AidanT Posted December 27, 2020 Author Report Share Posted December 27, 2020 Quick question Should the bottom cog just slide off? Mine seem to not want to go further than this or does it need a little more persuasion?? Link to comment Share on other sites More sharing options...
Roger K Posted December 27, 2020 Report Share Posted December 27, 2020 3 minutes ago, AidanT said: Quick question Should the bottom cog just slide off? Mine seem to not want to go further than this or does it need a little more persuasion?? More persuasion. You're at the end of the Woodruff key, which is probably raised a little bit stopping it from coming off. With a bit more effort the key will shift position slightly (the groove is 'C' shaped usually) and the sprocket will come off. Link to comment Share on other sites More sharing options...
Iain T Posted December 27, 2020 Report Share Posted December 27, 2020 1 hour ago, Roger K said: Interested to know how that is more accurate than using a dial gauge? Both systems work but rotating the crank clockwise and anticlockwise to a dead stop and taking the middle of the two readings seems easier than trying to rotate the crank while watching the dial gauge and seeing where the dwell point is. I've recently seen the piston stop method used in two engine shops I've visited. Iain Link to comment Share on other sites More sharing options...
AidanT Posted December 27, 2020 Author Report Share Posted December 27, 2020 Cog off and cam out. Let me know what you think of the condition I have taken a close up of one of the lives as it seems a little rough Link to comment Share on other sites More sharing options...
Pete Lewis Posted December 27, 2020 Report Share Posted December 27, 2020 there is likely corresponding wear on the follower its the rotating/ lifting actions that pluck the edge off the lobe that need a reprofile or replacing always new followers witha new cam /reprofile or the old follower will do the same to the new cam very quickly Link to comment Share on other sites More sharing options...
Anglefire Posted December 27, 2020 Report Share Posted December 27, 2020 Interesting wear on the cam gear too. I can recommend Newman Cams - PRICELIST-BROCHURE_2020-TRIUMPH.pdf (erstellen.co.uk) if you want to go for a new one. Or Canley Classics for a regrind. Link to comment Share on other sites More sharing options...
AidanT Posted December 27, 2020 Author Report Share Posted December 27, 2020 Won't s re-grind change the profile? I just want a std cam, nothing special so what's the best budget route? Afraid I can't open your link Angelfire Thx Link to comment Share on other sites More sharing options...
Iain T Posted December 27, 2020 Report Share Posted December 27, 2020 Look at the Newman website for your standard cam or if you need help give them a call they are very helpful but you MUST buy new followers. Iain Link to comment Share on other sites More sharing options...
AidanT Posted December 27, 2020 Author Report Share Posted December 27, 2020 It's really odd, I took all the followers out in order, and gave them a clean on the outside. I will check tomorrow that specific follower but they all looked in really good condition with smooth bums!! Is it possible the engines PO just fitted followers to an old cam?? Does a re- grind involve adding metal back and grinding back to the std profile?? Aidan Looks like new it will have to be esp re angelfires other comment. Link to comment Share on other sites More sharing options...
JohnD Posted December 27, 2020 Report Share Posted December 27, 2020 4 hours ago, Roger K said: Interested to know how that is more accurate than using a dial gauge? As the piston approaches TDC, the distance it moves per degree of rotation gets less, until it stops, and reverses direction. At TDC, there may be several degrees during which it doesn't move at all. So where is TDC? See my article on "Equal Lift on Overlap" on Sideways for a full description of the piston stop method. PS I'm sitting on the northbound M6 and have been for 45 mins while they scraped some bodies off the tarmac ahead, or something. Online ETA for "normal service" is in one hours time. What are they doing, having the bloody PM there and then? I shall need to get out and have a per soon! Link to comment Share on other sites More sharing options...
Nick Jones Posted December 27, 2020 Report Share Posted December 27, 2020 The gear is just the running witness Mark. That lobe is goosed though. Worth considering the Spit Mk3 grind or Newman PH1 which will wake up the midrange a little without spoiling tractability or idle. Nick 1 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted December 27, 2020 Report Share Posted December 27, 2020 15 minutes ago, JohnD said: As the piston approaches TDC, the distance it moves per degree of rotation gets less, until it stops, and reverses direction. At TDC, there may be several degrees during which it doesn't move at all. So where is TDC? See my article on "Equal Lift on Overlap" on Sideways for a full description of the piston stop method. PS I'm sitting on the northbound M6 and have been for 45 mins while they scraped some bodies off the tarmac ahead, or something. Online ETA for "normal service" is in one hours time. What are they doing, having the bloody PM there and then? I shall need to get out and have a per soon! True, there is a substantial rotation where the piston appears to sit still, but the crank moves quite a bit, in relation to the small adjustments available to the cam teeth, that is. Junctions 28 29 and 30 are all closed at present due to collisions. Might be the same one, just with very long skid marks. Link to comment Share on other sites More sharing options...
Roger K Posted December 27, 2020 Report Share Posted December 27, 2020 54 minutes ago, JohnD said: As the piston approaches TDC, the distance it moves per degree of rotation gets less, until it stops, and reverses direction. At TDC, there may be several degrees during which it doesn't move at all. So where is TDC? See my article on "Equal Lift on Overlap" on Sideways for a full description of the piston stop method. PS I'm sitting on the northbound M6 and have been for 45 mins while they scraped some bodies off the tarmac ahead, or something. Online ETA for "normal service" is in one hours time. What are they doing, having the bloody PM there and then? I shall need to get out and have a per soon! The correct method for using a dial gauge is to set the dial gauge before tdc at an arbitrary position, well 'on the ramp', and note the reading. Move the crank over until it reads exactly the same amount on the other side. Halve the value and set your pointer there - that is tdc. You will never get a decent result trying to read tdc directly off the dial gauge. Much easier, and more reproducible, than using piston stops in my experience, although of course that is a perfectly valid method. It's also the only way I know to get peak position on a cam lobe, as well. Link to comment Share on other sites More sharing options...
Pete Lewis Posted December 27, 2020 Report Share Posted December 27, 2020 you can make a piston stop from a bit of timber and a screw cheap effective and repeatable results unless you make it from plasticine or knicker elastic any home made stop will arrest the piston accurately enough . we are not on rocket science just simple good known mechanical observance of some simple basic facts , Link to comment Share on other sites More sharing options...
Anglefire Posted December 27, 2020 Report Share Posted December 27, 2020 2 hours ago, AidanT said: Afraid I can't open your link Angelfire Odd - worked for me - but it is the PDF download - try this Camshafts | www.newman-cams.com (newman-cams.com) and follow Triumph link Link to comment Share on other sites More sharing options...
AidanT Posted December 27, 2020 Author Report Share Posted December 27, 2020 17 minutes ago, Anglefire said: Odd - worked for me - but it is the PDF download - try this Camshafts | www.newman-cams.com (newman-cams.com) and follow Triumph link Thanks The ph1 looks to be my best bet for new then but will give them a call - i guess mine's for the bin as it's at the top of the lobe? Am unexpected cost but hey no such is life Link to comment Share on other sites More sharing options...
Anglefire Posted December 27, 2020 Report Share Posted December 27, 2020 I bought the Ph1 cam. Works well I think. Suits the 1500. The ph2 is a good alternative for the 1300 I think as that engine does Rev better. Link to comment Share on other sites More sharing options...
Roger K Posted December 27, 2020 Report Share Posted December 27, 2020 Would those in the know recommend a PH1 profile for an otherwise standard late stepped-block GT6 engine (sorry to hijack)? Link to comment Share on other sites More sharing options...
Clive Posted December 27, 2020 Report Share Posted December 27, 2020 3 minutes ago, Roger K said: Would those in the know recommend a PH1 profile for an otherwise standard late stepped-block GT6 engine (sorry to hijack)? The mk2/earlymk3 GT6 cam is a good all-rounder. Chris Witor also sells a hybrid cam which is worth a look. Need to compare compression ratio too. Not sure how the ph1 compares, possibly similar. If you want a fast-road cam (beware the slippery slope!) there are plenty of candidates. Link to comment Share on other sites More sharing options...
Roger K Posted December 27, 2020 Report Share Posted December 27, 2020 I've spent a fortune on fast-road components on the other cars - I want to keep the GT6 pretty well standard, as it can't compete anyway and that's not why I own it. Essential non-changeable items for my purposes are anything external - so that's carbs, exhaust etc. which limits things quite a bit. A nice cam that is a bit nicer than stock wouldn't hurt, though. From what you say, Clive, I take it the earlier stock cam is better than the later one? Link to comment Share on other sites More sharing options...
Clive Posted December 27, 2020 Report Share Posted December 27, 2020 https://www.chriswitor.com/cw_technical/camshaft_applications.pdf That may help. I am certain teh mk2 GT6 cam carried over onto the rotoflex/flat topped piston mk3 as well. The earlier cam is a little "warmer" but by no means wild. As I said, Witor does this as well https://www.chriswitor.com/proddetail.php?prod=CW3021EX but I have no idea how well it would work with the GT6 inlet. The mild extra lift can do no harm? Maybe worth a chat with him, or indeed Newman cams who I know have done hybrids. Link to comment Share on other sites More sharing options...
AidanT Posted December 28, 2020 Author Report Share Posted December 28, 2020 I believe my engine is the earlier mk2, with the better stick cam it how can I be sure? Was their an engine number range? Ok- answered my own question- the part is a 308778. Is that the better of the 2 mk2 cams? What's the best replacement per Rogers requirement as that's what I'm looking for ?? Thx Link to comment Share on other sites More sharing options...
Clive Posted December 28, 2020 Report Share Posted December 28, 2020 19 minutes ago, AidanT said: I believe my engine is the earlier mk2, with the better stick cam it how can I be sure? Was their an engine number range? Ok- answered my own question- the part is a 308778. What's the best replacement per Rogers requirement as that's what I'm looking for ?? Thx Aidan, "best" cam is an impossible question. You need to say what for. If you want the most powerful, it won't drive on the road. So re-phrase teh question, saying how the car will be driven. However, the MK2 GT6/Vit cam is a very good all-rounder. But if you like to drive a low revs, the 18-58 cam will shift the torque down the rev range a bit, but run out of puff earlier (but I note many drivers don't like hitting 5000rpm, many like to stay below 3000, so why bother with a cam that is best over these figures?) Link to comment Share on other sites More sharing options...
AidanT Posted December 28, 2020 Author Report Share Posted December 28, 2020 7 minutes ago, clive said: Aidan, "best" cam is an impossible question. You need to say what for. If you want the most powerful, it won't drive on the road. So re-phrase teh question, saying how the car will be driven. However, the MK2 GT6/Vit cam is a very good all-rounder. But if you like to drive a low revs, the 18-58 cam will shift the torque down the rev range a bit, but run out of puff earlier (but I note many drivers don't like hitting 5000rpm, many like to stay below 3000, so why bother with a cam that is best over these figures?) Your spot on, rarely drive the car hard I would say I'm a keep it below 3k range in general but wouldn't mind a bit extra pep to get to 70 mph I have overdrive to cruise. One of the reasons buying this engine was that the cam was said to be the best std one, so apart from the fact it's knackered and I'm now not 100% sure I have the engine with that supposed cam, that's where I'd like to get to Aidan Link to comment Share on other sites More sharing options...
Clive Posted December 28, 2020 Report Share Posted December 28, 2020 Sounds like you are a candidate for the late mk3 GT6 cam.... I ran a 2.5S engine in my vitesse, totally std. When it got tired, I acquired a TR6 short engine, and a head, plus a piper fast road cam. Yes, it was quicker, but I always regretted not using the 25/65 cam from MK2 GT6 etc, it would have suited the car better. Meanwhile, I have cheated and got VVT on my spitfire. Oddly, the factory timing gives a little advance over "normal fixed" timing at sub 2k, then retards the timing by 20 degrees in the mid range, before returning to what most fixed cams are timed to. (works only on the inlet cam, exhaust side is fixed timing) But retarding the inlet gives better mid range torque. Link to comment Share on other sites More sharing options...
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