Nigel Triumph Posted April 8, 2020 Report Share Posted April 8, 2020 I've just retorted the post to mods. Not appropriate. Nigel Quote Link to post Share on other sites
John L Posted April 8, 2020 Report Share Posted April 8, 2020 Don't forget to clamp the liners down before you try turning the crank, large washer and some tube on the head studs. Before you take the valves out you put some thinners into the ports to see exactly which valves are leaking, there shouldn't be any moisture on the head side, you could also do this once you have lapped in the valves as well to see how well you did it. John Quote Link to post Share on other sites
Lebro Posted April 8, 2020 Author Report Share Posted April 8, 2020 (edited) Thanks John. I know about holding down the liners. Pretty sure it is the exhaust valve, but will check before removing. I will be getting hard seats put in before any lapping in, & probably new exhaust valves. Prior to any machining I intend to re-work the ports & chambers& work out how much to take off the surface to get approx 9:1 CR Bob Just measured the bored out of interest. 83mm so standard. Edited April 8, 2020 by Lebro Quote Link to post Share on other sites
Motorsport Mickey Posted April 8, 2020 Report Share Posted April 8, 2020 Well done Bob, remember to check the liner heights as a matter of course, if you need to do anything now is the time to find out. Mick Richards Quote Link to post Share on other sites
Waldi Posted April 8, 2020 Report Share Posted April 8, 2020 Result:) Just for my understanding: is there a higher need for valve seat inserts on Triumph 4-cylinder engines, compared to the 6-cylinders? I did a full revision on my TR6, but did not see a need for inserts for my intended use, road driving, not racing. Thanks, Waldi Quote Link to post Share on other sites
Nigel Triumph Posted April 8, 2020 Report Share Posted April 8, 2020 When I took the head off my 2 litre GT6 engine a few years ago, it had covered 30-40k miles on unleaded without additives. There were slight signs of recession on the exhaust valves. It could have gone further with a clean up and no hardened seats but I choose to fit hardened seats anyway. Don't know if that makes it better or worse than a 4 cylinder Triumph. Nigel Quote Link to post Share on other sites
Lebro Posted April 8, 2020 Author Report Share Posted April 8, 2020 I have noticed no valve seat recession (ie the valve clearances have not tighened up) in the last 7 years. but now the head is off, I may as well get it done. Bob. Quote Link to post Share on other sites
Waldi Posted April 8, 2020 Report Share Posted April 8, 2020 Hi Bob, On the CP head I have done, the bridge between the inlet-and exhaust valve is rather narrow. My concern was this would result in a crack somewhere in the future because it would be even higher stressed. The bridge on this head does look similar, but others will know if it is worth the money and risk. Maybe not an issue on the 4-cylinder, and that was my question. Regards, Waldi Quote Link to post Share on other sites
John Morrison Posted April 8, 2020 Report Share Posted April 8, 2020 5 hours ago, michaeldavis39 said: Fireman 049 please edit your post as a father with half Chinese in family it is not funny and very offensive Hello Michael, I note Tom has ammended the offending remarks. One other post of similar ilk has been hidden. John. Quote Link to post Share on other sites
John Morrison Posted April 8, 2020 Report Share Posted April 8, 2020 3 hours ago, Nigel Triumph said: I've just retorted the post to mods. Not appropriate. Nigel See above Nigel, thanks for the report. John. Quote Link to post Share on other sites
Hamish Posted April 8, 2020 Report Share Posted April 8, 2020 Well done bob. That’s a great result and reward for your hard work. Quote Link to post Share on other sites
michaeldavis39 Posted April 8, 2020 Report Share Posted April 8, 2020 Thank you John Quote Link to post Share on other sites
Lebro Posted April 8, 2020 Author Report Share Posted April 8, 2020 1 hour ago, John Morrison said: Hello Michael, I note Bob has ammended the offending remarks. One other post of similar ilk has been hidden. John. Bob ??? Quote Link to post Share on other sites
Hamish Posted April 8, 2020 Report Share Posted April 8, 2020 11 minutes ago, Lebro said: Bob ??? Bob PM John he’ll correct it Quote Link to post Share on other sites
John Morrison Posted April 8, 2020 Report Share Posted April 8, 2020 Apologies to all Bob,s out there, corrected to Tom. John. Quote Link to post Share on other sites
MilesA Posted April 9, 2020 Report Share Posted April 9, 2020 Well done Bob - the power of tea! Keep it coming - another practical stream in the making to sit alongside Pete's 'That was the year that was' for us dunces! Miles Quote Link to post Share on other sites
Lebro Posted April 9, 2020 Author Report Share Posted April 9, 2020 18 hours ago, John L said: Before you take the valves out you put some thinners into the ports to see exactly which valves are leaking, there shouldn't be any moisture on the head side, you could also do this once you have lapped in the valves as well to see how well you did it. John half filled chamber with diesel, definately leaking past the exhaust valve Quote Link to post Share on other sites
Lebro Posted April 9, 2020 Author Report Share Posted April 9, 2020 Next installment. After cleaning head, & de-coking, valves were removed. The leaky valve, & seat did not look too bad The adjacent (not leaky) seat looked worse ! Still no crack between central water holes A 2nd test was done for leaks prior to removing valves, while de-greasing, & then hosing the head down, I filled all the ports up with water. all held tight except No. 3 exhaust which quickly emptied via the exhaust valve rim. All the guides were quite sloppy, so will need replacing, I'm surprised it did not smoke ! So, where should I get new valves & guides from - one of our usual suppliers, or let the machine shop get them (if they will) Bob. Quote Link to post Share on other sites
John L Posted April 9, 2020 Report Share Posted April 9, 2020 Bob Why not Chris Witor he has good stuff. John Quote Link to post Share on other sites
Waldi Posted April 9, 2020 Report Share Posted April 9, 2020 Hi Bob, I installed bronze guides with additional oil seals from Goodparts on my 6. A German friend with a TR6-V8, also on this forum:) did the valve seat cutting and a bit of porting for me (Danke!) Not sure if these are also available for 4-cyl engines. I bought new valves and springs from Chris Wittor. Waldi Quote Link to post Share on other sites
BlueTR3A-5EKT Posted April 9, 2020 Report Share Posted April 9, 2020 18 minutes ago, Lebro said: Next installment. After cleaning head, & de-coking, valves were removed. The leaky valve, & seat did not look too bad The adjacent (not leaky) seat looked worse ! Still no crack between central water holes A 2nd test was done for leaks prior to removing valves, while de-greasing, & then hosing the head down, I filled all the ports up with water. all held tight except No. 3 exhaust which quickly emptied via the exhaust valve rim. All the guides were quite sloppy, so will need replacing, I'm surprised it did not smoke ! So, where should I get new valves & guides from - one of our usual suppliers, or let the machine shop get them (if they will) Bob. All depends on what you want to do....How big is your wallet? Who would you use for the machine work? - Do you have a preferred machine shop, and are they open? - CME at Bracknell charge about £350. for a rebuilt exchange 4 cyl TR head. They did a low port TR2 for a friend last year and it looked fine. Gas flow and porting? You say you want 9.0 : 1 CR - Will you do the flow work or pay a company to do the whole job? They will need to know bore stroke, piston to deck height and gasket thickness, to get the chamber the correct size for your required CR. Work it out here https://www.summitracing.com/popup/calcsandtools/compression-calculator The Triumph Tune valves are well thought of but at over 40 quid a pop it gets expensive. Standard valves are under a tenner each. If you are going for all new valves use 136576 the TR4A exhaust valve that is 5/16 stem and therefore lighter - get the right guide to suit! see below. plus the standard 107626 inlets which also have 5/16 stems. The Technovance bronze valve guides were the business, but I do not know how to source them now. You will need to check which exhaust valve stem diameter you intend to use to get the correct guide as the OD changed as well as the ID - you may need to conversion guide that fits the small diameter valve in the head with the big hole for the large diameter valve guide (and valve stem) GUIDE ‘CONVERSION’, exhaust valve Notes: 17/32” od to 5/16” id pt no 136575 Valve Springs - Replace what you have or get what your cam supplier requires. As a man with a lathe I guess you can do almost all the engineering tasks. The alternative is get just the guides fitted, the face skimmed and the seats recut after you have done the polishing and porting. Kastner's guide will help with reshaping/lightening the valves. Here if you do not have a copy http://tr4a.weebly.com/triumph-tr-pdf-downloads.html Cheers Peter W Quote Link to post Share on other sites
harlequin Posted April 9, 2020 Report Share Posted April 9, 2020 I put the cylinder head of my TR6 into a local engine builders last year to have the guides replaced but when I picked it up they had bored the existing guides and fitted inserts, I did accept the head back as they had taken so long to do the job I got fed up with waiting. I don't know if others have any experience with this type of repair but I am a little sceptical and would not recommend this method George Quote Link to post Share on other sites
Lebro Posted April 9, 2020 Author Report Share Posted April 9, 2020 (edited) Hi Peter. I will be doing the porting & shaping myself, following the templates in David Visard's book "Cylinder Head Modification" which I have a copy of thanks to someone on here. Standard guides & valves is all I want, except I may as well get hard seats put in, & hard exhaust valves to go with. I may even re-use my inlet valves, I will check to see if/ how much they are worn tomorrow. I am thinking of using SRS Engineering in Sutton (close to me) they have a good reputation, & I only want them to insert new guides, machine & fit hard exhaust seats, & skim the head surface by an ammount which I will calculate after my re-shaping work. I have measured the capacity of the chambers as is (after de-coking) at 60mL. I'm sure the head has not been touched before, so, knowing what the standard CR should be (8.5:1) I can work out the volume of displacement + gasket, & use that to calculate what it would be with 89mm pistons. Is the 136576 valve suitable for use with hard seats & unleaded fuel ? I will never be racing this car, & only occasionally taking it above 4K revs, so I guess the thinner stems are not really going to make any difference. BTW part No. of my head is 302137, I can't find the document which details the differences in the 4 pot heads, but i think is it a standard 3/ 3A one Cheers Bob. Edited April 10, 2020 by Lebro correcting chamber size measurement Quote Link to post Share on other sites
Hamish Posted April 9, 2020 Report Share Posted April 9, 2020 Will this help with you head differences http://www.tr3a.info/FAQ_heads.htm Quote Link to post Share on other sites
Ian Vincent Posted April 9, 2020 Report Share Posted April 9, 2020 Bob, I converted a standard 3/3a head to 4a spec using Vizard's book. I also had hardened seats fitted and had the head skimmed 15 thou to deal with a slight bend. When I used a burette to measure the combustion chamber volumes, they were all 63.5 cc which if I recall gave a CR of 9.5 with 87mm pistons. BTW, at the risk of teaching grannies etc...for measuring the head volume accurately, I used a piece of perspex with a1/2" dia hole in it stuck to the surface of the head with vaseline. That way you can be confident that you are filling each chamber the same amount. I replaced the valve guides with the standard offering from Moss, ditto with the valves. If you are only going to use 4000 to 4500 revs, I wouldn't bother with the TR3a triple springs - they are hard on the camshaft and will give you coil bind if you have a high lift cam. The TR4a double springs work well. I was lucky and managed to pick up a set of s/h TR4a valve caps for next to nothing. I'm sure a purist will be along soon to advise against the above but it works for me. Rgds Ian Quote Link to post Share on other sites
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