote-read meat thermometer I turned into a dipstick temp sensor and it was always low by like 25-30 degrees. I know it wasn't my VDO gauge either because I got a sender that fit in place of the oil light switch (just for one run as a test) and it matched my dipstick sender.

This is with the oil drain plug sending unit (and letting it idle doesn't make a difference, I thought it might, with air flowing over the drain plate it might run slightly cooler or something, and at idle with no air flow I thought it might read higher then, but nope)

And this is what it read with a different sender placed into the oil pressure switch hole, right on.

Sat Aug 16, 2008 5:59 am

i found the exact same thing as u glutamodo
in the sump plate my temp never got over 140F
once fitted to the type3 block plate under the same conditions would sit at 190-195
i cant work out why
in both positions the probe is immersed in the sump oil
and like u said it doesnt come up when idling which disproves road draft cooling things off
go figure

Sat Aug 16, 2008 8:55 am

I have mine in the block plate as well (universal case). Tapped the plate with a 14mm x 1.5 and instaled sender. When I first started the car I thought it was not working in that it stays at 120 for 15 minutes. After I took it out on the road and drove a while, it went up to 185. I took it to some hills and after a few passes, it maxed at around 205. On the way home it cooled to 185. Immediatley after shutting off the engine it started to slowly cool. So, seems it is working well and reading normal.

Sat Aug 16, 2008 9:59 am

[quote="glutamodo"] Torkman wrote: I was comparing it to my custom remote-read meat thermometer I turned into a dipstick temp sensor and it was always low by like 25-30 degrees. I know it wasn't my VDO gauge either because I got a sender that fit in place of the oil light switch (just for one run as a test) and it matched my dipstick sender.

The moment you changes wiring and what ever on your custom made oil/meat thermometer, you destroyed its calibration/accuracy...

You can not believe its reading now unless you have tested and calibrated it against known valid values...

Dale

Sun Aug 17, 2008 1:37 pm

Dale M. wrote:
The moment you changes wiring and what ever on your custom made oil/meat thermometer, you destroyed its calibration/accuracy...
You can not believe its reading now unless you have tested and calibrated it against known valid values...
Dale

You mean my homemade thing is messed up? Yeah I know. I thought it might be too so last year I did some tests comparing it to other thermometers - and at that time, it was right on. I took a pic of one such test in boiling water...