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Roger

Revingtons suggest that you should have the weakest springs you can get away with. And that you start to uprate when high revs are used 6000 +

You just need to make sure there is no spring binding.

H

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FWIW having completely killed a set of valve springs I fitted a set of Racetorations progressive uprated valve springs and they have done sterling service in all conditions for the last 8yrs.

Stuart.

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Hi Hamish,

I've also heard that recently elsewhere. I shall do some digging on Monday.

 

Roger

 

Roger

You have enough on your hands

I found this as s start

 

https://www.revingtontr.com/product.asp?productid=301466&affiliateid=

 

And an extract .....

 

When installing a camshaft, to avoid excessive and premature lobe wear it is important to use valve springs which provide the correct seat pressure. We recommend standard spring pressure, certainly no more unless you are consistently revving to 7000RPM!

Only just enough spring pressure is required to ensure the valve stays closed when it should be, without valve bounce. Any more is too much and will put unnecessary load on the camshaft lobes, possibly resulting in premature lobe failure.

When choosing valve springs it is also important to check that the extra lift of our performance camshafts does not result in coil binding on full lift. This should be checked (even with standard camshafts) with the head and the valve gear assembled and valve clearance correctly set. It should be possible to leaver down the valve by an extra 3mm for safety with the valve at full lift.

Please see the appropriate catalogue section for a range of suitable springs.

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Hi Roger

 

I'm watching this one closely. After establishing the stock 4A cam as 17/57 57/17 and then searching here. Your info on the cam pulley sizing led me to the PH1 vs BP270. Just a few days ago, I ordered the Piper BP270. It will be a few months before I know, but sure hope I made the right or reasonable choice - long distance customer service fr5om suppliers kind made the choice.

 

I look forward to your outcome, as essentially I want the same - stock idle, torque and town driving performance

 

Go well,

Alf

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  • 4 weeks later...

Hi Folks,

hopefully I am getting to the bottom of all this chaos.

 

Why did the new standard cam with new followers wear out in less than two years.

Why does the TT1104N behave so vigorously

Why is there only one lake in the Lake District.

 

Today I pulled the newly fitted TT1104N cam. It looked perfect as do the followers.

Upon measuring the lobes I'm sure they came up at 0.290" lift. But!!!! the paperwork suggests 0.260" - that is quite a difference. I'll re-check tomorrow.

 

The Newman cam is exactly as per the paperwork.

 

I chickened out regarding holding the followers up with magnets and removed the head.

The new cam is fitted but not timed - AND then it started to rain.

 

Before calling it a day I removed a valve spring from the new (2 years old) head. I have a few old sets of original springs and wanted to compare the stiffness.

 

Here are some dimensions for the outer spring-

 

New Moss head spring Old /Original spring

Outside Diameter 1.25" 1.380"

Free length 1.875" 2"

Wire diameter 0.158" 0.158"

No of coils 4 to 5 7 to 8

 

I could not check the compression force with absolute values but for a similar movement of compression the hand force required for the new spring was nearly double the old spring. The new spring is significantly stiffer than the old spring.

This may be why the new standard cam of two years ago had such a short life.

 

So what have I discovered.

The new moss head uses stiffer more sportier springs. Good for the racer boys - bad for standard cams (Perhaps there should be a warning)

The New TT1104N cam may or may not be what it is meant to be (I'll recheck the lobe lift tomorrow). 0.260 to 0.290 is quite a big difference and may account for the rough running (coupled with the 108' installation angle - may be better with 110 or greater to calm it down)

 

Tomorrow I shall start to put it all back together - Wednesday could be fun.

 

Roger

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Hi Folks,

I fitted the old/original springs from a previous head rebuild to the Moss head.

I was surprised to find the exhaust were triple springs.

Even these three springs together needed a lower force to squeeze them down than the New Moss head springs needed.

 

So tomorrow I'll time the cam/crank/watch using the new vernier cam wheel and put it all back together.

 

I was hoping to have it buttoned up by Wednesday afternoon but it may well be Thursday now.

 

Roger

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We are all looking forward to your next episode Roger.

( well I am. Trying to learn TR stuff all the time. )

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Hi Hamish,

what amazes me is that even with a fair few years experience of buying parts I'm still fooled by the suppliers not giving all the useful info.

 

When I bought the Kent cam I wasn't told about the rough tickover etc etc.

All I wanted was a decent standard cam - they could not tell me anything about its pedigree.

 

When I bought the head 2 years ago I was not aware what the uprated valve springs would/could do. Why are they uprated?

 

I now know that softer springs may well be better than stiff springs - it depends on your driving needs.

 

Still I'm getting closer to what I'm after.

 

Roger

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Roger. I know I have said this before but you clearly have a lot of knowledge and skills yet still come across issues that have you scratching your head !

What hope for those like me that want to have a go but fear making it worse !!!!

 

And when suppliers add to the stumbling blocks it only makes things worse.

 

I have my fingers crossed for you

H

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Upon measuring the lobes I'm sure they came up at 0.290" lift. But!!!! the paperwork suggests 0.260" - that is quite a difference. I'll re-check tomorrow.

 

I cant believe that there's such a difference in the lift measurements. Do you think this has just been marked up wrongly/dispatched wrongly or is this just more wool that is being pulled over their customers eyes?

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Hi Nigel,

I rechecked the TT1104N cam this morning and the lobes do have a lift of 0.290".

I then looked at the paperwork and the words have magically shifted around and they now say 0.290".

 

Hopefully tomorrow or Thursday I'll be able to report back better info.

 

Roger

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Hi Roger

 

TT1004N STANDARD CAM WITH 0.260" LIFT

 

TT1104N FAST ROAD/ HIGH TORQUE 0.290 " LIFT

 

What did you ask for?

Which was supplied?

Which was written on the invoice/ box?

 

Just a thought

 

Iain

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I noticed the subtle numbering difference when I looked tonight. You could have something there Iain

 

 

So will you be selling the 290 cam roger.

 

Would it win me a sprint in my 3a ?

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Hi Iain,

where did you get your numbers?

 

here is the Moss webcat https://www.moss-europe.co.uk/shop-by-model/triumph/tr2-4a/engine/engines-components/performance-camshafts-tr2-4a.html

 

The TT1104N is described as the 'Road' cam with 0.290" lobe rise

The TT1004N is described as the 'Fast Road'

 

All very confusing.

 

Roger

Edited by RogerH
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Flaming confusing hence I got it wrong but

 

https://www.moss-europe.co.uk/camshaft-road-new-tt1104n.html

 

Standard Road lift 0.260" install 108

 

And

 

https://www.moss-europe.co.uk/camshaft-fast-road-new-tt1004n.html

 

Fast road but now has 0.300 lift.!install 103

 

Still begs the question(s)

 

Cheers Iain

Edited by iain
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Hamish the Kent Fast road is Ok it's a bit lumpy at tick over pulls like a train 2500 to too high for comfort. It loves to rev. Is it nice? Jury is out for me. I liked the low down torque of my original cam (knackered) coupled with the 4.1 :1 axle it makes a very responsive car.

Iain

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Hi Roger

 

Scroll down to the table lower down the weblink you posted here

 

https://www.moss-europe.co.uk/shop-by-model/triumph/tr2-4a/engine/engines-components/performance-camshafts-tr2-4a.html

 

 

Cams are tabulated and say different things again. No wonder we are confused....so are they!!!

 

Iain

Edited by iain
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Hamish the Kent Fast road is Ok it's a bit lumpy at tick over pulls like a train 2500 to too high for comfort. It loves to rev. Is it nice? Jury is out for me. I liked the low down torque of my original cam (knackered) coupled with the 4.1 :1 axle it makes a very responsive car.

Iain

Iain

A 4.1:1 rear diff. Now thats another ingredient to add to the mix hhhhmmmmmmmm

 

 

Good luck roger. Hope it all works.

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