Ok as some of you know i'm after a Stage 3 head (ported/polished, big valves, bronze guides, 3 angle Valve Seats, etc..), I emailed a few places regarding headwork spec and prices, and i've had some conflicting information!

Ian Howell from Area 6/Fiesta Frenzy said:

"The inlet port is too big, and the exh valve is too small.
Flattening the guides and modifying the seats will give you significant gain without doing actual porting work"

David Baker from Puma Race Engines says:

"The CVH responds very well to big inlet valves, The exhaust valves are actually far too big as standard Under no circumstances fit larger exhaust valves and any tuning firm that does this can be safely avoided as they have no clue how to modify this engine properly"

Andy weston from Cylinder Head Developments says:

"my ultimate big valve fully ported and flowed RS Turbo head has 43mm inlet and 38mm exhaust and are stainless steel"
So is increasing both inlet and exhaust sizes!

It was always my belief that the inlet side of the CVH head was most restrictive and not the exhaust, but Ian Howell has a good reputation and so i'm confused!

Does anyone have any opinions/experience regarding this as i want to get my head worked corectly!!

Cheers!

 

All tuners have their own ways of doing things, there is no right and wrong answer as such IMHO.

 

Thinking Laterally here...

Norris Motorsport and AP Tuning both have the fastest CVH's around, so phone them and ask for some head advice as they seem to be doing ok on theirs and should be able to offer advice on flow versus your required response as massive power heads do not usually make good heads for low end traction work.

 

Ok thanks Stu, will do!
So a high flowing head will give BHP gains at the cost of low end torque, similair to fitting a very agressive cam. I dont really want to gain any more lag so perhaps big valve and porting isnt the way to go, maybe one or the other?

 

What power are you after? I don't think you need a big-valve head to be honest.

 

Well Christian i'll be coming to you for a setup as soon as i get my head so your advice is very welcome!!

I'm looking for between 220bhp and 240bhp, my current spec is:

Rebuilt Standard Bottom end, with ARP bolts and ACL Bearings/Shells
Stage 2 T3 (exh 36 comp 55 IIRC)
Radtec FMIC
Apexi AVC-R
Ahmed Chipped ECU
AP Racing Clutch
Magnex SS Exhaust
K&N Filter

Head as yet unkown, but i'm thinking of running a standard cam so as to keep as much low down torque as poss (and they are cheaper to replace when they fall apart lol)

I am aware that my rods are on the limit around that sort of power and also that it depends on how much my metering unit can fuel for!

cheers!

 

IMO you dont need a massive head for what ur after but im sure karl would be able to help you be aware that Good head work aint cheap

 

save the money from what you would have spent on a ported head and put it toward aftermarket managment imo

 

Great idea if I had not already sold my head
I'm going to be building a all steel bottom end over the next year and changing management when that gets fitted to run some real power

Waiting on Christian's reply as to what to do cos APT will be tuning it!

 

Valves are pretty big as they are. David baker is more biased towards N/A engines it should be noted. Biggest gains are had from valve seat and throat work.

Rick.

 

[QUOTE=Karlos G;4013848]Ok as some of you know i'm after a Stage 3 head (ported/polished, big valves, bronze guides, 3 angle Valve Seats, etc..), I emailed a few places regarding headwork spec and prices, and i've had some conflicting information!

Ian Howell from Area 6/Fiesta Frenzy said:

"The inlet port is too big, and the exh valve is too small.
Flattening the guides and modifying the seats will give you significant gain without doing actual porting work"


funny how ian says prety much what i said to you last month!! and you said i was talking shit and you tryed to teach me all about how a head flows .

 

Ask yourself this... how would you go about developing a head without a flow bench or engine dyno?

I'm certain that one of the guys above has neither so i wouldn't take his advice.

 

That will be C.H.D then

 

IMO, just change the valves to stainless jobbies and to freshen up those tired std ones (larger inlets) then just open up/smooth the seat diameters on the inlet valves. This is all thats needed in my experience

 

Ultimately there's always going to be a difference in opinion on subjects like this...not every tuner does things the same do they?! They may well end up with the same bhp but doing things a totally different way, i'd choose someone with proven cars/experience and stick to their advice. I''ve got a mate who ports my heads, no one on here will of heard of him obviously but doesn't mean he doesn't know what he's doing....though from what i've seen of some 'tuners' work he probably has alot more knowledge than them lol.

 

The CVH inlet ports are tiny compared to the valve size 32 port vs 42 inlet valve size

Ian howell gets Jim G to do his top head work

 

Ive just had my head done at Cylinder Head Developments! Awesome job Andy did and a top bloke!

 

karlos you will need to figure out how much air the engine will need to consume at a given psi on the turbo your using to reach your intended bhp figure then see whether or not you need anything doing to the head to make sure it can flow the amount of air. personally i'd of thought the metering head is going to max out before the standard head or cam will in you pursuit of power, your going to need fifth injector or some other efi conversion too with what your planning, if it was me i'd efi it now and see what power you can ring out of your standards with around 20 psi through your stage 2 then you will know whether just to change cam or head or both and everything you do now will be able to be used when the steel bottom end comes along

 

I did the head on my S2 a few years ago, mainly because i was bored
I was already running a bar of boost, and had rebuilt the bottom end the previous year with some fancy bits, all lightened and balanced too. (Still on MFI)
Andy Weston the headwork, and although i didnt go for one of his "Ultimate RS Turbo" heads i had the maximum he could do without bigger valves. He also fitted a Kent CVH35 IIRC.
For £700 odd outlay on the head, plus gaskets, bolts etc that really made it the thick end of a grand, all i gained was a whopping 7bhp and shoved the useable power further up the rev range. Yay!
I'd like to think i need to be running more power to make the most of it. For what i wanted it for, it wasnt worth it TBH.

Incidentally i just rebuilt another engine for another RST, and one thing you can do yourself is to dowel and match the inlet / exhaust ports. The one i've just done was shocking! The head ports overlapped the bottom right quadrant of the inlet ports by a good 5mm... Soon put that right!

 

So many mixed opinions and information!
I think what i'll do is refurb an old S1 head i have here with new SS Valves, Guides if needed, springs, stem seals, cam/lifters, reface it, and clean it all up (including oil ways!), and see how it does with that!
No point spending money I dont have to right now, and maybe look at it again when i have my steel bottom end and EFI ready to go on.

Anyone know a good place to get SS valves from? I've looked about online and can only find standard ones.

Thanks for all your input

 

I borrow the thread, can you advice me how big different would be
STD ERST Head or STD EFI escort head used in escort rs turbo?

 

I think they are the same performance but inlet ports are different shape for injectors on EFi head.

 

Karlos, I have a very nicely ported / polished head for sale. It's my original head, not the new 1 I've just bought. It has a porblem tho, it rattles/knocks around 2000 rpm It's fitted with a piper285 cam but this could be worn causing the noise but I don't know for sure. I'll put some pics up for ya

 

Thanks adam PM them over to me and i'll take a look!

 

I don't know how to check valve angle seats

 

This is a much nicer job than the head I've just bought!

 

My NMS head gave me 210bhp @ 11psi @6000rpm with power still climbing, compared to 210bhp at 17psi i was running before. On the same day as i did the 210 11psi run, another engine i'd built with a std head running 18psi did 200bhp. The gains only get bigger when you increase the boost. It also lowered my boost threshold by nearly 500rpm.

Rick.

 

Anyone know a good place to get SS valves from? I've looked about online and can only find standard ones.

Thanks for all your input [/QUOTE]

I got my oversized stainless valves from Burton Power mate. When i had my head ported and added the newman cam/solids, as well as making more power, it made the engine 'rev' so much better, my engine makes power up to the 6.5k limiter which tbh it never did before.

 

gis a shout if ya want any more

 

Good comparisons Rick cheers!
It lowered your boost threshold by 500rpm!! I thought if anything it would have raised it as a result of a drop in port velocity? So it must have felt more responsive and less laggy than with the standard head?

I'm aiming for 220-240bhp depending what my metering unit can fuel for really, so my boost will be whatever it needs to be to make that power vs the VE of my engine, but what i dont want is more lag as a result of having a high flowing head as Stu has suggested.
I want a balance between flow and response, I dont want to run too higher boost as this will give me higher temps, increasing flow will drop the boost and as a result the temps but i dont want to lose response

I'm thinking maybe a ported head but with standard valve size's?

What was the spec of your NMS head?? If they can supply me with one that gives me more response low down (drops boost threshold) and higher flowing then thats the way i'm going!!!!

 

they are all good tuners i would go with area six or cyclinder head developements my only problem is are you still running mfi or efi as you got to get anuf fuel to get the power ur after ive had a mfi rst an 219bhp was its safe max before it run lean if your on mfi then your still looking at getting a fifth injector kit or management to get them figures but when you do they are brilliant so good luck mate bits are cheap at the mo as i just got full cossie management for £251 on ebay

 

its more to do with getting the right shape of the port than the size

 

I'm going to call NMS tomorrow and see what Karl says, with Ricks comparisons i'm sold on his work for sure!!