Nailhead Cooling Saga

[Weldar]

Ok, about a year ago I picked up another 65GS (see this posting: http://65gs.com/board/index.php?topic=1651.msg9411#msg9411) and it tends to run hot (210+) at idle speed and would get down to around 195F - 200F cruising. The motor is a 66 nailhead and according to the previous owner was bored 0.060" over (yea, I know) in 1972. I am running 91 with some percentage of ethanol (that is all I have available). So far I have done the following with temp being monitored with a heat gun and new temp gauge:

1) - Reset timing from 12 advance to stock timing and confirmed that advance time is functioning (along with new plugs and wires) - No Change, although I think the plug wire change made the motor run smoother.
2) - Removed heat riser valve in the pass side exhaust manifold - No Change
3) - Installed a recored 4-core rad, flushed the motor, replaced existing 180F Tsat with a new 180F Tstat, and refilled with 50/50 - No Change
4) - Removed what appeared to be an original 3 blade impeller water pump and installed a new 5 blade (only broke off one bolt), topped with 50/50 - No Change (to my amazement)
5) - Installed a fan shroud and replaced 16" 6-blade flex fan with a new 18" 7-blade Flex-i-Light - Noticeable increase in air flow with rate of temp increase at idle seeming to be slower but still makes it to 210F
6) - Drained some 50/50 and topped with water (I am guessing about 20/80 now) - No Change
7) - Added a bottle of Water Wetter - Rate of temp increase at idle seems to be slower but still makes it to 210F
8) - Advanced initial timing back to 12 and other set points (currently at ~8) and adjusted idle screws (were running lean) - No Change
9) - Took out the Tstat - Significantly slowed the rate of increase (after reaching 180F) but sill reaches 210F. Runs about 165F on the highway in 60F ambient temps.

At this point I can live with the idle condition and want to see what happens when summer in Wyoming finally gets here. If the cruising temp can stay around 170F or higher I will ok for the summer. If not, I will try a high flow Tstat. Based on all the above it seems clear to me that I have an air flow problem at idle and that I probably would not have the problem if the motor was not overbored to 0.060". I am considering converting to electric fans over next winter. Any thoughts or are there other things I need to try? BTW - I have actually enjoyed working through this problem although I have used it as an excuse for not making progress on my restoration.

Dwaine

[bobbybuick]

My new build is getting warm also mostly slow driving or setting.I put a 5 blade clutch fan on but the air is not pulling through the rad.
My son said to do the paper test on the grille and it failed .it also failed right on the radiator.So I measured the fan from the radiator and it was about 2 inches away .I bought a 160 stat last night and a spacer to get the fan right on the radiator.check the flow with a piece of paper

[elagache]

Dear Dwaine, Bob, and 1965 GS fans,

3) - Installed a recored 4-core rad, flushed the motor, replaced existing 180F Tsat with a new 180F Tstat, and refilled with 50/50 - No Change

. . . . . .

I am considering converting to electric fans over next winter. Any thoughts or are there other things I need to try?

I don't know what is considered "politically correct" around here but is an aluminum radiator something you would consider?  My trusty wagon has a different engine and a T/A-Performance aluminum radiator with electric fans and it was working extremely well for the little I've had the car running (all trials during winter though.)  Alas, T/A-Performance doesn't market an "off the rack" radiator for the 65 GS.  However, I learned through a snafu that T/A-Performance has another shop make their radiators anyway.  You might have a chance to have a custom radiator made and in any case there are a number of aluminum radiator outfits out there.  I didn't make any attempt to make my wagon's radiator look prototypical, but I believe you can do a lot to make an aluminum radiator look reasonably stock and if you are willing to consider electric fans . . . well, that isn't exactly stock anyway! 

My new build is getting warm also mostly slow driving or setting.

How many miles do you have on your new build Bob?  I thought a new build would run a little extra hot until everything was broken in.  Are you past that point already?

Cheers, Edouard 

[mrbuick65]

 My engine is also .060 O/S. and have done everything Dwaine has done plus more. NO CHANGE. Am running an electric fan on the front of the rad as well as the stock fan. I run 210 to 215. It seems like these engines are like this when that much O/S.
John

[sjfd04]

This link has really good info.  They do offer a nailhead pump, I just checked, you have to send them your core. Castings are no longer available.

http://www.flowkoolerwaterpumps.com/cooling_faq.html

http://www.flowkoolerwaterpumps.com/store/Water-Pumps-Buick-CID:-401/6.6L/c21_25_79/p44/1620-Buick-Nailhead-Waterpump(1961-1966)/product_info.html

[WkillGS]

In general, overheating at highway speeds is a capacity issue (radiator too small), and overheating at idle is an airflow issue.
I've had very good luck with:
1) oem 7 blade flex fan, used on various GM applications.
2) A/C clutch fan. I hit the junkyard and used a mid 80's V6 Regal clutch, and (the hard part) an 80's Cadillac fan.... I'll have to measure the diameter on it, but I think it was 18"
Both are used without shrouds.

Your 18" Flex-a-lite fan 'looks' like it will move some air, but they don't show a cfm rating. Perhaps there are some test results somewhere on the web, comparing it to stock GM fans.

Another consideration is water flow (speed). A/C cars use pumps with more impeller blades (5 vs 3) and also use different size crank and water pump pulleys to spin the pump faster and speed up the water flow. But faster isn't always better...
Considering JUST the radiator, pushing the water through the rad too fast will not give the water enough time to transfer it's heat to the radiator. Slowing water flow thru the rad can actually result the water being cooled more!

It would be difficult to determine what is too fast/or too slow unless you want to get real involved: Put temperature senders at the radiator inlet, and another at the outlet. (maybe an IR temp gun would work?) This could tell you 2 things: (1) temperature rise of the water going through the engine, and (2) how much heat the radiator is dissipating. I think you would also need to know the water flow rate to do the proper calculations. But simply checking the in/out temps of the radiator could tell you if one fan is more effective than another.

Sorry, I'm rambling! A couple of other ideas....mostly unproven theories...
-An eroded timing cover will not work well with the water pump.
-Fuel mixture and timing can affect combustion temperature. Which would increase exhaust temperature... perhaps you could change mixture/timing, and check exhaust manifold temp with an IR temp gun?
- an oil cooler might reduce engine temperature.
- if all else fails, a more efficient radiator should do it..

[Weldar]

Thanks to all for the input. Heat transfer is a very complex technical subject with many variables to consider which I think can be seen by the various comments and ideas (not only in this post but the many others that can be found out there). Went ahead and ordered a Hayden 19" fan and HD clutch along with a Milodon 180F high flow Tstat. Will give this set-up a try and report back. The saga continues.

Dwaine

[WkillGS]

Dwaine, will the 19" fan fit the GS fan shroud?
When I installed my 18" fan, I had a modified 300 shroud on there (mounted upside down and trimmed the depth some), so that was the max that would fit. I don't have any GS shrouds here...dunno if they are bigger.

And check your cap pressure.... low pressure in the system could cause boiling in the hot spots, adding steam to the coolant, affecting how well the pump works (cavitation).

Electric fans and/or an aluminum radiator might be the ultimate solution....

[Weldar]

Dwaine, will the 19" fan fit the GS fan shroud?
When I installed my 18" fan, I had a modified 300 shroud on there (mounted upside down and trimmed the depth some), so that was the max that would fit. I don't have any GS shrouds here...dunno if they are bigger.

And check your cap pressure.... low pressure in the system could cause boiling in the hot spots, adding steam to the coolant, affecting how well the pump works (cavitation).

Electric fans and/or an aluminum radiator might be the ultimate solution....

Walt - I think the 19" will fit but will check. I bought two of those fan shrouds that were listed on V8 Buick which I am assuming were patterned from a stock 65 GS shroud. Interesting, when I look in the 1965 Gran Sport Service Manual (pg. 2-3 under General Description & Specifications - Cooling System) I see the fan for an A/C equipped car came with with 20" 7-blade fan......

Also using a new 15 psi cap. I do think there is isolated boiling near the cylinders due to the overbore (was hoping the snakeoil i.e. Water Wetter was helping with that).

Dwaine

[bobbybuick]

I have a new engine but last weekend noticed my car heating while sitting still.so i put a piece of paper on the grille and it fell to the ground.This week i installed a 1.25 inch spacer to move the 5 blade clutch fan as close to the radiator as i could get it .Also I put a spring in the lower radiator hose .I installed a new 160 stant thermostat and a 15 lb cap.
I started it briefly tonight(Drove today running at least 50 degrees cooler) Did the paper test it and it pulled the paper from my hand into the grille.I know a made a HUGE difference for about 50 bucks.Also I always drill an 1/8 hole in the flange of the tstat

So a couple things to add .
If not running a shroud install fan very close to radiator within finger width

Fill opening must be the highest part of cooling system if not you must use a spill free funnel to fill and make sure all air is out of system

check temperature into and out of radiator to make sure fan is not pulling air from behind radiator or use the paper test

[Weldar]

Well, installed the 19" fan with clutch and the high flow Tstat. Plenty of air flow through the rad. Temp still creeps up ever so slowly but even moving at slow speed brings it down. Holds 180F constant cruising. I made it through last summer and I have slowed the rate of temp increase at idle so I will see how this summer goes. Of all the things I tried I believe the fan shroud had the greatest impact.

Bobbybuick - Looks like you have solved your problems. What is the model # of that aluminum rad your posted (looks like a nice setup, btw)? Do the stock type hoses fit? Did you have to make any mods for it to fit?

Dwaine