Type 1 cylinder heads

[AccidentalGenius]

I have found myself in a bit of a pickle and i am not sure what to do for the best...

I have been buying engine parts over the last year or so (as i could afford it) and i have almost got everything now. The last thing i ordered was the cylinder heads which were the CB Performance 044 Magnum in a 90.5mm as i am building a 1776 engine.

The dilemma i have is that VWHeritage only had 1 in stock so now i am waiting for the other to arrive in stock, which will be a couple of weeks. While i am waiting and getting impatient i started to look around and i have found the CB Performance 044 Panchito cylinder heads are only about £80 more (each). In researching them they seem to be a better head, but i am not 100% sure of that, and if it would be noticeable with my particular setup.

I now don't know if i should wait for the original 044 Magnum or send back the one i have and get the Panchito instead... By the time i have done all of this i will not have saved any time, so the real question is should i change the head for the additional cost or not bother?

Can anybody help me make this decision as i am not technical enough to be able to understand the difference this might make to the engine and its drivability.

In case it matters, the rest of my components are;

- SSP H-beam 5.5" Con Rods
- 69mm CB Forged Counterweight Crank
- SSP 6 Kilo flywheel
- Empi twin 40 HPMX Carb Kit
- Mahle Forged 1776cc Barrel / Piston Kit
- Scat C35 Cam
- Scat 1.1:1 Ratio Rockers
- Pertronics Flamethrower

Thanks

[Nige]

I don't know the difference of either really, but for the sake of not much more money or time I'd upgrade. You've obviously put a nice group of components together and if you go with the lower spec heads you'll always ask yourself what if.

Why don't you ask your engine builder or drop an email to CB Performance.

[AccidentalGenius]

Yes, very fair comments Nige.

I think the thing that has made me stop and think more than anything is that i hadn't realised the role the cylinder head could play in moving the power band... i thought this was more to do with the length of the stroke and the cam... but i am more worried about having no low end power to use when driving around town etc...

I am clearly a novice, reading lots of things and trying to understand what it all means. But speaking to the engine builder is obviously the best idea.

[Nige]

Who's doing the build?

[AccidentalGenius]

I think Limebug, just waiting for Craig to get back to me with the quote. If not it will likely be Afonso as my brother is using them/him to build an engine for his '73 Fastback.

[smallspeed]

If you're after torque lower down, don't go crazy on port sizes - I can't talk much regards vw engines, but certainly a lot of the BMW heads I've worked on for road cars I've added back as much (if not more) material than I've removed. High RPM is another matter, but that's not really what you're shooting for here..

One of the biggest factors in the shape of the power/torque curve (after cams) is intake length and diameter of the inlet tract - in general long / thin = low RPM torque, short / wide = high RPM power
There's a really interesting (some may dispute this term) article here by Emerald ECU's with testing to prove this point..

http://www.emeraldm3d.com/articles/emr- ... th-intake/

The length is measured from the back of the valve to the end of the runner, so this is affected by the head layout as well as what you bolt to it - on a VW Type 1 you're going to be fairly limited to the length of inlet manifold / carb you can get off the shelf, but it is worth paying attention to what you put on top of it (long velocity stacks into air boxes, short ones into filters, etc). Either way, don't go crazy on massive ports - provided they're big enough to flow the air into your engine, they will be good enough - adding 10-20% port area isn't going to turn a dog into a rocket ship

Ultimately (and I mean no offence by this) the engine you're building isn't "out of the ordinary" so do a bunch of reading up on what other people have used in the past with your combination - 69mm stroke, 1776, scat c35 or equivalent engle (120?) and their opinions on it - while butt-dyno's are notoriously unreliable at doing numbers, the average of several different butt dynos should give you a pretty good idea how various combinations perform..

hope that helps

[AccidentalGenius]

Thank you, that helps sooooo much!

You are quite right in that the engine i am building is relatively standard/common and that is one of the reasons i chose a 1776 because i believed it was a sensible mix of reliability and performance.

I genuinely had no idea about the intake length, and typical me was looking at an airbox/filter solution that i thought looked good, completely oblivious to the fact it could affect performance!!!

I had read about people changing their intake manifold length and thought that was just to do with the fuel staying atomised or something... I also read about compression ratios and have no idea what this is about to be honest, and therefore what difference it makes or how to affect it.

I will read the link you sent when i get out of work and can think about it fully!

[Bruce M]

With aircooled VWs, the aftermarket intakes are mostly designed to fit the packaging problem.

Heads are a big part of the combo for Type1 engines. The stock version is pretty restrictive unlike most modern engines which are harder to improve on, in that area.

I'd be wary of the carb kit. It will work but you will find it difficult to get the tuning spot on. They are not made to the same standard as real webers or dellorto carbs but then again they are a lot cheaper so...

[AccidentalGenius]

Thank you everyone for your help.

I did in fact speak to my preferred engine builder over the weekend and he convinced me of the following;

1) The Panchito cylinder head is the best off-the-shelf head on the market
2) If it was a straight decision between the CB 044 Magnum and the Panchito then go for the Panchito (if you can afford it)

However....

We discussed my engine in detail, and specifically how i want to use the car, and realised that producing peak power at 6000 RPM+ is not really what i need to be able to have fun in my car on a normal drive. My version of what he told me is as follows;

if i increase the valve size on my 1776 engine i am going to produce more power at 6000 RPM+ but i will lose power at the lower rev range which is not great for a daily driver, especially one with a freeway flyer gearbox in due to the gear ratios.

I think the details to why the you lose power at the lower rev range is to do with the speed at which the air travels through the valves? So a bigger valve can ultimately flow more air through it at higher revs (because it is bigger) but at the lower rev range the air flow through the valves is slower, giving you less power.

So we have decided to go for a head with standard sized valves (ideally an AA Performance version) but to do a competition valve job on and some pros work to the heads and manifold to increase the flow of air as much as possible.

This SHOULD give me lots of low end torque and a nice drivable engine that will happily rev up to 6000 RPM

I will of course let you know once it is built and in the car.

[KS]

Having built more VW performance motors (and written books on the subject) than I can remember, can I throw in my two penn'orth? Your engine is a pretty mild spec and either head will be fine. Unless you plan on increasing capacity at a later date, stick with 40mm x 35.5mm valves. The port volume on both heads is pretty modest, so port velocity is pretty high and they'll give plenty of torque. DON'T use stock sized valves - they are way too small and to all intents and purposes designed to restrict rpm on a stock engine. I built several 1776 motors for customers (plus plenty more far bigger, up to and including turbo race motors), and most were similar spec to yours but always with 40 x 35.5 valves. You'll kick yourself if you went stock... Seriously. Just don't do it. I'm genuinely surprised you've been advised otherwise. You will have plenty of drivability, so don't worry.

[Nige]

What Keef says! What he doesn't know about those motors isn't worth knowing.

You've been told now and it's instant forum ban and eternity on the naughty step if you do otherwise.

Surprised those heads come with standard size valves as an option.

[smallspeed]

[AccidentalGenius]

Oh god the pressure!!!

[Nige]

I have a well thumbed copy of this at home, you are welcome to borrow it. It's not a bad read