Still Major Overheating since 2017! Timing OK? - ClassicOldsmobile.com

Go Back  ClassicOldsmobile.com > Repair & Restoration > Engine > Small Blocks
Still Major Overheating since 2017! Timing OK? >

Still Major Overheating since 2017! Timing OK?

Still Major Overheating since 2017! Timing OK?

Old January 13th, 2019, 10:11 PM
  #1  
Registered User
Thread Starter
 
Sarum's Avatar
 
Join Date: Oct 2013
Location: Matamata, Waikato, New Zealand
Posts: 171
Still Major Overheating since 2017! Timing OK?

Yep I still have the major overheating problem with my '65 Cutlass. As the issue started after I replaced the distributor with one from Summit Racing (and installed a trick HEI module at the same time) I decided to check the engine's ignition timing and have attached a PDF containing the test results. Until very recently I had thought the ignition may be too far advanced but after reading some new info I am not so sure, hence this post.
1)Summit Racing's latest version Installation Instructions say that the distributor provides a maximum of 10 degrees of Mechanical Advance. https://www.summitracing.com/int/par...0006/overview/
2)Summit also also goes on to state that the new distributor’s Mechanical Advance provides 20 degrees total beginning with 6 degrees off idle progressing to full advance at approx. 1800RPM
3)The new distributor has a adjustable vacuum canister which is currently locked off.
4)The 2 previous sets of instructions for the distributor have also said that “The vacuum advance provides 10 degrees of advance”.This has been deleted from the latest version but as can be seen from the test results table I measured from 14 up to 19 degrees of vacuum advance with my Innova digital timing light so I am a bit confused about how I can test almost double what the distributor’s supposed to provide.
5)At the time of installation the new distributor was fitted with a Pertronix Flame Thrower 111 HEI Module D72000. Here is a link to it https://www.summitracing.com/int/par...2000/overview/ Another
customer advised to “check initial timing as the unit effects dwell”.I am of the opinion that all HEI modules effect dwell,that it is a part of what they do.
6) The thermostat has been replaced as has the water pump. The drive belt has correct tension to operate the pump and the hoses are not collapsing. The Derales fan controller and Derales electric fan are working normally although I have been switching the fan on manually while testing.
7) I had started thinking that I might well have a leaking head gasket and this is causing the overheating but there are no signs of any of the classic indicators eg bubbles in the radiator etc.
8) I took the car for a short run today and had the fan switched on manually the whole time and at 55-60mph cruise the temp was sitting at 200degreesF but as soon as the speed dropped the temp would start rising. Previous to this issue arrising I coud sit at the same 55-60mph cruise with fan switched off and the temp would be stable at around 150-180 degrees.This feels like a lack of coolant circulation to my way of thinking because if coolant was moving around the wind through the radiator was normally enough to reduce the coolant temp previously never mind the electric fan.
I think I will replace the thermostat again before testing for a head gasket leak with one of the kits you can buy that has a chemical that reacts to CO2 in the radiator coolant
Any ideas would be most welcome as I really want to use the car this summer.

Attached Files
File Type: pdf
Timing Testing 2 PDF.pdf (395.1 KB, 12 views)
Sarum is offline  
Old January 13th, 2019, 10:38 PM
  #2  
Registered User
 
Fun71's Avatar
 
Join Date: Feb 2013
Location: Phoenix, AZ
Posts: 5,831
The timing numbers look good to me, so I have no idea why you are experiencing overheating issues.
Fun71 is offline  
Old January 13th, 2019, 10:49 PM
  #3  
Registered User
Thread Starter
 
Sarum's Avatar
 
Join Date: Oct 2013
Location: Matamata, Waikato, New Zealand
Posts: 171
Hi Kenneth,
Thanks for your quick reply it's much appreciated. The only good thing about things going wrong with the Cutlass is that I learn something new! After reading an article on the very good 442.com website I am more comfortable with the timing results,Sounds like the majority of performance articles etc don't mention vacuum advance when talking timing,Actually if it wasn't for the overheating the car is going great as I also changed shift points on the trans recently.
Sarum is offline  
Old January 14th, 2019, 05:56 AM
  #4  
Moderator
 
oldcutlass's Avatar
 
Join Date: Oct 2009
Location: Poteau, Ok
Posts: 31,067
According to your chart, your distributor is providing 19* of mechanical and vacuum almost 20* and fluctuating a bit because its adjusted with the allen wrench to an internal higher spring pressure than you have vacuum available. First your initial is too low, in it self will cause the engine to run hotter. Disconnect and plug your vac adv and adjust your initial to 16/18. Leave vac adv plugged and take for a ride.

The Summit instructions must be a typo as for the amount of mech adv. Most HEI are set for 21*ish of mech advance.
oldcutlass is offline  
Old January 14th, 2019, 06:16 AM
  #5  
Registered User
 
olds 307 and 403's Avatar
 
Join Date: Dec 2006
Location: Melville, Saskatchewan
Posts: 4,477
Add more initial timing as said, it will help. What is the compression ratio on this motor? That and camshaft as well as the octane available along with altitude determine what timing it will tolerate. What radiator is in the car? What amps do the Derale fans draw?
olds 307 and 403 is offline  
Old January 14th, 2019, 05:16 PM
  #6  
Registered User
Thread Starter
 
Sarum's Avatar
 
Join Date: Oct 2013
Location: Matamata, Waikato, New Zealand
Posts: 171
Originally Posted by oldcutlass View Post
According to your chart, your distributor is providing 19* of mechanical and vacuum almost 20* and fluctuating a bit because its adjusted with the allen wrench to an internal higher spring pressure than you have vacuum available. First your initial is too low, in it self will cause the engine to run hotter. Disconnect and plug your vac adv and adjust your initial to 16/18. Leave vac adv plugged and take for a ride.

The Summit instructions must be a typo as for the amount of mech adv. Most HEI are set for 21*ish of mech advance.
Hi again Eric,
You might not remember but you have helped me previously hence the "again" I think some of the fluctuation is due to how difficult it is to get the desired RPM reading on the Innova timing tester's screen. Sometimes an analogue needle setup is much better to use than a digital screen.Re the Allen wrench used to adjust spring pressure I am assuming you are talking about the adjustable vacuum the dizzie has, correct? I am excited by what I have been reading so I am going to go and try and adjust the timing to 16-18 degrees initial and see what happens when I take it for a drive as you suggest.
Sarum is offline  
Old January 14th, 2019, 09:42 PM
  #7  
Chevy budget Olds powered
 
coppercutlass's Avatar
 
Join Date: Jul 2011
Location: Elgin, Illinois
Posts: 7,403
I dont think you have a timing issue. Look more into your radiator and fans. How big are your fans and how big is your radiator. I learned this a few years ago on CFM and area coverage . I had some be cool fans that where suppoused to be the cats azz. I ended up going back to the twin fans from a 95 impala ss. They pretty much cover my entire radiator. Went from having the same issues you had to Normal. I bought the fans thinking they where new and would be great. . I put my junkyard units back in lol.
coppercutlass is offline  
Old January 15th, 2019, 06:25 AM
  #8  
Registered User
 
olds 307 and 403's Avatar
 
Join Date: Dec 2006
Location: Melville, Saskatchewan
Posts: 4,477
As said, what radiator and what model Derale fans do you have? Some of the Derale fans are US made, run big amps and move huge air, some not so good.
olds 307 and 403 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Sarum
Small Blocks
39
December 2nd, 2017 05:39 PM
jkoester122
General Discussion
2
December 10th, 2010 02:46 PM
jkoester122
The Newbie Forum
5
December 7th, 2010 06:06 AM
jkoester122
General Discussion
1
December 6th, 2010 10:02 PM
442scotty
General Discussion
8
May 13th, 2009 06:42 PM


Thread Tools
Search this Thread
Quick Reply: Still Major Overheating since 2017! Timing OK?


Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2018 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.