Cam shaft timing

[John L]

I'm looking for somebody who could help me understand the correct timing of a camshaft, I would really like to speak to somebody who could help me understand why I'm not getting the correct opening/closing inlet and exhaust figures after setting the cam position correctly at TDC to the figures in the supplied fitment sheet. Would much appreciate help with this as its driving me crazy!  There must be something I'm doing wrong, unfortunately I'm on the other side of the channel, as I'm sure there would be lots who could help if I was on your side.

Ken Newman is at a loss. 

Hoping in anticipation perhaps a PM   John

PS, the 'camshaft checking distance' on the sheet is in MM, all others are in inches!

Triumph TR6 150BHP Timing.pdf

[ntc]

Are you allowing for valve clearance? Look up Burton Power on the web and follow their instructions on guides.

[stuart]

11 minutes ago, ntc said:

Are you allowing for valve clearance? Look up Burton Power on the web and follow their instructions on guides.

Direct link https://www.burtonpower.com/tuning-guides/tuning-guide-pages/camshaft-fitting-timing.html

Stuart.

[John L]

To add a bit more info, the TDC mark on the crank pulley was set with the head off and with a  DTI.

Using a DTI on #1 inlet valve pushrod, (second one in from the front) using the info on the sheet set camshaft to 0.032" lift, crank to TDC.

This was also verified using #1 inlet pushrod at full lift, the TDC mark on the timing wheel TDC lined up the same, so must be good?

Cam lobe lift on all measured at 0.251"

Set valve clearances on all 12 valves to 0.010"

Turn crank to start to lift #1 inlet valve, push rod just not turning so lash taken up, reading on the timing disc, I get 30 degrees before TDC.

Turn crank to #6 inlet valve just the same as #1 push rod nipped closing the lash, read timing disc, 40 degrees before TDC.

So using the tappet clearance as per the sheet inlet 0.014" the readings above will be opening with the wider gap, or later, so this is the bit I'm missing, how to get an inlet and exhaust to open at 38/78/78/38, which Newman say the cam should be?

I cannot understand the lines on the sheet C and D, and where do you put add the checking clearance mentioned in B?

I'm beginning to feel that the grind is perhaps not perfect?

John

 

[TonyC]

Elin Yakov, way over in Ontario, has a rather good YouTube article on ‘degreeing the camshaft’. Might be worth a look. Here is the link.

Here is the link.

Hope it helps.

TonyC

 

[Motorsport Mickey]

Perhaps it's too simple but I've always used the Tuning Standard Triumphs over 1300cc book by David Vizard. I seemed to have got the timing...ok. Maybe worth trying.

Tuning_Standard_Triumphs_Vizard.pdf

Mick Richards

[Motorsport Mickey]

3 minutes ago, Motorsport Mickey said:

Perhaps it's too simple but I've always used the Tuning Standard Triumphs over 1300cc book by David Vizard. I seemed to have got the timing...ok. Maybe worth trying.

Tuning_Standard_Triumphs_Vizard.pdf

Mick Richards

PM sent John.

Mick Richards

[BlueTR3A-5EKT]

1 hour ago, Motorsport Mickey said:

Perhaps it's too simple but I've always used the Tuning Standard Triumphs over 1300cc book by David Vizard. I seemed to have got the timing...ok. Maybe worth trying.

Tuning_Standard_Triumphs_Vizard.pdf

Mick Richards

Working link

https://www.scribd.com/document/12986341/Tuning-Standard-Triumphs-Vizard

[Motorsport Mickey]

 Thanks Peter for carrying me about.

Mick Richards

[John L]

Perhaps I have not written this incorrectly for what i'm try to understand,  It would appear the cam is timed to the spec sheet, could somebody confirm that please?

Then next bit I do not understand, is the quoted cam valve opening times,  the CP original cam is 35/65/65/35,  the new cam is  38/78/78/38.

How are these opening and closings related to the crank degrees?  I'm presuming (perhaps wrongly) that these are the points when the valve is actually beginning to open all tappet clearance taken up and pushrod tight and actually closing when the pushrod is then just free having taken up the valve clearance, would somebody confirm thats how it should be please?

With the new cam inlet valve clearance of 0.014" the opening of the valve will be much less than 30 degrees BTDC as the tappet clearance is bigger.

So my real question is how are the opening and closing figures taken, and where on the crankshaft?

My other query is #1 and #6 the crank TDC is the same, so the cam openings must be the same for both inlet valves, so why am I seeing a bit difference or the cam is not ground right???????

Are my questions clearer now?

John

 

[FatJon]

Simplest way I have found is to set the crank at 110ATDC and the cam at peak lift on no1 inlet with a swing on the dial gauge either way around the dead zone to find the exact peak lift point. No need to worry about clearances or anything else then. I'm surprised the peak lift degree number is not on the Newman document. All the cam figures are on their and site state a peak lift @ crankshaft degrees figure, and all bar the full race are 110ATDC.

[Rob Salisbury]

Hi John, the figures quoted for a cam are for the point when the valve begins to open or close, just before the opening point the follower rises on a clearance ramp taking up the set valve clearance, then at 35 deg or 38 deg BTDC or whatever the valve begins to open, as to why you have different figures for 1 and 6 anybody's guess but the cam sure needs careful checking.  

Cheers Rob 

[John L]

To follow on with this, Newman have agreed to have the cam back for measurement, I think its the best way.

I'm not sure whether to stick with this same cam with a better grind or go for a different one, what is the feeling of users on here, which would be a good cam for a CP PI?

Has anybody fitted the Newman PH2 on a CP PI, what's it like?

I'm hoping I can pull the cam out without having to take the oil pump out, can anybody confirm please?  I know I will have to hold up the lifters some how, I think cloths pegs spring to mind, or perhaps O rings might do it?  I don't really want to take the head off again with all that it incurs.

John

[JochemsTR]

14 minutes ago, John L said:

I'm hoping I can pull the cam out without having to take the oil pump out, can anybody confirm please?

just the driveshaft.

16 minutes ago, John L said:

I know I will have to hold up the lifters some how, I think cloths pegs spring to mind, or perhaps O rings might do it?  I don't really want to take the head off again with all that it incurs.

I would love to see you do this without removing the head. No joke. I hope it works, feel free to share and document here.

[charlie74]

Pretty sure the oil pump will stay where it is but the drive gear must be removed. 
I don’t know how you’d keep the tappets from dropping down and fouling the cam as you remove it…

[stuart]

6 minutes ago, charlie74 said:

I don’t know how you’d keep the tappets from dropping down and fouling the cam as you remove it…

A whole bunch of these Magnetic pickup tool

Stuart.

[charlie74]

I s’pose so…(edit): but I’d rather not be there if one drops while the cam is out!

Hopefully the OP will post back with results, and I hope he’s successful!

Edited December 19, 2022 by charlie74

[john.r.davies]

19 hours ago, John L said:

To follow on with this, Newman have agreed to have the cam back for measurement, I think its the best way.

I'm not sure whether to stick with this same cam with a better grind or go for a different one, what is the feeling of users on here, which would be a good cam for a CP PI?

Has anybody fitted the Newman PH2 on a CP PI, what's it like?

I'm hoping I can pull the cam out without having to take the oil pump out, can anybody confirm please?  I know I will have to hold up the lifters some how, I think cloths pegs spring to mind, or perhaps O rings might do it?  I don't really want to take the head off again with all that it incurs.

John

John,

Please consider abandoning the practice of 'degreeing' the cam shaft, and use the "Equal Lift on Overlap" method?

Your camshaft, indeed almost any Triumph shaft, is 'symmetrical' - see the figures your quote above "38/78/78/38" which refer to the angular distances between cam peaks.     Such cams will, at No.1 TDC show ' equal lift' of both exhaust and intake valves on No.6.   As one four stroke cycle is completed and another starts, the valves 'overlap'.   The lift on either is small, and may be measured with two dial gauges, or else I have another way, using a spririt level!   Please see:

https://sideways-technologies.co.uk/forums/index.php?/topic/7770-equal-lift-on-overlap-the-other-cam-timing-method/#comment-102165 for a full explanation of the theory and technique

and

https://sideways-technologies.co.uk/forums/index.php?/topic/9639-a-new-method-of-cam-timing/#comment-134275 for the spirit level method.

 

 

But, and this is a big but, what is the condition of your crank pulley, on which TDC is marked?     The pulley doubles a damper to inhibit torsional vibration in the crank.     It uses a thin rubber ring between the hub and an outer "inertia ring" on which the timing markings appear.     The original rubber was little different from tyre rubber, and time and exposure to heat and oil often destroy it.     If the rubber ceases to stick to the metal, the outer ring can rotate on the hub, making the TDC marking a complete fiction.   Have you checked actual TDC by using a piston stop against the TDC marking?    If they do not coincide, then your outer ring has moved and the damper is ineffective.    Either way, it's scrap although it can be rebuilt.

You can do that check.     I can test your damper pulley and tell you if it is still effective as a damper - about 20% of pulleys are no longer working!

 

Good luck!

John

Edited December 20, 2022 by john.r.davies

[astontr6]

19 hours ago, John L said:

To follow on with this, Newman have agreed to have the cam back for measurement, I think its the best way.

I'm not sure whether to stick with this same cam with a better grind or go for a different one, what is the feeling of users on here, which would be a good cam for a CP PI?

Has anybody fitted the Newman PH2 on a CP PI, what's it like?

I'm hoping I can pull the cam out without having to take the oil pump out, can anybody confirm please?  I know I will have to hold up the lifters some how, I think cloths pegs spring to mind, or perhaps O rings might do it?  I don't really want to take the head off again with all that it incurs.

John

I have fitted a PH2 to a CR engine it wakes the engine up along with a KMI Sprint MU. I have not tested the power on a local Dyno but judging by the way it drives there is a lot more torque/power in the mid range. My car sails up the local hills and creeps along in London traffic without any problems and tick over is very good.

Bruce.

[Dave McDonald]

On 12/19/2022 at 3:33 PM, John L said:

I'm hoping I can pull the cam out without having to take the oil pump out, can anybody confirm please?  I know I will have to hold up the lifters some how, I think cloths pegs spring to mind, or perhaps O rings might do it?  I don't really want to take the head off again with all that it incurs.

John

John,

Take the oil pump/distributor drive shaft and gear out and you will be able to withdraw the camshaft without disturbing the oil pump. Take careful note of it’s position before removal so that you get it back in correctly to avoid timing problems later on. 
The cam can be removed without removing the cyl head. It’s best with two pairs of hands. 
With the rocker gear removed, carefully press the push rod hard against the side of the cam follower and slide it up and it will lift the follower clear. With both push rods and followers per cylinder raised and keeping side pressure applied, cross the two push rods over and tie them together tightly. Electrical insulation tape works ok for this. The followers will stay up. Hence two people best for this job. Repeat for all 6 cylinders and cam will slide out. 
I’ve only ever done this with the new cam ready to fit straight back in, so don’t know if the followers would slowly slide back down in the long term. Therefore, if you’re sending your cam away for a check, it might be best to refit your old cam that I assume you still have, back in to hold the followers just in case any try to escape. Check they are all still secure before you try to fit the new cam when it comes back. 
If the engine is still in the car you will need to raise the front end slightly by unbolting the engine mounts and remove the grill to let the cam clear the grille opening in the front valance. 
Hope this helps. 
Dave McD

[John L]

Thanks Dave, Id forgotten about the grill and tilting the engine up a bit, I was hoping to use some small cloths pegs to hold up the followers, and yes I was intending to put a new one back in at the same time, so not letting the slippery followers sliding back down again.

John

[BlueTR3A-5EKT]

Fitted in a 2500s saloon I had an engine with a particularly stupid super hot camshaft fitted.   Went like stink from 3500 rpm, which was useless, as the car was an auto.      I decided to replace the cam with a 307621 TR250 cam, coz they were under a tenner new.    The outcome was a delight.
 

I considered the hold up the followers, slide out old cam, Slide in new cam trick but stopped when Al, the workshop engine builder asked what I would do if one of the lobes on my old cam looked rough or mis-shaped.

It took me a bit longer lifting the head but was I pleased when I found a tappet face breaking up.

Off with the head and check all the followers unless you are double dog sure of their integrity 

 

[john.r.davies]

3 hours ago, John L said:

Thanks Dave, Id forgotten about the grill and tilting the engine up a bit, I was hoping to use some small cloths pegs to hold up the followers, and yes I was intending to put a new one back in at the same time, so not letting the slippery followers sliding back down again.

John

Would a set of wooddowels with small.magets glued on their ends be better than clothes pegs?

[Rob Salisbury]

Hi John, tempting as it is not to remove the head, cams and followers these days are very picky things and need to be treated with the utmost respect during the running in period, so unless your engine has not actually been run you really need to see the followers faces before introducing them to a new cam, the alternative maybe a very short lived pairing and subsequent replacement of both new cam and set of followers, not to mention off with the head again!!   .   I agree, not what you want to hear but still,,,,,,,,,

Cheers Rob

 

[John L]

This cam has done about 5000 miles and had the Newman steel Nitride lifters DNCF3000 when put in, so hoping that they will still be ok, but will consult with Newman on the issue. Plus had cam bearings put in by Ivor Searle and matched to that camshaft, hope the next will also fit the same?

John