ok guys. my car is a stcok 2.0 w/ euro pistons and weber 44's. It has a stock oil pump on it. Today it was 100 degrees outside (yikes!!!). After driving my car to school and back (20 minutes at 70+ mph) the oil light will flicker on at idle, so i blip it with my foot to keep it above 1000 rpms. running castrol 20w-50

questions:
*Is my oil getting to the point where it thins out and pump cant pump it?
*Do i need a new oil pump? (im guessing- was a used pump, that had no scoring etc... good to go so i thought)
*would a tuna can help with this? (extra 1/2 quart of oil cant hurt)
*If i need a new pump, which one? how do i get a melling to not leak? WHat is involved in O-ringing the melling?

My carbs are tuned pretty well, dont think they are running lean...

Any idea what oil temps looked like? It is pretty common for the pressure to drop - esp at idle - when the oil gets up over 240ish. I suspect an HD pump might help with this but the better solution is probably to cool the engine.

I don't think a tuna can would help much at all as it is literally just a "cup" or so of additional capacity; I think even 1/2 qt (2cups IIRC) is generous.

BTW I knew it was gonna be a hot one when I saw 89°F in SANTA MONICA at the beach on the way to work at 9:30am! (Hey I am fighting a cold and slept in a bit.) Then coming home at 6:30 I saw 91F in Malibu Cyn. Yikes.

I'd check the oil temperature, you could have pressure loss from the oil thinning if it is over heating. Wear in the pump, or any of the bearings will also cause pressure drop. What is the pressure when it is not hot??

If you rebuilt the engine, and used the old pump, that is ok, as long as it meets wear specifications.

Anyway, get a oil temp reading if you can, that will tell you how to proceed. You either have a temp or a wear issue. Make sure your cooling system is up to par, all seals inplace, you can look up under the oil cooler with a bright light, and get an idea if it is clogged with junk from the fan (leaves getting in the fan can clog the oil cooler, and head / cylinder fins)

Also you must have the heat up flaps installed, even if not connected to the thermal bellows (it should be connected anyway for better warm up,) If flaps are not installed at all, the air flow thru the cooler is disrupted.

There is no perfect substiture for a temp gage, be it a stock sender int he sump, or a dip stick style thermal couple, you need to know you oil temp to know what you need to fix. One quick test is after getting fully hot, can you remove, and hold on to the dip stick without getting burned on the fingers. If it is too hot to hold for a few seconds or more, then your oil is likely to hot.

You also might want to get an oil pressure gage, to tell what the pressure is at all rpms. The idiot light can kick in from 2 to 10 psi, maybe even more range than that, so it is not that accurate. I am not sure about the 914, but the VW factory stated for Bugs that the idiot light is ok to flicker at idle when hot.

If you have a case of a high set point idiot light sender, high temp day, hard driving, you might be getting 10 psi at idle (on the low side, but not dead yet) and be ok.

You really need to know pressure at speed. at 70 mph, assuming about 3500 rpm, you should have a minimum of about 35 psi when hot. I believe factory specs are out there.

Maybe you have nothing to worry about (I hope so) But get some temp and pressure readings to be on the safe side. The cost of the gages is very small compared to an engine rebuild, and the gages may save you from that.

good luck

dave

thanks....

cooing flaps are installed and hooked up to working thermostat.
installing the 914/6 style temp gauge this w/e.
i had a temporary VDO pressure guage hooked up when we rebuilt the engine, and i believe it was around 8-10 psi per 1000 rpm.

should i be running a different kind of oil?


Whats the lowdown on a deep sump?

Deep sumps would be of marginal benifit if any in cooling, they just do not add much cooling area. It may take a little longer to get the more volume of oil as hot, but it will get there. Biggest benifit of a deep sump is in hard cornering, as the oil stays near the pick up tube better. Biggest drawback of a deep sump, is that it is suicide for the engine if it hits a speed bump. (my car is much too low for one) the sump if hit can pull out the mounting stud, which requires engine dissassembly for repair (ouch!)

An auxilary cooler can help alot, but must be mounted in the air flow, or have a fan. before adding a cooler, check everything else, as a stock 914 should not over heat if in good condition. With rebuilds, compression can be raised, which can lead to more heat. The stock cooling system should work, but then again, if you are driving on a super hot day, or pulling a long grade with high ambient temps, you might need to back off a little. Remember todays gas is not as high octane as in the past. Early 1.7 engine had fairly high compression, and all engines that have been fly cut on the heads have an increased compression ratio unless steps are taken to reduce it. This can add more heat.

Also make sure your timing is dead on, too much advance will give you a bit more power (yippie!) however it will cause more heat, and shorter engine life.

Again you might just have a idiot light that is a little too sensitive, combined with a hot day, on idle. The pressure gage can help you out.

Did you perform the hot dipstick in the hand test yet??? Pull the dip stick when engine is fully hot, and see if you can hold on too it. If it is too hot to hold, it would indicate you might be too hot. Consider adding an oil temp gage also.

Haynes 914 manual suggests:
30 wieght above 32F,
20 wieght for 5-32F,
10 wieght for below 5F.

So 30 weight is what is recommended, but there is a big difference between 100F, and 32F and that is not addressed by Haynes

Now my Bentley manual for a VW Vanagon (simular engine) lists a larger temp range

70F to 105F use 40 oil
32F to 85F use 30 oil
15F to 50F use 20 oil
-5F to 25F use 10 oil

Also multi weights are listed:

15F to 85F **use 20W-40 or 20W-50
5F to 85F use 15W-50 or 15W-40
-5F to 60F use 10W-30
-20 to 15F use 5W-20 or 5W-30


So the Vanagon manual addresses temps higher than the 914 manual, I would go for the 40 weight if you constantly have high temps when you drive. Be aware that thicker oil is difficult to pump and lube the bearings when it is too cold for its use, so you would need to change back to 30 weight as seasons change. ** Note too that the Vanagon manual does NOT recommend multiweight for above 85F ambient temps. this is interesting, maybe someone can pipe in on this?????

Vanagon manual states minimum oil pressure should be 29 psi at 2000 rpm at 176 F oil temp. (I am assuming using 30 weight) Your oil temp will be higher than 176F even on a good running engine when driven hard, so the oil pressure test limit listed here is with a warm engine rather than a hot engine.

good luck dave

20 is a little "weak" for 100F weather ...

that's more in the < 40F range.

get 30 or higher, that'll give you some more pressure on hot days,
Andy

The PO of my car ran 50W (Valvoline Racing) in the hotrodded four. It was apparently recommended by his wrench, a SCORE offroad guy who built desert rails and stuff. That may be extreme for a daily-driver, but this guy did live in a very hot climate (mid SF-Valley).