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1  Camaro Research Group Discussion / Maintenance / Re: Running Hot? on: October 04, 2014, 12:57:03 PM
Thank you John.  Glad to hear it is something as simple as you described.   
2  Camaro Research Group Discussion / Maintenance / Re: Running Hot? on: October 03, 2014, 06:32:25 PM
I finally got the AIR system inactivated.  Checked for a vacuum leak around the carb and couldn't find any.  Car seems to hold an idle now without slowly going down and dying.  One thing I have noticed since I have been doing a lot of work with the air cleaner off is that after the car has idled awhile, though still not anywhere near hot, after I shut the engine off a vapor or mist almost as thick as smoke comes out of the carb throat.  The carb is still cold to the touch when this occurs.  What is causing this? 
3  Camaro Research Group Discussion / General Discussion / Re: 69 Z/28 X77 garage/barn find on: September 21, 2014, 06:06:19 PM
It's great that you were able to talk with your car's original owner.  Hopefully he will be able to send you some of his old pics of it.  I was able to talk with the original owner of my '69 Z and get some history on it.  He sent me some photos of it when he had only had it 2 months.  I and a lot of others I'm sure enjoy finding out as much as possible about our car's early life.   
4  Camaro Research Group Discussion / General Discussion / Re: My New '68 Camaro Z/28 Butternut Yellow on: September 12, 2014, 05:51:55 PM
Good to hear everything is going so good for you and for your '68 Z.  Can you actually buy 116 octane leaded gas from a pump at Sears Point, or do you have to buy it by bulk in 5 gal. cans?  
5  Camaro Research Group Discussion / General Discussion / Re: Well My Camaro online Compadres, Time for a fight of my Life! on: September 10, 2014, 09:55:03 PM
That's great news Danny. 
6  Camaro Research Group Discussion / Maintenance / Re: Running Hot? on: August 10, 2014, 05:34:56 PM
I wanted to thank all you guys once again for your responses and help.  I am taking things one step at a time.  I think it has been narrowed down to a fuel percolation problem with excessive heat being produced from the exhaust manifolds due to the AIR pump pumping air all the time, due to a broken diaphragm in the diverter valve, plus a vacuum leak from the same cause.  The cooling system checks out fine.  The timing checks out fine.  I'm still looking for a racing gas distributor in my local area. 
What do you guys think about Joe Gibbs Driven Carb Defender Fuel Additive, for counteracting the ethanol in gas, possible help or waste of money?
7  Camaro Research Group Discussion / Maintenance / Re: Running Hot? on: August 06, 2014, 12:51:10 PM
I plan to have my smog pump deveined and the screws put into the exhaust manifolds in place of the extension tubes.  I have 2 questions:

What is the easiest or best way to completely degut the smog pump?  What do I take out and what do I leave?  I am guessing when done it will just have a rotating pulley on the outside, but what is left on the inside if anything; is there still something rotating on the inside? 

What screws exactly do I need for the exhaust manifolds?  I have read on other posts here on CRG that they should be stainless (I am guessing steel), #10 x 1/2 in., flat top.  Where is the best place to get them, hardware store or auto parts place? 

Thank you.  I really appreciate all the help from all you guys on this website.  I wish I knew more about first gen Camaros, especially mechanical wise. 
8  Camaro Research Group Discussion / Maintenance / Re: Running Hot? on: July 31, 2014, 01:10:31 PM

You don't have a cooling problem, you have a typical fuel percolation problem, aggravated by low E10 fuel boiling points.


Since John brought it up, let's discuss fuel for a second - any local station carry straight (non-ethanol) gas, and/or what are you running through the motor ? I would not recommend any E10 gas for any early engine, especially one that uses neoprene tipped needles in the carb, or rubber fuel lines. Like John indicates, the percolation is a problem, plus the stuff eats everything else, and has an affinity for moisture build up in the tank. Nothing draws a vacuum worse than ethanol in my opinion. Find a race gas distributor and run 100+ octane unleaded, or blend it with non-ethanol regular to stretch it.

I would, regardless, clean the cooling system completely, especially if the motor sits for a decent while without running up to operation temps regularly. Buildups are inevitable internally to the block, heads and radiator - keep them clean and they'll function accordingly.

2 cents -

I live in a small town in the Sierra Foothills in California.  There are no stations around here that I am aware of that sell non-ethanol gas.  I use premium Chevron, Shell, or 76 in it.  I'll do some research to see if I can obtain unleaded racing gas in my local area.  My car does sit every so often, sometimes up to 2 months between my taking it out for a spin.  I plan on having the radiator and engine gone completely over to check for gunk build-up.  Thanks for your info. 
9  Camaro Research Group Discussion / Maintenance / Re: Running Hot? on: July 31, 2014, 01:00:54 PM
Yep - the only thing else to do is slide a stainless steel shim in between the intake and the head on the drivers side right in the middle of the manifold to block that passage.  It will help to reduce the cooking of the carburetor and fuel percolation. Only do this if you have eliminated the heat riser function.

Just go to the kitchen when your wife is not around and find a flat bottomed stanless bowl.  Cut out a flat piece of material with tin snips just wide enough to fit between the manifold bolts in the center of the drivers side. Bend a small tab over to help you push it in.  Loosten the manifold bolts just a little and see if you can slide that metal down in there between the gasket and the intake. Try not to disturb the gasket too much.  Tighten the bolts back up and see if that helps.  It worked for me when I had the percolation issue.

PS - if you go snatch the bowl when the wife is watching, you are a BOSS!  Cheesy

Good luck!

-Mark.

I definitely will install the blocking shims on the driver's side intake manifold.  I know that my heat riser function has been disabled.  I am not going to take the chance of cutting the shim as you described whether the wife is around or not. She would miss the bowl even if she didn't actually see me take it.  Smiley
10  Camaro Research Group Discussion / Maintenance / Re: Running Hot? on: July 31, 2014, 12:52:50 PM
<< Well I was finally able to do some checking on the underhood temps.  I drove the Z for between 2-3 miles to get the engine up to temp.  The outside air temp was in the mid 80's.  While driving the temp gauge stayed right around the first quarter marking, maybe one mark up toward the half marking.  While idling in my driveway the gauge read right at the one half marking.  The engine would not hold a steady idle but slowly had the idle decrease until the engine died.  This happened 3-4 times.  While the engine was not running the temp gauge would increase until it was between the one half marking and the three quarter marking.  This I take to be normal due to heat soak. 
Here are the temps I recorded with an infrared gun: 

radiator hose at thermostat- 183, bottom radiator hose- 164  >>

The last line above are the only temps that mean anything, and they're normal - don't agonize over all the other external temps - they are what they are, and you can't change them. You don't have a cooling problem, you have a typical fuel percolation problem, aggravated by low E10 fuel boiling points. Insulating your fuel line from the frame to the carb will help, as will an aluminum heat shield that extends under both fuel bowls. E10 fuel boils at 150*F, and at extended idle, the fuel bowls get hotter than that.



Thanks JohnZ for your insight.  My car already had the aluminum heat shield installed when I bought it from the previous owner 18 yrs. ago.  I'll try insulating the fuel line as you suggested. 
11  Camaro Research Group Discussion / Maintenance / Re: Running Hot? on: July 31, 2014, 12:46:41 PM
Really does begin to sound more like a flow problem. Flush the system with the best product you can find, change the water pump and the thermostat. Check and/or change the cap - you need to run about 12-15 psi in the system to make it work properly. If no big improvement, I'd take the radiator out and replace with another known used clear radiator, or a cheap repop just to isolate the problem. Or, just core the old one like most of us are having to experience.

What does the coolant look like ? Dark colored, any foam in it ? Leaking head gaskets can cause hot spots/steam pockets like this. Oil clean ? Any coolant contamination ? Hoses collapsing ?

Bad flow across the radiator could also be a culprit, as we conjectured before. Bet the lower half is plugged - that's why the temp is so low in the bottom half.

One other thing - I witnessed a big block Chevelle do this once upon a time - turns out it was spun bearing (main), causing the engine to not only run hot, but choke down and die when it warmed up enough to start galling on the crank. Check your oil pressure with a mechanical gauge, and a mechanical temp gauge if you can. Just to make sure -

Regards, and good luck -

Thank you for your response.  I had the current radiator recored and a new thermostat put in 14 years ago.  The coolant looks fine, the correct color green and no foam.  The oil is very clean.  I have noticed no hose collapsing.  I have the coolant replaced every 2 years.  I'll have the shop were I usually take my Z check the radiator functioning, etc.  Sure hope it is no spun bearing or any internal engine problem. 
12  Camaro Research Group Discussion / Maintenance / Re: Running Hot? on: July 29, 2014, 03:45:47 PM
Well I was finally able to do some checking on the underhood temps.  I drove the Z for between 2-3 miles to get the engine up to temp.  The outside air temp was in the mid 80's.  While driving the temp gauge stayed right around the first quarter marking, maybe one mark up toward the half marking.  While idling in my driveway the gauge read right at the one half marking.  The engine would not hold a steady idle but slowly had the idle decrease until the engine died.  This happened 3-4 times.  While the engine was not running the temp gauge would increase until it was between the one half marking and the three quarter marking.  This I take to be normal due to heat soak. 
Here are the temps I recorded with an infrared gun: 

radiator hose at thermostat- 183, bottom radiator hose- 164
exhaust manifold left hand side (driver's) from front to back- 364, 455, 417
exhaust manifold right hand (passenger) side again from front to back- 433, 570, 562
intake manifold at the high rise part on driver's side- 227
radiator across top- 145
radiator across bottom- 99
valve cover driver's side- 164
valve cover passenger side- 194
driver's side head-194, right at the temp sensor was 179
passenger side head- 253

I wasn't able to get accurate readings anywhere else or didn't think of trying anywhere else.  Definitely the right hand side (passenger) of the engine is a lot hotter than the driver's side.  I wasn't able to check other things while taking these temp readings as the engine was too hot to touch.  Any ideas out there?  Thanks again guys for all your help and opinions.  Just to add a side note:  the engine used to be able to idle for extended periods right at 900-1,000 rpm, with the temp gauge reading not much higher than the one quarter marking and without dying.  It also would restart while warm or hot with no problem. 
13  Camaro Research Group Discussion / Maintenance / Re: Running Hot? on: July 21, 2014, 12:24:26 PM
Thanks guys for all your ideas and responses.  I do have an infrared gun so will start from there trying to narrow things down as I go.  You guys have given me some things to look at that I never thought of.  Thanks JohnZ for the article; it was very informative.  It might take awhile for me to check everything but will let you guys know what I find out. 

I did want to ask one more question.  Will blocking off the heat passages in the intake manifold still make a difference even with my car not having a flapper anymore in the heat riser valve? 

I guess what got me the most perplexed was that with all this (in my opinion anyway) excessive heat build-up and hard starting if the engine stalled, the temp gauge still showed well within the normal range. 
14  Camaro Research Group Discussion / Maintenance / Running Hot? on: July 19, 2014, 06:10:04 PM
I wanted to post this info to get some helpful feedback and perhaps new ideas, and just to put my mind at ease.  My 1969 Z/28 seems to me anyway to be running hot even though the temp gauge shows well within the standards, reading barely over the first quarter of the gauge when driving and only going to the halfway point after shutting the engine off when I am guessing heat soak comes into play.  Sometimes when I pull away from a stop after driving for a half hour the car bucks, backfires, and then stalls.  I can't get it restarted for about 15 minutes until it cools down.  When I open the hood it is like I can feel a blast of hot air.  Previously the heat riser valve was stuck closed, but I had the flapper taken out.  Wouldn't this mean that no more hot exhaust gases are being circulated up to the intake manifold anymore to warm the carb at start-up?  When starting the car cold it does take longer to warm up now. 
Is it correct that the sensor for the temp gauge is in the engine block?  Is it possible the heads and intake manifold are getting hot for some reason even though the gauge reads fine?  Could there be gunk blocking a coolant passage in the engine, fan clutch not working,  smog pump or AIR system not working properly, etc.? 
About 2 weeks ago I drove it only about 2 miles at no more than 35-40 mph.  When I got to my driveway and turned the engine off and opened the hood I could see heat waves coming up from the passenger side exhaust manifold.  It was a hot day, in the low to mid 90's.  None of my other cars, or truck, put out anywhere near the heat that my '69 Z does.  And yet the temp gauge still reads fine; could the temp gauge be inaccurate?  My own thought is that I am boiling the fuel in the carburetor even with a heat shield, and that is why it wants to stall or kill and is so hard to restart until it cools down.  Am I overreacting or misinterpreting something?  Thanks guys for any and all help and ideas. 
15  Camaro Research Group Discussion / General Discussion / Re: Question about original dealer license plate frames on: July 19, 2014, 04:37:36 PM
Based on photos the original owner sent me of my '69 Z, both the front and rear license plate frames had the dealer name and Chevrolet inside the bowtie logo on the top and location of the dealership on the bottom.  It was originally sold from Gledhill Chevrolet in Wilmington, CA.     
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