You had mentioned to my KC friend Brian that he might try installing flow restrictors in the water pump/intake bypass hose to help with his overheating issue in low airflow conditions. Do you have a link or suggestion on where to find the restrictors?
He found some that restrict the coolant flow at the thermostat housing in the intake (they actually replace the thermostat), but nothing for the bypass hose itself.
Should he try to put an appropriate sized washer into the bypass hose as an alternative, or make something himself?
Thanks!
Bobs_Place said
Jul 29, 2019
Yes, a washer is what I used. I found one that fit tight in the hose with a 3/8 hole, I think a 1/4 would be better however.
Also I found this which I thought was interesting. https://webstore.spalusa.com/content/files/content/PDF/30102130_SPEC.pdf Look at the voltage chart. With just 1in. of restriction on the water column the air flow through the radiator is cut to almost 1/3 and amperage goes up. This is inches of water not mercury. I takes approximately 14" water to equal 1" mercury. Inches of mercury is what we use to measure engine vacuum. So, if he has a 4 row with a high fin count rad., he might do better with a 7 blade engine driven with a clutch and over drive pulleys to overcome the higher restriction as opposed to he 1 1/4" tube two row aluminum rads are not as restrictive, so the high flow electric fans should be good.
SShink said
Jul 30, 2019
Thanks Bob! I'll share this with Brian.
He told me yesterday his local mechanic told him to drill a couple of bypass holes in his thermostat and replace the water pump. Sounds like that's his next step since it's relatively easy and inexpensive. Besides, he's replaced everything else on the cooling system other than those.
We talked about drilling the stat at the show, won't do much for reducing coolant temp but never a problem bleeding air from the system.
I've read about using the Ford fan assembly, I would think the OEM fan motors pull air better as they are designed to cool the truck with A/C and auto trans. I was suppressed to see how much air flow performance degraded with very little restriction on the low buck fans, the high end not so much.
Why is he changing the pump? Is it leaking or going to a high flow? I would also recommend overdrive water pump pulleys, the more turns the water makes the hotter the radiator runs so the air across the core will pull than pull more BTUs.
Has he wired the fans to the alternator yet or are they still at the battery?
SShink said
Jul 31, 2019
Brian's changing the pump because it's about the only thing left that hasn't been changed out (I believe it's a stock style and not hi flow), and it's cheap and easy.
He's still running the same direct to battery through a relay wiring that I know of on the electric fans.
SShink said
Jul 31, 2019
Update---He changed some things and now it's holding no higher than 185 degrees idling in the garage with the AC on:
High flow water pump
Holes drilled in thermostat
Restrictor washer in the bypass hose
The real test will be in traffic, so that's next on the list but it's much better all ready compared to before.
Bobs_Place said
Jul 31, 2019
That's good news, keep the updates coming.
Lost in the 60s said
Jul 31, 2019
This brings up the question of why is that hose there to begin with ? I see many people blocking the ports and eliminating the hose completely and claiming the engine stays cool just fine. If restricting that hose down to nearly nothing helps low speed cooling, why not just remove it ?
SShink said
Jul 31, 2019
Lost in the 60s wrote:
This brings up the question of why is that hose there to begin with ? I see many people blocking the ports and eliminating the hose completely and claiming the engine stays cool just fine. If restricting that hose down to nearly nothing helps low speed cooling, why not just remove it ?
All kinds of opinions out there on the interwebs on this one...but my understanding is it helps balance the thermal warming of the block between cylinders to not have cold spots for even combustion and cooling flow.
I'm sure some of the engine guru's may know more.
Bobs_Place said
Jul 31, 2019
On A/C cars there is a vacuum controlled water shut off valve in the heater line, and, with the stat closed, no bypass line the water pump can't move coolant. Due to the lack of coolant flow, the stat may not see enough temp to open in time, engine could then develop hot spots . Some say the water pump will cavitate and aerate the coolant, maybe. In a non A/C car there is flow through the heating system so shouldn't be any problem as long as one heater hose is routed near the stat. The holes in the stat also helps, but with no heater or bypass hose I would drill larger and more holes in the stat. On small blocks there is an internal passage in the block that runs from the water pump mounting surface to the cyl head.
jim larson said
Aug 3, 2019
Not sure where I read this or heard it; but I thought you didn't want coolant traveling though the radiator two fast as it wouldn't cool enough. I fought with overheating issues for the first few years after I bought my 66. Tried radiators and water pump with no luck. After finding out what cam I had, I was told my base timing was way to low. Bumped it from 10 to 16 and no further overheating issues.
Bobs_Place said
Aug 3, 2019
I have also heard that if the water flows through the engine to fast it will not absorb the heat. I don't believe it. The faster the water moves through engine/cooling system the more BTUs are pulled out of the engine and moved to the radiator, the hotter the rad runs the more efficient it is, then more BTUs are removed.
As for the timing As long as the engine starts good, (no kickback) and doesn't ping, I would add another 4 to 8degs initial, see how the engine responds.
SShink said
Aug 8, 2019
So after a hot and humid drive in KC, it's still running hot for him with the AC on in traffic. He's going to call the radiator company (I think it's Cool Craft?) since it's only a year old and a large capacity aluminum one,and see if they have any ideas. He's down to thinking there is a flow restriction in the rad reducing the cooling capacity. I suggested he put a pressure tester on it and see if it will get up to pressure and hold, or if it's not holding.
This has been a tough one to figure out, as he's checked, adjusted, tweaked everything and no change.
SShink said
Aug 9, 2019
Talked to Brian last night and he had called the rad company and they're going to replace his rad and upgrade the fan capacity. There is only a 10 degree drop between the inlet and outlet of the rad and they said it should be 30-40 degrees difference, so they think there could be a restriction (pinched tubes?). It's been acting this way since day 1, so he suspects the rad was bad from the get go when he installed it a year ago.
Lost in the 60s said
Aug 9, 2019
Good of them to stand behind their product..
I hope this will take care of the issue for him.
SShink said
Aug 9, 2019
Lost in the 60s wrote:
Good of them to stand behind their product..
I hope this will take care of the issue for him.
Yeah, the only painful part is he needs to ship it back first before they'll replace it, but at this point he's willing to do anything to fix the issue.
Bobs_Place said
Aug 9, 2019
So the rad company thinks there are restricted tubes? They must know something. With a good radiator, the drop in temp will be less with higher coolant flow. Assuming his temp readings were taken with the coolant temp well above the opened stat temp and his rad was not compromised with restricted tubes, than the air flow across the core is inadequate.
Good to here that they are supporting him, sounds like they are covering all the basses with the new rad and upgraded fan assembly. Is the rad upgraded or is it the same capacity?
SShink said
Aug 9, 2019
Bobs_Place wrote:
So the rad company thinks there are restricted tubes? They must know something. With a good radiator, the drop in temp will be less with higher coolant flow. Assuming his temp readings were taken with the coolant temp well above the opened stat temp and his rad was not compromised with restricted tubes, than the air flow across the core is inadequate.
Good to here that they are supporting him, sounds like they are covering all the basses with the new rad and upgraded fan assembly. Is the rad upgraded or is it the same capacity?
Yeah Bob, he said after describing all the things he's tried, they were pretty quick to say they would send a replacement rad.
Same size rad for the replacement, but higher output fans than what he has now.
Lost in the 60s said
Aug 9, 2019
SShink wrote:
Bobs_Place wrote:
So the rad company thinks there are restricted tubes? They must know something. With a good radiator, the drop in temp will be less with higher coolant flow. Assuming his temp readings were taken with the coolant temp well above the opened stat temp and his rad was not compromised with restricted tubes, than the air flow across the core is inadequate.
Good to here that they are supporting him, sounds like they are covering all the basses with the new rad and upgraded fan assembly. Is the rad upgraded or is it the same capacity?
Yeah Bob, he said after describing all the things he's tried, they were pretty quick to say they would send a replacement rad.
Same size rad for the replacement, but higher output fans than what he has now.
Good of them to stand behind their product, but cheesy to require him to send it back FIRST. It would be far easier for him to use the same packaging the new came in to return the defective one. Does he still have the original packing from a year ago ?
Bobs_Place said
Aug 10, 2019
Lost in the 60s wrote:
SShink wrote:
Bobs_Place wrote:
So the rad company thinks there are restricted tubes? They must know something. With a good radiator, the drop in temp will be less with higher coolant flow. Assuming his temp readings were taken with the coolant temp well above the opened stat temp and his rad was not compromised with restricted tubes, than the air flow across the core is inadequate.
Good to here that they are supporting him, sounds like they are covering all the basses with the new rad and upgraded fan assembly. Is the rad upgraded or is it the same capacity?
Yeah Bob, he said after describing all the things he's tried, they were pretty quick to say they would send a replacement rad.
Same size rad for the replacement, but higher output fans than what he has now.
Good of them to stand behind their product, but cheesy to require him to send it back FIRST. It would be far easier for him to use the same packaging the new came in to return the defective one. Does he still have the original packing from a year ago ?
You would think he could give them a credit card, he should only be charged if he doesn't send any thing back.
I fore got to ask, how does his A/C work when he is in the temp/driving conditions that cause the overheating.
Hi Bob,
You had mentioned to my KC friend Brian that he might try installing flow restrictors in the water pump/intake bypass hose to help with his overheating issue in low airflow conditions. Do you have a link or suggestion on where to find the restrictors?
He found some that restrict the coolant flow at the thermostat housing in the intake (they actually replace the thermostat), but nothing for the bypass hose itself.
Should he try to put an appropriate sized washer into the bypass hose as an alternative, or make something himself?
Thanks!
Yes, a washer is what I used. I found one that fit tight in the hose with a 3/8 hole, I think a 1/4 would be better however.
Also I found this which I thought was interesting. https://webstore.spalusa.com/content/files/content/PDF/30102130_SPEC.pdf Look at the voltage chart. With just 1in. of restriction on the water column the air flow through the radiator is cut to almost 1/3 and amperage goes up. This is inches of water not mercury. I takes approximately 14" water to equal 1" mercury. Inches of mercury is what we use to measure engine vacuum. So, if he has a 4 row with a high fin count rad., he might do better with a 7 blade engine driven with a clutch and over drive pulleys to overcome the higher restriction as opposed to he 1 1/4" tube two row aluminum rads are not as restrictive, so the high flow electric fans should be good.
Thanks Bob! I'll share this with Brian.
He told me yesterday his local mechanic told him to drill a couple of bypass holes in his thermostat and replace the water pump. Sounds like that's his next step since it's relatively easy and inexpensive. Besides, he's replaced everything else on the cooling system other than those.
I also just had this appear in my email inbox that is an interesting related read: LINK TO SUPER CHEVY HEAT ARTICLE
We talked about drilling the stat at the show, won't do much for reducing coolant temp but never a problem bleeding air from the system.
I've read about using the Ford fan assembly, I would think the OEM fan motors pull air better as they are designed to cool the truck with A/C and auto trans. I was suppressed to see how much air flow performance degraded with very little restriction on the low buck fans, the high end not so much.
Why is he changing the pump? Is it leaking or going to a high flow? I would also recommend overdrive water pump pulleys, the more turns the water makes the hotter the radiator runs so the air across the core will pull than pull more BTUs.
Has he wired the fans to the alternator yet or are they still at the battery?
Brian's changing the pump because it's about the only thing left that hasn't been changed out (I believe it's a stock style and not hi flow), and it's cheap and easy.
He's still running the same direct to battery through a relay wiring that I know of on the electric fans.
Update---He changed some things and now it's holding no higher than 185 degrees idling in the garage with the AC on:
High flow water pump
Holes drilled in thermostat
Restrictor washer in the bypass hose
The real test will be in traffic, so that's next on the list but it's much better all ready compared to before.
That's good news, keep the updates coming.
All kinds of opinions out there on the interwebs on this one...but my understanding is it helps balance the thermal warming of the block between cylinders to not have cold spots for even combustion and cooling flow.
I'm sure some of the engine guru's may know more.
On A/C cars there is a vacuum controlled water shut off valve in the heater line, and, with the stat closed, no bypass line the water pump can't move coolant. Due to the lack of coolant flow, the stat may not see enough temp to open in time, engine could then develop hot spots . Some say the water pump will cavitate and aerate the coolant, maybe. In a non A/C car there is flow through the heating system so shouldn't be any problem as long as one heater hose is routed near the stat. The holes in the stat also helps, but with no heater or bypass hose I would drill larger and more holes in the stat. On small blocks there is an internal passage in the block that runs from the water pump mounting surface to the cyl head.
Not sure where I read this or heard it; but I thought you didn't want coolant traveling though the radiator two fast as it wouldn't cool enough. I fought with overheating issues for the first few years after I bought my 66. Tried radiators and water pump with no luck. After finding out what cam I had, I was told my base timing was way to low. Bumped it from 10 to 16 and no further overheating issues.
I have also heard that if the water flows through the engine to fast it will not absorb the heat. I don't believe it. The faster the water moves through engine/cooling system the more BTUs are pulled out of the engine and moved to the radiator, the hotter the rad runs the more efficient it is, then more BTUs are removed.
As for the timing
As long as the engine starts good, (no kickback) and doesn't ping, I would add another 4 to 8degs initial, see how the engine responds.
So after a hot and humid drive in KC, it's still running hot for him with the AC on in traffic. He's going to call the radiator company (I think it's Cool Craft?) since it's only a year old and a large capacity aluminum one,and see if they have any ideas. He's down to thinking there is a flow restriction in the rad reducing the cooling capacity. I suggested he put a pressure tester on it and see if it will get up to pressure and hold, or if it's not holding.
This has been a tough one to figure out, as he's checked, adjusted, tweaked everything and no change.
Talked to Brian last night and he had called the rad company and they're going to replace his rad and upgrade the fan capacity. There is only a 10 degree drop between the inlet and outlet of the rad and they said it should be 30-40 degrees difference, so they think there could be a restriction (pinched tubes?). It's been acting this way since day 1, so he suspects the rad was bad from the get go when he installed it a year ago.
Good of them to stand behind their product..
I hope this will take care of the issue for him.
Yeah, the only painful part is he needs to ship it back first before they'll replace it, but at this point he's willing to do anything to fix the issue.
So the rad company thinks there are restricted tubes? They must know something. With a good radiator, the drop in temp will be less with higher coolant flow. Assuming his temp readings were taken with the coolant temp well above the opened stat temp and his rad was not compromised with restricted tubes, than the air flow across the core is inadequate.
Good to here that they are supporting him, sounds like they are covering all the basses with the new rad and upgraded fan assembly. Is the rad upgraded or is it the same capacity?
Yeah Bob, he said after describing all the things he's tried, they were pretty quick to say they would send a replacement rad.
Same size rad for the replacement, but higher output fans than what he has now.
Good of them to stand behind their product, but cheesy to require him to send it back FIRST. It would be far easier for him to use the same packaging the new came in to return the defective one. Does he still have the original packing from a year ago ?
You would think he could give them a credit card, he should only be charged if he doesn't send any thing back.
I fore got to ask, how does his A/C work when he is in the temp/driving conditions that cause the overheating.