Having the engine rebuilt at the mo, due to a bit of a disaster.
Anyway, found out that my stage 2 head could be beyond repair, and even if it is repairable it could cost a bit, unless anyone on here knows someone? Good job, good price.

Another question is that if just a standard head goes on, is this going to affect the performance in a bad way?
Ive heard before that the C & B cams (which is something I have) work best with headwork.
Anyway any comments and help is much appreceiated....

Well before all the guys come on here and say go to guy croft. I will ask what sort of power are you aiming for? The standard head is quite good and if you lightly remove the casting marks you will benefit. I am not impressed by the C&B cams but if you already have them then the head can be worked to match you cam timing. There are many machine shop that can do light porting but to open the head up further you need an expert with a flow bench etc, this is where i draw the line because i want a road car not a race car.

Well I think Im limited with power because of the turbo I have (RSR) but still 350ish bhp is plenty for me and like you I just want a fast road car not a race car.

So what do you think If I had no head work at all.

Personally I doubt you need head work at that level, I've seen 400 on a stock head and C&B cams

But as with everything, a better head will flow better, develop the same power for less boost perhaps

If you can afford headwork as well, go for it - if you can't it won't stop you making 350 bhp levels

If that’s the case then suggest just removing the casting marks, this should cost around £300.

Spend the money on nice seat angles and new faces on the valves and maybe a bit of bowl blending before worrying about the casting lines would be my call. Who you get to do a nice job is another matter all together.

I'm not sold on the C&B's either

Nik

What, so as for the cams, leave them as standard??????????
I have got a standard set, and I could do with the money by selling the C&B cams.??????

Do it. Sell the C&B's I have never seen then make an impact for me to rush out and buy a set.

I wouldn’t mess with the valves or seats. Just clean them up and removing casting marks including the bowl. This is the best in terms of gain for money value.

On my car DrFrag had a RR before and after the cams and saw 10lbs/ft more throughtout the rev range with the cams.

Keep the Cams. Alessandro and I had virtually identical cars at one time and I noticed the cams did make a difference. The car felt like it pulled a bit harder when coming on boost.

Keep the cams as you have them already, you will sell them easy enough, but at a lost. They will make a difference, possibly even more of a difference if you can take time to play with the came timing a little

I would be interested in seeing the print outs from them RR sessions before and after the cams were fitted, also i would not mind betting that they increase spool up time

don't get me wrong, I'm sure cams would yeald a performance advantage but i don't think the cb cams profile is all that good, especially in a near to standard head, they need to offer a wider range of profiles


Also for peice of mind squids car made over 400lb-ft and over 400bhp with standard cams and a fairly mild porting job


In a ideal world you would design your head work around your ambitions, the port size Is governed by valve size and valve size is governed by space constraints and the amount of flow you need, not to mention that cam lift and duration control that valve and there is no point in having loads of lift if at that lift your going beyond what the port can flow


In short to get the best setup you should work around what your requirement are and in a lot of casses that sometimes means you don't need massive ports or valves or even cams


Porting heads is really very difficult to get right and very few people can actually do a good job but what alot of the bad ones do is enlarge the ports to the maximum and that does in most cases give you better peak power but it completly ruins the drivability of the engine and low down performance

ricky

I can't see photobucket from work so I don't know if its still there, you'll have to let me know. But this should be the link

http://i4.photobucket.com/albums/y148/sur1ps/Group%20Buys/CBcamsvsoriginals.jpg

It's not working mate, I would love to see it so if you can sort it please let me know

I do have back to backs on the cams but it will take a small miracle for me to find as it was a long time ago. But there was head work already there and the turbo wasn't delivering its full potential. It did improve spool up I think that was largely due to the ramp rate being more agressive as I vaguely recall.

Marcus made 380BHP with an RSR 0.64 @ 1.5 bar (I think that was the boost), C&B cams and some headwork. It also had a forged bottom end so it was safe. It was a good car to drive and a really good compromise between spoolup and power. That was without proper mapping as well, it just had the fuelling matched with an adjustable FPR.

Of all my engines (!) the first was my favourite, standard head, C&B cams, T34 (1.6 bar) - 413bhp, 390 lb.ft and so tractable. None of the engines since have been so nice to drive

But have never tried one other than totally stock engine without uprated cams

Not sure what to do........
At the end of the day havent got much choice really, because I havent got the money to have headwork done, maybe as TurboJ said £300 worth even that is a bit much for my liking after spending the amount of money that I have alreday spent on everything else.

Might have to just leave the C&B cams and leave the head standard.
At the end of the day, ill still have one of the best turbos around (RSR)(In Fleas view anyway) all forged with aload of other top end supporting mods.

The quickest way to improve the quality of flow is by providing the valve seats with the correct angle, diameter and width to suit the valve. I'm not familiar with the 20v head as it comes from the factory but the 16v usually has a horrible step at the bottom of the valve seat inserts which cries out for blending into the port, thats the next best thing to do in my opinion as inevitably a little bit of easing of the SSR goes hand in hand. The casting lines aren't helping I agree but they'd be third on my order of things to do, this can and should snowball into a proper bit of port work but then budgets getting away from you unless you have a DIY at the dingle berries.

It's just I don't see myself buying C&Bs rather than them being inferior, they work plenty fine for lots of people. I can only look at it from the 16v point of view as thats what I'm interested in and for my money and taste there are other camshafts I'd prefer to buy. Admittedly very similar in duration numbers but I am drawn to the change in timing numbers along with the lobe centre line change amongst some other subtle differences.

Keep your cams I'd say unless you really want the money, They look to be pretty purposeful having had a little look at the website. A little look is enough to cause brain melt down, it's not an easy subject by any means It's all i can do to get feel for the 4cyl without confusing myself looking at that cam and its use in a 5cyl!

That car made 380 with with the NOS and at powerstation dyno? No way could it make that with that turbo.

1NRO your spot on with what your saying but as the standard head is so good it's very difficult to gain any real gains from just the seat and valve, not really for the diy'er, well beyond what I'm willing to undertake anyway

all in all there seems to be ways to improve the 20vt head in every area but they are small improvements in lots of areas rather than big gains in any one area, I can only put it down to fiat doing a great job to start with


You should read guy crofts thread on the 20vt head, it makes great reading and can explain what I'm trying to explain a lot better than I am


After looking at the head my self my view is now that either get a pro to do it or pretty much leave it alone unless your skilled at porting heads and while I can port heads I'm not skilled enough to get the best out of 20vt head

ricky

It did make 380 (well 378) WITHOUT nitrous and 408 or something like that with nitrous. It had a stage 4 head with big in and ex valves

It was dynoed at PTS Luton and running 1.8bar boost. It was certainly fast and managed to run a couple of 12.7 quarters with the nitrous.

Whats your views on all this Flea? You map cars, what do you think please?

Matt's Head work




I think guy got 14% more flow.

It's a great thread Guy did, I've watched it at the time. Just looking through it again in a hurry it looks to me like half of the gains in airflow came at the beginning with the seat work which although Guy is talking himself out of work in his conclusion shouldn't stop people getting him to do just the seats. Having just got my DIY head back from him he does a crisp job in this area which along with the back cuts on the valves and the lapping involved doesn't break the bank, fair job for a fair price imo (having paid a couple of times to have such work done by others only to be so disappointed I didn't have the strength to complain).

You don't honestly believe this do you? No way can it run an RSR with 0.64 housing at 1.8BAR, unmapped with std injectors and produce 380BHP. I smell pub figures. Come on people are struggling to break 400 with gt2871’s.