Performance cam shaft on a m20

Post Thu Jan 12, 2006 3:22 am

I have been told by the previous owner of my car that its fitted with a stage 3 performance camshaft. As I have discovered, the stage 3 camshaft is not the best for flat land driving in the city doing 60km/hr, the car is inefficient and goes through fuel like no tomorrow, acceleration in low revs is poor to non existant and its only at about 4k rpm that I get the pull that I want. A mechanic said the only way to help the engine would be to adjust the timing but this seems impossible as the timing is coming straight off the camshaft? I might be able to get an alpina spec stage 2 camshaft, just wondering if this would help with Fuel and acceleration? Also wondering if maybe just getting the standard head and camshaft from a wreck and putting that on would be a better way to go in terms of usable acceleration and better fuel consumption? Does anyone know if the 323 head and camshaft are compatible with the 325 2.5 engine?

Post Thu Jan 12, 2006 3:25 am

Ignore the part about the 323 head, I am almost 100% sure they aren't compatible.

Post Thu Jan 12, 2006 8:21 am

Can't imagine anyone fitting a high performance camshaft without making other modifications to induction and exhaust, etc it would be almost pointless so you might be better off identifying the spec of the whole engine. If it is high, you might be better off selling the whole lump to someone who wants that kind of performance and sourcing a standard engine from somewhere to give you the economy you are looking for.

Post Thu Jan 12, 2006 8:28 am

I may be wrong but what about having the chip re- mapped

Post Thu Jan 12, 2006 8:36 am

Re-mapping would certainly show an improvement but you'd be looking at about 4-5 hours on a rolling road at about Ãƒ”šÃ‚£50 per hour to achieve a perhaps poor compromise. It would also need to be the later Motronic system too.

Post Fri Jan 13, 2006 10:26 am

MONSPORT42 wrote:Can't imagine anyone fitting a high performance camshaft without making other modifications to induction and exhaust, etc it would be almost pointless so you might be better off identifying the spec of the whole engine. If it is high, you might be better off selling the whole lump to someone who wants that kind of performance and sourcing a standard engine from somewhere to give you the economy you are looking for.

This guy did lots of stupid things on the car that left me scratching my head nothing would suprise me. He put a wire across the + - back window ciruit breaker so that the switch wouldn't work. Put a screw in the fuel pressure regulator and many other things. Getting a whole engine is expensive for me because there aren't a lot of 325's in South Australia there are mainly 318's (new engine without gearbox is about A$3000 for a 6). Probably getting a new head with standard cam shaft or putting the alpina cam in I think would give me big improvements. The alpina cam is quite mild. The other benefit with swapping the camshaft is it costs less overall than a whole new head and camshaft and I can get the head inspected and cleaned and then put it in the cam knowing its in good condition.

Post Fri Jan 13, 2006 11:17 am

Sounds like you bought the car from a bit of a lunatic! From what you say, changing the cam to something less wild will do what you want. I would go with the Alpina cam if I had the chance and it was in good nick. Keep us up to date.

Post Mon Jan 16, 2006 10:14 am

MONSPORT42 wrote:Sounds like you bought the car from a bit of a lunatic! From what you say, changing the cam to something less wild will do what you want. I would go with the Alpina cam if I had the chance and it was in good nick. Keep us up to date.

Yeah he was! I just wish he was an intelligent lunatic, not a botched home job lunatic. I have got holidays in two weeks so hope to carry out all the work then. The specs of the cam I hope to buy are as follows, Cam lift 269 intake 269 exhaust Duration Adv 270 intake 270 exhaust Duration @ 050 215 intake 215 exhaust Valve Clr 0.008 intake 0.008 exhaust Valve lift 0.3415 intake 0.3415 exhaust phase 110. To be honest I can't remember the specs of the installed Cam, but the seller said this one was a stage 1 or 2 and mines a stage 3. If anyone has any information to the contrary please let me know

I have been trying to get onto the mechanic that worked out the specs of my cam but I think he's on holidays.

On another note does any one have any ideas/suggestions on what parts you should replace when swapping the camshaft?

Post Mon Jan 16, 2006 11:06 am

I know exactly which cam it is that you have your eye on... Not sure why it has been listed for a second time, I didn't notice if the specs had changed.
The same guy was selling double valve springs and rockers too if I remember correctly, but may have sold them already.

Post Tue Jan 17, 2006 8:35 am

aus325 wrote:I know exactly which cam it is that you have your eye on... Not sure why it has been listed for a second time, I didn't notice if the specs had changed.
The same guy was selling double valve springs and rockers too if I remember correctly, but may have sold them already.

I noticed that too and asked him about it. He said he had two, the specs were the same for both. cheers