Thermo clutch check

[Vaaraz]

Hello dear Avanti owners !

I am french and I take care of an 63' Avanti R2 near Paris.

Engine, chassis, drive trains, etc... have been restored.
I have restored or change everything in the cooling circuit : new hoses, new HD water pump, radiator remade, new thermostat, new thermo clutch, no excessive ignition advance (just settled)... but it's still overheating a little under hot weather, especially at idle speed...

I have just dropped the radiator to a workshop which is supposed to install a more efficient core and I will put everything back in the car soon.

I just have a question concerning the thermo clutch (1560257) : I have changed it recently and I am wondering why is it so easy to turn the fan by hand when the engine has just been stopped but still hot... shouldn't it be hard to turn ? What about yours ?

Also, I am changing the normal coolant for the permanent Evans (http://www.evanscoolants.co.uk/Coolants/Automotive/classic_cool_180), are there any feedback about using that kind of coolant on his car ?

Last question : has anybody tested the 6 fans ventilator ? Is it more efficient than the original one ?

In less than two weeks, I am supposed to drive the car to Le Mans Classic (http://www.lemansclassic.com/language/en/home/#primary) , under the sun of july...

Thanks for your help...

Merci !

Daniel

[Gunslinger]

When you're at the Le Mans Classic, look for a gold 1969 Corvette convertible. I sold it a few months ago to a fellow in England who's a designer for Jaguar/Land Rover and he intends to take it there. Tell him hello from me.

[Vaaraz]

if, by chance, I can see him... sure, I will say hello !

[JLBKY]

Hello dear Avanti owners !

I am french and I take care of an 63' Avanti R2 near Paris.

Engine, chassis, drive trains, etc... have been restored.

I have restored or change everything in the cooling circuit : new hoses, new HD water pump, radiator remade, new thermostat, new thermo clutch, no excessive ignition advance (just settled)... but it's still overheating a little under hot weather, especially at idle speed...

I have just dropped the radiator to a workshop which is supposed to install a more efficient core and I will put everything back in the car soon.

I just have a question concerning the thermo clutch (1560257) : I have changed it recently and I am wondering why is it so easy to turn the fan by hand when the engine has just been stopped but still hot... shouldn't it be hard to turn ? What about yours ?

Also, I am changing the normal coolant for the permanent Evans (http://www.evanscoolants.co.uk/Coolants/Automotive/classic_cool_180), are there any feedback about using that kind of coolant on his car ?

Last question : has anybody tested the 6 fans ventilator ? Is it more efficient than the original one ?

In less than two weeks, I am supposed to drive the car to Le Mans Classic (http://www.lemansclassic.com/language/en/home/#primary) , under the sun of july...

Thanks for your help...

Merci !

Daniel

Daniel...........I can't comment on the Stock Thermo Clutch as I changed mine over several years ago to a BMW clutch. It requires some machine work to make it all work, and with a short window to solve your problem, I'd not encourage you to go that route.

I would however suggest that while the radiator is out of the car, that you pull the water pump and confirm that the impeller clearance to the back of the water pump housing is correct. I can get you exact measurements if you wish. The fast check method is to scrape the water pump gasket off and hold the pump in the housing and turn it by hand. A VERY slight contact should/might be heard. If there is no contact you can measure the distance with some children's "Silly Putty". Place an amount of putty about the size of a marble on one of the impeller vanes and place the water pump in the housing.........again WITH OUT the gasket. Remove the pump and you will see the clearance. It should be as close to the back of the housing as possible. A ever so slight contact with the hosing is OK with no gasket in place. The gasket that I use is .004 thick and will provide the necessary clearance when in place, if you have the slight contact I described. With a gear puller you can pull the impeller further back of the shaft.

Another thing you can examine with the water pump out of the housing, is the hole in the housing where the water returns to the water pump via the lower radiator hose. If I recall correctly that hole in the housing where the lower radiator hose connects is about 5/8 inch. Jon Myer encourages that it should be drilled to 3/4 inch to allow more water flow.

I assume you have the fan shroud and are using it. If not it needs to be in place.

You asked about a six blade fan. I can't comment on that I've not used one. I can comment on the optional 7 blade fan. I have one on my car and it works well.

Regarding the Evans Cooling. My limited understanding is that it does not lower your temperature, but rather raises the boiling point. The net result is no boil over.

Your state that the engine has been restored. Was the engine rebuilt? Were the Freeze Plugs removed and the bare block boiled to remove the rust and sludge in the cooling jackets? If not, this could be part of the problem. IF the block was not boiled/cleaned internally, and with only a couple of weeks to work on this I'd suggest that you look for the block drains on either side of the engine. Usually they are plugged with a square headed plug. Remove the plugs ( an 8 point socket works well here) and see what comes out. It could be perfectly clean if the block was properly boiled/ cleaned. Or, you might have to poke a screw driver into the drain hole to get the crude to come out. If you find crude and sludge, you have found a good portion of your cooling problem in my opinion. In a perfect world, one would remove all of the freeze plugs and scrape and flush the crude and sludge out of the cooling jackets. Replacing freeze plugs with the engine in the car is a pain in the ass. When I rebuilt my engine I found sludge and crude half way up the cylinder cooling jackets. I also found old freeze plugs in the cooling jackets that had been pushed in rather than removed.

I've driven in and out of Paris on two occasions in June/July and can relate to the stress that one incurs. Add to that an overheating Avanti and the stress and frustration levels would reach the boiling point. No pun intended.

Hope this helps. If you have further questions, post them here on the Forum.

John Brissette

Louisville Kentucky

[wwundt]

Revisit "everything has been restored." How completely was the engine "restored"? Did that include removing the freeze plugs and cleaning out the block? If not, there may be 50 years worth of sediment and rust in the engine block restricting cooling system capacity (and ready to plug up your clean new radiator).

[Vaaraz]

Daniel...........I can't comment on the Stock Thermo Clutch as I changed mine over several years ago to a BMW clutch. It requires some machine work to make it all work, and with a short window to solve your problem, I'd not encourage you to go that route.

I would however suggest that while the radiator is out of the car, that you pull the water pump and confirm that the impeller clearance to the back of the water pump housing is correct. I can get you exact measurements if you wish. The fast check method is to scrape the water pump gasket off and hold the pump in the housing and turn it by hand. A VERY slight contact should/might be heard. If there is no contact you can measure the distance with some children's "Silly Putty". Place an amount of putty about the size of a marble on one of the impeller vanes and place the water pump in the housing.........again WITH OUT the gasket. Remove the pump and you will see the clearance. It should be as close to the back of the housing as possible. A ever so slight contact with the hosing is OK with no gasket in place. The gasket that I use is .004 thick and will provide the necessary clearance when in place, if you have the slight contact I described. With a gear puller you can pull the impeller further back of the shaft.

Another thing you can examine with the water pump out of the housing, is the hole in the housing where the water returns to the water pump via the lower radiator hose. If I recall correctly that hole in the housing where the lower radiator hose connects is about 5/8 inch. Jon Myer encourages that it should be drilled to 3/4 inch to allow more water flow.

I assume you have the fan shroud and are using it. If not it needs to be in place.

You asked about a six blade fan. I can't comment on that I've not used one. I can comment on the optional 7 blade fan. I have one on my car and it works well.

Regarding the Evans Cooling. My limited understanding is that it does not lower your temperature, but rather raises the boiling point. The net result is no boil over.

Your state that the engine has been restored. Was the engine rebuilt? Were the Freeze Plugs removed and the bare block boiled to remove the rust and sludge in the cooling jackets? If not, this could be part of the problem. IF the block was not boiled/cleaned internally, and with only a couple of weeks to work on this I'd suggest that you look for the block drains on either side of the engine. Usually they are plugged with a square headed plug. Remove the plugs ( an 8 point socket works well here) and see what comes out. It could be perfectly clean if the block was properly boiled/ cleaned. Or, you might have to poke a screw driver into the drain hole to get the crude to come out. If you find crude and sludge, you have found a good portion of your cooling problem in my opinion. In a perfect world, one would remove all of the freeze plugs and scrape and flush the crude and sludge out of the cooling jackets. Replacing freeze plugs with the engine in the car is a pain in the ass. When I rebuilt my engine I found sludge and crude half way up the cylinder cooling jackets. I also found old freeze plugs in the cooling jackets that had been pushed in rather than removed.

I've driven in and out of Paris on two occasions in June/July and can relate to the stress that one incurs. Add to that an overheating Avanti and the stress and frustration levels would reach the boiling point. No pun intended.

Hope this helps. If you have further questions, post them here on the Forum.

John Brissette

Louisville Kentucky

Dear John,

Many, many thanks for your long and precise answer !!!

Here are some pictures of the time of the restoration :

https://www.facebook.com/O-ONE-135370756510340/photos/?tab=album&album_id=136252399755509

As you can see, all the engine was put in parts, the freeze plugs have been replaced and the block has been flushed completely.

I was not there when the work was made and cannot be sure at 100% that everything was made perfectly but I have no reason to doubt that all the engine jackets were not flushed.

Some too dark pictures I needed to over lighted under Photoshop prove me that one of the two plugs (driver side) had well been unscrewed but I can't tell about the other one...

Yesterday, to be completely sure, I wanted to check and unscrew the other plug (passenger side) but it was just impossible to open... We even tried to warm it with a blowtorch... I am afraid to go further.

Maybe the mechanic who restored the car (different from today's) had the same problem... I asked him but I still have no answer.

I've read that some people use white vinegar or CLR (Calcium Lime Rust) : http://www.jalopyjournal.com/forum/threads/best-for-cleaning-water-jackets.665267/

What do you think of that ?

Thanks a lot for your good advices about the water pump, I had already read something about it but didn't understand very well.

Should I take the risk to pull the water pump if I don't have any new gasket (I am afraid I don't...) ?

If I understand well... if the space behind the propeller is deep enough, I should pull the propeller on its shaft until it almost touch the back of the housing then place the pump again by using a 004 thick gasket, is that right ?

My question is : because it's always in movement, won't the propeller move back on its shaft ?

I like the idea to increase the diameter of the hole.

The car must be ready in... less than 3 days... Good news come from the sky... the weather is a little less hot now ;-) !

Again, thanks a lot John, your advices are very helpfull.

Daniel

[JLBKY]

Dear John,

Many, many thanks for your long and precise answer !!!

Here are some pictures of the time of the restoration :

https://www.facebook.com/O-ONE-135370756510340/photos/?tab=album&album_id=136252399755509

As you can see, all the engine was put in parts, the freeze plugs have been replaced and the block has been flushed completely.

I was not there when the work was made and cannot be sure at 100% that everything was made perfectly but I have no reason to doubt that all the engine jackets were not flushed.

Some too dark pictures I needed to over lighted under Photoshop prove me that one of the two plugs (driver side) had well been unscrewed but I can't tell about the other one...

Yesterday, to be completely sure, I wanted to check and unscrew the other plug (passenger side) but it was just impossible to open... We even tried to warm it with a blowtorch... I am afraid to go further.

Maybe the mechanic who restored the car (different from today's) had the same problem... I asked him but I still have no answer.

I've read that some people use white vinegar or CLR (Calcium Lime Rust) : http://www.jalopyjournal.com/forum/threads/best-for-cleaning-water-jackets.665267/

What do you think of that ?

Thanks a lot for your good advices about the water pump, I had already read something about it but didn't understand very well.

Should I take the risk to pull the water pump if I don't have any new gasket (I am afraid I don't...) ?

If I understand well... if the space behind the propeller is deep enough, I should pull the propeller on its shaft until it almost touch the back of the housing then place the pump again by using a 004 thick gasket, is that right ?

My question is : because it's always in movement, won't the propeller move back on its shaft ?

I like the idea to increase the diameter of the hole.

The car must be ready in... less than 3 days... Good news come from the sky... the weather is a little less hot now ;-) !

Again, thanks a lot John, your advices are very helpfull.

Daniel

Daniel............it sounds to me that the block is OK and was flushed properly. Let's move on.

As to pulling the water pump. If you do not have a gasket , you can make one. But make sure you know the thickness of the gasket material.Yes, the space BEHIND the pump impeller to the water pump manifold should be very very close. Pulling the impeller further back is not real easy to do.Once moved it is not going to move by itself on the shaft. Yes you understand correctly how to measure the clearance. Using some "Putty" to confirm the clearance is the best way I know to check the clearance. But do it with out the gasket in place. If you pull the impeller back on the shaft to the point where it just clears or has slight interference, you should be fine. The actual clearance will be increased by the thickness of the gasket. If you pull the pump, increasing the size of the return hole in the water pump housing is rather straight forward and easy and should help. Your short time frame may prevent you from doing any of these things I've suggested. Yes, your description of what to do with the pump impeller is correct.

I'm not aware of using white vinegar to clean the water jacket. As to CLR..........I guess it might work. If the block was properly cleaned, I don't see the need for further cleaning. But you should use a Rust Inhibitor along with anti freeze when you refill the radiator.

If you have questions, let me know. I'll check this site again on Monday morning .

John