318 runs hot, low oil pressure

[1975DusterGuy]

Hey guys, I'm new to the site and was hoping to see if I might be able to get some help because at this point I'm out of ideas.

I've got a 1975 Plymouth Duster with a completely stock 318 5.2L with the Carter 2bbl on top and a 727 auto tranny underneath. I've been working off and on for at least a year now trying to figure out why my engine is running at 205-210 degrees. Additionally, after warmup, the oil PSI hangs around 10-12 PSI which I feel is pretty low, but I'm wondering if the oil is thinning out too much because the engine is so hot. Luckily I haven't had any issues with boiling the gas and stalling the car, and it seems to run fine on roads and highways, but it's just awfully hot and the oil pressure seems awfully low. I've had the car for probably 7 or 8 years now and I've never known it to run this hot; the oil PSI I'm not sure about, I never had a gauge until I installed some new ones last summer.

Here's some background info: I had the engine rebuilt a few years back so it has less than 5000 miles on it. After rewiring the car last summer, I went ahead and removed the AC since I really wasn't using it. The car idles around 750 RPM in drive; 950 in neutral and sounds great. After tinkering today, I set timing at 2 ATDC to see if that might bring the temp down (I believe stock specs say 2 BTDC). The car does have a fan shroud with the stock fan pulling air through, and a 190 stat I installed last fall because I thought maybe my old stat was bad, that didn't seem to help the issue.

That may be enough info to get us started, but if you need more, don't hesitate to ask! I'm a few steps close to pulling my hair out over this one since I've been fighting this for a while now. Anybody got any ideas? I would really appreciate it!

Thanks,
Ben

 

[RLF Cuda]

Timing should be set for maximum power and fuel efficiency. Small Block Mopars typically like 36 degrees mechanical advance at 2500 RPM and in the 50's under vacuum. initial advance follows setting total mechanical advance. Make sure your distributor advance weights are free moving and that the advance moves smoothly as RPM's increase from idle to 2500. If total mechanical advance (with the vacuum line off and plugged) doesn't come in until much higher RPM's, I would suggest getting an advance kit with lighter springs to bring total advance in at 2500. Check that the vacuum advance is also working using a MightyVac or the like, or just hook it up to a vacuum source on the manifold.

This whole exercize is much easier with timing tape on the vibration dampner, a cheap addition to the car.

From my experience, the 318 has a very slow advance in stock form which was used to control NOx emissions in the early days. That is why they went to zero or even negative initial timing before the advent of 3-way catalysts which controlled NOx by reduction.

Good luck,
Bob

 

[tekslk]

210 isnt too hot but try 15 degrees timing and check total . oil you may want to try a 20w-50w check your radiator might be time to flush good also.

 

[Bulldozer]

rule of thumb is 10 pounds for every 1000 rpm. a fan shroud works miracles for cooling. i have a 180* thermostat, and factory 4 blade solid mount fan, a 2 core 26" radiator and shroud out of an 86 lebaron and its all i can do to get it hot.

 

[pishta]

He has a shroud, hot oil is fine, it doesnt get too thin if using a multiweight. I would get the radiator rodded out first. Check with your hand if the radiator is uniformly hat or if there are some cool spots. I think the dummy guages lit off at 7 so 10 at idle is fine. Did the guy do your cam bearings too? Notorious for sapping oil pressure.

 

[flyfish]

Sounds like your radiator is old, and plugged full of crap. Easiest and most cost effective solution is replace the radiator. I think Summit has some universal radiators that are ~150 bucks....or you can pay a little over 2x that for a direct fit radiator....take your pick.

 

[1975DusterGuy]

Hey guys, thanks for the replies. This gives me some stuff to look into. I'll hit the garage this weekend and see what happens.

To the question about the radiator, I had a friend of the family who had his own industrial radiator business who took care of that for me. I wouldn't think I'd have problems with it, but good call. Better flush and check it over. Probably should have done that earlier...

Thanks for the help! Now to finish the work week so I can get out there and work on it again...

Ben