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I replaced my original CP camshaft in 2019, because a couple of the cam lobes were not lifting the the valve enough.

I ordered a new cam from Newman with the appropriate follows from them.  They advised it should be this cam as a replacement, but the valve openings/closings are not the same as an original cam.  I eventually got a spec sheet from them as to how it should be set, but I still don't think I have got the timing correct. 

Newman suggested that I should use the std tappet setting 0.010" for the valves, which has been done, but in the attached it says something different, or am I reading or miss understanding  the settings given on the sheet.

I'm sure there are guys on here that can put me right, in simple language and getting the cam set as it should be please.

Although Newman say this cam replaces the TR CP original I'm not convinced, these specs dont line up with any of their cams they offer on their website for the CP injection, should I stick with it, or perhaps choose another.  I going to get the block line bored soon so will need to get the right cam bearing dimensions for that job.

John

Triumph TR6 150BHP Timing Newman Cam.pdf

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Hi John,

You're correct, the data sheet gives different tappet setting advice to the direct comms you've had from Newman. I suggest asking them why that is.

Looking at the data sheet, I'd say you have a wilder cam than the standard CP series. The lobe separation is correct, but the duration looks (much) longer. The CP cam had an advertised duration of 280deg for both intake and exhaust, which I believe to be at 0.010" camshaft lift. See this handy reference sheet.

Assuming that the "checking clearance" is the cam lift at which the timings in c, d, and e are measured, and that "0.25" means 0.025" (odd, but I can't see how else to interpret it), I would expect a duration of about 240 degrees. That's based on measurements I took of my CP series before I installed it; I got 285 degrees @ 0.010" and 260 degrees @ 0.020". I didn't take a measurement at 0.025"; 240 degrees is an interpolated estimate. Much less than the 276 degrees Newman are quoting. Of course I may be wrongly interpreting their sheet!

I'm sure others with more experience and stores of data than I will come along. I bow in advance to their superior knowledge...

John

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Can not open the data sheet but can gives you hints.

Valve lift in tdc overlap ist a good figure to find out what you have. The more the lift, the wilder the cam.

Fit the cam, go to tdc overlap and open the rocker screws until they are free. Turn crank 360 degrees and measure valve clearence with the feeler gauge using more than one blade If needed. Found number minus advertised valve play ist the lift. 

In almost cases the metering unit ist not set properly. So this ist a good point to measure under full load exhaust AFR and adjust properly according to what the cam needs. Ignition ist not affected from these minor differences. Look for 30 degrees max at 3500rpm.

 

Newman cams are not bad, stay with them. Add enough zddp to your motor oil just from beginning, not to Ruin next cam by eating the lobes at idle.

Edited by TriumphV8
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32 minutes ago, stillp said:

I'd have guessed that "0,25" means 0,25 mm, close to 10 thou

That would work. Bizarre that other lift dimensions are in thou! In which case, it's close to a CP cam. Maybe a little conservative.

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JohnC did you ever fit that 6:3:1 exhaust and reassess the power deliver of your motor?  I recall reading a series of interesting posts of yours some years ago where you experimented with stock and TT1200(?) manifolds.  

Jim

 

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5 hours ago, Jim F said:

John, does your newman cam have a serial number or references embossed or engraved on the end?  Newman offered a close to stock replacement for the TR5 PI cam and the end markings are referenced in the photo below.  

Jim

IMG_2753[2].jpg

Jim

I must say I didnt check that end, but the spec sheet uses that same reference, I was told by Newman that it did replace the CP injection cam, but I still dont really understand the spec on the sheet, or the openings and closing of the valves, but I think it reads crank at TDC, inlet lift with 0.032" and fit the chain is that correct, and what tappet setting should I use?

John

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8 hours ago, Jim F said:

JohnC did you ever fit that 6:3:1 exhaust and reassess the power deliver of your motor?  I recall reading a series of interesting posts of yours some years ago where you experimented with stock and TT1200(?) manifolds.

No, my experimentation is best described as glacial in pace! The stock manifold gave much better torque in mid range (vs TT1200 - good memory!), at the expense of power at 5500RPM+ (not a place I go much). After 18 years I have finally replaced the horrid cam (profile suited to an Escort Cosworth) with a CP cam (plus quite extensive work porting & flowing head & throttle bodies). I'm now calibrating the MU for that setup, after which there will another instalment in the series "one owner spends loadsa money in the pursuit of insignificant improvements"! After that, the 6:3:1. But don't tell the boss.

John

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2 hours ago, John L said:

still dont really understand the spec on the sheet, or the openings and closing of the valves

I'm not sure whether your calcs are correct, but they don't reflect how I've been taught to time a cam (which is all about where the centre point of the max lift is in relation to TDC). I really think your best course of action is to talk to Newman direct. You should also search the TR6 forum for instructions on how to time a cam. It's not hard, once you understand it. Personally I was really irritated (=confused) by the lack of consistency/clarity from cam suppliers in quoting cam degrees vs crank degrees!

John 

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I have a CP spec cam in my driver with Webers with 99K miles and counting. It was supplied by Cambridge Motorsports circa 2002 and I never had it examined for its faithfulness to the factory spec. I don't know who actually made it; blank was new. It was timed in by the book, set at 2-3 degrees c/s advance to compensate for sprocket/chain wear. Clearances are 0.010".

I don't understand why the 35/65/65/35 valve timing isn't mentioned above nor in the Newman data sheet. Instead, similar but different timings are shown with slightly less duration, lift and centerline the same however. I have one of their so-called "150" cams I won't be using ( due to a falling out between us 10+ years ago, all revealed on this site at the time ) and it happens to say "STANPART" on the shaft. I'll be using a PIPER instead on my current build. If anyone has faith in NEWMAN and wants it he can PM me; otherwise it goes on ebay touting the marking above.

 

Tom

 

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Looking at the sheet - the figures for gaps & lift are imperial, and comparing to the figures for the CP cam on Chris Witor's web site, this is not a CP camshaft, it may perform similarly hence the 150 title.

Doing a calculation from some of the on-line calculators I think a good starting point for setting it up would be to set up with with No1 inlet maxiamally open with the crank at 110 degress after tdc. The aternative would be to set it up on the rock which should give you similar timing. A degree or so either way doesn't matter hugely but with any given cam the more you advance the timing, the higher in the rev range the peak power comes, I'd try not to retard it too much if you can't get it spot on with the standard cam sprocket.

Set tappets to 14thou inlet and 16 exhaust as stated - again this is another indication that it is not the same cam profile as the original Triumph CP 150 bhp profile but if you set it at the 10thou you will have the inlets open too early and the exhausts open too early which may mess with the fueling.

It doesn't look too radical a cam so the standard metering unit and dizzy set up won't be too far out, but for ultimate performance a roling road set up with someone who understands the Lucas PI system once its run in might be useful.

Not sure what happened between Tom & Newman but most cam grinds these days are on new blanks rather than re-profiled used cams. Re-profiling old cams tends to result in short service lives but was for a while the only option.

 

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I can add a bit more info now, the 0.25" is the lobe lift of both exhaust and inlet cams.

The 110degrees is the lobe centre of the inlet valve lobe.

I would like to know now, how it should be set, what position should the crank be in and how do I get to find the 110 degrees on the camshaft?

Any help would be much appreciated.

John

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The 110° is after top dead center of the crankshaft, to find this by

1)  set to top dead center marks on flywheel, or better to use a dail gauge on a piston, or through a spark plug hole if head is still on.

2) attach a timing wheel to the crank, & arrange a piece of wire to act as a pointer to point at 0°

3) rotate crank till pointer is at 110° After tdc

4) find the peak of the inlet cam on No. cylinder & set at the top.

5) attach timing chain without disturbing the cam position

  836174796_SettingValvetiming1.thumb.jpg.cbf6f1c4110300c043bd6ea6ab1dd83f.jpg  747653136_SettingValvetiming2.thumb.jpg.3c87c82047dd7cf958f5d9ff89590811.jpg

This is a 4 pot engine, but the theory is the same

Bob.

Edited by Lebro
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1 hour ago, John L said:

The 110degrees is the lobe centre of the inlet valve lobe.

Hi John,

Sorry if this comes across as pedantic, but the Newman sheet specifically says that Camshaft Peak Difference (a) "Is the angular difference of exhaust and inlet cam lobes." That's not the same as "the lobe centre of the inlet valve lobe". Bob is dead right with in his instructions, but only if 110 degrees the the inlet valve timing. BTW the original CP cam had, coincidentally, 105 camshaft degree intake/exhaust lobe separation, and intake max lift @105 crankshaft degrees ATDC (intake and exhaust had identical, symmetrical profiles). So you may be fine, but worth making sure. It's surprising that a supplier as long-established as Newman doesn't provide better documentation.

Cheers,
John

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Thanks John and Bob,  I am learning but slowly.......

From a mail back with Newman he said,  the Lobe centre angle on the TR6 Cam is 110 Degrees,   if I use one of the cam profile templates on the net will it confirm the 110 degrees, centre between with the figures of 38/78/78/38?   I will try it.

I have not been impressed with Newman detail at all, in fact has me more confused.

John

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From the Newman data you supplied, the cam timing is open 28° BTDC, close 68° ATDC  if you do the sums:

28  + 180 + 68 (gives the duration of 276°) divide by two to find the full lift angle with respect to start of opening = 138°

then subtract the 28° BTDC to get it realative to crank TDC = 110°,  so my method above is correct.

Bob.

Peter posted while Iwas typing !

Edited by Lebro
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Bob

I'm still a bit confused here, Newman say the inlet opens at 38 and closes at 78, are you taking off the tappet clearance to get your 28 and 68?

Newman say 0.014" for inlet and 0.016" for exhaust.

John

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Nothing to do with tappet clearance.

The Newman page is confusing. The only part of it that makes sense to me is d)  Actual valve timing,  & e) Duration

if you use the figures in d) you get the correct duration in e)

Numbers in c) don't make any sense  & "38 & 78" do not appear on that chart those figures would give you a duration of 38+180+78=296°

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Why ?  all you are doing is finding the crankshaft position where the cam lobe (No.1 inlet in this case) is at it's highest,

which in the case above (& the standard triumph cams as well) happens to be 110° after TDC.

Bob.

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47 minutes ago, Lebro said:

Why ?  all you are doing is finding the crankshaft position where the cam lobe (No.1 inlet in this case) is at it's highest,

which in the case above (& the standard triumph cams as well) happens to be 110° after TDC.

Bob.

Just finding full lift does not do it

Camshaft Fitting & Timing (burtonpower.com)

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4 minutes ago, ntc said:

Just finding full lift does not do it

Camshaft Fitting & Timing (burtonpower.com)

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

Stuart.

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Gosh this is getting.........

As the engine is together at the moment, If I turn the crank to 110 degrees after TDC, compression on #6,  number #1 inlet should be stationary, fully open and any movement on the crank either side of the 110 degrees the inlet should show movement. This is my logic now, correct? 

I suppose this timing should really be be done with a DTI direct on the cam follower, taking out any valve clearance and ratio of the rocker?

Surely now depending on what tappet setting is used the valve timing will be a bit advanced or retarded to what figure I'm not sure?

John

  

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