Rexracer77

At what point should I be worried? I noticed I was getting up to ~293f in the 20 minute sessions around PIR.

Engine needs a rebuild, but hoping to put it off a year and work on suspension.
Thanks

Bill Dearborn

What is driving the rebuild? Start with an oil cooler and a racing radiator. That will bring the oil and coolant temps down 20 to 30 degrees each which is fairly reasonable.

Bill

Sidney004

I routinely saw between 290 to 305 for 14 years on a stock LT1(probably over 200 track hours) using Redline 20W-50. It blew up last year from a non oil or temperature related issue. The teeth sheared off the sprocket.

Rexracer77

Ah good to know, I wasn't sure what was "normal" on these engines.

Rexracer77

180k miles, I figure its cheaper to rebuild it before it lets go. Good oil pressure at RPM, but does drop off to 20psi at idle. I know this is common, but isn't comforting.

When I get to it, I would just do Rings/bearings, longtube headers, maybe a cam, larger oil cooler and a racing type oil pan, maybe Accusump. Reliability is #1 priority, a bit more power would be nice.

Do I really need a different radiator, the water temps stay low

rfn026

You get more bhp running hot. Too many people are actually running too cool these days. Here's an article I wrote last year about cooling systems.

Richard Newton

BrianCunningham

a road race pan is a good idea and will help lower temps

With the supercharger I went all out.

Rexracer77

Thanks Richard. From what I can tell the car originated out of Arizona, so guessing that owner wanted the car to run cooler, so it holds a steady 185 deg now. Is there an easy way to adjusted it back to factory to run in the 210-220 range?

Brian, that Accusump is mounted where the spare tire was, correct? Do you just carry fix-a-flat with you? Or is it a race only car that you trailer the car typically?

Bill32

Rex, First and most important.........have you verified that your dash readings are correct?

Sensors with 180k miles could be easily off by 10-15 degrees.

A C4 Lt1 will normally cruise on the highway at 194-198 water temp.
Obviously, it will go up on the track.
Oil temps on my Lt1 on track are always 290-300 and that doesn't bother me at all.

Is the 185 oil or water temp?

If it's water, I question the reading. That won't happen on an LT1 unless the previous owner put a big radiator in.

emptnest

My 1993 LT1 ran on Mid Ohio yesterday. With air temps in the 50's to low 60's, I was running coolant temps around 200 and oil around 230 at the end of a 20 minute session. Street temps are 193 for coolant and about 203 for oil.

Stock Z07 set up. No aftermarket coolers.

Do my oil numbers look so low that I should replace my sensor??

Bill32

Nope, my 92 runs about the same on the street.
I feel that the oil temp is probably 5-10 degrees low but that's not enough for me to change the sensor even when the car's on the track.

93Rubie

These cars have factory fill full synthetic for a reason. Oil temps in the upper 200's are not uncommon in a hot climate on a track day. There is no factory oil cooler. Use a good oil and you will be fine.

Rexracer77

No I haven't verified the reading, I thought I had read that you can get a computer change or some add on that would turn the fans on earlier, thus causing it to run cooler. Will get a manual gauge into it to verify whats actually going on.

And yes, 185 for water temp, 220 oil temp for street driving, went up to ~300 on track.

Thanks for the replies everyone.

BrianCunningham

Both actually

If I'm running a street tire class, or just taking it for a spin, but I also trailer it.

Bill32

Actually, since you're tracking the car, it's way easier to put in a manual switch to turn 1 or both fans on whenever you want to.

The fans are controlled by the ECM grounding the fan relay(s). All you have to do is splice into the ground wire on the relay, run that to a toggle switch.

I did this a long time ago on my 92 but I hardly ever use it (sometimes at the track).

Activating the fans with the switch will throw a code in Module 4 for the Quad Driver #3 but this doesn't mean anything , it doesn't turn the "check engine" light. Quad Driver 3 just monitors voltage in the fan circuit and throws a code 28 if it sees more voltage than it's supposed to.
I don't even bother to clear the code anymore and I've used the switch for 6 years.

Rexracer77

Assuming that the car is running at 185 (to be verified), am I hurting anything besides HP doing this?

Bill32

Nope, there are millions of small blocks out there running at that temp. Even though the LT1 cooling system is different (reverse flow), you are fine. The difference in normal running temp is only 9 degrees, 194-185.

And the horsepower difference is minimal since the stock LT1 runs that hot water thru the throttle body.

When you verify your gauge, you'll know where you really are.

But it's nothing to be real concerned about.

Supercharged111

I'd like it if there were some quantitative data in there regarding power vs coolant temps. ALL of my cars run harder at 180 vs 210, the tune pulls timing when it gets hot not to mention the added heat passed to the air being ingested by the motor. Sure oils thin out when hot and that will add a couple hp up top, but it's no match for the torque lost across the board as the PCM pulls timing back when the engine gets hot. Motors are cleaner and more efficient when hot, but definitely don't make more power.