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Unless you reduced the advance it shouldn't make a difference in temp. I can see where there might be a slight reduction in temps when running below where total is all in but not an increase.
 

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You sure nothing else in the timing or anything else changed? If the timing is really retarded it will run hotter but advancing the timing shouldn't cause a 23* change in temp.
 

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66 Chevelle SS396 & 66 Chevelle 327 Convertible.
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Discussion Starter · #4 ·
with orgional springs total didn't come all in until about 5000 rpms, so total was never all in. with lighter spring total is all in around 3500 rpms, so when running at 2800 on the hwy there is now more advance. The more advance is what I was thinking was causing the higher temps.

So Hank, what your are saying is that running more advance at 2800 rpms should not cause more heat. Thanks.
 

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Yes, retarded timing will cause the engine to run hotter. A very lean fuel mixture will also cause higher temps. Any vacuum leaks? That would cause a lean mixture.
 

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Agreed,retartded timing runs hotter but the additional timing the motor is getting now should not make it run hotter.

Your total should be all in by 2800-3k rom and not the 3500rpm you at,thats too late unless your running a lot of gear and have hi cruise rpm.

When at cruise the total should be basically fully in .

What base and total timig are you currently running and what camis in the motor?(if i remeber right you dont know exactly what camis in motor which is an issue)

If running an aftermarket cam you need approx 18 base & 36 total.

You have posted mult times on having timing issues before and should have this corrected by now,what up that your still having issues and running the full total at 3,500 rpms,that's way too late IMHO which could have the timing retarded for all we know increasing motor temp.

Also, is this the 1st time the car has been out i warmer weather so youhave not been in that situation before?

Also,are you running a clutch fan and maybe the clutch is going bad esp if its running hoter at low speed or in stop/go traffic.

scott
 

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66 Chevelle SS396 & 66 Chevelle 327 Convertible.
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Discussion Starter · #7 ·
Thanks Scott. Just got the spring kit a few weeks ago and installed it then. Had the car out yesterday for about 100 miles and it ran at about 190 degrees, guessing by looking at the old temp guage (thermostate is 185). Mostly hwy traffic; but some in town and outside temp was about 70 degrees.

Yes, not sure about the cam; but best guess is a stock gm cam from 1970 CE 402/350hp short block , which is bored 30 over. Stock 1966 702 heads and stock1966 holley intake, stock 1966 water pump, stock harrison radiator, and stock 1966 holley carb. Don't know about the pistons; I imagine they were replaced when the engine was bored in 1980. Compression is even @ around 180 per cylinder.

I am running a factory SB clutch fan from the 60's which sits about 1/4" further inside the fan shroud than origional. But I think it is OK.

I don't think I gave the car a good enough test the first time I ran it this spring. Just a short trip around town and when I parked the car and shut off the engine, I measured the engine temp with an infrared guagae and it red about 208 for the block and heads. Will have to test the car some more.

I tested two sets of the springs that came in the mr. gasket kit. By Using a mark on the balancer that was 1/10 the circumferance from the 0 mark. Silver was all in at about 3000, gold was all in at about 3600, and black I guest assumed was the stiffest spring and didn't test it. With My original springs total was all in at about 5000. I deceided to use the silver spring. It looked like the distributor was adding about 30* at the balancer. ( The 66 chassis manual I have says to set initial at 4* and the distributor mechanical is 0* at 900, 14* at 1275, 19* at 1600 and 30* at 5000)

I set the inital timing at 10*.

I think the vacuum cannister adds about 14*at idle. Origional specs says 0* at 7" and 12* at 12". Car idles at about 12" and when crusing at around 2600 rpms reads at about 17".

I rarely drive the car over 4000-4500 rpm. Usually at around 2700 rpms on the hwy.

If the distributor adds 30* as it seems should I set the initial at 6*? That would give a total of 36* plus the vacuum advance which I think is around 14*. Or is it OK to leave inital timing at 10*? Also seems like you are suggesting I use the lighter springs, so total come in sooner. I generally use 91 or 92 octane fuel, since that is what is available here in MN. I did order some of the supreme 130 today and plan to try that. Also have some of the Crane breakin lube that you suggested to add to the oil. THANKS.
 

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Hi James,yes the total should be in by 3k rpm the latest.

Also,the 10 base timing is fine with stock cab BUT if its a mild aftermaket cam the 10 deg base your runoing is retartded by approx 8 deg which is a lot so keep that in mind.

Anyway,your looking for approx 36-38 total all in by 3k rpm without vac adv and approx 50-52 deg with the vad adv attached.

Boy i wish you knew what cam was in your motor weather it be stock gm or aftermarket becasue i could then give you a solid ign curve to run and could also tell you what to have the mech adv curve set to to run with the base timing you would need .

BTW,did you every try 16-18 deg base timing to see how it would respond because that would tell you if it was a stock gm cam or aftermarket. The stock gm cam would not run well a all with 16 deg base timing but an aftermarket perf cam would run fine with 16deg base timing.

Then you could have the mech adv in the dist recurved for 18 deg in by 2800-3k rpm so then 16-18 base timing + 18 deg in the dist would = 36-38 total all in by 2800-3k rpm. It would be so easy then,after the dist was recurved you could either set base timing to 16-18 or set the total to 36-38 and you would be good to go. But unfortunately you cant do that because we dont know if you have a stock gm cam or a mild aftermarket perf cam.

Too bad you didnt live close to me becasue i could check it out for myself and could very likely be able to tell in a few mins what type cam you have and what base timing to run but unfortunately thats not the case.

Good luck.

Scott
 

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66 Chevelle SS396 & 66 Chevelle 327 Convertible.
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Discussion Starter · #9 ·
Thanks for all you help Scott. I did try the initial at 16*, it ran at idle; but really pinged when accelerating. Think I will drive the car and check the temp with the infared temp guage, then change to the lighter springs and check the temp. When I talked to the former owner who rebuilt the engine in the early 80's, he thought he only bored it and did a valve job; but that was trying to remember back 25 yrs.
 
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