Altering 401 Heater pipe arrangement on engine.


Geoff Kingston
 

If I can summon up the enthusiasm one of the jobs on the to do list is to fit a Davies Craig electric water pump to one of the 401's, I have an early water pump where I could see the take off for the heater was on the pump housing, on the later engines obviously its on the back of the head and is effectively robbing coolant just before the full flow back along the head, I noticed with the heater valve shut that when the engine was revs were increased from idle the temperature dropped on the gauge for a short while due to the increased flow . The car is one of the ones suffering a hot spot problem in the block which has been flushed out as best we could with the engine in the car, the radiator has been repaired cleaned and flow tested and the thermostat changed, after a short run the gauge in the car reads over a 100 degrees while the water in the rad is never more than about 65 degrees, the water pump has been rebuilt and is working properly as is the temp gauge. At least one fellow owner has cured this problem by using a Davies Craig pump to increase the flow of water through the system. I am wondering however if in conjunction with doing this altering the layout of the feed and return pipes to the heaters would also be worth while, so has anyone done this, what was the new layout and was it effective? 
Geoff.  


Michael Brooks
 

Sounds like there's just too much of the flow bypassing the engine through the heater. Worth fitting a valve in the hose to the heater and experimenting with different levels of throttling. This would be a cheap and easy thing to do before spending out on an electric pump, wiring etc. Just a thought.

Mike




On Tuesday, 19 July 2022 at 12:17:48 BST, Geoff Kingston via groups.io <geoffkingston15@...> wrote:


If I can summon up the enthusiasm one of the jobs on the to do list is to fit a Davies Craig electric water pump to one of the 401's, I have an early water pump where I could see the take off for the heater was on the pump housing, on the later engines obviously its on the back of the head and is effectively robbing coolant just before the full flow back along the head, I noticed with the heater valve shut that when the engine was revs were increased from idle the temperature dropped on the gauge for a short while due to the increased flow . The car is one of the ones suffering a hot spot problem in the block which has been flushed out as best we could with the engine in the car, the radiator has been repaired cleaned and flow tested and the thermostat changed, after a short run the gauge in the car reads over a 100 degrees while the water in the rad is never more than about 65 degrees, the water pump has been rebuilt and is working properly as is the temp gauge. At least one fellow owner has cured this problem by using a Davies Craig pump to increase the flow of water through the system. I am wondering however if in conjunction with doing this altering the layout of the feed and return pipes to the heaters would also be worth while, so has anyone done this, what was the new layout and was it effective? 
Geoff.  


Geoffrey Herdman
 

Dear Geoff

Although you have changed the thermostat it does sound as if the new one may be playing up?? Have you tried popping it in your favourite saucepan to see what happens?

Geoffrey




On 19 Jul 2022, at 13:09, Michael Brooks via groups.io <hypercubic@...> wrote:

Sounds like there's just too much of the flow bypassing the engine through the heater. Worth fitting a valve in the hose to the heater and experimenting with different levels of throttling. This would be a cheap and easy thing to do before spending out on an electric pump, wiring etc. Just a thought.

Mike




On Tuesday, 19 July 2022 at 12:17:48 BST, Geoff Kingston via groups.io <geoffkingston15@...> wrote:


If I can summon up the enthusiasm one of the jobs on the to do list is to fit a Davies Craig electric water pump to one of the 401's, I have an early water pump where I could see the take off for the heater was on the pump housing, on the later engines obviously its on the back of the head and is effectively robbing coolant just before the full flow back along the head, I noticed with the heater valve shut that when the engine was revs were increased from idle the temperature dropped on the gauge for a short while due to the increased flow . The car is one of the ones suffering a hot spot problem in the block which has been flushed out as best we could with the engine in the car, the radiator has been repaired cleaned and flow tested and the thermostat changed, after a short run the gauge in the car reads over a 100 degrees while the water in the rad is never more than about 65 degrees, the water pump has been rebuilt and is working properly as is the temp gauge. At least one fellow owner has cured this problem by using a Davies Craig pump to increase the flow of water through the system. I am wondering however if in conjunction with doing this altering the layout of the feed and return pipes to the heaters would also be worth while, so has anyone done this, what was the new layout and was it effective? 
Geoff.  


Dorien
 

Geoff  I'm not sure I follow your theory? When the heater is turned off you have already effectively by-passed it. I would also get an infrared gun...they are quite cheap...and take readings around the engine at different places and RPM. Not having that problem on my 400 I've no experience, but I would not be considering an auxiliary water pump given yours works well.
Did you use citric acid in your engine cleaning? Best for that sort of job.

Dorien



On Tuesday, July 19, 2022 at 08:09:08 a.m. EDT, Michael Brooks via groups.io <hypercubic@...> wrote:


Sounds like there's just too much of the flow bypassing the engine through the heater. Worth fitting a valve in the hose to the heater and experimenting with different levels of throttling. This would be a cheap and easy thing to do before spending out on an electric pump, wiring etc. Just a thought.

Mike




On Tuesday, 19 July 2022 at 12:17:48 BST, Geoff Kingston via groups.io <geoffkingston15@...> wrote:


If I can summon up the enthusiasm one of the jobs on the to do list is to fit a Davies Craig electric water pump to one of the 401's, I have an early water pump where I could see the take off for the heater was on the pump housing, on the later engines obviously its on the back of the head and is effectively robbing coolant just before the full flow back along the head, I noticed with the heater valve shut that when the engine was revs were increased from idle the temperature dropped on the gauge for a short while due to the increased flow . The car is one of the ones suffering a hot spot problem in the block which has been flushed out as best we could with the engine in the car, the radiator has been repaired cleaned and flow tested and the thermostat changed, after a short run the gauge in the car reads over a 100 degrees while the water in the rad is never more than about 65 degrees, the water pump has been rebuilt and is working properly as is the temp gauge. At least one fellow owner has cured this problem by using a Davies Craig pump to increase the flow of water through the system. I am wondering however if in conjunction with doing this altering the layout of the feed and return pipes to the heaters would also be worth while, so has anyone done this, what was the new layout and was it effective? 
Geoff.  


Geoff Kingston
 

Mike at the moment the heater valve appears to be shut but might still letting water through the system, the odd thing is on my other 401 it is open and we have no problem, Geoffrey I did test the new thermostat and it seems fine, the old one was stuck shut and fitting the new one did not cure things which was when the head scratching started, Dorien the thinking follows an article I read some years ago by Spencer Lanes Jones who had a 404 or 405 that was overheating badly when the heater tap was opened, I remember he said it went against logic but the heater matrix had been enlarged and it was effectively robbing too much coolant out of the system and reducing the thermo syphon effect from the block, I seem to remember he said they modified the water pump housing, looking at the remains of an early water pump I have I could see there was already a water outlet on it, I must look up what Spencer said but I don't recall any drawings or photographs of the revised pipe layout. We have done a physical and high pressure clean of the block with both end plates off and as I said the rad has also been repaired, a slight leak on the header tank, a chemical clean flow and pressure test by a local engineer and that's as far as it got so far. Before fitting the pump I intended to either treat the system with holts speedflush or Fenox which is likely to be a bit more drastic but more effective. If that works I will have a new Davis Craig water pump surplus to requirements!

I had not seen mention of Citric acid to clean the system so what is the best approach with that?

The reason for going down the Davies Craig route was that Andy Gibbs put me in touch with a club member who had exactly the same problem in his 400 with an uprated engine. He overcame the hot spot issue but has a further write up for BODA coming as it showed up the need to rebuild the rad, now maybe that is where I should start, except the advantages of the Davies Craig pumps are quite compelling.

Geoff.




------ Original Message ------
From: "Dorien via groups.io" <hydroglen@...>
To: "bocforum@groups.io" <bocforum@groups.io>
Sent: Tuesday, 19 Jul, 22 At 15:57
Subject: Re: [bocforum] Altering 401 Heater pipe arrangement on engine.

Geoff I'm not sure I follow your theory? When the heater is turned off you have already effectively by-passed it. I would also get an infrared gun...they are quite cheap...and take readings around the engine at different places and RPM. Not having that problem on my 400 I've no experience, but I would not be considering an auxiliary water pump given yours works well.
Did you use citric acid in your engine cleaning? Best for that sort of job.

Dorien



On Tuesday, July 19, 2022 at 08:09:08 a.m. EDT, Michael Brooks via groups.io <hypercubic@...> wrote:


Sounds like there's just too much of the flow bypassing the engine through the heater. Worth fitting a valve in the hose to the heater and experimenting with different levels of throttling. This would be a cheap and easy thing to do before spending out on an electric pump, wiring etc. Just a thought.

Mike




On Tuesday, 19 July 2022 at 12:17:48 BST, Geoff Kingston via groups.io <geoffkingston15@...> wrote:


If I can summon up the enthusiasm one of the jobs on the to do list is to fit a Davies Craig electric water pump to one of the 401's, I have an early water pump where I could see the take off for the heater was on the pump housing, on the later engines obviously its on the back of the head and is effectively robbing coolant just before the full flow back along the head, I noticed with the heater valve shut that when the engine was revs were increased from idle the temperature dropped on the gauge for a short while due to the increased flow . The car is one of the ones suffering a hot spot problem in the block which has been flushed out as best we could with the engine in the car, the radiator has been repaired cleaned and flow tested and the thermostat changed, after a short run the gauge in the car reads over a 100 degrees while the water in the rad is never more than about 65 degrees, the water pump has been rebuilt and is working properly as is the temp gauge. At least one fellow owner has cured this problem by using a Davies Craig pump to increase the flow of water through the system. I am wondering however if in conjunction with doing this altering the layout of the feed and return pipes to the heaters would also be worth while, so has anyone done this, what was the new layout and was it effective?
Geoff.


Dorien
 

I'm not at home to go and look at my 400 but I can offer the following...
On my Hudson Indy racer I can't race it with the thermostat in place. On a warm/hot day it will overheat or run extra warm LOL even though the thermostat opens nicely in a pot of hot water.
No thermostat, and all is well and that = greater water flow. This is interesting in that the block is clean the radiator fine and in addition Hudsons have a water distribution plate/manifold going down the inside of the block with holes placed, so as to have a relative even water distribution.

It would be an easy test to try...running without the thermostat.

Dorien


On Tuesday, July 19, 2022 at 01:06:25 p.m. EDT, Geoff Kingston via groups.io <geoffkingston15@...> wrote:


Mike at the moment the heater valve appears to be shut but might still letting water through the system, the odd thing is on my other 401 it is open and we have no problem, Geoffrey I did test the new thermostat and it seems fine, the old one was stuck shut and fitting the new one did not cure things which was when the head scratching started, Dorien the thinking follows an article I read some years ago by Spencer Lanes Jones who had a 404 or 405 that was overheating badly when the heater tap was opened, I remember he said it went against logic but the heater matrix had been enlarged and it was effectively robbing too much coolant out of the system and reducing the thermo syphon effect from the block, I seem to remember he said they modified the water pump housing, looking at the remains of an early water pump I have I could see there was already a water outlet on it, I must look up what Spencer said but I don't recall any drawings or photographs of the revised pipe layout. We have done a physical and high pressure clean of the block with both end plates off and as I said the rad has also been repaired, a slight leak on the header tank, a chemical clean flow and pressure test by a local engineer and that's as far as it got so far. Before fitting the pump I intended to either treat the system with holts speedflush or Fenox which is likely to be a bit more drastic but more effective. If that works I will have a new Davis Craig water pump surplus to requirements!

I had not seen mention of Citric acid to clean the system so what is the best approach with that?

The reason for going down the Davies Craig route was that Andy Gibbs put me in touch with a club member who had exactly the same problem in his 400 with an uprated engine. He overcame the hot spot issue but has a further write up for BODA coming as it showed up the need to rebuild the rad, now maybe that is where I should start, except the advantages of the Davies Craig pumps are quite compelling.

Geoff.




------ Original Message ------
From: "Dorien via groups.io" <hydroglen@...>
To: "bocforum@groups.io" <bocforum@groups.io>
Sent: Tuesday, 19 Jul, 22 At 15:57
Subject: Re: [bocforum] Altering 401 Heater pipe arrangement on engine.

Geoff I'm not sure I follow your theory? When the heater is turned off you have already effectively by-passed it. I would also get an infrared gun...they are quite cheap...and take readings around the engine at different places and RPM. Not having that problem on my 400 I've no experience, but I would not be considering an auxiliary water pump given yours works well.
Did you use citric acid in your engine cleaning? Best for that sort of job.

Dorien



On Tuesday, July 19, 2022 at 08:09:08 a.m. EDT, Michael Brooks via groups.io <hypercubic@...> wrote:


Sounds like there's just too much of the flow bypassing the engine through the heater. Worth fitting a valve in the hose to the heater and experimenting with different levels of throttling. This would be a cheap and easy thing to do before spending out on an electric pump, wiring etc. Just a thought.

Mike




On Tuesday, 19 July 2022 at 12:17:48 BST, Geoff Kingston via groups.io <geoffkingston15@...> wrote:


If I can summon up the enthusiasm one of the jobs on the to do list is to fit a Davies Craig electric water pump to one of the 401's, I have an early water pump where I could see the take off for the heater was on the pump housing, on the later engines obviously its on the back of the head and is effectively robbing coolant just before the full flow back along the head, I noticed with the heater valve shut that when the engine was revs were increased from idle the temperature dropped on the gauge for a short while due to the increased flow . The car is one of the ones suffering a hot spot problem in the block which has been flushed out as best we could with the engine in the car, the radiator has been repaired cleaned and flow tested and the thermostat changed, after a short run the gauge in the car reads over a 100 degrees while the water in the rad is never more than about 65 degrees, the water pump has been rebuilt and is working properly as is the temp gauge. At least one fellow owner has cured this problem by using a Davies Craig pump to increase the flow of water through the system. I am wondering however if in conjunction with doing this altering the layout of the feed and return pipes to the heaters would also be worth while, so has anyone done this, what was the new layout and was it effective?
Geoff.