RogerH Posted September 30, 2016 Report Share Posted September 30, 2016 Hi Folks, as mentioned in another thread I took the engine out of the 4A to make sure the new crank was happy. Every thing was fine. So I'm in the process of buttoning it up. Setting the valve timing is doing my head in - again. The WS manual suggests that the camshaft is 17/57/57/17. I have a new cam sprocket and new cam. Both have no timing marks. I transferred the timing marks feom the old sprocket and cam to the new - but that doesn't appear to give the right result. Next I move the cam to get #1 Inlet to just about to start to open and set the crank to 17 BTDC. However it finishes its cycle and closes at something other than 57'ABDC. The more I did it the worse the readings got. I followed the WS Manual and with #1 push rod fully up set #8 rocker gap to 0.040" then #2 rod and #7 gap This didn't appear to work either. Life got more complicated - I dropped a cam follower down into the sump. Tonight I will be reading John Davies's article on equal lift or #7&8 cam lobes. I know this is much the same idea as the WSM but its worth a try. Roger Quote Link to post Share on other sites
Lebro Posted September 30, 2016 Report Share Posted September 30, 2016 What fun you have Bob. Quote Link to post Share on other sites
RogerH Posted September 30, 2016 Author Report Share Posted September 30, 2016 Hi Bob, it gets more confusing the more I look. The Moss catalogue give what looks like a good break down of cams with all their parameters. However the cam used in the 4 and 4A is the same cam but has different parameters The 4 is 10/60/60/10 where as the same cam in the 4A is 17/54/54/17 OK it is only 1' different and offset by 7'. But I can't get any numbers to tally. Tomorrow we do battle. Strip it all down again and start afresh. Roger Quote Link to post Share on other sites
Guest ntc Posted September 30, 2016 Report Share Posted September 30, 2016 Roger I have told you before unless it is a uprated cam do as posted Quote Link to post Share on other sites
boxofbits Posted September 30, 2016 Report Share Posted September 30, 2016 Sounds like you dropped more than a cam follower Roger! Better luck tomorrow! Kevin Quote Link to post Share on other sites
MichaelH Posted September 30, 2016 Report Share Posted September 30, 2016 (edited) Hi Roger,; Cam timing divides into timing with the head off and with it already assembled and bolted on With the head off look at the camshaft to find point of max lift :17/54 add 180 =251 max lift in a symetrical cam will be half way 125.5 but it starts to open (inlet) 17' BTDC Therefore max lift for inlet is 125.5-17=108.5 after TDC With a dummy pushrod (a little piece of bar with a flat top turned down to fit into a cam follower) you can measure the rise of the cam with a DTI. Attach 360'degree plate to the crank and adjust it to 0' at tdc cylinder one (make a little pointer and bolt it into the front of the engine) with the cam wheel and crank and chain in place loosen it so that the chain can be advanced a link at a time to alter the crank to cam relationship Thus knowing tdc and the dummy pushrod in the 2nd hole (the first is the exhaust and we are not trying to time that are we? don't ask how I know!) the cam ca be rotated to approx the right place - =max lift at 108.5 The trick is to measure not max lift which is very difficult and a bit fuzzy, but to measure 20thou before max and 20 thou after and divide to get an accurate spot (same applies to TDC of course) The cam shaft wheel has two sets of holes which are offset and it can be reversed so there are four different holes to sprocket combinations you can get to about 1/2 a sprocket accuracy Final issue is to always work in engine direction because there is a little slack in the timing chain and that slack needs to be between cam and engine not between engine and cam ie where the tensioner is Got all of that If the head is on then tdc on cylinder one must be the same point as the equal point rock of rockers on cylinder 4 good luck MichaelH Edited September 30, 2016 by MichaelH Quote Link to post Share on other sites
Guest ntc Posted September 30, 2016 Report Share Posted September 30, 2016 And you need to allow for valve clearance defo if not std Quote Link to post Share on other sites
RogerH Posted September 30, 2016 Author Report Share Posted September 30, 2016 Hi Neil, it is a standard cam. Hi Michael, didn't know about the angle of the lift etc. I will be studying John D's article shortly and hoping I can understand it. Roger Quote Link to post Share on other sites
iain Posted September 30, 2016 Report Share Posted September 30, 2016 Roger. A good guide is on M Macy's websites. http://www.macysgarage.com/myweb6/cam_degree.htm Worked for me. Cheers Iain Quote Link to post Share on other sites
MichaelH Posted September 30, 2016 Report Share Posted September 30, 2016 (edited) Tuning Standard Triumphs over 1300CC by David Vizard page 98 Triumph Competition Manual 5th edition R W Kastner page 27 shows a diagram of a dummy pushrod is the origin of my rather poor explanation Michael PM sent Edited September 30, 2016 by MichaelH Quote Link to post Share on other sites
RogerH Posted September 30, 2016 Author Report Share Posted September 30, 2016 Hi Iain, I have been basically doing what Macy's describes but something s making feel ify about it. Tomorrow will be a better day. I think I was trying to hard today to get a result and things were going wrong. Deep breaths Roger Quote Link to post Share on other sites
iain Posted October 1, 2016 Report Share Posted October 1, 2016 Hi Roger I know that feeling .......time(ing) and time(ing) again you do it and you still question is it right. I nearly resorted to a vernier cam wheel last time all that rotating 90 degrees and flipping the wheel over was confusing my little grey cells! Good luck today and as you say, depth breath and relax! Iain Quote Link to post Share on other sites
Lebro Posted October 1, 2016 Report Share Posted October 1, 2016 (edited) This is probably completely wrong, but - if the cam is symmetrical, ie, Inlet starts opening as exhaust is closing, can you not: 1. set crank at TDC - compression stroke on No. 4 2. adjust No.1 tappet clearance's to be equal. (on back of cam) 3. turn cam sprocket till No. 1 rockers are "rocking" ie equal dip on both 4. fit chain. Standing by to get shot down in flames Bob. Edited October 1, 2016 by Lebro Quote Link to post Share on other sites
RogerH Posted October 1, 2016 Author Report Share Posted October 1, 2016 Hi Bob, I haven't a clue. Between the WSM and the Moss cat I have as many numbers required to do the lottery. I am going to use Michael's method and have a look at JohnD's method on the way. Roger Quote Link to post Share on other sites
Graham Harris Posted October 1, 2016 Report Share Posted October 1, 2016 Bob, if you set number one on TDC on the compression stroke you would need number 4 to be rocking? i think. Graham Quote Link to post Share on other sites
RogerH Posted October 1, 2016 Author Report Share Posted October 1, 2016 Hi Folks, success. Having fiddled and f*rted around for two days now I decided to use the method in the WSM again. Get #1 push rod to top of travel and set #8 rocker gap to 0.040" Get #2 push rod to top of travel and set #7 rocker gap to 0.040" Rotate the crank and find where where #7 & 8 gaps are identical. The problem that I have been having is not realising that actual movement required to give this equal gap is almost nothing. having got the equal gaps I can now rotate the crank and get the #1 Inlet valve opening and closing according to the WSM The method laid out by John Davies looks very very similar but using DTI's to detect the equal lobe position (rocker gap) perhaps now I can build the engine. sigh Roger Quote Link to post Share on other sites
Lebro Posted October 1, 2016 Report Share Posted October 1, 2016 Bob, if you set number one on TDC on the compression stroke you would need number 4 to be rocking? i think. Graham Clarified my post - thanks Graham Quote Link to post Share on other sites
RogerH Posted October 1, 2016 Author Report Share Posted October 1, 2016 Hi Bob, that is basically what I ended up doing. #1 pot on TDC raise #1&2 and gap #7&8 It was all to do with understanding the very small movements required. Roger Quote Link to post Share on other sites
Guest ntc Posted October 1, 2016 Report Share Posted October 1, 2016 Roger Told you so on std cam if it has run right while testing you should have punched the cogs. Quote Link to post Share on other sites
RogerH Posted October 1, 2016 Author Report Share Posted October 1, 2016 Hi Neil, the process in the WSM is in fact very simple but there are some things that need to be discovered along the way. The engine ran quite well during the summer but there was a nagging thing going on in my head suggesting something wasn't quite right. Hopefully using this standard process it should be back to normal. Roger Quote Link to post Share on other sites
Guest ntc Posted October 1, 2016 Report Share Posted October 1, 2016 Roger The WSM is correct and you will find what you have now is as close as you will get. The head must be the hat Quote Link to post Share on other sites
RogerH Posted October 1, 2016 Author Report Share Posted October 1, 2016 Quote Link to post Share on other sites
RogerH Posted October 3, 2016 Author Report Share Posted October 3, 2016 Hi Folks, having got the engine back together I have turned my attention to the GB. I have two queries on this. 1 - oil leak from the selector rods. 2 - input splined shaft vertically mis-aligned with the bearing carrier extension sleeve (apprx 0.020"). I have some Q-seals winging their way to me as I type. These are to replace the 3 O-rings. I have also order some very small lip seals and may try another Idea - I have a cunning plan. The mis-alignment is less messy (for the driveway) but possibly more important. During the Summer I experienced a thing called ratchet clutch. The pedal jerks on the way back causing the car to leap around a lot.. I thought I had sorted it but it was starting to return after only 6-8 weeks. I have worked out a theory whereby the above mis-alignment could cause the problem. So the mis-alignment needs sorting. This morning I manufactured a 0.020" tapered shim to go behind the bearing carrier extension sleeve. I made this out of 0.004" Ali shim of which I have a thick pack. This has tilted the extension such that the splines and the sleeve now align. Will it work - I haven't a clue; but i can't do nothing. I can now fit GB to engine and simply toss it into the car - no problem. Roger Quote Link to post Share on other sites
stuart Posted October 3, 2016 Report Share Posted October 3, 2016 Hi Folks, having got the engine back together I have turned my attention to the GB. I have two queries on this. 1 - oil leak from the selector rods. 2 - input splined shaft vertically mis-aligned with the bearing carrier extension sleeve (apprx 0.020"). I have some Q-seals winging their way to me as I type. These are to replace the 3 O-rings. I have also order some very small lip seals and may try another Idea - I have a cunning plan. The mis-alignment is less messy (for the driveway) but possibly more important. During the Summer I experienced a thing called ratchet clutch. The pedal jerks on the way back causing the car to leap around a lot.. I thought I had sorted it but it was starting to return after only 6-8 weeks. I have worked out a theory whereby the above mis-alignment could cause the problem. So the mis-alignment needs sorting. This morning I manufactured a 0.020" tapered shim to go behind the bearing carrier extension sleeve. I made this out of 0.004" Ali shim of which I have a thick pack. This has tilted the extension such that the splines and the sleeve now align. Will it work - I haven't a clue; but i can't do nothing. I can now fit GB to engine and simply toss it into the car - no problem. Roger I hope you have put plenty of sealer on the gasket and not forgotten the copper washer. Stuart. Quote Link to post Share on other sites
RogerH Posted October 3, 2016 Author Report Share Posted October 3, 2016 Hi Stuart, I'm now panicking - which gasket, what copper washer??? Help!!! Roger Quote Link to post Share on other sites
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