Cross-Flow (TS) valve-train life with performance cam?

[Richard48Y]

Wondering about expected valve-train life for an 807 with TS head.
I believe my engine is fairly low mileage since the last rebuild but the valves and seats are shot, the lifters had a lot of wear.
Cam was not good either.
I've been trying to put together a setup that would not strain the system so hard but it is being frustrating.

So I may have to just give in and run the stock setup with some Ti. retainers for at least a little weight relief.

Also looking at 6mm stems, but that brought up the question of does 6mm provide enough surface area for the rocker tips?

I used to know a really wizard engine builder but he passed on a few years ago.
So here I am, annoying everyone trying to figure it all out.

[jbcollier]

I would stick with the stock set-up just because everything is much easier to source.  Coating the followers would be a great idea.  Other than that, wear is directly related to rpm.

Not uncommon for worn valve train in North American sold Renaults.  Consumers changed the oil once a year whether it need it or not and never minded maintenance schedules.  Lots of engines with excellent reps elsewhere, didn't last long here.

[Richard48Y]

I am making another run at 6mm stem valves in order to make Beehive springs possible.
Custom guides are the cheapest part.
Custom springs require a two-hundred piece minimum order.
That is twenty-five sets so I expect it would take a LONG time to recoup the investment.

[Willa]

HI Richard,
I am using beehive springs from an SR20 and have modified the head a little to suit, they are purchased as a set of 16. My engine is a modified 821 pushing just over 140hp at the wheels. Kelfords in New Zealand were the supplier. Good luck with the project,
Cheers,
Willa.

[Richard48Y]

Unless I am mistaken an 821 is the wedge head?
Not certain if a TS/Cross-Flow can be fitted?
My head is a cross-flow.
I will look into those springs but I think cross-flow will be different.
What sort of pressures are you running and has it made a difference in valvetrain life?

[GavinT]

I suspect 6mm stems may be difficult to find in large head diameters. These small valve stems were a characteristic of more recently developed four valve heads which inherently use smaller valves - just multiples of them.

[Richard48Y]

Cross-posting here for those who may not follow the regular "Garage" threads.

Gave up on the Beehive springs, they are possible but difficult and not as much gain as hoped.

Got my tricky Ford 7mm stem valves, guides, and Ford springs from Salv Sacco today.
Going to be a bit of work to install them but I am sure they will be worth it.

Nor certain how spring weight figures into valve-train calculations, but these weigh 48 g instead of 91 g.
Even if only half the weight is calculated as mass the savings are still significant.
Spring retainers in steel 14 g vs 32 g.
Aluminum would be 6 g, Titanium are 9.07 g and about $175.00.
7mm Intake 68 g vs 80 g.
7mm Exhaust 57 g vs 78 g

So I save at least 30 g - 39 g per valve not including the springs.
The Mini site claims each 10 g savings is good for an additional 350-400 RPM of revs.
I know my RPM is dictated by how long I want my crank to live, so no increase in RPM but hopefully significantly longer cam and valve-train life.

Head will be taken to HBR in Las Vegas at the end of this month for the valve work and very light porting.

[GavinT]

Valves look neat - were you able to find 42mm inlets?
Weight savings on reciprocating gubbins is invariably welcome, I reckon.

[Richard48Y]

Yes, Salv fixed me up.
"In for a penny, in for a pound", so I will probably bite the bullet and get Ti. retainers too.
Another 5 g off each valve. 
Depending on who you ask valve spring weight is figured as half or one-third.
So another 20 g taken off.

Certainly all overkill for a street engine and I know it will not raise my crank-life ordained redline.
But do believe I will get a fraction more flow and less strain on the valve-train.
Lighter should open and close with less inertia, that has to be a good thing.

Now to figure out how to remove the tubes around the spark plugs?