New Design Type 4 Heads

[Piledriver]

Wally: No I have NOT tried it, because I wouldn't even consider it unless it was absolutely required for packaging reasons.

I haven't yet been forced to do it wrong.

I would probably cut/box the car first, or just run carbs for that vehicle.

If you wish to spray directly at the port wall and it works for you at WOT, and that's all you care about, knock yourself out.

Just because something "works" does not remotely mean it is correct or the best solution. It also does NOT mean the right way is only "theoretical".

Regardless, a second (or even third for NOS) set of injector mount bosses precast in manifolds for those few running staged won't hurt, or cost more at this stage.

[Piledriver]

Here's the latest version with outboard injector boss and stud pattern for bus.
The hole for the bus head is 12mm diameter for a barrel nut and cuts right through the wall. The tract on the casting will be a lot smaller so it will probably go with some die grinding and if you want a massive port on a std head then you are in for some serious welding and grinding anyway.
What do you think of the raised pads on the flange to make access easier?

Nice.

Might want to try bringing the bolt boss on the outside studs all the way out, and use long bolts or such.

[Paul H]

Yes I can bring the boss out but it would have to come out 85-90mm before it would solve the problem

[Wally]

What do you think of the raised pads on the flange to make access easier?

Its a compromise in such a way that the preferred way is to use studs as the head is alu. This solution would require larger stud length and even more room sideways therefore.
Thicker footprint of this manifold is a good thing for stability, but not mounting wise imho.

[Paul H]

The footprint is exactly the same as the mounting flange on a 914 head and use of long studs will cause problems getting them off in situ personally I'd put inserts in the head and use allen bolts. The toolmakers usually get the final say on the detail "go" or "no go" on certain features

[Paul H]

Couple of Q's about the heads

1 Rocker box-does it really have to be that shape and would a different design be welcomed with some new bolt down covers-the way the pushrods enter is pretty bad
2 Intake flange can it be moved away from the rocker box by say 4mm as the spring seat cut is very close to the port
3 Rockers -could type 1, 1.4 rockers be made to work-depends on distance between push rod and valve-I haven't got any rockers here to look at yet.

4 What's the part number for those 10mm spark plugs and any objections to using 12mm plugs in the normal location ?

So far the type 1 exh port is looking real good, the thick wall intake tract is also looking good just the little interference with the head nut washer.

[Piledriver]

Couple of Q's about the heads

1 Rocker box-does it really have to be that shape and would a different design be welcomed with some new bolt down covers-the way the pushrods enter is pretty bad
2 Intake flange can it be moved away from the rocker box by say 4mm as the spring seat cut is very close to the port
3 Rockers -could type 1, 1.4 rockers be made to work-depends on distance between push rod and valve-I haven't got any rockers here to look at yet.

4 What's the part number for those 10mm spark plugs and any objections to using 12mm plugs in the normal location ?
.

1: Not unless you plan on using T4 valve covers (and PR tubes) Custom covers add to the cost. It might be easier to make "hybrid" t1/T4 tubes, but then the heads have to come off for a reseal, not having to do that is one of the features of the T4. I'd try to keep the stock setup unless it's a show stopper and the alternatives are cost effective and reliable.

2: Smaller OD springs provide more clearance.

Came across some duals for a MC the other day that are ~1.2" OD, 1.550 installed height, and allow .770 lift...
(might be a typo.. or not)

I'm sure PSI has or can make some springs with <450 lbs over the nose (pro stock OHC drag bike springs, so less would be desired, perhaps just the outers?)

http://psisprings.com/index.php?option= ... view&id=20

The 2.0 Porsche intake shape is fairly close to "ideal"...
Some effort should be considered to scan it in and "scale" it in software for later CNC reproduction with larger valves. Major changes to shape are going to need a good head guy to work out/validate.

3: The 10mm plugs are pretty common and available in many heat ranges and brands. It's the 8mm plugs that are a bit hard to source...
12mm most common and should be fine for MOST apps.

One more bloody thing to think about, not sure what your plans are for plug location or chamber shape, but there ARE better chambers than a 2.0 914... Since ~everyone T4 runs flattops or dished, a late model Ford or Chevy Vortec>late LS motors shape might be an option. (also make sourcing pistons a bit of cake for the large bores for those that actually might want domes)

[Paul H]

From what I understand the bugbear of the T4 is leaking pushrod tubes and rocker covers and what I can't understand is why they designed the pushrod entry point half in and half out unless it was just to keep the rocker box flange area as small as possible to enable use of a cheap clip on cover or just to keep the rocker box as small as poss for engine bay contraints. Producing a decent cast rocker cover is easy and cheap and the spring loaded machined pushrod tubes with o ring seals work fine on the type 1's and can be changed with head on. Most of the time the only need for removing a tube in situ is because it's leaking

[Piledriver]

From what I understand the bugbear of the T4 is leaking pushrod tubes and rocker covers and what I can't understand is why they designed the pushrod entry point half in and half out unless it was just to keep the rocker box flange area as small as possible to enable use of a cheap clip on cover or just to keep the rocker box as small as poss for engine bay contraints. Producing a decent cast rocker cover is easy and cheap and the spring loaded machined pushrod tubes with o ring seals work fine on the type 1's and can be changed with head on. Most of the time the only need for removing a tube in situ is because it's leaking

Most of the spring loaded T1 PR tubes are junk. The good ones are fairly expensive.
Good+custom T4>T1 "hybrids" are ~ guaranteed to be expensive, although the guys using the other HiPo aftermarket T4 heads might use them and have a solution I am unaware of.

The T4 PR tube leak "issue" is very overblown anyway, there are several solutions ranging from "neat trick" (Jakes use of Pipe thread sealant) to mine --- Power-Scotchbriting the bores in the head and knocking off the factory oring shredding edges... Both are highly effective and only take a few minutes.
(Jakes lasts ~forever, but may god help you get that stuff back off once fully baked)

Have a look at a stock head, many/most have very sharp machined edges the oring MUST slide past, and/or bead blasted bores... Orings require smooth>polished surfaces, esp as they have to slide as the motor expands/contracts. The oring also must NOT have chunks taken out of it, and they usually do.


I'm not going to totally disagree with the cast covers, but...
The only times I have ever had a stock valve cover lose a drop is if I "miss", and when installing them on AMC heads. (The sealing surface on the AMCs is usually too BIG, just enough to cause a great deal of cussing, not an issue once "straightened out")

I have found bent covers occasionally. Some folks don't use gasket adhesive... Etc.

The "normal" bolt-on ones can and do usually leak like sieves past the nuts--- They need oring sealed cap nuts or such, but that's not what you get. The trick T1 ones (For Superflows etc) mostly avoid that by having the bolts OUTSIDE the sealing surface, but there might Be Issues getting at teh upper bolts on a 914 etc depending on the design. 1 bolt on each end (with matching heads, but limits the market...) might work.

A "captured" viton oring for a valve cover gasket WOULD be ~ideal, as it should last for years, but a totally proper setup may be quite expensive.

Clip-ons with a captured silicone oring would probably be the best compromise.

CarbonJoes molded CF ones were trick as hell.... and clip-ons, looked just like stock except in CF.

I don't THINK he makes them anymore, but someone should.

[helowrench]

pile, there is an oring imbedded washer that I see by the name of statoseal.
that would make bolt on covers a non leaker.
the neat thing is that the way it is made, the washer portion makes sure you cannot over flatten the oring portion

Rob

[Paul H]

The other bugbear of the T4 is valve springs I notice a lot of people using dual type 1 setups which are not up to the job of controlling a 48 or 50mm T4 long heavy valve. If they are running less lift than a T1 and less RPM then it stands a better chance and it may or may not stay cooler than a T1 but from my experience if we use anything more than a FK 10 with 42mm valve we go upto to small chevy style springs and after that fk87-89 with 44-46 we use K800 or similar.For this head I'd be looking towards a stronger single spring of stock diameter with an optional inner and maybe even a conical spring for smaller lighter retainer

[Rba]

First I'd like to say that I really like the idea of a new design to T4 head.
And I have some points I've been thinking about.

The good thing about have 10mm sparkplug is that there's a smaller hole in the head and therefore a stronger chamber, less tendency to crack between the sparkplug and valves. And as Piledriver says there are avaiable in a wide heat- and brandrange.
I imagine that is better to have both plugs as similar as possible too(dual 10mm instead of one 12 & one 10mm).

If you use T1-style exhaust you really exclude alot of potential customers, such as the 914-guys.

As for springs I like the idea of a Beehive spring, especially with the potential of a super light weight retainer, and make the design so that a common spring like one chevy-intended (don't know if this is physical doable)

The intake with bosses for intake both on the in- and outside seem like a good idea, if you don't wanna cut in your body you can use the inner or if you run dual staged injectors both bosses could be used.

As for the valve cover and push rod tubes I really don't see the real benefit of using anything other that stock, as been said there are simple fixes to the aledged problems.

[Paul H]

Here's the building site so far all the dimensions,shapes and angles roughed out. I altered the intake flange angle to get rid of the original S shape we can machine this back to the original angle for existing manifolds and that's a 52mm intake valve seat in there just to see what room there is. With smaller valves should be able to get the inlet tract even smoother Just another few hundred hours to go

[doc]

Just following along. Way over my head so don't have anything to add. But great stuff. Great pics. Thanks for sharing.

Many on STF follow the T4 projects but for many of us it has simply been too expensive and hard to make happen. Anything that can bring pricing and availablity nearer to reality will undoubtedly have a positive impact on participation. The improving value of the dollar vs. the pound/Euro may also help your eventual US participation. Hope this works out. Keep slaving away. Many here are interested.

Regards,

doc

[Type 4 Unleashed]

Here's the building site so far all the dimensions,shapes and angles roughed out. I altered the intake flange angle to get rid of the original S shape we can machine this back to the original angle for existing manifolds and that's a 52mm intake valve seat in there just to see what room there is. With smaller valves should be able to get the inlet tract even smoother Just another few hundred hours to go

Here is something that should be considered : By going such a large Int, a large Exh will also be needed to keep the valves in balance. The problem is in order to get the valves to fit, the guides will have to spread apart, then the securing points for the rocker shafts will have to spread apart wider also. So now the stock rocker shafts may be to short ?

Another problem I see, is with the valves spread farther apart the rockers have to follow the move, the valve side of the rocker shouldn't be a problem, but the push rod side of the rocker will.. Lets say you moved the Int guide over .075" to make room for larger seats, the rocker has to move over that much, now the push rod cup in the rocker is no longer in line with the push rod cup in the lifter, the push rod is now at a .075" degree angle, and with the spring pressure's that will be needed not only for nice hefty cams, but also for the increased weight of the larger valves, this force applied to the push rods at an angle, will be transmitted to the lifters, and because this force is transmitted at an angle will cause increased lifter bore wear. This applies to the exh also since it will have to be relocated.

I did put 50mm x 42mm valves in a 914 2.0 ltr head, and had to relocate the guides to do this, resulting in the increased angle of the push rods.

I've pulled the motor down and have found wear marks on the lifters, but only at the top and bottom of the lifter, the center was mark free, I have been meaning to inspect & measure the lifter bores but haven't got around to it yet...

A fix I see, is to do new rockers with an increased push rod & valve tip off set ?