The V8 Owners Forum -

Hi there all i am looking to replace my worn cam shaft in my land rover discovery v8. I was thinking off a mild fast road cam shaft instead off a aftermarket std cam shaft. Also thinking off upgrading the cam shaft timing gears from plastic std cam gear to a all metal gear set up and updated chain.

While it was apart and various parts was being cleaned up I was thinking off polishing the plenum chamber on the inside lowering the trumpets by 15mm and fitting a new performance chip into the Ecu.
Any information on what's a good idea and not a good idea to do I'd like a useable but mild state off tune. Thanks Michael

I've used Real Steel's Viper Cyclone cam to good effect in the 3.9 EFI engines. It was designed specifically to work with EFI. Their all-steel timing gear sets are also an excellent upgrade.
I wouldn't waste too much time polishing the plenum too much, very little to be gained there in all honesty, we aren't talking about an extremely high specific power output after all.... Same goes for dropping the trumpet height, shortening the intake effective length will favour high-rpm operation at slight detriment to low-end torque, which is probably not good in a heavy 4x4....
Just my thoughts.

No this is fantastic advice. Hence why I wanted some views on cam shaft choice and what to do and what not to do with regards to the trumpets and polishing the plenum chamber I didn't think anything was to be gained by doing that.
As regards to the cam I'm wanting to find one that can be used with std timing gears and provides a stable idle and doesn't require the heads to be removed and extra springs added that's what I am trying to avoid doing at the moment. Thanks Michael

Just looked at there website and wow what a good price for the cam shaft looks like I will be using that cam shaft and the hydraulics are a reasonable price also. Just one other question would I have to check the pre load off the engine if I fitted new push rods and hydraulic lifters with a cam shaft?

If you fit new camshaft/rockers/lifters then yes you would have to recheck all the rocker preload etc.

Easiest way to get cheap power out of a Rover V8 is to port the heads, they're a bit restrictive in standard form. As yours is in a Disco, any high torque cam is going to be worthwhile.

Well I take it that checking the preload is fairly easy job to do. I'm half tempted to get the adjustable preload push rods from real steel. As already stated a updated cam should be okay it seems to pull well and go well in the std form but with the engine being so old I have no idea I'f some one has done any work to it already.

I'm not after sports car performance but just a touch more power would be a good thing.

Hi
If you want to make a differance that will be noticable on this car I would get a cam as recommended for EFI either a new 3.9 standard cam or the cyclone add a set of stage 1 ported heads (ported by someone with a flow bench and a reputation for doing good heads) add a set of long tube headers and skim the heads to up the CR a bit. I would not use adjustable push rods, they are heavy and a weekness in the valve train buy 1 use it to measure the required push rod length and then buy 16 the right length. Checking your preload is simple with a new set of lifters. those mods, if you can bodge the FI to give wou a fairley good mixture will make the engine come alive.
Best regards
Mike

Just spoke to the gentleman at real steel very knowledgable. I was thinking of pulling the heads off and having them ported and polished.
Watching some pipes on eBay the 4-2-1 headers and a mark Adams chip on eBay.
I think the only place that I am going to fall down is the pre load setting on the engine after the new cam and followers are fitted to the engine.

"I think the only place that I am going to fall down is the pre load setting on the engine after the new cam and followers are fitted to the engine."
Hi
in reallity it is a very simple job to do, fit the tappets/lifters dry and the valve gear with the push rods, take 3 pieces of bent wire as feeler gauges, one at the preload thickness, one ten thou over and one ten thou under and use the rocker to compress the tappetby hand, use the feeler gauge to put the tappet clearences into size, +10 thou - 10 thou ignor the exact size ones and add up the others for each bank (with their sign), devide by eight and either use that to determine how much to skin/shim the pedistals (allowing for rocker ratio) or what length to make up a set of pushrods up from the grind to length ones (add take off the number found to the length of the standard push rods) I would not bother with adjustable push rods.
Best regrads
Mike

If your interested in a a tornado chipped ecu, 20AFM etc then I have one for sale that I removed from my car prior to supercharging. What Mark Adams chip are you looking for?

Jesus Doesn't sound easy but I guess that once it's done it's done it is one thing that will never have to be touched again. Looks like I'm going to have to add another item to my shopping list then

One word for what its worth, on the 4-2-1's I had some on a 3.9 110 a couple of years back and I think they were only about 1 3/4" diameter which was ok and an improvement on the old cast iron ones but I believe 2" or bigger would be less restrictive and work well if you are porting.

mateyboy67 wrote:One word for what its worth, on the 4-2-1's I had some on a 3.9 110 a couple of years back and I think they were only about 1 3/4" diameter which was ok and an improvement on the old cast iron ones but I believe 2" or bigger would be less restrictive and work well if you are porting.

Hi
You might want to read this thread,
http://www.v8forum.co.uk/forum/viewtopic.php?t=6657

Mike