Compression ratio of 11 and Cam choice???

[Bluebottle]

MPO said:

Bluebottle said:

My old engine was 11:1 with ported and gas flowed head running std 14CUX. Rebuilt with mc2 cam really strong engine but would run lean over 5k RPM . You can see the graphs on my profile

Hi

I remember you telling me you were running 11… Can’t find the graphs you refer to, got a link to the topic?

MPO

PS The seat is still on my to-do list :-)

Scroll to the links at the bottom of my Profile

[blitzracing]

MPO said:

Guys

Have I missed the boat?

It looks like going LS in a Griff is the icing on the cake...

Hey Ho, maybe I'll leap frog, lets see what Les comes up with :-)

For now, it's TVR/RV8.


As there seems to be issues with poor drivability at low revs with some cams is it worth looking at Rhodes Lifters (I hear they do sound quite rough though!)?

But do they work?

MPO

The Rhodes followers allows the oil to drain from them at low camshaft speeds, so it opens up a big gap between the follower and the push rod. The effect is the valves opens later and closes sooner, so you reduce the duration and some lift- so its like putting a low performance camshaft in for low speed use- but the price you pay is a lot of mechanical noise at low speed from the valve gear as you have massive clearances. Never actually seen anyone use them however so that tells you something...

[Sardonicus]

blitzracing said:

The Rhodes followers allows the oil to drain from them at low camshaft speeds, so it opens up a big gap between the follower and the push rod. The effect is the valves opens later and closes sooner, so you reduce the duration and some lift- so its like putting a low performance camshaft in for low speed use- but the price you pay is a lot of mechanical noise at low speed from the valve gear as you have massive clearances. Never actually seen anyone use them however so that tells you something...

+ running a flat tappet cam with excess valve clearances/loose is bad for the cam and follower cant see why these would be any different I heard a small block Ford on them and it sounded just fine but then I have also heard people fit them and regretted it soon after most I have heard run these bleed down tappets/Rhoads etc on the RV8 have not been successful

[Wedgefan]

Brummmie said:

I have an Ls3 stroker with 11.5:1 I have never heard it pink yet, however on the single plane I let it kangerood terrible under 1800rpm on light load, the kinsler ITB system sorted it out 580bhp/620lbsft. Cam is 244/256.

Thanks very much for that feedback Brummie. I've just ordered the Jenvey low-profile setup which I'm expecting will cure, or at least help with my slow-running problems. Your experience suggests it will!

Pete

[MPO]

Sardonicus said:

blitzracing said:

The Rhodes followers allows the oil to drain from them at low camshaft speeds, so it opens up a big gap between the follower and the push rod. The effect is the valves opens later and closes sooner, so you reduce the duration and some lift- so its like putting a low performance camshaft in for low speed use- but the price you pay is a lot of mechanical noise at low speed from the valve gear as you have massive clearances. Never actually seen anyone use them however so that tells you something...

+ running a flat tappet cam with excess valve clearances/loose is bad for the cam and follower cant see why these would be any different I heard a small block Ford on them and it sounded just fine but then I have also heard people fit them and regretted it soon after most I have heard run these bleed down tappets/Rhoads etc on the RV8 have not been successful

That’s interesting…

I would have thought with the correct Rhodes Lifter pre load clearance, this would take up the slack but not open the head valves so far…

And when the Rhodes lifter was fully open the head valves would open further

What causes the noise?

I was also thinking of using adjustable push rods to perfect the preload...


MPO

[Wedgefan]

Does anyone make roller cam followers for the RV8? They work really well in the LS engines - very quiet. I shall have to measure up for the Rover engine. If they could be made to fit the Rover block, who might grind a cam to suit?

Pete

[carsy]

I think the Wedgeshop does.

[Wedgefan]

Thanks carsy - you're right they do! - not heard of them until now - good find.

Thanks again

Pete

[dnb]

Has anyone here tried a roller cam in a rover v8. I have to say I am tempted to give it a go next winter. (Job queue permitting)

[carsy]

It would certainly get rid of the cam wear issue of the RV8.

I think its a matter of sorting some decent profiles out, as obviously with roller followers the valves can be opened quicker and for longer. Maybe the Wedgeshop has already done this. Its got to be the way forward for wear and bhp but no i dont know anyone who has gone this way on the RV8.

[MPO]

I like the sound of this there must be someone who has tried it???? I'll happily give it a a go. Is the wedge shop in the States?


MPO

[seaside]

Yes, Wedgeshop is in the US (Taunton, MA).
They do have a bunch of stuff for RV8 including roller cams

[Sardonicus]

Longer than I expected

[Wedgefan]

I'll definitely be going that route when the time comes - probably another year though before I get to the engine build - just starting the chassis/body refurb.

Pete