Can you help me find a solution to this old car problem?
Discussion
Hive mind of PH classic car gurus... can your collective wisdom and knowledge of all things engineery help me find a solution to this problem?
I'm currently working on a pre-war engine and trying to cure a bad case of incontinence.... The problem is simple - there are plates bolted to the sides of the block that form part of the water jacket. The interface between the plates and the block is sealed with a cork gasket and that seals great!
The threaded holes that take the bolts to fasten the plates to the block are 'open' and coolant is free to work it's way up the threads, whereupon it weeps out between the underside of the bolt head and the plate. Originally the manufacturers solved this with some sort of lipped, copper crush washer, but these are no longer obtainable, were all spent and it wasn't possible to re-use them post rebuild. Upon reassembly regular copper washers were tried, but these gushed out coolant. A new set were tried but with a semi-setting sealant compound added - better, but still poor. Lastly, bonded nitrile hydraulic washers (the little washers with the rubber seals bonded into them) were tried, and whilst better, it STILL leaks more coolant than is acceptable.....
What else can I use or try to seal these threads and holes? Are little copper crush washers with good gap filling capabilities still available? Is there another product or a modern alternative that's better? or a modern non-setting thread sealer?
The bolts are imperial and measure 6mm dia on the shank, the holes into which they fit are only slightly bigger so there is capacity to create a seal between the underside of the bolt head and the plate... if we can find something that will seal that joint! Part of the problem is that this gap is not particularly parallel or uniform, so there needs to be a decent amount of variation in the seal, which needs to be able to deform to fill that gap...
PH hive mind - what are your thoughts?
As pictures always help, here is the issue....
I'm currently working on a pre-war engine and trying to cure a bad case of incontinence.... The problem is simple - there are plates bolted to the sides of the block that form part of the water jacket. The interface between the plates and the block is sealed with a cork gasket and that seals great!
The threaded holes that take the bolts to fasten the plates to the block are 'open' and coolant is free to work it's way up the threads, whereupon it weeps out between the underside of the bolt head and the plate. Originally the manufacturers solved this with some sort of lipped, copper crush washer, but these are no longer obtainable, were all spent and it wasn't possible to re-use them post rebuild. Upon reassembly regular copper washers were tried, but these gushed out coolant. A new set were tried but with a semi-setting sealant compound added - better, but still poor. Lastly, bonded nitrile hydraulic washers (the little washers with the rubber seals bonded into them) were tried, and whilst better, it STILL leaks more coolant than is acceptable.....
What else can I use or try to seal these threads and holes? Are little copper crush washers with good gap filling capabilities still available? Is there another product or a modern alternative that's better? or a modern non-setting thread sealer?
The bolts are imperial and measure 6mm dia on the shank, the holes into which they fit are only slightly bigger so there is capacity to create a seal between the underside of the bolt head and the plate... if we can find something that will seal that joint! Part of the problem is that this gap is not particularly parallel or uniform, so there needs to be a decent amount of variation in the seal, which needs to be able to deform to fill that gap...
PH hive mind - what are your thoughts?
As pictures always help, here is the issue....
Edited by larrylamb11 on Wednesday 10th March 21:36
What about something like these:
https://www.riffraffdiesel.com/fuel-end-plug-banjo...
Also, Porsche use bolts for that run through oil galleries under pressure. Google "Porsche case through bolts" you'll see examples. You may be able to copy the design concept.
https://www.riffraffdiesel.com/fuel-end-plug-banjo...
Also, Porsche use bolts for that run through oil galleries under pressure. Google "Porsche case through bolts" you'll see examples. You may be able to copy the design concept.
One of the Holts radiator stop leak products. You may frown upon such a "bodge" but it will certainly solve your problem.
These sort of products may nowadays be considered a bodge to solve a problem before you sell a car, but they work remarkably well. In the early sixties in Australia new Ford cooling systems had the addition of Bars Leaks, and a little label on the bulhead proudly informing the owner of this!
These sort of products may nowadays be considered a bodge to solve a problem before you sell a car, but they work remarkably well. In the early sixties in Australia new Ford cooling systems had the addition of Bars Leaks, and a little label on the bulhead proudly informing the owner of this!
The solution has to be to stop water passing the thread and if you use studs, you could simply bed the stud in your sealant of choice. As there would then be no need to seal the nut/plate face, a spring (or shakeproof) washer could be used under the nut.
In theory retaining the setscrews and using sealant should work, but getting a good seal from the sealant would be less certain.
In theory retaining the setscrews and using sealant should work, but getting a good seal from the sealant would be less certain.
Few thoughts.
Copper washers are used to seal between diesel injectors & the engine so the pressure in your application shouldn't be an issue.
Possibly the copper washers would benefit from annealing as being stamped out would work harden them. I had fun & games with my sprinter as the genuine ones were very hard.
The hole in the washer may be too large to crush up against the bolt body.
The washer may be too thin.
RRC V8 (mine's an '86 3.5) have a number of long thin bolts that pass through the water pump, the timing cover & into the front of the block.
The threaded holes in the block open into the waterjacket & LR recommend the threads be treated with sealant.
The specified sealant has changed over the years, the factory manual for mine says Loctite 572 which is a white paste.
I do know if they aren't they can corrode, be an absolute pig to remove & can shear. That in turn affects the sealing of the water pump to timing cover gasket & if one does shear during water pump swaps needs a lot more work!
Copper washers are used to seal between diesel injectors & the engine so the pressure in your application shouldn't be an issue.
Possibly the copper washers would benefit from annealing as being stamped out would work harden them. I had fun & games with my sprinter as the genuine ones were very hard.
The hole in the washer may be too large to crush up against the bolt body.
The washer may be too thin.
RRC V8 (mine's an '86 3.5) have a number of long thin bolts that pass through the water pump, the timing cover & into the front of the block.
The threaded holes in the block open into the waterjacket & LR recommend the threads be treated with sealant.
The specified sealant has changed over the years, the factory manual for mine says Loctite 572 which is a white paste.
I do know if they aren't they can corrode, be an absolute pig to remove & can shear. That in turn affects the sealing of the water pump to timing cover gasket & if one does shear during water pump swaps needs a lot more work!
GAjon said:
Drill out the existing threads fit Helicoils with a finer or tapered thread.
Should seal with a good sealant and fibre washer on new threads.
I wouldn't want to alter anything in that way unless it was absolutely necessary. The solder idea, and/or the gasket paper would seem favourite to me, however, if cork won't make a seal? ......Should seal with a good sealant and fibre washer on new threads.
Does the block casting do this with the tapped holes in?
Are the tapped hold blind or through?
If so can you make a new Cork gasket that lands bolt bosses to seal there instead of trying to seal the head.
Dowty washers are the norm to use in these situations. Is the bolt fully threaded or does it have a portion of plain shank?
Bolt is likely to be a 5/16ths (~7.9mm)
Are the tapped hold blind or through?
If so can you make a new Cork gasket that lands bolt bosses to seal there instead of trying to seal the head.
Dowty washers are the norm to use in these situations. Is the bolt fully threaded or does it have a portion of plain shank?
Bolt is likely to be a 5/16ths (~7.9mm)
Edited by Ambleton on Wednesday 10th March 23:39
Edited by Ambleton on Wednesday 10th March 23:40
Gassing Station | Classic Cars and Yesterday's Heroes | Top of Page | What's New | My Stuff