5 replies to this topic

[idlethumbs]

The mini is now tucked away for winter and I'm planning on putting a better flowed head on it to push the power a little.
I don't want the engine out to do the cam just some bolt on bits.
It's well serviced and goes well but when it comes to cylinder heads I am new to all this.
Minispeed do an spi stage 3 head which is well priced at about £450 after surcharge. They also do a stage 4 for little extra.
Is there any point in going to stage 4, will it run better or be too much for road use?
If cost will go far enough I'll get some roller rockers too, but from reading a lot on here think I'm going to go 1:3:1. I understand these should give me a marginal lift increase, but it should all move a little easier and feel a little smoother to drive?

[gizmo1994]

I have the stage 4 SPi head from MiniSpeed on my car and it works well. Certainly an improvement on standard but whether it is any better than the Stage 3, no idea.

However, the head has been on the car since 1998 and has had no problems. A recent strip down showed no signs of wear.

I had a previous SPi head on there from another Mini store which lasted all of 6 months before it started smoking.

[Carlos W]

Rather than just picking numbers it's a better idea to measure and calculate the compression ratio then have the head skimmed if needs be.

 

An over ported head on an otherwise standardish engine will lose you performance. 

 

I bought mine from Turbophill on here, he spent ages with me asking questions about the rest of my setup before he would sell me a head.

 

AC Dodd is another really good option.

[brivinci]

Yes, MUCH better to go and have a chat with a head-guy to get exactly what is needed. I used Keith Calver and can't say enough good things. Like others have posted, these guys know their stuff and will sell you a head that will work with what you have, not just the most expensive (and usually unneeded) one. 

 

Would be a good idea to do a compression test and leak down test before you pull anything. So you have a better idea on the condition of the motor.

[CarsOrBikes]

The 1.3:1 rockers are standard lift, you might want 1.5:1 which give some lift, and are what JCW used to fit.

 

Stage four may be fine for the road, then different companies refer to different specs when naming their version of a 'stage'

[brivinci]

Even though standard rockers are stated at 1.3, Calver said he has never seen a set that actually is 1.3. They are closer to 1.2. That is why a proper set of 1.3's isnt just upgrade in quality but sometimes in performance...be it slight.

 

If you are not doing a cam though, fitting 1.5's would add a bit of performance.