47 replies to this topic

[mini-geek]

The valve doesn't shut in time for the next cycle

[Allrounder]

And what's the effect you getting because of this as it's not something I've experienced before?

[carbon]

Interesting they are all within 0.5mm of 36mm I can't see that causing insufficient spring compression..

Surely I shouldn't get valve float at 5000rpm with the correct springs in..

 

Are you using both inner and outer valve springs from the VS2 set, or just the outer?

[mini-geek]

Both

[carbon]

Strange, would have thought the VS2s would allow over 7000rpm even with 286 using high lift rockers.

 

Is there anything else fitted which might give similar(ish) symptoms, such as a rev limiter?

[Swift_General]

Why do you think you're getting float?

[mini-geek]

Tuner/mapper has confirmed it

[Allrounder]

So I take it that the engine is missing over 5000 rpm. How did they come to the conclusion that it is the value springs?? Did they use a oscilloscope!

Think the only way to be sure is to check to poundage of the springs you've got, but then you need to know what they should be. Would of thought in the area of 180 to 200 lbs but Kent cams should be able to give you that information.

[mini-geek]

The guy is very experienced I have no doubt over his diagnosis.

But what else could it be.. it's a popping crackling noise at high RPM and the power dips off as it happens.. it runs fuel injection it has fuel it has spark so the only thing missing is compression..

I'm planning to put in 280lb springs I know they are a tad high but for the limited use it gets and the type of driving, I also like to be able to rev an engine I think it will be fine.

[nicklouse]

All the valve specs are in the product brochure

Installed pressure. Max pressure , installed height.bind etc etc

http://www.kentcams.... catalogue 2016(7).pdf

http://www.kentcams....atalogue 2016(7).pdf

Crap links.

http://www.kentcams....lly/#fragment-1

Link on the right.

Edited by nicklouse, 26 February 2017 - 10:22 PM.

[mini-geek]

Sorry what information am I looking for?

[Northernpower]

The guy is very experienced I have no doubt over his diagnosis.

But what else could it be.. it's a popping crackling noise at high RPM and the power dips off as it happens.. it runs fuel injection it has fuel it has spark so the only thing missing is compression..

I'm planning to put in 280lb springs I know they are a tad high but for the limited use it gets and the type of driving, I also like to be able to rev an engine I think it will be fine.

It's could be low fuel pressure, have you checked it's maintaining the pressure at high revs under load?

[mini-geek]

It has fuel that's been checked, like I say he knows what he's doing

[nicklouse]

Sorry what information am I looking for?

The spring specs. As you asked for.

286 uses a set of VS2 springs. As to the number you have stated. You will have to ask KENT direct if it is actually one of their single springs.

[mini-geek]

They where bought in a kit from Kent

I think the only way I can eliminate the valve springs being the cause is change them