JohnD Posted July 2, 2015 Share Posted July 2, 2015 I've always thought that the TR6 engine needed a cross-flow head, so much so that I did drawings of the normal head and ports, to try and work out if it could be done, or if a head from another engine could be adapted. The relative lack of modern six cylinder engines, and the very over-square design of those that there are, mainly BMWs, meant I couldn't find one. A thread about the TRX on http://www.tr-register.co.uk/forums/index.php?/topic/52715-trx/?hl=sale mentionedthat a cross-flow head had been designed for that, and of course Rimmers sell them for earlier TR marks. And I discovered that that Canley's tried to cast some in 2006, but nothing more was heard: http://www.canleyclassics.com/blog/2006/02/alloy-cylinder-heads.html Anyone know why? It's got to be possible - only cost prevents. John Link to comment Share on other sites More sharing options...
GT6MK3 Posted July 2, 2015 Share Posted July 2, 2015 Pretty Sure the Canley Alloy experiment wasn't a crossflow , but an alloy adaptation of the current head. Ended in tears, they all cracked. It's something I really would like to try, couple of hurdles in the way, but when I first thought of it there were more than a couple. I reckon a single sided head would be a damn good start. C. Link to comment Share on other sites More sharing options...
Nick Jones Posted July 2, 2015 Share Posted July 2, 2015 I think the Canleys one was more or less a straight copy of the iron one with some detail changes to the valve throats and ports. Not cross flow. ONLY cost......? Very costly project to bring in, so either you need to charge very handsomely for the end product (and Triumph owners are notoriously tight!) or you need to sell lots. 4 cylinder TR heads are available new in iron or alloy at very similar cost and although quite pricey I think they are quite good value. http://www.revingtontr.com/shop/collection_display.asp?cartype=tr4&cid=55 What drives the TR2 - 4 head production though is the very limited availability of usable, or even salvageable, originals. The 6 pot head does not yet suffer from this being shared with the saloon range. Nick Link to comment Share on other sites More sharing options...
Nick Jones Posted July 2, 2015 Share Posted July 2, 2015 Argh - typing too slow..... Had forgotten the cracking part, though I think you mentioned it before Craig? Nick Link to comment Share on other sites More sharing options...
toofast2race Posted July 2, 2015 Share Posted July 2, 2015 I have a part of one of those alloy heads - I'm not sure it ever progressed past non functioning prototype - for a start there were no valve seats and no obvious room for an inlet and exhaust seat that wouldn't fall out and a decent valve size - so a bit of a non starter Problem with cross flow is you then need to fit ports past pushrods - re-engineer dizzy position, standard MU no good - manifolds no good - it really is a complete non starter Just find a Rover 2600 engine - bore to 3 litre and find prototype Spint style 24v head - bet one existed. Link to comment Share on other sites More sharing options...
CHRIS211083 Posted July 2, 2015 Share Posted July 2, 2015 I spoke to Jigsaw back when I was looking at the 1147 8 port heads. He said they quoted him £15,000 to design an manufacture. Thats alot of dosh that would take years to come back. On the other hand John......Jango was looking to put a TVR 6 cylinder in a Gt6??? At least you would still have your Six-fix!!! Link to comment Share on other sites More sharing options...
JohnD Posted July 2, 2015 Author Share Posted July 2, 2015 An alloy copy of the OE head would save some weight, about 22kgs, not to be sniffed at, but in a car that weighs, say, 900 kgs it's not a lot, 2.4% in fact. The volumetric efficiency improvement of cross flow offers a lot more in performance. Most (all?) crossflows use an OHC which raises all sots of probs as Andy says, driving the shaft and the dizzie. The simplest would be to retain the in-block cam, and revise the push-rod or rocker layout. Simulation has come on so much in the last ten years that it might be possible to model the performance improvement of a theoretical design. Indeed, so has simulation of casting, to promote density and low porosity. That could encourage support of such a programme. Casting in alloy, would be easier (cheaper?) in small quantities than in iron, so that the weigh advantage would accrue as well. I found this article, specificly about casting a cylinder head, most interesting: http://www.researchgate.net/post/What_is_the_most_suitable_casting_process_to_manufacture_motorcycle_engine_cylinder_head The answerer, deals with water cooling as well as air cooling. Back to the drawing board! John Link to comment Share on other sites More sharing options...
Nick Jones Posted July 2, 2015 Share Posted July 2, 2015 The TR4 head prices are very similar iron vs alloy. Nick Link to comment Share on other sites More sharing options...
CHRIS211083 Posted July 2, 2015 Share Posted July 2, 2015 Specialist components have done this with the mini etc. They do alot of these sort of projects. Link to comment Share on other sites More sharing options...
Larry Porter Posted July 4, 2015 Share Posted July 4, 2015 I'm pretty sure I've read in past about the Datsun 6 cylinders (240z, etc) having a Crossflow head manufactured by a Japanese tuner years ago. Similar design? Link to comment Share on other sites More sharing options...
esxefi Posted July 5, 2015 Share Posted July 5, 2015 was a more expensive car to start with so it may have attracted more buyers seeking the extra power/weight saving. I would say the triumph version is achievable but it may need thicker casting sections to provide reliable strength which ultimately may make it not much less weight than the iron head and possibly prohibitively uneconomic(but since when has that ever stopped us buying stuff?) Link to comment Share on other sites More sharing options...
Oilslick Posted May 2, 2018 Share Posted May 2, 2018 On 7/2/2015 at 5:28 PM, JohnD said: An alloy copy of the OE head would save some weight, about 22kgs, not to be sniffed at, but in a car that weighs, say, 900 kgs it's not a lot, 2.4% in fact. The volumetric efficiency improvement of cross flow offers a lot more in performance. Most (all?) crossflows use an OHC which raises all sots of probs as Andy says, driving the shaft and the dizzie. John Its not a percentage of the overall weight, its a percentage of the weight over the front axle the momentum of the large mass ahead of the centre of mass. 22ks, give or take 50lbs would give much the same effect as moving the engine back 6 inches and would give a near 50/50 balance. Millions of Ford Kent engines were crossflow Link to comment Share on other sites More sharing options...
obe Posted May 17, 2018 Share Posted May 17, 2018 Interesting thread resurrected In the TVR world which is where I come from, this company linked below do a head for the straight six tvr engine sold through Racing Green / TVR Parts Ltd .. it's very small volumes, probably less than 20 units sold so far ? but they must have thought it worthwhile pursuing, which for a business means they thought they'd make money from it which means good value for money for very low volume production. http://www.ultimatep.com/index.asp Reading the associated website blurb suggests the owner Simon Armstrong is a pretty clever cookie! Might be worth a look for someone with determination and deeper pockets than me. Link to comment Share on other sites More sharing options...
Scooter Posted May 17, 2018 Share Posted May 17, 2018 I'm sure Dave Pearson had an alloy Triumph Six head done in the past. Link to comment Share on other sites More sharing options...
JohnD Posted May 17, 2018 Author Share Posted May 17, 2018 obe, more detail on the Ultimate TVR head? It doesn't appear on their site. Presume you mean on for a 2.5L Triumph engine? Was it cross-flow? John Link to comment Share on other sites More sharing options...
obe Posted May 17, 2018 Share Posted May 17, 2018 Sorry no it's not for a triumph engine it's for TVR's own straight six engine, I was just saying that as this company have done a small run of heads for a parts supplier then maybe they'd be cost effective if anyone / a group was to approach them for a triumph head? Link to comment Share on other sites More sharing options...
Nick Jones Posted May 17, 2018 Share Posted May 17, 2018 Dave at CC did get some way down the alloy head route though AFAIK it was mainly intended for weight reduction with no substantial design changes such as crossflow design. Cost killed the project I think. Suspect TVR is more likely to be viable as higher value vehicles / richer owners (though Triumph ownership profile is changing) and also, it's a pretty low volume production engine anyway with known issues in the head area so there are potentially people in the position of having a badly knackered head and little chance of finding a good used one at reasonable cost (or at all) so pressures to pay well for a new head are there! Nick Link to comment Share on other sites More sharing options...
oldtuckunder Posted May 17, 2018 Share Posted May 17, 2018 On 7/2/2015 at 5:28 PM, JohnD said: An alloy copy of the OE head would save some weight, about 22kgs, not to be sniffed at, but in a car that weighs, say, 900 kgs it's not a lot, 2.4% in fact. With the latest post, i reread some of this thread and wondered why I hadn't picked up on this earlier, there is no way an alloy head could save 22kgs, that about the weight of the head anyway (if that)! If that was supposed to be 22lbs then why bother use a MK1 head, its 15lbs lighter than the Mk2 head anyway! Alan Link to comment Share on other sites More sharing options...
Scooter Posted May 18, 2018 Share Posted May 18, 2018 I would have thought an alloy 6 head was now reaching financial viability. Alloys 4 heads seem to sell well enough, and TR6's are now starting to attract serious money. Getting harder to find good used heads, seat cracking is an issue thats only going to get worse. Iron head? Acid dip, re-machine, new seats and guides, you are talking about a fair wedge of cash these days. Link to comment Share on other sites More sharing options...
JohnD Posted May 18, 2018 Author Share Posted May 18, 2018 AFAICR, that weight reduction was based on the weight of a standard head and the rerlative densities of steel and aluminium. As they are 7850 and 2700kg/m^3, but without weight the head again and doing the calcs, there would seem to be plenty of room for as much as 22Kgs. Was I wrong? JOhn Link to comment Share on other sites More sharing options...
oldtuckunder Posted May 18, 2018 Share Posted May 18, 2018 Well it could be the MK2 head is way way heavier than the MK1, I had been told it was 15lbs heavier but have never weighed. Its just that my Mk1 head I can lift and carry and would gauge to be less than a bag of cement "25Kg" I always recon a bag of cement is on my limit of wanting to carry, so was just querying how an alloy head could be 22Kg lighter, than an iron one that at my guess had to be in the 25Kg ball park. I could be totally wrong! its not unknown Alan Link to comment Share on other sites More sharing options...
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