Faiers Posted July 21, 2021 Report Share Posted July 21, 2021 My 1964 TR4 developed a leak from the core plug (near the battery housing). I ordered a replacement part, removed the old core plug (with difficulty) and put in the new one with some gasket cement. However, the replacement plug was not brass like the original one and the new plug is leaking slightly. Question 1: Can brass core plugs be sourced? Question 2: should the core plug be fitted concave or convex? All advice gratefully received. Quote Link to post Share on other sites
Lebro Posted July 21, 2021 Report Share Posted July 21, 2021 I was not aware of brass ones. the plug should be fitted with the bulge outermost, & sealant behind it (in the hole) Once fully in position at the back of the recess, the bulge needs to be pressed (hammered) inwards till flat. This forces the edges firmly into the hole sides & locks it it. Bob. Quote Link to post Share on other sites
Faiers Posted July 21, 2021 Author Report Share Posted July 21, 2021 Thanks Bob. I left the plug with the bulge outwards. I will try to flatten it into place. Quote Link to post Share on other sites
Lebro Posted July 21, 2021 Report Share Posted July 21, 2021 If you don't, it will leak, then fall out. Bob. Quote Link to post Share on other sites
RogerH Posted July 21, 2021 Report Share Posted July 21, 2021 (edited) Hi Faiers, welcome to the forum. That looks like a very nice TR4 have you a name we can call you by. Like Bob, I have never seen a brass core plug. They are/were cadmium plated that may leave a Brass like finish. Roger Edited July 21, 2021 by RogerH Quote Link to post Share on other sites
boxofbits Posted July 21, 2021 Report Share Posted July 21, 2021 (edited) Brass core plugs are available, but not as common in use as mild steel as Bob says. I used red hermatite as a sealant, but it is worth giving the opening a good clean with Emery to ensure any deposits due to leakage are removed. Kevin Edited July 21, 2021 by boxofbits Quote Link to post Share on other sites
Lebro Posted July 21, 2021 Report Share Posted July 21, 2021 What engine is that ? Bob. Quote Link to post Share on other sites
Motorsport Mickey Posted July 21, 2021 Report Share Posted July 21, 2021 On a 4cyl TR the core plug used at the back of the head is a plug to seal a waterway which is under pressure 4 - 20lb whatever the cap poundage is, and needs to be a round dished core plug like this shape ) . This allows the core plug disk to contact all around it's circumference at the bottom of the machined opening when beaten flat in the centre, the hole diameter of which is opened up slightly at the bottom to aid restriction fitting. They should be fitted with your choice of sealer around their circumference (I use araldite wiped around the hole into the bottom corner). Mick Richards Quote Link to post Share on other sites
boxofbits Posted July 21, 2021 Report Share Posted July 21, 2021 3 hours ago, Lebro said: What engine is that ? Bob. Hi Bob It was a 'stock' pic purely because it showed the brass plug, but is a TR6 Engine according to this site... https://www.google.com/search?q=core+plug+triumph+tr&source=lnms&tbm=isch&sa=X&ved=2ahUKEwj7i9O1mvTxAhXREcAKHSXXBkkQ_AUoAnoECAEQBA&biw=1536&bih=775#imgrc=uyUKt3HvnzNeTM Regards Kevin Quote Link to post Share on other sites
Lebro Posted July 21, 2021 Report Share Posted July 21, 2021 OK thanks. Bob. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 21, 2021 Report Share Posted July 21, 2021 2 hours ago, Motorsport Mickey said: On a 4cyl TR the core plug used at the back of the head is a plug to seal a waterway which is under pressure 4 - 20lb whatever the cap poundage is, and needs to be a round dished core plug like this shape ) . This allows the core plug disk to contact all around it's circumference at the bottom of the machined opening when beaten flat in the centre, the hole diameter of which is opened up slightly at the bottom to aid restriction fitting. They should be fitted with your choice of sealer around their circumference (I use araldite wiped around the hole into the bottom corner). Mick Richards ……..Unless it is a TR4A head which used the cup type. That is the shape of the brass type pictured. Peter W Quote Link to post Share on other sites
Motorsport Mickey Posted July 21, 2021 Report Share Posted July 21, 2021 5 hours ago, BlueTR3A-5EKT said: ……..Unless it is a TR4A head which used the cup type. That is the shape of the brass type pictured. Peter W AAaahhh I stand admonished. Mick Richards Quote Link to post Share on other sites
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