TR6 with Harald Sharp Rockers

[JochemsTR]

Hello TR-Friends,

our german TR Forum interested me in the Harald Sharp Rockers.

Some just installed them without any further modification. However, this website addressed the issue of the installation:

http://www.flowspeed.com/harland-sharp.htm

 

 

Did anyone consider the 90° @ 50-66% Rule?

 

Which Pushrods were used (PI, Adjustable) and were the rockerpedestal shimmed?

 

Best Regards from germany

Jochem

[TriumphV8]

Hi Jochem it is essential to bring rockers to the proper height.

Normally with any cam with more lift you have to skim the pedestals, not to shim!

Otherwise you will get a massive wear on the valve guides.

 

Its often forgotten, even from well known tuners.

Also the timing suffers what I did not recalculate but some claim real differences

with rockers set not properly what also includes the pushrod length.

Seems to be a complex geometry problem........

 

Anyway we can discuss a lot but it is just the biggest progress to have the rocker

shaft at the perfect height. That is already the end of many home tuners because

a milling machine and some precision is required to get real improvement.

 

With the ROVERV8 it is completely crazy, they recommend to shim to bring the proper

setting for the self adjusting tappets. So if you take a cam with more lift and shim

you do completely the opposite to what is the right thing.

From that a lot of people live with that wrong setup and the engine runs anyway.

 

Also you have to check the area the roller rolls over the valve tip with blue color from

differential setting. Do not know the name in English. (Touchierpaste)

 

That skimming of pedestals is seldom done because you quickly run out of proper length of pushrods.

You can take the shorter PI pushrods but than it becomes difficult.

So if you skim the head and the pedestals it becomes nasty.

Some sell even shorter pushrods than the 206.

 

I make my own pushrods vom tubes where I press the ends of the modified

ends of the TR pushrods into.

It is a copy of the Bastuck tubular pushrods that can be cut to any length.

You can buy them still at Bastuck and they are recommended for high rpm.

 

The Harlands are pretty good rollers although they are not full rollers like the Goodparts.

That makes the difference in the price.

You get rid of the problem with the valve guide wear but still have to deal with the rocker shaft.

 

I only use full rollers both on my TR6 engine and my RoverV8 where I went to mighty 1,80 ratio

to feed the big valves of the modified head. This might not work without full rollers.

 

Full rollers are pretty cheap in USA, they started from 15USD some time ago.

Unfortunately they are all straight and we need a shift to one side to fit.

So all offered rollers are not a bargain for our TRs.

 

I bought them for the TR6 because I lost the fresh set of bushed rockers from MOSS

after only 20.000 Km and they destroyed the valve tips, too.

It was that problem with not properly hardened tips of the rockers.

[JochemsTR]

Hello Andreas,

I appreciate the quick reply. Unfortunately I am still not sure how to go forward. The rocker shaft should be positioned (height) correctly. This can be done by adding shimms under the pedestals.Moss offers TT1910 shimms. These are thin. I may have to make them myself.

The question is, how to correctly calculate the required height. Kent 270 (TH12-6) has a 0.287" camlift.....and now? On the flowspeed website, they calculate a 0.313" pedestal shim. This is very much !

Did anyone actually do this?

 

Jochem

Edited March 7, 2018 by JochemsTR

[ed_h]

It looks like they may be describing "mid-lift" geometry: http://bullfire.net/TR6/TR6-19/TR6-19.html

Ed

Edited March 7, 2018 by ed_h

[JochemsTR]

Hello Ed,

yes we are!

Jochem

[JochemsTR]

Just curious, who else installed these HS Rockers and whether modifications were made to the pedestals and pushrods, or not....

Jochem

[roulli]

Hi Jochem,

 

I had a similar bad experience as Andreas, with my new bushed rockers from Moss.

I got the tips even laser hardened in your home country. But the material of these Moss rockers was so crappy, that the hardened surface kind of peeled off after e few miles of usage...

Eventually I ended up with the HS rockers.

I bought them from a US dealer who offered them machined to fit directly on the TR6. which means that some rockers were already machined on the side, so they aligned exactly to the the middle of the valve tip.

 

The HS is not a plug and play solution as the Goodparts, and I used exactly the same instructions as the ones you posted above, to bring the rolers into the correct height.

For the Newman cam I had to skim off the pedestals.

2 Years later, I swapped the Newman cam against a WBC cam, with higher lift, and I had to use shims to bring the rockers into a higher position.

 

It's a bit of work, but it can easily be done by a home mechanic, who has time.

 

Patrick

Edited March 7, 2018 by roulli

[TriumphV8]

The question is, how to correctly calculate the required height. Kent 270 (TH12-6) has a 0.287" camlift.....and now? On the flowspeed website, they calculate a 0.313" pedestal shim.

 

Let me say first again that I expect to take material from the posts, not to add shims!

Let me say second that this problem does not play that role with rollers.

 

What makes the problem is the somewhat scratching of the rocker like a dog with his

front foot on the ground. The rocker scratches on the valve tip what is very bad a top lift.

You can see that clearly if you have a head at hand and fit only the inner valve spring and the rocker

and make that lift by hand and some more than normal lift you see that "scratching"

 

Calculation:

Measure the height from valve tip to head surface.

let us say that is 50.

take the lift of cam, lets say that is 6.666

take the rocker ratio, lets say 1.5

calculate valve lift what is 10

Take 60% of valve lift what is 6 and subtract from tip

That will give 44.

 

44 is the height of the valve tip at the recommended 60% valve lift.

We do not take 50% what is geometrical the best because we

want less "scratching" at max lift with max spring power. Its worse to

have moving of rocker on tip at max lift than at lift beginning due to rising spring power.

 

Measure the top of the rocker shaft to head surface what is 55

Measure the diametre of the shaft what is 20.

middle of the shaft is 45 above head surface.

 

We want to have it at 44 so we have to skim the posts 1mm.

Hope this helps & good luck!

[JochemsTR]

Hello Andreas,

this is exactly what I needed.

I will post the results in a few days. I know one of my friends (you know him too!) added material and not removed it ! So I am very curious what will happen in my case.

Jochem

[Waldi]

That is a very good explanation Andreas!

Thanks,

 

Waldi

[ed_h]

On a stock tr6, raising the rocker shaft by a small amount will move the valve stem contact patch outward, and make it narrower, just as a geometrical analysis predicts. Also, valve lift increases slightly, up to a point.

 

Ed

[Tom Fremont]

On a stock tr6, raising the rocker shaft by a small amount will move the valve stem contact patch outward, and make it narrower, just as a geometrical analysis predicts. Also, valve lift increases slightly, up to a point.

 

Ed

Seems those valves in your pictures aren't rotating. Is this normal/desirable?

 

Tom

[ed_h]

Tom--

 

Those patterns were made by just a single cam rotation, turning the engine by hand. So I can't say whether the valves rotate under normal running conditions.

 

Ed