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Good afternoon all,

I recently bought a TR2 (see my other post) that was completely rebuilt in 1996/7 but has not been on the road since. I've been doing a number of recommissioning jobs over the past month and was at the point (I thought) of firing her up.

The engine has been turned over periodically, but I don't know when it last actually ran. The oil looked clean on the dipstick, but there was very little coolant in the rad. So having replaced all the hoses, thermostat etc I filled it up with water. Wondering why it was taking so much, I was dismayed to see water leaking out of the dipstick hole :(. When I removed the dipstick it poured out.

So, I'm aware that possible causes are leaking head gasket or figure of 8 gasket. Any other ideas please? The engine was supposedly rebuilt to a degree and I have receipts for new rings and small end bushes, and at different dates for a head rebuild and later camshaft, so the head must have been off a few times. What can have gone wrong with it sitting in a garage for over 20 years?

I feel a bout of depression and a pain in my wallet coming on.....

Brian

 

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Brian, some ideas

Could be

1.Corrosion of figure of 8's

2. Head Gasket, though the water seemed to get there pretty quickly. 

3. Aluminium plug in the top face of the head, between rockers for pistons 2/3 could have corroded away

4 . Cracked block......I hope not

Lets hope its number 3!

Iain

 

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If there was any water in the rad it’s difficult to see how it could be Fo8 gaskets because they are at the lowest point in the system and there would be no coolant at all with a leak there. And a catastrophic leak from the head gasket also seems unlikely. So maybe it is the ally plug. 
 

Rgds Ian 

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28 minutes ago, iain said:

Brian, some ideas

Could be

1.Corrosion of figure of 8's

2. Head Gasket, though the water seemed to get there pretty quickly. 

3. Aluminium plug in the top face of the head, between rockers for pistons 2/3 could have corroded away

4 . Cracked block......I hope not

Lets hope its number 3!

Iain

 

It was No 3! (sighs of relief) Water leaking out of the core plug and straight down the push-rod tubes. Now if I'd checked the tappets first.....

I've never replaced a core plug - does it just tap in? Also, now I've bathed all the oily bits with water do I just drain and refill the oil or are there any other precautions I should take?

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I’ve just done this job. No it doesn’t tap in but is screwed in. Your first challenge is getting the old one out, then cleaning up the threads as the current one will have been glued in, probably with Araldite or something similiar, which you can use on the new one. Although the thread in the head is straight and not tapered, the impression is that the plug will only go in so far because its thread and that in the block are not identical.

Run a search on the Forum, there was quite a lot of exchanges on this very subject late last year, this spring

Good luck

james

 

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Thanks Roger, that's really useful. 

James, the old plug was half out - not much of it left and pulled out with my fingers.

I'll order a new one from Moss and use Loctite thread lock, which I recently used with success on a shower valve! I'm intrigued if they come in a block of several - and wonder why it costs £16.70....a bit cheaper than an engine rebuild though.

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Hi Brian,

if they are the same diameter as the oil gallery plugs then I have some.  I'll measure  mine tomorrow PM and get back to you.

They normally come on a stick of 4 or so.   The end of the stick is square so you screw the end one in and the cut it off.

 

Roger

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you may see from the searches that i did this in the last 18 months .  Mine so badly corroded almost too powder so used a small wire brush in a drill to clean the thread. But i used wellseal when fitting.

Roy

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14 hours ago, Brian Eldred said:

 

It was No 3! (sighs of relief) Water leaking out of the core plug and straight down the push-rod tubes. Now if I'd checked the tappets first.....

I've never replaced a core plug - does it just tap in? Also, now I've bathed all the oily bits with water do I just drain and refill the oil or are there any other precautions I should take?

Brian

Result!

Let us know with pictures, how you get it out!

Iain

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1 hour ago, Ian Vincent said:

Presumably these things corrode from the inside so you don’t know you have a problem until you have a sump full of water and the oil pressure disappears. 
 

Rgds Ian 

They tend to look new on the oily side right up to the point where you can push your finger through. 
It’s worth giving them a sharp tap with a centre punch when the rocker cover is off to test the integrity  and new ones may benefit from a coat or two of paint on the wet side before fitting. 

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How do you remove them without removing the head?

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On 7/21/2020 at 11:10 AM, Lebro said:

 

 

To answer the next question:-

1" NF thread & each plug is 3/8" long     

The thread is probably 12 or 14 tpi pitch, but it may well be the same as 1"  UNF - there was a standardised tolerance from 1948 onwards introducing Unified thread forms.  If making your own screwed plugs on the lathe double check the thread pitch in the head.

  NB Measure the thread pitch before any tapping procedure in the head too.

The part number gives us....

PS  Plug Screwed 16 sixteenths of an inch diameter  03 eigths of an inch long.

Triumph also used and specified UNF threads for this type of plug and the prefix changes from PS to PU.  There was a PU1605 plug available at one time. Other thread forms like Whitworth or Gas were prefixed with SP.

Cheers

Peter W

PS I'll get my anorak.

PPS I stand corrected on my diameter interpretation.  - Its sixteenths not eigths for the diameter of the plug  16/16 = 1

 

Edited by BlueTR3A-5EKT
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21 hours ago, RogerH said:

Hi Brian,

if they are the same diameter as the oil gallery plugs then I have some.  I'll measure  mine tomorrow PM and get back to you.

They normally come on a stick of 4 or so.   The end of the stick is square so you screw the end one in and the cut it off.

 

Roger

Hi Roger,

Thanks but the part number has only one application. I think from another post that I found that you said yours were 3/4'' not 1''. 

I've ordered a single one from Revington - don't know why anyone would need 4? Not sure how I'll screw it in though...

Brian

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Some pictures. The plug was sitting at an angle attached on one side only - I just pulled it off with my fingers. The threads are going to take some cleaning up.

I'm only pleased I found it now and not on the car's maiden voyage - it would have been truly titanic.....

Cyl head plug 1.jpg

Cyl head plug 2.jpg

Cyl head plug 3.jpg

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A reminder : these are tractor engines, they don't need rocket science to maintain them. 

You have the same supplier as me. Just cut a slot on the crown of the plug with a hack saw and screw driver it in to cleaned up threads in the head. First a dry run then if all is well glue it with Araldite.

james

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23 hours ago, Brian Eldred said:

Peter, doesn't 16 eighths = 2 inches? Sorry :rolleyes:

Yes you are right I got my correlation the wrong way round - Its sixteenths  not eigths.

Peter W

 

Edited by BlueTR3A-5EKT
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1 hour ago, Brian Eldred said:

Some pictures. The plug was sitting at an angle attached on one side only - I just pulled it off with my fingers. The threads are going to take some cleaning up.

I'm only pleased I found it now and not on the car's maiden voyage - it would have been truly titanic.....

Cyl head plug 1.jpg

Cyl head plug 2.jpg

Cyl head plug 3.jpg

It is threaded then?

I am thinking I have had a TR4A head that had a metal bucket type core plug in this hole.

This sort of thing

Cheers

Peter W

 

 

.jpg

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