pfenlon Posted April 2, 2017 Report Share Posted April 2, 2017 Soon I am to start to take apart my USA spec engine from my 1970 TR6, and intend to run it on carbs I want to recondition it as much as I can by myself. The engine ran (I haven't driven the car) very well without smoking or rattling, so what do I need to do? I have access to a 2500S cylinder head, what bore size should I deem ok and just re ring the original pistons. Crank condition I have yet to see, another fingers crossed one, before knowing whats needed. I do need a new Camshaft, which one do I need to buy? all help appreciated. Quote Link to post Share on other sites
foster461 Posted April 2, 2017 Report Share Posted April 2, 2017 Pete, is this car a keeper or one that you plan to flip ?. If it is a keeper there are things that you can do to put back some of the sparkle that was lost due to the castration applied to the exported cars. As an example milling the head for 9.5:1 compression and fitting the PI cam will fix the main engine and then tweaking the carbs to match. There is not much needed to the core of the engine for a street car. Just refurb the bores, pistons etc, crank and bearings, lifters etc etc Stan Quote Link to post Share on other sites
astontr6 Posted April 2, 2017 Report Share Posted April 2, 2017 My advice is to strip the engine down and take the key components to a reputable engine m/c shop and have bores and crankshaft journals etc. measured and then go from there. But in the mean time decide what you want from the engine in performance as per thread #2 or more? The 2500S head is the best head as standard because of the valve throat design. Lastly if the car has no overdrive do you want that added? If so, go to ORS in Sheffield as they do this conversion all the time. Lastly check the lay gear bearings / lay shaft in the gearbox as this is always one of the favourite things to go first. Only buy these parts from ORS as the others often sell soft lay shafts and have so for years. Bruce. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted April 2, 2017 Report Share Posted April 2, 2017 (edited) Do you have the manifolds and carbs from the 2500S? You may need them as the TR6 1970 may have the narrow intake port design, which does not match the 2500S head - Check the manifold gasket against the two heads to be sure. 2500S cam is a an OK profile too. The entire 2500S engine would be a good basis for a rebuild donor, even if it is an ex auto installation unit. What exhaust do you intend to use? Single down pipe as fitted now or go to twin downpipe type from post 1973 carb car and all PI TR? Peter W PS 2500S is a 2.5 litre capacity unit same as an original TR5/250/6. You can get into overboring the existing unit if you wish....and some one who knows more will be along in a moment. Edited April 2, 2017 by BlueTR3A-5EKT Quote Link to post Share on other sites
rhine Posted April 2, 2017 Report Share Posted April 2, 2017 Pete, you might want to consider just leaving it alone for now and running the car to see what is needed. It's very easy to spend a lot of time and money 'perfecting' an engine, but you spend more time in the garage than on the road. It's a choice we all have to make. Back to the garage for me ;-) Richard Quote Link to post Share on other sites
Guest ntc Posted April 2, 2017 Report Share Posted April 2, 2017 New pistons every time or it will burn oil. Quote Link to post Share on other sites
astontr6 Posted April 3, 2017 Report Share Posted April 3, 2017 +1 for Neil. Thats how my engine died after 40 years! Bruce. Quote Link to post Share on other sites
john.r.davies Posted April 3, 2017 Report Share Posted April 3, 2017 Why/how do pistons burn oil? The lands for the rings might be worn, so even new rings may not seal well so measure them (compression 64-65 thou, oil control 157-158 thou) New rings, of course, and honed bores, but used pistons are not inherently leaky. 2500 inlet manifold was bent, to compensate for the way that the engine was cant-mounted for a lower bonnet line and mount the carbs horizontally. As this was to the right, when mounted upright, they poke upwards. This will foul a 'small-chassis' car's bonnet - don't know about a TR6's. And if you're doing all this work, I suggest steel exhaust valve seat inserts for valve recession peace of mind. John Quote Link to post Share on other sites
TR NIALL Posted April 3, 2017 Report Share Posted April 3, 2017 (edited) They don't foul the Bonnet they come clean through and that's with the Lower Dashpots. Edited October 26, 2019 by TR NIALL Quote Link to post Share on other sites
JJohn Posted April 3, 2017 Report Share Posted April 3, 2017 I fitted my TR6 with a 2500S head and a CP camshaft. The best reading on the rolling road was 154 bhp at the flywheel and 175 lbft @ 3900 rpm. It's on twin SU H6's and has the tubular sport exhaust manifold and twin system. It is incredibly smooth and pulls sweetly from 1000 rpm in any gear, including O/D top. 30 to 33 mpg is normal on a long run driving at up to the speed limit. Jim Quote Link to post Share on other sites
Denis Posted April 3, 2017 Report Share Posted April 3, 2017 Nobody seems to have mentioned the weakest part of the Triumph 6 pot motor...The weedy half Thrust Washers! With the motor out it's the perfect opportunity to measure for the dreaded Crankshaft End-Float! Don't bother with the original white metal T/Washers, always use the Bronze ones! Check out the British Sports Cars USA website, for the ultimate Thrust Washer modification. Quote Link to post Share on other sites
pfenlon Posted April 3, 2017 Author Report Share Posted April 3, 2017 I am grateful for the wealth of information so far provided, and a thank you to all those who took the time to do so. NTC has a bit of knowledge I imagine, but can he let me know what manufacture of pistons to buy please, the threads are full of super stuff I will ask for further info as I progress, thanks again Pete. Quote Link to post Share on other sites
graeme Posted April 4, 2017 Report Share Posted April 4, 2017 Hi Pete, You may wish to read this, useful info about available pistons. http://www.wishboneclassics.com/tech/tr6/engine/triumph-tr6-cast-piston-comparison Cheers Graeme Quote Link to post Share on other sites
pfenlon Posted April 4, 2017 Author Report Share Posted April 4, 2017 Hi Pete, You may wish to read this, useful info about available pistons. http://www.wishboneclassics.com/tech/tr6/engine/triumph-tr6-cast-piston-comparison Cheers Graeme Thanks Graeme that was an eye opener! Quote Link to post Share on other sites
john.r.davies Posted April 4, 2017 Report Share Posted April 4, 2017 (edited) Niall, !!!! Picture worth a thousand words. Or in my case fifty eight. And Graeme. What a good article (on pistons)! If the TRR wants to scrutinise quality (as in the proposed Gold system) that is what it should be doing. Thank you both! John Edited April 4, 2017 by john.r.davies Quote Link to post Share on other sites
TR NIALL Posted April 4, 2017 Report Share Posted April 4, 2017 (edited) On 4/4/2017 at 1:57 PM, john.r.davies said: Niall, !!!! Picture worth a thousand words. Or in my case fifty eight. And Graeme. What a good article (on pistons)! If the TRR wants to scrutinise quality (as in the proposed Gold system) that is what it should be doing. Thank you both! John This is how I run it at the moment,it makes for good conversation. Edited October 26, 2019 by TR NIALL Quote Link to post Share on other sites
pfenlon Posted April 4, 2017 Author Report Share Posted April 4, 2017 This is how I run it at the moment,it makes for good conversation. Lovely car Niall, now then, if you want to be rid of that old looking lump of alloy under the bench, Im looking for one for my CC TR6............... We all need a bit more room, has to be an "A" type one I think. Quote Link to post Share on other sites
TR NIALL Posted April 4, 2017 Report Share Posted April 4, 2017 Lovely car Niall, now then, if you want to be rid of that old looking lump of alloy under the bench, Im looking for one for my CC TR6............... We all need a bit more room, has to be an "A" type one I think. Nice try Pete but that's my Spare J Type that came all the way from Manchester some years ago,Mr Bancroft. Quote Link to post Share on other sites
pfenlon Posted April 4, 2017 Author Report Share Posted April 4, 2017 Nice try Pete but that's my Spare J Type that came all the way from Manchester some years ago,Mr Bancroft. FMD Quote Link to post Share on other sites
Nigel A Posted April 5, 2017 Report Share Posted April 5, 2017 Hi Pete That's one abbreviation my daughter hasn't taught me luckily Cheers Nigel Quote Link to post Share on other sites
kiwican Posted April 5, 2017 Report Share Posted April 5, 2017 FMD...not one I know either If the last two words are ...me dead.. I can work out the first word. Simon Quote Link to post Share on other sites
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