TonyAus Posted October 15, 2009 Share Posted October 15, 2009 I am having great difficuty in locating a welch plug for my 1925 series in Australia. The plug is the one under the exhaust manifold.What I need is a lens rather than cup type in an odd size. Being an American car, would have thought that the core hole would be an even imperial size. however, it measures .985" rather than an even inch. Consequently, a one inch plug will not fit - or am I missing something?I thought the idea is for the plug to be a neat fit in the core hole and it is expanded in place by flattening with a suitably sized drift. The undersize hole would clearly work with a cup type plug but the reverse is not true for a lens type. It must use a lens type as the recess is relatively shallow and the inner core hole is as cast.My bright idea was to use a 25 mm plug but alas this size is one made in cup type.As I am surely not the first person to replace a welch plug on a 1925 Dodge, someone out there must have solved the problem.Help Link to comment Share on other sites More sharing options...
platt-deutsch Posted October 15, 2009 Share Posted October 15, 2009 Make one on a Lathe? Link to comment Share on other sites More sharing options...
JACK M Posted October 15, 2009 Share Posted October 15, 2009 .985 may expand out to an inch when you smack it. They dont cost much, I would give it a try. Use some sealer. Link to comment Share on other sites More sharing options...
dwollam Posted October 15, 2009 Share Posted October 15, 2009 I think what he is saying is the hole is .985 and the available plug is 1.00 . Vern Barker, as a machinist and a DB parts supplier, got an answer for this gentleman? Link to comment Share on other sites More sharing options...
hchris Posted October 15, 2009 Share Posted October 15, 2009 Try Les Sonter - 02 98717647 Link to comment Share on other sites More sharing options...
Guest Backyardmechanic Posted October 16, 2009 Share Posted October 16, 2009 Hello,We use a one(1) inch cup Machine it to .002-.005 over the bore install it useing a sealer then grind the excess off flush with the block.Vern. Link to comment Share on other sites More sharing options...
TonyAus Posted October 16, 2009 Author Share Posted October 16, 2009 Thanks a million for that Vern - just the info I needed.How do you hold the plug in the lathe for machining? I assume that it could be driven onto a tapered stub mandrel and light cuts taken.Thanks againTony Link to comment Share on other sites More sharing options...
JACK M Posted October 16, 2009 Share Posted October 16, 2009 Oops, I read that backwards. Link to comment Share on other sites More sharing options...
jan arnett (2) Posted October 16, 2009 Share Posted October 16, 2009 There are two types of plugs. One is a moon shaped plug that you insert and there is the one that has sides on it and the bottem is flush. I am not sure which is correct but I have had freeze out plugs that would not take one style take the other. The moon style fits in the hole and then you hit it with a ball peen hammer which expands the plug in the hole. Just one old mans experience. Link to comment Share on other sites More sharing options...
Guest Backyardmechanic Posted October 17, 2009 Share Posted October 17, 2009 True Jan Buyt if one use the concave type of plug there has to be material for it to stop in the bore to rest too so one can pound against.Vern Link to comment Share on other sites More sharing options...
TonyAus Posted October 17, 2009 Author Share Posted October 17, 2009 Success (possibly)I used Vern's method - a cup-type plug turned down to a five thou interference fit and well sealed with gasket cement. Looks OK but I will leave it to dry overnight before refilling the radiator.Resizing was no a problem - I turned up a tapered stub mandrel to hold the plug. This way I was able to reduce both the diameter and the length with ease.Thanks to all - will be back when this leaks! Link to comment Share on other sites More sharing options...
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