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This morning I noticed a coolant leak on a flange that connects the feed from the water pump to number two cylinder jacket. I thought it would be a simple matter of fitting a new gasket, so I stripped it down, cleaned it off, made a new gasket and re-assembled it with some Red Hermetite. Unfortunately, it was then that I realised the real cause of the problem: one of the two 1/4 BSF studs had only just been holding and the vibrations mixed with old age and my action of tightening up the nut just pulled it right out. Stripped threads in cast iron are a real pain - the only real solution is to tap it out to 5/16 BSF and make a new stud and nut to fit! Aaaaagghh!

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This morning I noticed a coolant leak on a flange that connects the feed from the water pump to number two cylinder jacket. I thought it would be a simple matter of fitting a new gasket, so I stripped it down, cleaned it off, made a new gasket and re-assembled it with some Red Hermetite. Unfortunately, it was then that I realised the real cause of the problem: one of the two 1/4 BSF studs had only just been holding and the vibrations mixed with old age and my action of tightening up the nut just pulled it right out. Stripped threads in cast iron are a real pain - the only real solution is to tap it out to 5/16 BSF and make a new stud and nut to fit! Aaaaagghh!

could it not be helicoiled to retain the original stud size.

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The stripped hole could be filled with a resin metal putty then redrilled and tapped to the original size.

Or fill the hole with metal putty and refit the stud and allow to dry, the down side of this is you will probably never be able to remove the stud ever again.

Edited by Big COL
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I've done a lot of heli-coiling, & it would work fine in this situation. It's better suited to aluminium castings, & as cast iron is very abrasive, it could be a bit harsh on expensive heli-coil taps.

For a job like this, I would make up a "stepped" stud. Secure with thread loctite, no one will ever know. As it's a stud, rather than a bolt, it's likely it will never need to come out.

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This morning I noticed a coolant leak on a flange that connects the feed from the water pump to number two cylinder jacket. I thought it would be a simple matter of fitting a new gasket, so I stripped it down, cleaned it off, made a new gasket and re-assembled it with some Red Hermetite. Unfortunately, it was then that I realised the real cause of the problem: one of the two 1/4 BSF studs had only just been holding and the vibrations mixed with old age and my action of tightening up the nut just pulled it right out. Stripped threads in cast iron are a real pain - the only real solution is to tap it out to 5/16 BSF and make a new stud and nut to fit! Aaaaagghh!

Well, as an antidote to the Aaaaagghh, I can report that I refitted the water pump to my FR2 yesterday, and it doesn't drip! Thanks to Baldock and Peter Thompson for their assistance in saga of water pump rebuild.

 

MP.

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For a job like this, I would make up a "stepped" stud. Secure with thread loctite, no one will ever know. As it's a stud, rather than a bolt, it's likely it will never need to come out.

 

The stepped stud Idea is a very good one - especially if I use brass nuts on stainless steel studs - the result will be much stronger and less likely to give trouble.

 

I am also intrigued by the epoxy resin solution - has anyone had any experience of repairing cast iron with epoxy resins?

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The stepped stud Idea is a very good one - especially if I use brass nuts on stainless steel studs - the result will be much stronger and less likely to give trouble.

 

I am also intrigued by the epoxy resin solution - has anyone had any experience of repairing cast iron with epoxy resins?

the resin method will only be an option if the hole is blind ie not right through as the resin would escape , however if the hole is blind and you can get the cast clean which is doubtful as cast is porous it would work.

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the resin method will only be an option if the hole is blind ie not right through as the resin would escape , however if the hole is blind and you can get the cast clean which is doubtful as cast is porous it would work.

 

 

The hole is blind and the stud did not reach to the full depth but the cast iron around the thread has partly deteriorated to the extent that it has the appearance of powdery black carbon. Another option I have considered is to tap it out using a 5/16 cycle thread (BSC) which has the same tpi as 1/4 BSF and then make a special stepped stud to suit - all good fun!

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The hole is blind and the stud did not reach to the full depth but the cast iron around the thread has partly deteriorated to the extent that it has the appearance of powdery black carbon. Another option I have considered is to tap it out using a 5/16 cycle thread (BSC) which has the same tpi as 1/4 BSF and then make a special stepped stud to suit - all good fun!

hello again Graham rethreading is probably the best option i dont quite understand the 5/16 1/4 bit but thats not important ie 26tpi but different pitches. Only thing to look for are "pulls" where the area arount the threaded hole will rise as itis rethreaded and will have risen when the stud pulled out, it may not matter if the gasket is thick enough but it could fail under heavy load and when you least expect it, regards, stuart

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I blame the fluorescent lime green coolant.

 

You'd have never have noticed it with normal water, it would have then calcified over and self sealed

 

(until one day blowing right off and depositing all of the coolant in to the bilge in < 10 seconds) :P

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hello again Graham rethreading is probably the best option i dont quite understand the 5/16 1/4 bit but thats not important ie 26tpi but different pitches. Only thing to look for are "pulls" where the area arount the threaded hole will rise as itis rethreaded and will have risen when the stud pulled out, it may not matter if the gasket is thick enough but it could fail under heavy load and when you least expect it, regards, stuart

 

Re-threading to 5/16 BSF is probably the best way forward - preferably with a step down to 1/4 BSF. Sadly, I do not have access to a lathe on the boat and wonder if there is anyone on the forum who can help by turning some 5/16 BSF bolts down to 1/4" for half their length?

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Re-threading to 5/16 BSF is probably the best way forward - preferably with a step down to 1/4 BSF. Sadly, I do not have access to a lathe on the boat and wonder if there is anyone on the forum who can help by turning some 5/16 BSF bolts down to 1/4" for half their length?

roughly how long would the stud need to be

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what size are you after exactly as there used to be an engineering supply shop in notts that did all sorts of weird and wonder full bolts etc old stuff whitworth etc they've moved but i may be able to find out were they`ve gone to

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I blame the fluorescent lime green coolant.

 

You'd have never have noticed it with normal water, it would have then calcified over and self sealed

 

(until one day blowing right off and depositing all of the coolant in to the bilge in < 10 seconds) :P

 

Stripped threads are a real pain on old engines. Originally, I blamed myself but I think that in some cases (especially when it is something that hasn't been touched for years and then starts to go) it is just a mixture of vibration fatigue and corrosion.

 

roughly how long would the stud need to be

 

I figured that they could be made out of some 5/16 BSF stainless steel bolts or threaded bar. The finished length 1.25 turned down to 0.25 diameter over a distance of 0.750 and this to be threaded 1/4 BSF along 0.625 or just over. All dimensions Imperial inches.

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Stripped threads are a real pain on old engines. Originally, I blamed myself but I think that in some cases (especially when it is something that hasn't been touched for years and then starts to go) it is just a mixture of vibration fatigue and corrosion.

 

 

 

I figured that they could be made out of some 5/16 BSF stainless steel bolts or threaded bar. The finished length 1.25 turned down to 0.25 diameter over a distance of 0.750 and this to be threaded 1/4 BSF along 0.625 or just over. All dimensions Imperial inches.

i have some stainleess 5/16 bolts and the old guy next to me at work is an agricultural engineer with all the gear i,ll try him tommorow are you sure about stainless regards stuart

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what size are you after exactly as there used to be an engineering supply shop in notts that did all sorts of weird and wonder full bolts etc old stuff whitworth etc they've moved but i may be able to find out were they`ve gone to

 

Thanks, Denis. I can get bolts and threaded rod easily - they make all sorts of Imperial stuff in India these days to meet the demands of vintage car and motorcycle enthusiasts, and this is available at more than a dozen outlets. My difficulty, is finding someone with a lathe who has the time to turn them down so that they have a different diameter at each end. I learned long ago, that you never buy or make one of anything - because the minute you have finished it another one will be needed, so I figured on making half a dozen.

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Thanks, Denis. I can get bolts and threaded rod easily - they make all sorts of Imperial stuff in India these days to meet the demands of vintage car and motorcycle enthusiasts, and this is available at more than a dozen outlets. My difficulty, is finding someone with a lathe who has the time to turn them down so that they have a different diameter at each end. I learned long ago, that you never buy or make one of anything - because the minute you have finished it another one will be needed, so I figured on making half a dozen.

hello graham i think ive sent you a message direct but i,m not too clever with these things did you get it regards stuart bell 07984785861

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This morning I noticed a coolant leak on a flange that connects the feed from the water pump to number two cylinder jacket. I thought it would be a simple matter of fitting a new gasket, so I stripped it down, cleaned it off, made a new gasket and re-assembled it with some Red Hermetite. Unfortunately, it was then that I realised the real cause of the problem: one of the two 1/4 BSF studs had only just been holding and the vibrations mixed with old age and my action of tightening up the nut just pulled it right out. Stripped threads in cast iron are a real pain - the only real solution is to tap it out to 5/16 BSF and make a new stud and nut to fit! Aaaaagghh!

Don't think so,

Cast Iron has very low tensile strength, it tends to be granular and hence, crumbly. Therefore, a Helicoil would pull out again.

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Graham,

 

If you give me a ring on 07990628315 with dimensions I'll knock some up this week and they'll be in Aylesbury Friday night.

 

Better to re-tap the cast iron with a coarse thread rather than BSF. WW would be OK, or UNC. I could do either on the big end.

 

Regards

 

Nigel (with a J2 and lots of odd-sized studs).

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I've often used Helicoils in cast iron in the past. If you can get the right Imperial thread version, a Helicoil will work in this application and will allow you to use an 'original' design stud.....

"Heli-Coil® has the most effective and universally accepted method of thread repair. HeliCoil® quickly, easily and permanently restores stripped, worn or damaged threads to original condition.

HeliCoil® inserts can be used in any material: cast iron, steel, copper, brass, bronze, aluminum, magnesium, plastics and wood. After installation, they never shift, wear or back out. Stripping, fatigue, corrosion, crossthreading and seizing are eliminated."

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I've often used Helicoils in cast iron in the past. If you can get the right Imperial thread version, a Helicoil will work in this application and will allow you to use an 'original' design stud.....

 

I've got a 1/4" BSF helicoil tap you could borrow. No inserts, though.

Find some inserts & I'll take a few :P

 

Tim

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Try Here Tim: http://stores.ebay.co.uk/Davethetoolss-Emp...9QQftidZ2QQtZkm

Edited to say: Sorry, can't get the clicky to work, you'll have to paste the link into your browser!

 

The clicky worked for me.

Thanks for that, I've got a few Helicoil taps with no inserts, at his prices for 10 I can probably afford to stock up on a small selection.

 

Tim

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