RobertM

Hello It would appear from the BMC 1.8 manual that the CH32 (AG32) plug is used, not the CH50. I also assume this to be the case for the BMC 1.5 too. So the CH50 would only be used in the BMC 2.52 Daniel, do you know where I can buy 4 of these CH50 glow plugs please?

Thank you I hoped that would be the case, I will feel more confident when I try the newer alternative I have identified, as the thread is the same spec M10x1.00 and the heater is longer than the CH32 and shorter than the AG50. The glow plugs are in a swirl chamber (see the cross section below), the possible replacement is used in older European cars like Peugeots and Fiat and the Citroen AX and Saxo. The only catch is that the distance between the shoulder (at the top of the heater) and the start of the threads on the AG50 is 19mm and on the NGK Y-503J it is 23mm, this means that 4 threads fewer will be holding the glow plug in place (probably leaving about 6 or 7 threads holding it instead of 10). I have calculated assuming a peak cylinder pressure of 1000PSI and heater tube diameter of 5.5mm (sorry to mix units) that the maximum force pushing the glow plug out is just 17kg, again assuming the head is cast steel and not aluminium, I believe that 6 threads holding the plug in will be enough to withstand the force. On another note, I have found that the dimensions of the KLG GS103L plug (which was recommended in the manual alongside the Champion AG50) is similar to the Champion CH32/CH39, so my conclusions are as follows: 1. There is no availability of Champion AG50 replacements. For reference Champion AG50 cross comparisons are: Champion CH50 - obsolete Delphi HDS265 - obsolete Durite 0-130-50 - obsolete 2. The other recommended glow plug in the engine manual is KLG GS103L. This plug has a shorter thinner heater and cross compares as follows: Champion CH32 - Obsolete Champion AG39 - Obsolete Beru GV112 Bosch 0 250 200 035 Delphi HDS227 - Obsolete NGK Y-302 - obsolete E200PE The down side with these appears to be the fragility of the heater (being only approx 3.5mm diameter - compared with the AG50 of 4.9mm), but they are more available and appear to have been fitted to the Morris Marina and Leyland 154 tractor. I am going to try the NGK Y-503J once they arrive, mainly because I would prefer to have the bigger diameter heater to reduce the risk of the heater breaking during extraction in the future, and having a slightly longer heater it might also improve starting performance (my hope is to reduce smoke emissions which occur for a short while immediately after starting from cold). These NGK Y-503J cross refer as follows: Beru GN912 Bosch 0 250 202 020 Champion CH168 Champion CH185 Lucas HDS350 I have gleaned all this information from various online sources (except for the details about the AG50 plugs fitted to my engine which are first hand information). I hope this is helpful to others, but if not I should be able to refer back to it in years to come in case I forget it all :-)

And an update on my last: The online shop I used to order the HDS265 plugs cancelled the order and refunded it because the HDS265 is obsolete and they cannot source them any more. So its either CH32/HDS227/Bosch 0250200035/NGK Y-302 (which are also obsolete, not quite the right size - and the price is rising) or finding a suitable alternative.

I have found this thread very useful in searching for replacement plugs. I found the old (now obsolete) Champion AG50 fitted To my BMC 2.52. Latterly called CH50, I found the spec for these as follows: overall length:100.5mm thread size: M10x1.0mm heater length: 31.7mm heater diameter: 4.9mm hex size:16mm terminal:M4x0.7 voltage: 11.5v The conclusions I could make from this were that the 4.37mm drill bit recommended by the manual to ream out the carbon in the heater tube would be too small, as mentioned above, and when I tested this on one plug tube I found I was removing only carbon (no metal) when using a 5.5mm drill bit. On searching for a suitable replacement, sure enough the Delphi HDS265 has the same spec as the CH50, but also appears to be obsolete. I have ordered some from a Delphi shop online and will check them against the AG50s when they arrive. Also in anticipation of the ongoing need I have identified a current type which appears to be broadly similar to the CH50, the CH185 or the NGK Y-503J. They has a slightly shorter heater (but not a short at the CH32) and a smaller hex size, but otherwise could well be an ongoing possibility. I have also ordered some, after they arrive I intend to check and compare. If they are suitable I will test the NGKs on the engine. Has anyone else found current suitable alternatives?