Camshaft choose

Opel-V8 · Post by **Opel-V8** » Sat Apr 23, 2011 6:12 pm

Hello.
I want a performance camshaft. But which to choose?
There's lots to choose from.
I assume that the cam there are installed in my engine now is the standard 3.5 or 3.9 EFI cam.
I just think when the engine is running in idle, it goes just so quiet and very smooth. dull sound.
It's a V8 so I want a much more hard-running engine at idle, so it is more uneven. "choppy"
So I hope there is many here who can help me to choose the right cam?
I have read many of the old posts through, but what I seek is not there.

I could imagine that the overlap when both valves are open at the same time shut be very much, to get the "hard choppy running” in idle.??

Maybe anyone has a video ??? so I can hear how the engine is running???

My engine is a 3.5 EFI recently converted to 3.9
Megasquirt management.
Great Plenum with 2 large air throttle.
2x2.5 "exhaust system.

Martin.

CastleMGBV8 · Post by **CastleMGBV8** » Sun Apr 24, 2011 10:40 am

Martin,

Standard heads?

kevin.

Opel-V8 · Post by **Opel-V8** » Sun Apr 24, 2011 4:56 pm

CastleMGBV8 wrote:Martin,

Standard heads?

kevin.

Jep, only standard.

CastleMGBV8 · Post by **CastleMGBV8** » Sun Apr 24, 2011 7:05 pm

Martin,

In that case not a lot of point installing a wild lumpy cam as you will make the car slower!

Best place to start would be with some decent heads and match the spec of the heads to the use of the the car. and then fit a cam that matches the spec of the heads.

Nice car by the way.

Kevin.

Opel-V8 · Post by **Opel-V8** » Mon Apr 25, 2011 10:40 am

CastleMGBV8 wrote:Martin,

In that case not a lot of point installing a wild lumpy cam as you will make the car slower!

Best place to start would be with some decent heads and match the spec of the heads to the use of the the car. and then fit a cam that matches the spec of the heads.

Nice car by the way.

Kevin.

It is not because it's about getting more power.
It is more to get a little more hard-running at idle.

Yes, when the time is right, I've thought about getting a set of 4.6 heads on.
But it will not be this summer.

Martin.

CastleMGBV8 · Post by **CastleMGBV8** » Mon Apr 25, 2011 12:51 pm

Martin,

No advantage using 4.6 heads same valve size and ports as earlier heads and they have different accessory bolt positions to the the earlier heads

As stated the sort of cam that will give a lumpy idle will have a power band much higher up the rev range with a substantial loss of power off idle to around 3000 RPM with poor drivability in traffic.

Over those revs the limiting factor is still the heads as they wont be able to flow to the potential offered by the cam, so you lose both ways!

A simple upgrade to stage 1 heads with standard valves sizes and standard cam wil give approx + 30 BHP with no loss at lower RPM.

I haver a Crower 50232 cam ( slightly lumpy idle) with stage 3 heads on my 4.35 engine and this has proved to be a good combination providing approx 260 BHP.

Kevin

Opel-V8 · Post by **Opel-V8** » Mon Apr 25, 2011 3:18 pm

I thought 4.6 cylinder heads have larger ports / valves, and that they fit straight onto my engine.
But okay, then my older just have to be ported, once.
The Crowe 50232 cam, is I also been recommended to use. by paul V8tuner.co.uk for my setup.

dogman · Post by **dogman** » Mon Apr 25, 2011 5:27 pm

Standard TVR 4.0 idle is a bit lumpy. Dont know what cam exactly but I dont think they're that wild. There should be an equivalent cam available but obviously it depends what your vehicle is. I wouldnt have thought a TVR cam would be any good in a LR/RR?