Dave Bean Water pump

[Graham B]

I have been through the saga of fitting a Burton cartridge water pump and cover and would like to pass on my findings.

My water pump failed in 2017 and I removed the engine and dismantled it. I decided to fit the Burton cartridge and cover and bought all the parts from Burton shortly after. The engine and parts sat in the garage until covid19 and lockdowns when the time was right to finish the job.
The engine was re-installed early 2021 but it was soon apparent that coolant was leaking into the sump. Engine out and dismantled again to reveal the O ring had burst out of the side of the groove and split. Examination showed that the side wall was very thin (0.7mm) and a short section had broken off. Also, the O ring had been extruded out between the machined faces. This looked like the problem a number of people had reported before.

I contacted Burton and, as others have found, had great difficulty in them accepting it was a manufacturing fault (mis-located casting on the cnc machine). Since they supplied the kit 4 years before, we finally agreed they supply a new back plate at half price.

When the new cover arrived, I decided to investigate the fit of the O ring further and found the volume of the O ring is about 12% more than the volume of groove. First, the cross-section area of the O ring is greater than the csa of the groove by 14%. Second, the length of the O ring material is shorter than the groove length and will stretch when pressed into the groove. This is indicated by the difficulty in keeping the O ring in the groove during assembly.

The O ring material is virtually incompressible which explains why the O ring burst out through the thin side wall and why it extruded out between the machined faces. I have no idea why Burton designed it this way and ignored standard design guides.
To correct this, I chose a metric sized O ring which has a smaller section and is slightly shorter. The O ring groove is 2.36mm wide by 2.0mm deep. The volume of this O ring is approx. 1.8% more than the groove.

The Burton supplied “O” ring is 2.62mm dia. x 101.27 bore in Nitrile.
The new “O” ring is 2.5mm dia. x 100mm bore in Viton (better high temperature performance).
When bolted up the “O” ring height is compressed by 0.5mm and width by 0.14mm. It will fill the groove completely but the ring is stretched slightly when fitted in the groove, this should allow the O ring to grip the groove during assembly.

In an ideal world O rings should be in grooves wider than the diameter so that they are free to expand sideways and only compressed in height. It is not practical to re-machine the groove because the path is complex. From metric O ring design guides, the correct groove size for the 2.5mm section is 3.90mm wide x 1.90mm deep. This change should stop the compressive force put on the groove side wall and stop the “O” ring material extruding out between the joint faces.

The cartridge O ring was also changed to Viton material.

Most of the kit bolts supplied were incorrect lengths for my engine with an alternator fitted. The 3 bolts holding the cartridge were changed to Torx headed, available from Harley Davidson spares, and fit neatly behind the water pump pulley.

For various reasons, I also decided to go back to the original engine, removed back in 1986, and asked Paul Exon to rebore and rebuild it for me. I produce an information sheet for him which has copious notes on fitting the Burton cover based on my experiences.

I hope you find the posting and notes useful. Burton may have corrected their machining and kit of parts since I purchased mine in 2017 and 2021, if not it will give pointers of where to look for problems.

Disclaimer - This was what I found with my engine and parts from Burton. Do check your assembly and satisfy yourself all is ok.

Graham

[alan.barker]

In a Generator there are Bushes which have more friction than the bearing races in an Alternator.
You can use the Fan Belts with notches in that are very flexible and grip well.
Alan

[Stevie-Heathie]

Craig of Craig Beck Racing Engines in Newmarket also makes a cartridge water pump solution for Twincams, so there is now a third option. Got to be good.

He’s just fitted one to my S3. Going to post separately with a recommendation but thought would mention in this thread too.

Best
Steve

[2cams70]

I have been through the saga of fitting a Burton cartridge water pump and cover and would like to pass on my findings.

My water pump failed in 2017 and I removed the engine and dismantled it. I decided to fit the Burton cartridge and cover and bought all the parts from Burton shortly after. The engine and parts sat in the garage until covid19 and lockdowns when the time was right to finish the job.
The engine was re-installed early 2021 but it was soon apparent that coolant was leaking into the sump. Engine out and dismantled again to reveal the O ring had burst out of the side of the groove and split. Examination showed that the side wall was very thin (0.7mm) and a short section had broken off. Also, the O ring had been extruded out between the machined faces. This looked like the problem a number of people had reported before.

I contacted Burton and, as others have found, had great difficulty in them accepting it was a manufacturing fault (mis-located casting on the cnc machine). Since they supplied the kit 4 years before, we finally agreed they supply a new back plate at half price.

When the new cover arrived, I decided to investigate the fit of the O ring further and found the volume of the O ring is about 12% more than the volume of groove. First, the cross-section area of the O ring is greater than the csa of the groove by 14%. Second, the length of the O ring material is shorter than the groove length and will stretch when pressed into the groove. This is indicated by the difficulty in keeping the O ring in the groove during assembly.

The O ring material is virtually incompressible which explains why the O ring burst out through the thin side wall and why it extruded out between the machined faces. I have no idea why Burton designed it this way and ignored standard design guides.
To correct this, I chose a metric sized O ring which has a smaller section and is slightly shorter. The O ring groove is 2.36mm wide by 2.0mm deep. The volume of this O ring is approx. 1.8% more than the groove.

The Burton supplied “O” ring is 2.62mm dia. x 101.27 bore in Nitrile.
The new “O” ring is 2.5mm dia. x 100mm bore in Viton (better high temperature performance).
When bolted up the “O” ring height is compressed by 0.5mm and width by 0.14mm. It will fill the groove completely but the ring is stretched slightly when fitted in the groove, this should allow the O ring to grip the groove during assembly.

In an ideal world O rings should be in grooves wider than the diameter so that they are free to expand sideways and only compressed in height. It is not practical to re-machine the groove because the path is complex. From metric O ring design guides, the correct groove size for the 2.5mm section is 3.90mm wide x 1.90mm deep. This change should stop the compressive force put on the groove side wall and stop the “O” ring material extruding out between the joint faces.

The cartridge O ring was also changed to Viton material.

Most of the kit bolts supplied were incorrect lengths for my engine with an alternator fitted. The 3 bolts holding the cartridge were changed to Torx headed, available from Harley Davidson spares, and fit neatly behind the water pump pulley.

For various reasons, I also decided to go back to the original engine, removed back in 1986, and asked Paul Exon to rebore and rebuild it for me. I produce an information sheet for him which has copious notes on fitting the Burton cover based on my experiences.

I hope you find the posting and notes useful. Burton may have corrected their machining and kit of parts since I purchased mine in 2017 and 2021, if not it will give pointers of where to look for problems.

Disclaimer - This was what I found with my engine and parts from Burton. Do check your assembly and satisfy yourself all is ok.

Graham

Seems like you read my post from several years ago about the Burton water pump where I suggested to use the Harley bolts. Mine was ok but it may be that O rings aren’t fitting properly because the backplate has been machined too thin in production due to poor quality control and the o ring groove consequently isn’t deep enough. You should not have used silicone sealant around that o-ring by the way. Like I said where the wall of the groove has broken away is on the coolant side. Breakage here should not cause a leak into the timing chest. If it was on the outside of the groove yes but not on the inside.

[2cams70]

In a Generator there are Bushes which have more friction than the bearing races in an Alternator.
You can use the Fan Belts with notches in that are very flexible and grip well.
Alan

Sorry I tell a lie. Ford put a bigger bearing in the pushrod engine’s water pump just for the hell of it.

[alan.barker]

Not bad because of poor quality control.
Bad because of bad machining.
QC checks to confirm if to Specification .
Sorry but i was a QC Engineer for 20 years.
Alan

[Graham B]

Graham[/quote]

Seems like you read my post from several years ago about the Burton water pump where I suggested to use the Harley bolts. Mine was ok but it may be that O rings aren’t fitting properly because the backplate has been machined too thin in production due to poor quality control and the o ring groove consequently isn’t deep enough. You should not have used silicone sealant around that o-ring by the way. Like I said where the wall of the groove has broken away is on the coolant side. Breakage here should not cause a leak into the timing chest. If it was on the outside of the groove yes but not on the inside.[/quote]

Hi 2Cams70,
The O ring had actually split in two having been forced out through the gap leaving a leak path to the timing chest. see third picture.
The main point I was trying to make was that O rings should NOT be fitted in grooves too narrow such that the compression, from the two parts being bolted together, does not force the O ring against the groove walls.
O rings are NOT compressible, they should just change shape within the groove. That compression was the reason the thin wall was pushed out and, where the groove was stronger, the O ring was extruded out between the mating faces. see second picture.
Thanks for the Harley bolt suggestion, it worked well.

[rgh0]

In a Generator there are Bushes which have more friction than the bearing races in an Alternator.
You can use the Fan Belts with notches in that are very flexible and grip well.
Alan

Sorry I tell a lie. Ford put a bigger bearing in the pushrod engine’s water pump just for the hell of it.

Who knows why Ford put a bigger bearing in. Maybe due to higher loads from the introduction of alternators(especially high output ones on rally cars) or change to the radiator plastic multi bladed fan style and pump impellor or maybe from some combination of all of this. Maybe due to some standardisation with bearing suppliers and other engines. Maybe due to warranty claims from people over tightening the V belt. Maybe just for the hell of it. I am guessing just like you are unless you have some orginal Ford design documentation from the period ( not marketing BS documentation)

All I know is that in a Twincam if you leave the belt loose enough when cold, even with an alternator typically used on an Elan these days and especially with an Electric radiator fan rather than the water pump pulley mounted fan then the bearing does not fail as the belt does not overload the bearing when the engine is hot.

No one has to believe me on any of this...... this is just the Internet and its your car and your engine.... sometimes I wonder why I bother trying to explain what I have found from 45 years of building and maintaining and helping people with these engines and what I understand from my broader mechincal and chemical engineering training and experience

cheers
Rohan

[alan.barker]

Good points and ideas.
Also on the Europa Twin Cam Water Pumps last longer
Alan

[rgh0]

Yes once you take out the adjustment (and some of the loads and thermal expansion) the problem largely goes away. Hard to tell what is the major factor but the lack of belt adjustment is a major factor in my assessment on the Europa

cheers
Rohan

[alan.barker]

Hi Rohan,
Are you burning the midnight oil maybe 1hoo am in Aussie. 15hoopm here in France with Saumur Champigny.
Yes nothing to adjust on the Europa Twin Cam. Give them things to adjust and they will always mess it up.(ref "chubby chapman")
Alan

[rgh0]

Hi Alan only 12:45 Am here in Melbourne . Up early to tommorrow as i have a local guy coming in the morning for me to measure up his block cylinder and main tunnel bores and wall thicknesses to see whether its recoverable.

I love looking at Twinks as you always learn the more you look and measure



cheers
Rohan

[fatboyoz]

Hi Steve,
Any pictures of the CBR cartridge water pump?
Cheers,
Colin.






quote="Stevie-Heathie"]Craig of Craig Beck Racing Engines in Newmarket also makes a cartridge water pump solution for Twincams, so there is now a third option. Got to be good.

He’s just fitted one to my S3. Going to post separately with a recommendation but thought would mention in this thread too.

Best
Steve[/quote]

[HCA]

This all makes me feel that my choice of a std water pump with a not-overtightened toothed belt for my new engine is the right choice after all…

[reb53]

All I know is that in a Twincam if you leave the belt loose enough when cold, even with an alternator typically used on an Elan these days and especially with an Electric radiator fan rather than the water pump pulley mounted fan then the bearing does not fail as the belt does not overload the bearing when the engine is hot.

cheers
Rohan

Totally agree Rohan.
Figured this out 35 years ago when the pump failed due to my over tightening the belt in a vain attempt to make the dynamo actually earn it's living.
Replaced the the dynamo with an alternator, repaired the pump with standard parts, and left the belt loose enough to be able to easily push the alternator pulley around with a finger.
Alternator and pump still working fine.

Ralph.