Gain extra benefits by becoming a Supporting Member Click here find out how!
Classic Performance Products Classic Parts
American Auto Wire Classic Industries
Chevs of the 40sDanchuk Catalog
Hellwig Products IncPerformance Rod & CustomEcklers AutoMotive
Nu-Relics Power Windows
Impala Bob's Bob's Chevy Trucks Bob's Chevelle Parts Bob's Classic Chevy

Ecklers AutoMotive
Username Post: Car idling rough when hot, overheats in heavy traffic        (Topic#357182)
Schiavoneluke 
Contributor
Posts: 166

Reg: 05-16-16
07-10-19 07:24 PM - Post#2770417    

327, Rochester 4gc. Have a new 3core radiator, factory style AC setup. Drove the car 40 miles the other day and when I got into the city the car idled low and stumbled occasionally. Had to turn AC off or it would cut out. Later in the day in 91 degreees and heavy traffic the hot light came on for a minute before getting back on the highway- stalled once at a light and stumbled a bit- hard to restart. Is this a carb issue? Fuel?



 
Ecklers AutoMotive
junky 
Valued Contributor
Posts: 3008

Loc: Northeast CT
Reg: 06-27-10
07-10-19 08:42 PM - Post#2770423    
    In response to Schiavoneluke

Check your timing first. It could be a number of things, so the best way is to start checking each system systematically. All too often people jump around checking and adjusting various items, only to find that they made the problem worse. Depending on how many miles on the engine, it can be a bad timing chain/gears, or incorrectly set ignition points.
If you find that the point gap has closed up, check the rubbing block on the point set. Points coming from China have very soft rubbing blocks, and they wear quickly. For this reason, I always buy NOS points whenever I find them reasonably priced. Another thing to check is the ignition coil. I have seen them drop voltage when they get hot, because the windings are shorting out.

Never argue with an idiot. He'll drag you down to his level, then beat you with experience.


 
Schiavoneluke 
Contributor
Posts: 166

Reg: 05-16-16
07-11-19 09:05 AM - Post#2770466    
    In response to junky

Checked the timing and it seemed to be a bit advanced, 8 to 10 initial. I set it back to 6. Did have some pinging under hard acceleration but I thought it 1as bad gas. Does this sound like ot could've been the problem?



 
Tri5man 
Valued Contributor
Posts: 3781
Tri5man
Loc: Possums Crotch, KY
Reg: 06-26-07
07-11-19 10:04 AM - Post#2770472    
    In response to Schiavoneluke

Drive it and find out.



 
IgnitionMan 
Valued Contributor
Posts: 3586

Reg: 04-15-05
07-11-19 10:39 AM - Post#2770474    
    In response to Schiavoneluke

Please outline the timing used on the engine:

Initial: 6
Total:
Mechanical advance start and limit rpm's:
Vacuum advance degrees:
Vacuum advance sourcing (ported or full manifold):

Also, please outline the cooling system:

Radiator: 3 row
Full shroud, yes, no:
A/C clutch fan setup, yes, no:
Thermostat used:
Does the water pump have closed, or open fin impeller:
What concentrate of anti-freeze to tap water:
What anti-freeze is used:




 
Schiavoneluke 
Contributor
Posts: 166

Reg: 05-16-16
07-11-19 01:17 PM - Post#2770480    
    In response to IgnitionMan

Okay I knew the numbers I gave didnt sound right. I must've still been asleep this morning when I was counting lines on the timing tab. Timing WAS set to 12-14 degrees advance, timing is now set to 10 and the car still wants to be a bit on the high side with the air conditioning on. Hard to say if it changed anything. The issue now is that the idle seems rougher with the timing retarded and the engine wants to cut out. Raising the idle speed helps but the car is not idling particularly smooth and I worry that at a stoplight it could cut out.
To answer your questions:
180 degree thermostat. Total, with mechanical advance 24 degrees is 34. Kicks in around 750 rpm. Yes full fan shroud, 6 blade stock AC fan. Not to sound stupid but I'm not sure what you mean by the water pump, I'm guessing open impeller? Running a 70/30 mixture with a bottle of water wetter. Stock configuration on 327 powerglide with the "dealer" AC, only thing different is a mild RV cam





Edited by Schiavoneluke on 07-11-19 01:18 PM. Reason for edit: No reason given.

 
junky 
Valued Contributor
Posts: 3008

Loc: Northeast CT
Reg: 06-27-10
07-11-19 03:13 PM - Post#2770486    
    In response to Schiavoneluke

Have you checked the condition of the timing chain? Take the distributor cap off, and have someone rock the crankshaft with a socket and breaker bar, and see if the distributor moves immediately, or if there is a delay. A delay would indicate that the timing chain is loose, and it might have jumped a tooth or two.
You can also bring the engine up to top dead center, and check the number 1 piston to see if it is at top dead center. Removing the valve cover will show that both valves should be closed. I believe that it is a mechanical problem more than a carburetion problem.

Never argue with an idiot. He'll drag you down to his level, then beat you with experience.


 
IgnitionMan 
Valued Contributor
Posts: 3586

Reg: 04-15-05
07-11-19 03:58 PM - Post#2770488    
    In response to Schiavoneluke

Ok, your INITIAL timing is 10, how much IDLE timing with vacuum advance plugged in?



 
del.impala 
Contributor
Posts: 563

Loc: delaware
Reg: 04-13-11
07-12-19 05:07 AM - Post#2770514    
    In response to junky

Junky,original 327 from 62-64 have no bolts on crankshaft unless drilled and tapped for it.



 
Schiavoneluke 
Contributor
Posts: 166

Reg: 05-16-16
07-12-19 10:05 AM - Post#2770528    
    In response to IgnitionMan

With advance plugged in I'm getting about 24. Drove it today and no overheating on road but after 10 minutes of driving I set it on the driveway at idle, hotlight came on after about 4 minutes. Ambient air temp 88 degrees



 
blkss64 
Contributor
Posts: 150

Reg: 07-22-12
07-12-19 09:13 PM - Post#2770572    
    In response to Schiavoneluke

Do you have a vacuum gauge? A vacuum gauge will tell you more about your engine than any other tool. If you don't have one, get one and read up on how to use it.



 
brokenspoke 
Poster
Posts: 66

Reg: 02-28-08
07-14-19 04:42 AM - Post#2770652    
    In response to Schiavoneluke

Hot light isn't a very good way to determine the temp of the engine. Get a good mechanical guage



 
IgnitionMan 
Valued Contributor
Posts: 3586

Reg: 04-15-05
07-14-19 01:00 PM - Post#2770685    
    In response to Schiavoneluke

24 at IDLE with engine running is good. After getting to the 24 IDLE degrees, was the carb easier to adjust? No vacuum leaks?

Please outline any changes from dead stock for the cooling system, please, it might make a significant difference.



 
Schiavoneluke 
Contributor
Posts: 166

Reg: 05-16-16
07-15-19 07:43 AM - Post#2770730    
    In response to blkss64

Got vacuum readings this morning. Pulls 18 at idle. I will say when I put the car in drive to adjust idle mixture, the vacuum gauge fluctuated very little, only moved between 14 and 15 and wanted to bounce around so it was hard to get a max reading



Edited by Schiavoneluke on 07-15-19 07:47 AM. Reason for edit: No reason given.

 
Schiavoneluke 
Contributor
Posts: 166

Reg: 05-16-16
07-15-19 07:50 AM - Post#2770732    
    In response to brokenspoke

At what temp is the hot light supposed to come on? Someone posted on here that 246 is what they originally came on at but that seems awfully hi, would hate if the engine got that hot at idle



 
Schiavoneluke 
Contributor
Posts: 166

Reg: 05-16-16
07-15-19 10:04 AM - Post#2770740    
    In response to IgnitionMan

I should clarify a bit here, the car did not come with AC. I found a 64 NOS dealer AC unit and added it to the vehicle, it has the old style condenser and compressor. This is after I replaced the radiator with a new factory style three core which was noticeably thicker than my original. I do feel as though airflow with the condenser is limited. There is only about an inch of room right now between the radiator fins and condenser



Edited by Schiavoneluke on 07-15-19 10:05 AM. Reason for edit: No reason given.

 
Tri5man 
Valued Contributor
Posts: 3781
Tri5man
Loc: Possums Crotch, KY
Reg: 06-26-07
07-15-19 11:08 AM - Post#2770749    
    In response to Schiavoneluke

Unfortunately the hot does come on in the 240's.



 
Schiavoneluke 
Contributor
Posts: 166

Reg: 05-16-16
07-15-19 12:07 PM - Post#2770752    
    In response to Tri5man

Feel a bit stupid for asking this but I think my fan might be mounted backwards, currently pushing air through the radiator. I've attached a photo

https://www.flickr.com/photos/169318484@N05/ 482923...



 
Verne_Frantz 
61-64 Subject Matter Expert
Posts: 5570
Verne_Frantz
Loc: Hightstown,NJ USA
Reg: 08-22-00
07-15-19 01:08 PM - Post#2770755    
    In response to Schiavoneluke

Yep, that's backwards. That's probably your only problem. After adding A/C, you should actually be running a clutch fan.

Verne



 
turbo38s10 
"8th Year" Gold Supporting Member
Posts: 1648
turbo38s10
Loc: Agawam,MA
Reg: 09-17-09
07-15-19 02:36 PM - Post#2770764    
    In response to Verne_Frantz

Your right. The clutch fan is their but the blade is mounted backwards. Take it off and reassemble correctly and your problem might just go away.



 
carbking 
Senior Member
Posts: 1461
carbking
Loc: Missouri
Reg: 06-14-03
07-20-19 06:57 AM - Post#2771131    
    In response to turbo38s10

When you added the AC, did you also add the carburetor modifications used with AC?

The non-AC and AC equipped 327's used a different carburetor.

And I do not have a Chevrolet parts book covering these years to check, but many of the air conditioning cars had an idle speed-up control that automatically raised the idle a few hundred RPM when the AC was on, to prevent overheating at idle.

Jon.

Good carburetion is fuelish hot air!

The most expensive carburetor you will ever buy.....is the incorrect one you attempt to modify!

If you truly believe "one size fits all", trying walking a mile in your spouse's shoes!


 
Verne_Frantz 
61-64 Subject Matter Expert
Posts: 5570
Verne_Frantz
Loc: Hightstown,NJ USA
Reg: 08-22-00
07-20-19 07:40 AM - Post#2771135    
    In response to carbking

Jon,
He didn't mention what year his car is but '62 was the last year that used an idle speed advance with the A/C on. It was a cable to the accelerator lever operated from the pull knob that controlled the A/C.
'63 & '64 had no such idle speed increase mechanism. Idle speed was set with the A/C on and in drive (if automatic). So in neutral with no A/C it idled over 1000rpm. Poor design in my opinion.

Verne



 
carbking 
Senior Member
Posts: 1461
carbking
Loc: Missouri
Reg: 06-14-03
07-20-19 07:56 AM - Post#2771137    
    In response to Verne_Frantz

Verne - thanks, my parts books are not that new; however, the carburetors for 1964 are different for AC cars. Without checking, probably more idle fuel.

In the for what its worth category, our first air conditioned car was a 1963. When Dad bought it new, the salesman cautioned against running the air conditioner at idle. Air conditioning is one automobile feature that has greatly improved over the years. Of course, not everyone lives in a state where the humidity is sufficiently high that one can fish for bass in the back yard in the middle of the summer

Yesterday, raw temperature 102 with 55 percent humidity. Heat index chart for these figures is scary!

Jon

Good carburetion is fuelish hot air!

The most expensive carburetor you will ever buy.....is the incorrect one you attempt to modify!

If you truly believe "one size fits all", trying walking a mile in your spouse's shoes!


 
Verne_Frantz 
61-64 Subject Matter Expert
Posts: 5570
Verne_Frantz
Loc: Hightstown,NJ USA
Reg: 08-22-00
07-20-19 07:29 PM - Post#2771181    
    In response to carbking

Yep, the '63 was also a different 4GC for A/C cars. I have specs for all of them but I haven't bothered to look up what the differences were.

We just had a 99deg day here with RH in the 90s. Took your breath away.

Verne



 
Ecklers AutoMotive
Icon Legend Permissions Topic Options
Report Post

Quote Post

Quick Reply

Print Topic

Email Topic

639 Views
FusionBB
FusionBB™ Version 2.1
©2003-2006 InteractivePHP, Inc.
Execution time: 0.085 seconds.   Total Queries: 17   Zlib Compression is on.
All times are (GMT -0800) Pacific. Current time is 11:18 AM
Top