New Design Type 4 Heads

[Paul H]

Hello

Just toying with the idea of producing some new affordable heads for the type 4 engine.

Yeah Yeah heard it all before I know but this is a serious idea.

Just a few questions for the type 4 people.

Do we make the exhaust ports like a type 1 ( I say yes)
Do we alter the pushrod tube entry point more like a type 1 ?
Do we alter the rocker mounting system to cater for more type 1ish set up?

The heads will be die cast of similar alloy to the original VW and as the cad work and tooling will be close on $30k we need to get it right and to cater to the masses rather than radical modified stuff.

Fire away

[gilbequick]

With exhaust ports like the type 1 that sure would make it easier for a lot of people to match up an exhaust. Type 1 style exhaust systems are PLENTIFUL.

Changing the pushrod tubes would make it easier to replace them if they get damaged with the spring loaded ones, but I don't think that'd be a big selling point. Unless you're going from a parts availabilty standpoint.

[Unkl Ian]

How much dyno testing do you plan on doing ?

[jrandy]

Some friends of mine ran a de-stroked 1700 T4 in a 1600cc circle track car.
I ended up owning it for a year or so, but never ran it.
The racers worked in a machine shop and one of the guys was really good at welding aluminum. He welded up the heads and gave them T1 ports so that they would flow better, use a T1 header, and fit the class which was limited.
The rocker shafts were modified 2ltr parts & used custom spacers.

I wish I had kept the thing, but I swapped it out for some other parts to an dis-believing Porsche repair shop & Volks Authority before they closed.

I think keeping the rockers and pushrod tubes T4 style would keep the parts common & the T1 exhaust ports would make the heads easier to use in the bugs the built T4s are going into.

[bj]

i would say that if the heads flow well and can take abuse from improper tuning etc... i would say that they would sell.

T-1 ports = in my book. upright exhausts are expensive!!

changing the pushrod tubes....i would say leave alone. otherwise custom work will have to be done to the block or custom PR would have to be made, adding to the cost. besides, makes checking of lifters a lot easier...going through that right now

geometry, same as above for PR tubes.

also, i'd like to see what the definition of 'affordable' is in terms of the heads. everyone has their own definition/budget.

i really appreciate the efforts you are making in this hobby/industry.

bj

[Paul H]

Thanks for the replies

We are thinking initially $800 a pair complete with some fairly decent valves,springs and retainers. Once tooling cost have been absorbed then they would be less.

Regards to dyno tuning they will be getting a good work out but at that point the dies will be made so the outcome of dyno testing would not change much but as power comes from the size and shape of the inlet exhaust tracts and chamber design it's no big deal to make a few different sand cores for the ports and write a new program for the multi axis CNC milling machine to zip the chamber out. These sort of mods can be done on batches as low as 50 heads.

[dawie]

Make provision for twin spark plugs, so that it can just be drilled and tapped later if needed.

Maybe increase the cooling surface area. If it has better cooling than a standard t4 head it would be an advantage. Then less energy is needed by the fan.

T1 exh ports is a good idea, t1 exhausts are cheap, but doesnt that port position block some cooling air that normally flows in that position on a t4 head? On the other hand bottom of heads should be cooler with the absence of the exh ports there, and it should be easier to fit twin plugs.

Another idea would be to have chambers similar to the 2.1 wasserboxer DJ series high compession engine. That has far better efficiency,allowing a higher compression ratio to be used with reduced knock tendency.
Advantages are: more power, reduced fuel consumption and lower emissions. Also runs cooler while giving more power,as more energy is converted to power and less wasted heat to get rid of.
Wasserboxer dished type pistons would then be needed, wasserboxer has 24mm piston pins like t4, not sure what the pin height is.

[Wally]

Hello

Just toying with the idea of producing some new affordable heads for the type 4 engine.

Yeah Yeah heard it all before I know but this is a serious idea.

Just a few questions for the type 4 people.

Do we make the exhaust ports like a type 1 ( I say yes)
Do we alter the pushrod tube entry point more like a type 1 ?
Do we alter the rocker mounting system to cater for more type 1ish set up?

The heads will be die cast of similar alloy to the original VW and as the cad work and tooling will be close on $30k we need to get it right and to cater to the masses rather than radical modified stuff.

Fire away

If you are really serieus, I will give you my thoughts, but I am not sure they agree with your ideas, which seem to be already somewhat made up...(?)

Type 4 heads with type 1 style exhaust ports already exist for many years. Hell, there are even two kinds made and I don't think you will improve much on those...
I know thay are much more expensive, but $ 800,-- for a set of new type head castings is hardly to be taken seriously if they would be of any quality at all. With quality I mean not throwing away one of the main benefts of the type 4 head casting: cooling ability!
A set of type 4 heads that would look and cool like a solid Eliminator casting or something like that would NOT be an asset to the type 4 community imho.

A cross-flow head style that a type 4 head really is, has been made for more than one reason by VW. One of them is torque producing.
The rigid idea that a type 4 exhaust port flows less than a type 1 head is really, really been outdated!
I and some others have 'proved' this by using a stock 914 head casting and with NO WELDING done produced 220 hp in N/A form!! The exhaust ports were also only touched very limitly.

Actually most of the things you opt to change out are benefits to the type 4 over the type 1. The fixation of the rockers for instance: the type 4's 4 studs are WAY better than the 2 studs the type 1 head uses!!

The only thing you mention that would help abigger exhaust on a type 4 somewhat is a slight moving of the pushrods so that a larger exhaust header could fit more easily.
Not mentioned, but an item of a type 4 head that could be improved upon is the stiffness of the head itself. Due to the uneven head stud location, warping is always close by with a type 4 head, so more strength in the head at the right location AND a better aluminium sort would do some real good for tuning with large bores (103's).

The twin plug remarks are spot-on as well of course

You really are prepared to spend $ 30K on a start-up? What parties are behind this idea then? So I believe this is serieus or just day-dreaming.

[Paul H]

Good information

The difference between this project and others is that the tooling will be a cast iron die these are good for producing large quantities of high quality castings. The die makers and casting company here are suffering a small recession and have lost a lot of buisness to the far east so they are seriously considering these smaller projects.
After some thought I'm leaning towards stock port configuration but with some extra material added here and there to allow better modification potential.
Dual plugs falls in the "radical" section but if it's just a matter of adding some material in the right place then it wouldn't be a problem

We'll slicing a head up soon and getting the alloy tested to see what VW used.

[Wally]

Ok, thanks.
You could also look into the alu that AMC uses for new stock type 4 head castings. That alu is considered an improvement already at the moment as opposed to alu that vw used.

As far as plug location, I'd consider only making the 914 2.0 configuration, as this is really the best. The head intake you could still leave 4-studs if you'd like, so most anybody's intakes (as most are 4-stud) would fit.

Since you are in the UK, I'd suggest teaming up with a type 4 engine builder that has a decent bit of experience building type 4 engines, like John Maher as this should be done 'right' the first time

[Paul H]

I hope that AMC have improved things as one of our reasons for producing
a head useable for stock aplications is that the AMC is prone to valve seat sinkage and softening around the barrel seating area rendering them scrap after only a few miles-and this is recent information. The VW alloy has proved itself over the years so just a matter of getting the correct heat treat

[L.A.R.D]

Ok, thanks.
You could also look into the alu that AMC uses for new stock type 4 head castings. That alu is considered an improvement already at the moment as opposed to alu that vw used.

As far as plug location, I'd consider only making the 914 2.0 configuration, as this is really the best. The head intake you could still leave 4-studs if you'd like, so most anybody's intakes (as most are 4-stud) would fit.

Since you are in the UK, I'd suggest teaming up with a type 4 engine builder that has a decent bit of experience building type 4 engines, like John Maher as this should be done 'right' the first time

he,s already teamed up

[Piledriver]

Kudos for motivation, but I'll have to agree with Wally for the most part, the primary reason VW and Porsche put the ex on the bottom of their later air cooled engines is COOLING, the T1/356 style ex port limits the cooling airflow uniformity through the head seriously.. The bottom gets hot too....

What kills ACVW head castings is HEAT, regardless of the exact alloy. Aluminum has its limits.

I agree that it would be nice to be able to slap a cheap T1 header on it, but failure of the aftermarket to mass produce T4 headers (due to lack of volume) shouldn't drive engineering decisions... Make a good, cheap one and it will sell. It's NOT rocket science.

The 2.0 Porsche heads design "issues" are pretty well understood, but ~all of them could be eliminated with extra meat in the castings in the right places, esp depth around the deck, and a little extra meat in the right places around the int and ex ports/bowls would allow extremely serious performance.

As to the ex port: If anything, change it to a D port and increase the short side radius. It wouldn't take much to raise the whole thing bit either, and the added meat under the port (between the port and the chamber/sealing surface is a weak point) would be an added bonus of both raising and a D port config. How BIG it is is secondary to how it flows...

If your die allow limited casting shift, consider the Squareport style ex ports, they can be made into std ovals by simply removing material, and they add meat in critical areas and move the ex studs out from under the chamber.(esp if raised)
Also increases the adaptability of the casting: AMC does this.

A tiny amount of material added where the third stud goes (just ~copy the 2.0 Porsche casting in that area) would allow the heads to be drilled for 3 or 4 stud patterns trivially (just not at the same time)

I second the dual plugs--- A little meat cast in in the right place is all it would take to allow it. When making new castings, it would add ~zero cost. Also consider relocating the 2.0 plug a tad and using a 10 or 12 mm plug...

One more thing that should be considered is when adding additional material easing using equal length studs with barrel nuts at the head/plugs in the rocker box.
(Can't find the link at the moment)

A little extra meat in just the right places could do wonders.

[Unkl Ian]

Thanks for the replies

We are thinking initially $800 a pair complete with some fairly decent valves,springs and retainers. Once tooling cost have been absorbed then they would be less.

Endyn is selling repop Honda 4 valve cylinder heads,complete with valves springs,and retainers, for around the same money,so it is definitely possible.

[Piledriver]

Thanks for the replies

We are thinking initially $800 a pair complete with some fairly decent valves,springs and retainers. Once tooling cost have been absorbed then they would be less.

Endyn is selling repop Honda 4 valve cylinder heads,complete with valves springs,and retainers, for around the same money,so it is definitely possible.

And they look like very nice heads, too...


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