MRG1965 Posted May 12, 2015 Report Share Posted May 12, 2015 HI All, looking for some advice. I've noticed that the core plug at the back of the cylinder head on my TR4 is weeping slightly and I need to change it. Looking at the usual suspects sites I can see that there are two types of 1 5/8" core plug, a cupped and a dished version. Dished currently in place. Is there any recommendations as to which is the best to use, or does it depend on the head and if there is a shoulder or not in the hole. Also I used a locktight formula to seal the plugs in place, many years ago, is there anything currently recommended to use to seal the core plug? I'm also assuming I can replace it with the head still in place by removing the battery, is this practical? Mark Quote Link to post Share on other sites
Motorsport Mickey Posted May 12, 2015 Report Share Posted May 12, 2015 Aradlite, and I'm not sure about doing it in situ. Mick Richards Quote Link to post Share on other sites
Fireman049 Posted May 12, 2015 Report Share Posted May 12, 2015 Hi Mark ~ I think it would be very difficult, if at all possible, to fit the coreplug with the head in situ as you need to use a hammer and drift to 'flatten' the coreplug. Tom. Quote Link to post Share on other sites
RogerH Posted May 12, 2015 Report Share Posted May 12, 2015 Hi Mark, never done it insitu but anything is possible. You do need to give it a good wallop to distort it into position. I have always used Welseal and it has worked. I reserve araldite for my fingers and hair. Roger Quote Link to post Share on other sites
Rob Salisbury Posted May 12, 2015 Report Share Posted May 12, 2015 I've done this a couple of times, over the years, in situ, (just take the battery out) using the dished type and sealed with Hermatite Red(the old sort with IMS as the solvent) as it's sealing water, just needs a well aimed bop with a ball pein hammer. Cheers Rob Quote Link to post Share on other sites
peejay4A Posted May 12, 2015 Report Share Posted May 12, 2015 Kalimex K-Seal if you want to put it off for a bit. Quote Link to post Share on other sites
kob666e Posted May 12, 2015 Report Share Posted May 12, 2015 Stick the frost plug in the freezer for an hour beforehand, and then work quickly! Quote Link to post Share on other sites
Lebro Posted May 13, 2015 Report Share Posted May 13, 2015 I changed the core plug at the rear of the cylinder head of my 1935 Hillman. It was the same problem - no space to swing a hammer, so I used a long lever, short end up against the bulkhead, fixed a dome shaped chunk of metal a few inches up, & placed in centre of core plug, then force the long end of lever forwards. the gives plenty of push against the plug, & it just popped inwards, the same as if it had been hit with hammer. Not tried it on a TR, but you get the idea. Bob. Quote Link to post Share on other sites
stuart Posted May 13, 2015 Report Share Posted May 13, 2015 Not overly difficult on a 4 with the battery out just make sure you remove any old sealant and I find a socket and lump hammer gets it in nicely. I use a bit of Hylomar round it. Stuart. Quote Link to post Share on other sites
MRG1965 Posted May 13, 2015 Author Report Share Posted May 13, 2015 Thanks Guys, as usual all advice much appreciated, will give it a try insitu and let you know how it goes, maybe a couple of weeks though. Mark Quote Link to post Share on other sites
shuggie159 Posted May 16, 2015 Report Share Posted May 16, 2015 Yes pls keep us informed. I too have a problem with that core plug. It looks as if it is cracked. I was planning on socket and lump hammer (I think mines the cup version) - I was more concerned about how to get the old one out cleanly. I was thinking it needed drilled and a screw to yank it out. Wishfully, it might just pop out on its own, but nothing on my TR has ever proved simple! Quote Link to post Share on other sites
stuart Posted May 16, 2015 Report Share Posted May 16, 2015 A good sharp screwdriver through the centre and then twist it out usually works. Stuart. Quote Link to post Share on other sites
qkingston Posted June 26, 2023 Report Share Posted June 26, 2023 On the drive down to the Moffat Show yesterday I was suddenly enveloped in white steam from the engine bay; pulled over and popped the bonnet; after a little searching water could be seen running out of the rear cylinder head core plug. Having called out the RAC and returned home, I found that the (almost new) core plug was now actually missing!! (still, solves the removal issue). I can only assume that the disc hadn't been properly peened/flattened during the restoration, nor had it been sealed (my bad). So now I will attempt to fit a replacement plug in situ. Any other further advice/experience to that above gratefully received Many thanks David Quote Link to post Share on other sites
Chilliman Posted June 26, 2023 Report Share Posted June 26, 2023 Had one blow out on me last year travelling back home on the A303, fortunately the plug was still in the engine bay so I cleaned the area & smacked it back in, topped up with water at the next garage & continued the next 100 miles home, and after that experience I now carry a spare core plug with me..... Quote Link to post Share on other sites
qkingston Posted June 28, 2023 Report Share Posted June 28, 2023 (edited) New core plug fitted. For info, there is sufficient space with the battery removed to swing a lump hammer and suitable short drift to flatten the disc; I also tried a small bottle jack with a 5mm steel plate across the rear bulkhead to spread the loading, that would have worked too. Red Hylomar to seal PS I also now carry a spare Rgds David Edited June 28, 2023 by qkingston Quote Link to post Share on other sites
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