Valve springs, retainers and rocker shafts

[Nick Moore]

I'm sorting out my 3.5's valvetrain at the moment, and need some advice.

Firstly rocker shafts - I've rebuilt a few Triumph engines, and most of their aftermarket rocker shafts are rubbish, made of soft metal and wearing rapidly. Is there a similar problem with any Rover V8 shafts? I'm using Yella Terra bronze-bushed roller rockers. She'll be revving...

Secondly, I need to chose some suitable valve springs. The cam's a Crower 50232 with 488thou lift. (The 50233 would have been interesting but I didn't want to have to pocket the pistons). I'd prefer double valve springs for safety. Crower's cam card specifies 105-115lbs closed and 265-275lbs open. I haven't found any for a Rover with those exact poundages, but V8 Tuner sell heavy duty double valve springs - has anyone used these?

Would I need to machine the spring bases in the heads, or fit steel shims to avoid the springs eating into the heads?

Lastly, Crane valve spring retainers. Reliable for the odd thrash?

Thanks in advance!

[katanaman]

Looks to me like this is a hydraulic cam with a peak of 5500 so why all the high rev stuff? You can do that easy on single springs and standard valve gear.

[Nick Moore]

The main reason for the high-revving parts is that they're stronger than factory parts. The Crower camshaft has higher lift than standard, and given the Rover's penchant for wearing cam lobes, I want it to last. Of course stronger parts don't necessarily reduce wear.

Des Hammill's book is great reading, but comes with warnings about the limitations of various components. Some SD1 valve spring retainers, for example, are rated to 5800rpm. That's above my peak torque, but if the Crane ones are fine to 7000rpm (just a guess), it's that much more of a margin of safety. Likewise, the Yella Terras came along at the right time via FleaBay. They're supposed to reduce lateral stress on the valvestems than standard rockers, so I thought "why not?".

If no one's had standard rocker shafts fail, they'll be fine. The double valve springs, well, that's what Crower specify, and having seen the results of single springs breaking, fitting two seems like a good idea. And presumably they also resonate at different frequencies, which should avoid valve float.

[katanaman]

Of course its entirely up to you what you spend your money on. Heavy duty single springs will be just fine as will standard retainers. I wouldn't consider any of that stuff personally until I went for a mech cam. Your cam although a long way from standard still isn't that big a cam. I would advise you call Paul from V8 tuner and ask his advice. He is a Crower distributor and will know what parts you need.