stressed Posted September 2, 2014 Report Share Posted September 2, 2014 Just found out that the cylinder head is cracked between the valves, whats the best option ,repair ,replace with second hand or recon exchange. cheers Graham Quote Link to post Share on other sites
thescrapman Posted September 2, 2014 Report Share Posted September 2, 2014 Replace with secondhand as there is still plenty of spare ones about is probably the way to go. It will probably be rejected as an exchange as "unsuitable" for recon. Cheers Colin Quote Link to post Share on other sites
openroad Posted September 2, 2014 Report Share Posted September 2, 2014 Hi Graham, sorry to hear that, never a dull moment with this restoration lark.... Good luck, Conrad. Quote Link to post Share on other sites
RogerH Posted September 2, 2014 Report Share Posted September 2, 2014 Hi Graham, how bad is the crack. If the exhaust seat was cut out for a hard (lead free) insert would that do the trick. is it possible to weld/braze the area - some fancy brazing techinques would certainly handle the heat. Roger Quote Link to post Share on other sites
Andy Moltu Posted September 2, 2014 Report Share Posted September 2, 2014 As Roger says the process of fitting hardened valve seats may well machine out the crack between the valves. Unlike a normal unleaded conversion where only an exhaust insert is fitted both inlet and exhaust inserts would need fitting - in the process the cracked area is machined away. Quote Link to post Share on other sites
elclem1 Posted September 3, 2014 Report Share Posted September 3, 2014 Depending on the severity of the crack it can be pinned. JSWL in waterlooville can help they have just done a friends one cheaper than getting a 2nd hand one bought then checked. Cheers andy Quote Link to post Share on other sites
stressed Posted September 3, 2014 Author Report Share Posted September 3, 2014 Thanks for all the replies. I don't know the full extend of the crack yet as I have not been down the machine shop to look at it . the machinist was reluctant to convert it to unleaded to begin with due to leaving very little metal once the hardened seats had been cut back to suit the valves and becoming even more prone to cracking. I am a welder by trade so might have a go at welding it myself then getting it recut but as people will know welding cast is problematic you must get the pre & post heating correct or it will crack again . I will contact a couple of local club members so see if they have anything available ,that might be the easyist and cheapest route. cheers even more stressed Quote Link to post Share on other sites
RogerH Posted September 3, 2014 Report Share Posted September 3, 2014 Hi Graham, back in the 90's during my 4A rebuild I found the exhaust manifold down pipe cracked at the join between 2 & 3. I took it to a welder who said an Al/Nickel/bronze brazing technique would do it. This looked like ordinary braze but obviously wasn't. This lasted a coupole of years before I moved on to an extractor manifold. I would have thought if the crack could be opened up and cleaned, then brazed as above and then recut to take the hardened seats you would have success. However this is all costing money so do your sums first. Have you put a post in the B uy/Sell/TRade forum - there may be one out there with your name on it. Roger Quote Link to post Share on other sites
DaveN Posted September 3, 2014 Report Share Posted September 3, 2014 I don't think you can fit hardened seats in both the exhaust and inlet due to their proximity, that's why only the exhaust seat is replaced. The cooler charge fuel/air mixture protects the inlet valve and its seat. IIRC the whole head would need heating before welding or brazing and there is a limit to that too before the carbon in the steel changes structure. Not impossible but difficult, maybe with speaking to a specialist weld company. Quote Link to post Share on other sites
Andy Moltu Posted September 3, 2014 Report Share Posted September 3, 2014 You can fit to both inlet and exhaust. However does require the right machine shop with access to the correct inserts - many are too thick. Quote Link to post Share on other sites
RogerH Posted September 3, 2014 Report Share Posted September 3, 2014 Aluminium heads have hard seats in both places. Roger Quote Link to post Share on other sites
DaveN Posted September 3, 2014 Report Share Posted September 3, 2014 Aluminium heads have hard seats in both places. Roger Agreed but would there be enough room in an iron TR head? BTW whatever happened to the alloy heads someone was proposing? Quote Link to post Share on other sites
RogerH Posted September 3, 2014 Report Share Posted September 3, 2014 (edited) You need to be careful when re-making a cast iron head out of Ali. The TR4 head works well in steel but is a little delicate for the racing boys in Ali. Roger Edited September 3, 2014 by RogerH Quote Link to post Share on other sites
Dave Smith Posted September 3, 2014 Report Share Posted September 3, 2014 Years ago I used Metalock to stich cracks on a historic cast iron bridge, I think the technique can be used on cylinder heads, by other companies. Quote Link to post Share on other sites
Dave McDonald Posted September 3, 2014 Report Share Posted September 3, 2014 Graham I cracked a head some years ago and took it to a specialist cast iron welder in Measham, Leics., just off the A42. Can't remember name but he was experienced in repairing rare Vintage vehicle components, etc. However price quoted, without any guarantee of success, together with the need to probably have it skimmed to remove any bow/bend that could have developed in the pre heat/controlled cooling sequence made it economically unattractive. I didn't proceed and bought another head. I could probably find the name if you wanted it? Alternatively, I have another head available (no, it isn't the previously damaged one!!.) It was on a Fast Road engine and has enlarged exhaust valves. The inlet port spacings are the narrow type, as fitted to USA carburettor cars, so not suitable for UK PI induction. It's in Retford, Notts. If interested, PM me for a price. Dave McD Quote Link to post Share on other sites
Nick Jones Posted September 3, 2014 Report Share Posted September 3, 2014 Unless the head has had expensive gas flow work done, getting an uncracked replacement is undoubtedly the best way forward. They are not rare or expensive as many of the big saloon heads will provide an equivalent casting. It is possible to fit inlet and exhaust seats together if the crack is not deep, but quite a tricky operation where the valves are so close together and many will not attempt it. Nick Quote Link to post Share on other sites
stressed Posted September 4, 2014 Author Report Share Posted September 4, 2014 I agree about the double inserts to machine the crack out but the machine shop is very reluctant to do this. To weld/braze the head would need very careful and intense heat management which could result in a warped /twisted head and would require extensive machining to bring it back and very likely to cost more than a fully recon head from any of the suppliers. Lots of second heads are out there but many are not suitable for P.I engines and you also take a chance with condition unless they have been machined or crack tested before hand. Many thanks dave but as you said the head would not be suitable for my P.I car. I will have to weigh up all the options ,it might as well be the cheapest and easiest route to purchase a new recon head from moss/rimmers/revington etc. cheers graham Quote Link to post Share on other sites
Dave McDonald Posted September 4, 2014 Report Share Posted September 4, 2014 Graham Best sources for 2nd hand heads are Chris Witor in West Country, check his website, or Mike Papworth in Coventry. Can't put my hand on his number at the moment but could probably find it if needed. Dave Quote Link to post Share on other sites
AlanT Posted September 4, 2014 Report Share Posted September 4, 2014 You should be able to repair this with nickel-bronze brazing. If you are a welder then it wont cost you much to try. You will need the right rods, temp-sticks and a heat-blanket. An ordinary OA welder will do fine. Grind out, preheat, fill and cool slowly. I can help with more advice if you go this way. Quote Link to post Share on other sites
stressed Posted September 4, 2014 Author Report Share Posted September 4, 2014 You should be able to repair this with nickel-bronze brazing. If you are a welder then it wont cost you much to try. You will need the right rods, temp-sticks and a heat-blanket. An ordinary OA welder will do fine. Grind out, preheat, fill and cool slowly. I can help with more advice if you go this way. Hi alan, I have been out off the welding game for some time but keep my hand in on the hobby stuff, what rods would I need to repair the head ,is the head cast iron or cast steel, I have oxy/act and arc welding equipment for the heating and welding process. its probably worth a go considering the heads f@@ked anyway cheers graham Quote Link to post Share on other sites
Nick Jones Posted September 4, 2014 Report Share Posted September 4, 2014 http://www.ebay.co.uk/itm/Triumph-2000-Cylinder-Head-313248-High-Compression-/301301146415?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4626f2a32f This would do it. Listed as T2000, but the casting number matches up the 219015 (most likely) and 219016 which means it's also suitable for 2.5 and even listed for later TR6 PI. These have smaller exhaust valves so less likely to be cracked. If you are planning to have unleaded seats fitted anyway then valve sizes can be increased at the same time. Useful list of head numbers here http://www.triumphclub.co.nz/?page_id=653 Nick Quote Link to post Share on other sites
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