johny Posted July 27 Report Share Posted July 27 Im thinking if a head thats too deep has been used it could have bigger combustion chambers and so reduced the compression ratio, enough to see when testing because although balanced the readings would be lower than normal🤔 Link to comment Share on other sites More sharing options...
Puglet1 Posted July 27 Author Report Share Posted July 27 2 hours ago, Peter Truman said: Will check tomorrow, too miserable tonight to go out to the garage Hi Peter. Can you also take a photo of the numbers location? Link to comment Share on other sites More sharing options...
JohnD Posted July 27 Report Share Posted July 27 9 hours ago, Peter Truman said: Found it John at the front RHS number 517528, had to rub some surface rust off, only lightly stamped into the cast iron, interesting you were half right, whilst not on the LHS the stamping is pointing inwards towards the rocker cover, so easier to read from the LHS. Interestingly the official "Leyland Vitesse 2 Lt Mk2 Spare Parts Catalogue" doesn't list the bare head part number, but only the Cylinder Head Assembly with valves, springs etc 517609, & less valves, springs etc 517610 (I assume it has the guides). Peter, the stamped number isn't a Part number. It's a serial number, each is different . There are published lists of those, when they were used etc. but I can't give you a reference. Chris Witor??? John 1 Link to comment Share on other sites More sharing options...
johny Posted July 27 Report Share Posted July 27 Are you sure John because looking at Witors list I posted above the stamped numbers dont seem to be unique like engine serial numbers... 1 Link to comment Share on other sites More sharing options...
trigolf Posted July 27 Report Share Posted July 27 All,here's a pic of my Vit Mk 2 head. The stamped serial no. is at the front RHS. My number tallies with Chris Witors list as fitted to Vit Mk2 Flat Top pistons. 1 Link to comment Share on other sites More sharing options...
johny Posted July 27 Report Share Posted July 27 Out of interest Trigolf does it measure 3.3" deep as indicated in the list? Link to comment Share on other sites More sharing options...
Peter Truman Posted July 27 Report Share Posted July 27 11 hours ago, Puglet1 said: Hi Peter. Can you also take a photo of the numbers location? Photo attached, tried measuring the head depth, it's very difficult on the car but looked about 80mm or 3.15in so I assume its 3.3in consistent with a 517528 spec head. Link to comment Share on other sites More sharing options...
johny Posted July 28 Report Share Posted July 28 Thanks. I seem to remember that in the end Triumph wanted to use a common head for both 2 and 2.5L engines so the deeper (4.4"?) version became the common one fitted with flat top pistons on the bigger engine and domes the smaller to get the correct compression ratio. The MK3 GT6 with stamped head number 219015 is an example of this so should, according to the list, measure 4.4" and have domed pistons. Obviously if flatties were used with this head in a 2L the ratio would be lowered.... 1 Link to comment Share on other sites More sharing options...
johny Posted July 28 Report Share Posted July 28 (edited) oh and I see it seems even some mk2 GT6 with head number 218225 had the same arrangement although of course with the bigger exhaust valves. Edited July 28 by johny 1 Link to comment Share on other sites More sharing options...
trigolf Posted July 28 Report Share Posted July 28 18 hours ago, johny said: Out of interest Trigolf does it measure 3.3" deep as indicated in the list? Ok Johny, as near as I can see,mine measures 83mm or 3.3". So, I take it that we have positively identified Puglets cyl/head🤔🙂 Gav. 1 Link to comment Share on other sites More sharing options...
johny Posted July 28 Report Share Posted July 28 well to sum up on Puglets head, we have a cast number that the list shows as a TR250 but no readable stamped number. It also indicates this head should be very deep but that isnt the case so it may have been machined or doesnt correspond to the info given. Now we await compression figures and confirmation of it using dome or flat pistons which should give more clues ie. flat pistons + low compression all cylinders = possible wrong head Link to comment Share on other sites More sharing options...
Puglet1 Posted July 28 Author Report Share Posted July 28 Gentleman. Thank you ALL for your help in trying to identify why my Vitesse doesn’t have the “Zip” that my old one from the 70’s had. I have taken the compression readings and also put an endoscope inside the cylinder. The readings for cyls 1,4&5 are 120psi, the remaining cyls are all 115 psi. Which is massively low compared to Peter Trumans. The car has done a genuine 47,000miles, it has good oil pressure, it doesn’t burn oil, and sounds really sweet. I have attached a photo of the piston area which I believe is a flat top. I’m not sure it the head will be suitable for skimming as I guess that quite a lot of material will need removing? Any suggestions are always welcome. Link to comment Share on other sites More sharing options...
johny Posted July 28 Report Share Posted July 28 Yes that certainly doesnt look like a dome top piston like this one. You might see more clearly looking directly in a spark plug hole with piston at TDC... Link to comment Share on other sites More sharing options...
johny Posted July 28 Report Share Posted July 28 It would need 0.1" off to equal a standard head which is a lot and Ive no idea if it could take it. However can you use your compression tester on another car or get a second opinion on yours? Link to comment Share on other sites More sharing options...
Puglet1 Posted July 28 Author Report Share Posted July 28 1 hour ago, johny said: It would need 0.1" off to equal a standard head which is a lot and Ive no idea if it could take it. However can you use your compression tester on another car or get a second opinion on yours? That’s a good idea, I will give it a go. Link to comment Share on other sites More sharing options...
DanMi Posted July 28 Report Share Posted July 28 Agree with Puglet1, try testing a known engine with your compression tester as they are not calibrated ( or other way around) 1 Link to comment Share on other sites More sharing options...
JohnD Posted July 28 Report Share Posted July 28 (edited) 3 hours ago, Puglet1 said: The readings for cyls 1,4&5 are 120psi, the remaining cyls are all 115 psi. Which is massively low compared to Peter Trumans. Puglet, Compression meters are NOT precision instruments, nor are they calibrated! You cannot compare two compression readings taken by different people with different guages, on different days ( weather) each with their own technique. A CR meter is a most valuable bit of kit, for comparing the cylinder pressures on the same engine, on the same day, by the same person! Yours are within +/- 2.5 psi, which is fine! John Edited July 28 by JohnD Link to comment Share on other sites More sharing options...
Iain T Posted July 28 Report Share Posted July 28 3 hours ago, Puglet1 said: The readings for cyls 1,4&5 are 120psi, the remaining cyls are all 115 psi. Which is massively low compared to Peter Trumans Did you have the carburettor at wide open throttle? If not your reading will be low as air cannot be sucked in. Iain Link to comment Share on other sites More sharing options...
Puglet1 Posted July 28 Author Report Share Posted July 28 Hi Iain. Yes, the throttle was wide open. I have just tried another old school compression tester which gave exactly the same results. Link to comment Share on other sites More sharing options...
Puglet1 Posted July 28 Author Report Share Posted July 28 1 hour ago, JohnD said: Puglet, Compression meters are NOT precision instruments, nor are they calibrated! You cannot compare two compression readings taken by different people with different guages, on different days ( weather) each with their own technique. A CR meter is a most valuable bit of kit, for comparing the cylinder pressures on the same engine, on the same day, by the same person! Yours are within +/- 2.5 psi, which is fine! John Hi John. Having looked at the bores and general condition of the engine I’m quite happy. The whole point is the car seems really lazy under acceleration. The engine was recently set up beautifully on Peter Burgess rolling road and runs smoothly. However, the engine BHP is way down from standard - 88bhp as opposed to 104bhp. I am simply trying to get it back towards the factory power or similar. So I’m guessing that if the compression ratio can be increased and the correct cylinder head fitted it might help? Thank you. Pete. Link to comment Share on other sites More sharing options...
trigolf Posted July 28 Report Share Posted July 28 Has it been confirmed from the engine no, that the bottom end is Vit Mk2? I'm no expert, but would a heavier flywheel i. e. ex 2000/TR affect acceleration?? Just a mad thought. Link to comment Share on other sites More sharing options...
johny Posted July 28 Report Share Posted July 28 Yes as posted previously serial number is HC 58239HE... Link to comment Share on other sites More sharing options...
Puglet1 Posted July 28 Author Report Share Posted July 28 Link to comment Share on other sites More sharing options...
Peter Truman Posted July 28 Report Share Posted July 28 When you do a compression test to convert this to the engine compression ratio I believe the formula is, there is also a correct way to measure the piston compression to get the max value. actual cylinder compression pressure as measured by pressure gauge (psi), divided by (the piston cross sectional area (in sq) by the actual piston stroke (in)). In my case with a piston csa of 6.79insq ( ie piston bore of 2.94in), engine stroke of 2.992 in & a compression of 188psi, the compression ratio is 9.25 QED. Link to comment Share on other sites More sharing options...
Puglet1 Posted July 28 Author Report Share Posted July 28 Just now, Puglet1 said: 7 minutes ago, Peter Truman said: When you do a compression test to convert this to the engine compression ratio I believe the formula is, there is also a correct way to measure the piston compression to get the max value. actual cylinder compression pressure as measured by pressure gauge (psi), divided by (the piston cross sectional area (in sq) by the actual piston stroke (in)). In my case with a piston csa of 6.79insq ( ie piston bore of 2.94in), engine stroke of 2.992 in & a compression of 188psi, the compression ratio is 9.25 QED. Is your vitesse a standard Mk2 2 litre? If so, I have just applied your formula to my compression test results. 120psi divided by 6.79insq divided by 2.992. =5.91? Something must be wrong but I don’t know what? Link to comment Share on other sites More sharing options...
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