charlieb Posted August 4, 2008 Share Posted August 4, 2008 The GAPS are different because of the Camshaft lift. Not GAPS, CAPS! I noticed your inlet & exhaust valve caps are different & wondered why. ps. Who is (was) Mr Reid GT? Link to comment Share on other sites More sharing options...
lordleonusa Posted August 4, 2008 Author Share Posted August 4, 2008 Not GAPS, CAPS! I noticed your inlet & exhaust valve caps are different & wondered why. ps. Who is (was) Mr Reid GT? Sorry, I was typing at O'dark thirty and was almost asleep! They are indeed different, either GT6-3 or Vitesse Mk.2 ? I will check the parts books and get back to you on that one! L Link to comment Share on other sites More sharing options...
GHR630 Posted August 4, 2008 Share Posted August 4, 2008 Nope I'm talking about Leon's cam which was actually made at the time the designer was alive. His cam designs in my opinion have always been considered more powerful and better than their rivals Cosworth. You don't use wide clearances with Cosworth profiles either. I don't use KC or Piper for my cams, - never have. (except for some steel blank stuff, and copying my own stuff) :-/ So you reckon I could close up my clearances? When I suggested that to Kent they muttered dark things about burned valve seats etc! But I don't like the clatter of wide clearances. Link to comment Share on other sites More sharing options...
GT6Steve Posted August 4, 2008 Share Posted August 4, 2008 Sorry, I was typing at O'dark thirty and was almost asleep! They are indeed different, either GT6-3 or Vitesse Mk.2 ? I will check the parts books and get back to you on that one! L I read somewhere, and it may have been GT's book, that the two piece caps on the exhausts were to promote or at least not inhibit valve rotation and reduce the likelihood of burning the valve. The author advised NOT replacing them with single retainers as on the intake. Strikes me they came on the TR5 but I wouldn't swear to that. I have some similar ones in the drawer. Link to comment Share on other sites More sharing options...
GHR630 Posted August 4, 2008 Share Posted August 4, 2008 I think even the early GT6 had the two piece cap as standard. Anyway, I've kept mine, I think I read the same thing in GT's book as you Steve. Have you seen the various alloy lightweight items on Fleabay etc? Couldn't bring myself to trust such things. Probably made out of old milk bottle tops! Link to comment Share on other sites More sharing options...
GT6Steve Posted August 4, 2008 Share Posted August 4, 2008 I've had a set of TT alloy caps on the race head for about seventeen years now. I can't believe the abuse they've happily swallowed over the years. No evidence of the keepers recessing but I'm going to retire them anyway! 8) Link to comment Share on other sites More sharing options...
James Posted August 4, 2008 Share Posted August 4, 2008 My saloon Mk1 engine has the mix of double caps and single caps... Link to comment Share on other sites More sharing options...
Nick Jones Posted August 4, 2008 Share Posted August 4, 2008 I though all the 6 pots had these? The 5 heads I've got in my garage all have them and they cover a pretty wide range of ages (Vit Mk2 - late GT6/3 - 2500S). Nick Link to comment Share on other sites More sharing options...
DaveNotSoSideways Posted August 4, 2008 Share Posted August 4, 2008 So you reckon I could close up my clearances? When I suggested that to Kent they muttered dark things about burned valve seats etc! But I don't like the clatter of wide clearances. I found 15thou inlet and 16thou exhaust seemed to work best on sidedraughts using TH5-TH7. I tested from 12 to 24 thou, settled @ 15-16. Link to comment Share on other sites More sharing options...
GHR630 Posted August 5, 2008 Share Posted August 5, 2008 Cheers Dave. I shall try that as you recs have always been spot on! Link to comment Share on other sites More sharing options...
GT Posted August 5, 2008 Share Posted August 5, 2008 Not GAPS, CAPS! I noticed your inlet & exhaust valve caps are different & wondered why. ps. Who is (was) Mr Reid GT? John Reid was boss of Holbay racing engines until that accident. I'm not sure of the exact background but I've suspicions a lot of them like Costin came from Dehavilland. You know the company that made more or less the world's first commercial jet liner (the comet was a flop but still flying in the shape of nimrod btw). Link to comment Share on other sites More sharing options...
lordleonusa Posted August 6, 2008 Author Share Posted August 6, 2008 Here's a cool link to a forum where they are discussing Holbay engines... http://www.rsmotorsport.com.au/forums/viewtopic.php?t=621&sid=8deafd0dd1eb9f7da1a9d22561153ca9 L Link to comment Share on other sites More sharing options...
lordleonusa Posted August 6, 2008 Author Share Posted August 6, 2008 The de Havilland Comet was the world's first commercial jet airliner to reach production. Developed and manufactured by de Havilland, it first flew in 1949 and was considered a landmark British aeronautical design. After a successful introduction into commercial service, early Comet models suffered from catastrophic metal fatigue, causing a string of well-publicised accidents. The Comet was withdrawn temporarily and redesigned. The Comet 4 series subsequently enjoyed a long and productive career of over 30 years, although sales never fully recovered. [the 'square' tail was pure pre-jet airliner, and the original 'square' cabin windows did nothing for the original aircraft's structural integrity]. The Hawker Siddeley Nimrod, the military derivative of the Comet airliner, is still in service. The original decades-old airframes are being rebuilt with new wings and engines to produce the Nimrod MRA 4, expected to serve with Britain's Royal Air Force until the 2020s, almost 70 years after the Comet's first flight. Not withstanding recent events, the Comet does not sound like a failure to me, just a bit ahead of it's time, with a lack of R&D budget in it's earliest days. Sounds like typical British engineering to me. A Brilliant idea, ultimately poorly executed, at first due to lack of investment...and the best parts of the work later taken up by others, improved upon but ill acknowledged. [FWIW, I was actually at Gatwick Airport to witness the final commercial flight of the Comet in the hands of Dan Air (London)]. Further reading is here: http://en.wikipedia.org/wiki/De_Havilland_Comet Link to comment Share on other sites More sharing options...
Spitfire2500 Posted August 6, 2008 Share Posted August 6, 2008 A Brilliant idea, ultimately poorly executed, at first due to lack of investment...and the best parts of the work later taken up by others, improved upon but ill acknowledged. Generally fair comment IMHO -- but metal fatigue in the context of airframes wasn't really very well understood at that time (it was partly the accidents with the Comet that advanced our knowledge in that area) so IMHO it's debatable whether or not one of the end effects of more investment would have been non-square windows The fact they didn't glue and rivet the windows as they were designed to be and only riveted them is probably more significant. Link to comment Share on other sites More sharing options...
GT Posted August 6, 2008 Share Posted August 6, 2008 Here's a cool link to a forum where they are discussing Holbay engines... http://www.rsmotorsport.com.au/forums/viewtopic.php?t=621&sid=8deafd0dd1eb9f7da1a9d22561153ca9 L How on earth did you find this stuff?? I know it's 2 year's old but??!! I couldn't find a fat lot about that engine, apart from the weird stuff about Warrior was going on while I was trotting around there...was already an almost fatal blow to the Co, as those Warrior heads although flowing great, were a mess. The upshot of it....Holbay ignored advice to fit the YB head....which after the mess, everybody ended up doing anyway... I won't go into the ins and outs, but I lost an awful lot of hardware after that, and you never lose one friend at a time, you nearly always lose LOADS all in a go! Another time, another age it seems now;... : Thanks for the fascinating link, if you only knew the connection today sitting in my hallway? ;D Link to comment Share on other sites More sharing options...
Mother Teresa Posted August 6, 2008 Share Posted August 6, 2008 Apologies for the further devation away off topic but, I was enjoying a cab ride (sitting with the train driver) in the RH seat of an HST doing a good 125mph(+more ;D!) as we charged down Dauntsey Bank: great fun in itself, when I noticed some planes in close formation at low-ish altitude. As we go closer, it was none other than the then last airworthy Comet airliner- the wonderfully titled A+AEE's Canopus, in close formation with the pre-war DH88 Comet racer Grosvenor House. The 'Photo-ship' was a nearby Lyneham based Hercules with the tail-gate open and a photographer strapped on it! That would have been early 1996 I reckon? What a marvellous memory. quote:This long telephoto view of Dauntsey Bank clearly shows the steepness of the incline faced by eastbound trains on Brunel's Great Western Railway route from Bristol to London, a line not normally associated with steep gradients. 43192 leads the 07:38 Paignton to Paddington First Great Western service up the incline on 9 August 2007, and is just approaching the point, at milepost 86, where the 1 in 100 gradient eases to 1 in 660. Link to comment Share on other sites More sharing options...
AJ.Lintern Posted August 6, 2008 Share Posted August 6, 2008 Ah it's not the same since they replaced all the Valenta engines in HSTs with boring German MTU diesels Link to comment Share on other sites More sharing options...
Mother Teresa Posted August 6, 2008 Share Posted August 6, 2008 The old HST's were deafening at full chat- and as for the smoke, they'd give a steam train a run for its money ;D! Link to comment Share on other sites More sharing options...
AJ.Lintern Posted August 6, 2008 Share Posted August 6, 2008 Exactly! ;D Link to comment Share on other sites More sharing options...
GT Posted August 6, 2008 Share Posted August 6, 2008 OK, there's something that's always bothered me in tis OT thingy. Why do the old HST's STINK of brakes when they slow down? Proper trains never do that! Also why on earth did they smoke so much? I know they used furious high boost levels on constant speed diesels, but why did they HAVE to overfuel them so much, or were the tolerances so bad they just burned their own lub as well?? Just a little question? Even russian diesels are clean and monsters in comparison. Link to comment Share on other sites More sharing options...
lordleonusa Posted August 7, 2008 Author Share Posted August 7, 2008 HSTs always seemed dirty to me, here is the one I took to Edinburgh's Waverley Station in 1989 to go and collect my Herald from Chic Doig after he repaired some accident damage paid for by the insurance company, (someone hit me)... L Link to comment Share on other sites More sharing options...
lordleonusa Posted August 7, 2008 Author Share Posted August 7, 2008 And just coz I like the photo of this prototype Comet with square windows... and this East African Airways one... it's OK Dave, they are tiny! L Link to comment Share on other sites More sharing options...
Mother Teresa Posted August 7, 2008 Share Posted August 7, 2008 My expertise is the Signalling- not the rolling stock sadly. I can try to find out though.... I like the HST's for their noise levels, as you can generally hear them coming if you are working trackside, far more so than their modern equivilants. I was sighting the signal shown in the picture at the time. That's always entertaining when chundering along at 125mph, the signals and associated equipment hoves into view superquick. Then you have the driver talking at you 50 to the dozen, as he's so glad to have company for a change, and you're supposed to be taking in the sighting/condition/placement/aspect, signage and conflictions of the signalling equipment- and make ledgible notes at the same time! Even better, is doing it all again in the winter for the the darkness cab rides- without the cab light on as it is a distraction to the drivers view.... ;D Link to comment Share on other sites More sharing options...
GT Posted August 7, 2008 Share Posted August 7, 2008 OK back to engines. Perhaps appropriate to give you a quick shot of Mr Reid himself in happier days, and now a something which I'm going to get roped into thanks to you. : Now these air horns are very similar to the ones I had made for the Triumph, although they are for Webers not Pi. Now, Holbay's air horns ARE FANTASTIC, nothing like you ever saw or used or bought before. (Pity mine got all progressively stolen.) More's the point their engine was doing 375bhp from a (stretched) 2.0L back in 1974....on a H+F dyno, no rolling road stuff here.... Link to comment Share on other sites More sharing options...
GT Posted August 7, 2008 Share Posted August 7, 2008 Oh and btw that must have been the time Mad max was at March! Look at that beautiful exhaust......gotta have been a Len Hartley one made to measure on one of only 15 engines made..... : Link to comment Share on other sites More sharing options...
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