Hi there, I have been working on this problem off and on for over a year now with my 2.25 Petrol engine in a 1971 Series IIa ex-MOD LHD from Continent. The coolant "fitting for cylinder head" RNC663 that goes into the cylinder head does not fit my threads. I ordered this because the original connection there started to leak. Upon inspection, the connection was jury rig of a British valve from a Triumph used to control the flow of coolant to a Smith heater in the truck. The control valve was epoxied into what looks like a bolt head that was cut off and had a drill press hole drilled through it. Because the valve started to leak, I needed to attach the new valve I sourced back into this contraption. I tried to solder it, but it is not strong enough.
The RNC663 looks to be a 5/8" with course thread (can anyone confirm this?). The one that is in the head now is a TINY bit smaller with a finer thread. (Which makes me think it was not stripped and then rethreaded since the existing hole is smaller than the "standard" part) I have found posts that refer to it being M16x1 in some engines. BUT, I have not seen any for sale.
The questions I have before I try to find a shop to braze the part on the old bolt head are:
1.) If this is a "standard" fitting (what I think is M16x1), is there a place to source it? Our hosts only carry the one I ordered which I think is 5/8"NC or NF. I will confirm by buying a M16x1 bolt and making sure it fits what is there.
3.) Any foreseen problems with re-tapping to the larger thread in a cyclinder head to match what seems to be the factory standard 5/8" NC.
The photo on the far left has three types of heater attachments. The second from the left if the one I ordered and the one I usually see in photos on the back of the cylinder head. This is the one that does not fit as it has too course a thread. The contraption to the right of it is the valve that was epoxied into the little bolt head below it. This has a pretty fine thread.
The second photo is of the cylinder head where the piece screws into. The last one is just a photo of the original part that leaked.
I found this post which makes me think I am not the only one having the same issue. http://www.series2club.co.uk/forum/f...?topic=59842.0
The RNC663 looks to be a 5/8" with course thread (can anyone confirm this?). The one that is in the head now is a TINY bit smaller with a finer thread. (Which makes me think it was not stripped and then rethreaded since the existing hole is smaller than the "standard" part) I have found posts that refer to it being M16x1 in some engines. BUT, I have not seen any for sale.
The questions I have before I try to find a shop to braze the part on the old bolt head are:
1.) If this is a "standard" fitting (what I think is M16x1), is there a place to source it? Our hosts only carry the one I ordered which I think is 5/8"NC or NF. I will confirm by buying a M16x1 bolt and making sure it fits what is there.
3.) Any foreseen problems with re-tapping to the larger thread in a cyclinder head to match what seems to be the factory standard 5/8" NC.
The photo on the far left has three types of heater attachments. The second from the left if the one I ordered and the one I usually see in photos on the back of the cylinder head. This is the one that does not fit as it has too course a thread. The contraption to the right of it is the valve that was epoxied into the little bolt head below it. This has a pretty fine thread.
The second photo is of the cylinder head where the piece screws into. The last one is just a photo of the original part that leaked.
I found this post which makes me think I am not the only one having the same issue. http://www.series2club.co.uk/forum/f...?topic=59842.0
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