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Andrew.Coward
United Kingdom
77 Posts |
 Posted - 05/04/2022 : 10:00:32
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| I wonder if anyone can help after replacing the head gasket on my PA have now discovered the head is cracked beyond repair does anyone know of a replacement head. Many thanks Andrew |
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coracle
United Kingdom
1966 Posts |
Posted - 05/04/2022 : 10:46:17
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How badly cracked?
Are you sure it is scrap? This one was repaired.
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Roger Cadogan
United Kingdom
493 Posts |
Posted - 05/04/2022 : 11:52:20
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Laser welding can be a possible and practical option. Had the process been around years ago many of our blocks and heads would have been saved from the scrap yard.
Obviously it depends what you define as "cracked beyond repair " but you may be surprised at what is now possible. Any chance of some pictures?
Roger |
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Andrew.Coward
United Kingdom
77 Posts |
Posted - 05/04/2022 : 13:09:44
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| Thanks Roger I will try to send some pictures away at the moment so will try tomorrow |
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Andrew.Coward
United Kingdom
77 Posts |
Posted - 05/04/2022 : 13:10:38
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| Thanks to coracle too |
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bernard.scott
United Kingdom
194 Posts |
Posted - 05/04/2022 : 19:43:14
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An example of a laser-welded repair to a non-stressed area of my J2 head at EMP Havant. Contact was Alan Barker 023 9249 2626.
They were busy building up valve seats and mending cracks on other MMM heads back in 2017 when I had mine mended. Not cheap but they did quote for the job before I committed to it. There are, I am sure, other providers of this technique. Well worth investigating the relative cost.
Bernie Scott
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Andrew.Coward
United Kingdom
77 Posts |
Posted - 06/04/2022 : 11:23:59
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Thanks again for all your replies and photos. I’ve attached some of my own and tried to chalk the cracks on no 1 and no4. I’ve spoken to a company that claims that they can repair pretty much any crack in cast iron so sounds hopeful.
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coracle
United Kingdom
1966 Posts |
Posted - 06/04/2022 : 12:11:32
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Would that be Cast Iron Welding Ltd? https://www.castironwelding.co.uk/ I dealt with Harold Palmer at the time but think it may be a Son in charge now.
I had the head done in the photo by them a few years ago. Both the middle cylinders were the problem with very old and bad cracks. I went the whole hog at the time and had all the valve seats built up as they were significantly recessed.
The first go was not a great success as there were blow holes evident when the head was re-machined but they did it again (under guarantee, no additional charge.) This worked out OK but I had to resort to machining the combustion chambers all over and a lot of work subsequently to match them.
It worked out at less cost than a new head but, with all the trouble and heart ache, I just bought a new head for the next motor.
From the pictures in your case, I would say it should not be such a problem. They should be able to sort that out and with new valve seat inserts it would keep you going for some years.
I don't know about laser welding but it looks from what I have read, an attractive option. If I were you I would investigate both options.
I certainly don't think from what I can see that your head should be scrapped. |
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Andrew.Coward
United Kingdom
77 Posts |
Posted - 06/04/2022 : 14:35:27
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| Thanks Coracle I have spoken to a company called Slinden services they’ve said they will repair fit new valve guides machine as necessary to fit my valves.They will pressure and crack test then give me a quote |
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Roger Cadogan
United Kingdom
493 Posts |
Posted - 06/04/2022 : 16:08:41
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There is a significant difference between the specialist cast iron welders who use a technique that has been around for years that involves heating the whole casting up to a high temperature, welding and then a lengthy cooling time and laser welders.
Apart from working through a binocular microscope and being able to place a weld to less than 0.5 mm that big difference is that it is substantially a distortion free weld obviating the possible need of re machining the flat surfaces.
EMP repaired cross seat cracks that were much worse than yours with total success this was done about eight years ago on a (regularly thrashed) blown PA.
Roger |
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Barry Walker
United Kingdom
232 Posts |
Posted - 06/04/2022 : 20:34:48
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Hello Andrew. I have a fully crack tested AND pressure tested PA/B cylinder head in stock. If you care to e-mail me at barry@barrywalker.com, we should be able to get you sorted.
Yours, Barry Walker. |
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PeterL
United Kingdom
1729 Posts |
Posted - 06/04/2022 : 22:10:21
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How much are you asking for it Barry?
Cheers
P |
Edited by - PeterL on 06/04/2022 22:11:22 |
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