tim hunt Posted May 13, 2015 Report Share Posted May 13, 2015 Went for a long weekend in Devon in the 4A last month. The car ran perfectly as usual until I parked at Brixham harbour. After two hours the car re-started on 3 cylinders. I checked for the obvious then tried the engine again and it refused to start. I then called the AA. The patrol man was unable to diagnose the problem though in his opinion the engine had a weak spark. We even swapped the 123 ignition distributor for the original Lucas item I had in the boot - no joy. We were relayed home. I finally got around to checking the car out the other day and a cold compression check revealed 140psi on 1,2 and 3 with nothing on 4. removing the head revealed that the inlet valve insert had dropped out and lassoed the valve head, jamming it open. Luckily this had happened when the car was parked and it had subsequently only run briefly at low revs, resulting in a minor depression in the piston.I yesterday took the head to my local specialist who had done such a good job on it following gasket failure on the 2012 Autoecosse (due to one non-hardened head nut washer -not guilty!). I just got the bad news - testing revealed a 10mm crack down the throat of no 4 inlet valve seat. Whilst the specialist could stitch the head they would not be prepared to guarantee such a repair and did not want to be liable for a wrecked engine should a new insert let go.The long and short is that I need a new head and have nothing restorable as en exchange. My old head was the original, having been converted by SAH in the 70s with larger inlet valves. I fancy something a little better than standard, Can anyone recommend a new uprated cast iron head from Moss or am I better trying to find a NOS (hen's teeth?) or good crack tested used head and have it converted by a specialist? Any suggestions gratefully received! Tim Quote Link to post Share on other sites
Tom Boyd Posted May 13, 2015 Report Share Posted May 13, 2015 The new moss heads are top quality!!! Out of stock at the moment though...... Tom Quote Link to post Share on other sites
Paul Harvey Posted May 13, 2015 Report Share Posted May 13, 2015 Ring Peter Burgess on 01773 520021 He fettles lots of TR heads and you might just get lucky Quote Link to post Share on other sites
AndyR100 Posted May 13, 2015 Report Share Posted May 13, 2015 +1 for Peter Burgess Quote Link to post Share on other sites
LGFromage Posted May 14, 2015 Report Share Posted May 14, 2015 You could try these guys who sorted the head on my 4A. http://www.castironweldingrepairs.co.uk/. They are experts in welding cast iron and are used by a variety of classic car owners. It would be a shame to lose an SAH modified unit as it would take a lot of work to replicate. Good luck, Tim Quote Link to post Share on other sites
pfenlon Posted May 14, 2015 Report Share Posted May 14, 2015 Went for a long weekend in Devon in the 4A last month. The car ran perfectly as usual until I parked at Brixham harbour. After two hours the car re-started on 3 cylinders. I checked for the obvious then tried the engine again and it refused to start. I then called the AA. The patrol man was unable to diagnose the problem though in his opinion the engine had a weak spark. We even swapped the 123 ignition distributor for the original Lucas item I had in the boot - no joy. We were relayed home. I finally got around to checking the car out the other day and a cold compression check revealed 140psi on 1,2 and 3 with nothing on 4. removing the head revealed that the inlet valve insert had dropped out and lassoed the valve head, jamming it open. Luckily this had happened when the car was parked and it had subsequently only run briefly at low revs, resulting in a minor depression in the piston. I yesterday took the head to my local specialist who had done such a good job on it following gasket failure on the 2012 Autoecosse (due to one non-hardened head nut washer -not guilty!). I just got the bad news - testing revealed a 10mm crack down the throat of no 4 inlet valve seat. Whilst the specialist could stitch the head they would not be prepared to guarantee such a repair and did not want to be liable for a wrecked engine should a new insert let go. The long and short is that I need a new head and have nothing restorable as en exchange. My old head was the original, having been converted by SAH in the 70s with larger inlet valves. I fancy something a little better than standard, Can anyone recommend a new uprated cast iron head from Moss or am I better trying to find a NOS (hen's teeth?) or good crack tested used head and have it converted by a specialist? Any suggestions gratefully received! TimErrant insert.JPGKiss on piston.JPG Call John at J@E engineering in Rossendale, highly recommenders firm. Quote Link to post Share on other sites
LGFromage Posted May 14, 2015 Report Share Posted May 14, 2015 Have just had a thought. If you go to http://www.castironweldingrepairs.co.uk/, or even another cast iron welding facility, the head is heated to a temperature suitable for welding for which the push rod tubes are removed. Make sure that this is done carefully and that they can be reused as if you try to fit new ones they are 22 thou too big in diameter and will not fit. Tim Quote Link to post Share on other sites
tim hunt Posted May 14, 2015 Author Report Share Posted May 14, 2015 You could try these guys who sorted the head on my 4A. http://www.castironweldingrepairs.co.uk/. They are experts in welding cast iron and are used by a variety of classic car owners. It would be a shame to lose an SAH modified unit as it would take a lot of work to replicate. Good luck, Tim Thanks for the suggestion Tim. I will see what these guys have to say before junking my head. As a matter of interest what was wrong with yours and what was done to sort it? Tim Quote Link to post Share on other sites
LGFromage Posted May 15, 2015 Report Share Posted May 15, 2015 Hi Tim, The head on my 4A suffered with an external water jacket breakthrough in the region of no 4 spark plug hole. I was told that it is a known problem on late production 4As and tried to sort it with Devcon plastic metal but needless to say it did not work as it was an awkward shaped hole. To fix it the head was stripped and heated to a high temperature and the whole area was welded up. When the head had cooled the plug hole had to be recut and the head refaced to make sure there was no distortion. At the same time new inserts for lead free fuel were fitted. It was a complex process which was successfully completed at a price significantly cheaper than a new head. Beforehand I visited the shop with my car's damaged head to get an opinion on the fix. The place had the right feel about it and they clearly knew what they were doing so the head was left for repair. It also had the added attraction of a 120 mile one way drive without any traffic lights. Tim Quote Link to post Share on other sites
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