MoFoCo 050 Heads.

[Steve Arndt]

Pay attention to John Connolly's posts to cut through the BS.

[shepherd]

Also, I recall that cb, aircooled.net, empi, and scat all offer different thickness shims. So if you can't find what you want with one vendor you might shop around

[stevepugh]

Yeah, i've just finished it all. John knows his stuff.
I think that Roy takes it all wrong. He asked why the masses didn't want the step, but nobody has done a back to back comparison, so he didn't get the answer to that question. But if enough people won't buy it because $ for $ it's almost the same as a tried and tested CB head, then buy the CB. I have to admit. I too was just gonna buy the CB head as it worked out the best and there are real world examples of power and how they run.
BUT I got these as part of a bundle and it'd cost me more to try and get new heads.. So I'm hoping for minimal machining to make them work.

Looks like he's made the change to offer a zero Step head. But won't punt it out as the norm. And because it's an OPTION, it's more money as he can't stop the normal run of heads.
But if the STEP was the option, then he could put out NO step heads to what is clearly the mass request at no extra cost.. Weird.

Anyway. Think I'm just gonna machine it off.

It was interesting that at least 3 Mofoco users, machined the step off and instead of being left with a 43cc chamber they had close to 48cc. This would be helpful.. as 43 CCs will put me into Race Fuel territory.. I'm trying to find a disk that fits INSIDE the step to let us measure that and prove the point.

But John also makes a strong argument for machining the step out 100% and then putting back in a copper "Step" gasket as the Copper will act as a heat shield between the head temp and that transferring to the cylinder. This can only be a good thing.

[Piledriver]

The provided step, smaller than bore size, is worse than useless.
Even AT bore size it's still an additional (and probably not planned for by the engine builder) issue.

What part of that does he not understand?

Considering copper conducts heat better than aluminum, not much of a heat shield.
I don't see the upside to taking it out completely,esp as you had +.060 deck to begin with, you are now going to need more spacer and have less meat in the head for future clean ups...

[Piledriver]

CB Performance has a .060 shim. With that on bottom and .050 top you are in the clear as far as hitting parts goes. For compression, someone on samba says that they had the chambers opened back to 54cc, but that's just internet hearsay.

So I'd be running a .010 positive deck on the cylinder and .050 in the head. That's total .060. Any issue there tho with the piston poking its head over the top of the cyl on every stroke?

Positive deck usually means piston comes out of the jug some (to me anyway)
If that is so, your deck would be .040" not .060".

What is your MEASURED CC INCLUDING the step?
Very easy to calculate the static and dynamic CR from that...

[Steve Arndt]

FYI

Positive deck clearance is "down" in the hole by that distance.
Negative deck is sticking up proud of the top of the cylinder by that distance.

The inverted nomenclature may have been confusing to the first timers.

[Piledriver]

FYI

Positive deck clearance is "down" in the hole by that distance.
Negative deck is sticking up proud of the top of the cylinder by that distance.

The inverted nomenclature may have been confusing to the first timers.

Confusing me too... I can't even keep it straight anymore.
That thread on TOS barbecues your MIND

[woodsbuggy1]

It is so sad to see what some people are willing to accept from a vendor. I have had my experiences and I insist upon a higher level of quality and customer service than some are willing to offer (I am sure that you know what vendor I am referencing).
Thanks
Kenric

[Piledriver]

I read a few more pages, had to stop before I broke my monitor.

It's more sad to see a vendor whose best and final excuse is "It's OK I've been doing it this way for 20 years".

(`es been doing it WRONG for 20 years, in spite of ~the world telling him so constantly)

I guess MOFOCO 050s are OK if you need ~46CC chambers, because that is what they have, regardless of all the hand waving and blowing smoke .
(It may be due to the way they are cast, perhaps he copied flycut heads when he made the patterns)

I wonder if there's enough meat in the T1 heads for a T4 2L Porsche chamber?
I know the valve angle might be a little different, but THAT works with very low timing, and the T1 plug location ~works.

Note that Len Hoffman uses a ~.035 step at ~bore size (OTOH he will TELL you that) The piston crown is usually 1mm or more smaller than bore size. (pictured heads are for 93-96mm bore, std 1.8-2L 105mm register)
On T4 heads you have a limited amount of meat in the deck, so you flycut as little as possible.
Link from http://www.ephotomotion.com/914engine/page22.html

[farmer]

Yeah, i've just finished it all. John knows his stuff.
I think that Roy takes it all wrong. He asked why the masses didn't want the step, but nobody has done a back to back comparison, so he didn't get the answer to that question. But if enough people won't buy it because $ for $ it's almost the same as a tried and tested CB head, then buy the CB. I have to admit. I too was just gonna buy the CB head as it worked out the best and there are real world examples of power and how they run.
BUT I got these as part of a bundle and it'd cost me more to try and get new heads.. So I'm hoping for minimal machining to make them work.

Well. I told Roy what happens, and I have told him before. No I did not take a comparison on the same engine, but on engines with the same components, only with and without steps in the heads. The difference was/is virtually impossible to overlook. But Roy doesnt want to hear what I say.
I was never a fan of coppershims or any shim between the heads and cylinders. Its only one more place it can leak. And there is no benefit of doing it IMHO.
If there is a problem getting the volume needed, it is way better to :
1, machine the heads WITH a step, but in the same diameter as the cylinder, so you can 0 deck the cylinders and use the "step" as deck height. It works well and keeps a lot of the burn heat to be dissapated by the cylinderhead.
Or 2, Machine the step away, make the combustion chamber a little larger (If there is room for that. The 050 have room) and then machine a dish in the pistons to correct the volume. for instance Ø 66 mm with 45 degree sides and 1,7 mm deep will give you about 5,5 cc.

Doing it one of these ways will retain good squish and better burn and temperature control.

Whether the mofo heads can dissapate more heat over conventional finned heads, I dont know. I stopped using those heads about a decade ago, because of uneven machining of plug holes etc. and the engines with those heads always delevoled a leak. Im suspecting the expansion rate of the denser alloy to be wrong. And I did not notice any improvement in cooling capacity over conventional finned heads.
HOWEVER, the idea with extra cooling fins on the underside is quite obvius, as that is how the Porsche 356 heads are cast. But the casting is STILL not so dense (!) I´m thinking that there is a reason.

T

[stevepugh]

I have been crunching the numbers and the MoFoCo heads that we have are acutally 56cc after measuring them.
If we machine the step away completely we have calculated that we get about 46cc. This with a .060 deck is 11:1 Compression Ratio.
This is too high.

My machine shop has then suggested a Hemi Cut to grab a few more CCs back in to the heads. I cannot find anything useful about hemi Cutting...

But it should grab us the few CCs that we need to get back to around 10-10.5:1.

Do I do this? what affect does Hemi Cutting have to power other than being a way of lowering the CR again?

all the info I've found is about stock heads back in the day being Hemi Cut to lower the CR to give better MPG but where power is not a requirement.

[helowrench]

I will be gaining my cc from unshrouding the valves.
in mine, the exhaust valve is very tight against that side of the chamber.

[farmer]

Yes I´m sure the chamber can benefit from being made wider, like f.i. a CB CNC mini wedge or wedge port. If that is not an option, dish the pistons like i wrote above, and get that deck height down.

T

[shepherd]

Helowrench and farmer have good ideas. I studied mine for a while, and sent them to Tims for his opinion. His guess (and mine) was that you could probably get 4-6 cc unshrouding the valves, and opening up the chamber a bit. The pistons would still need to be notched or dished (4-5 more cc) to get my compression ratio where I wanted it though. Too much money, so I sent the heads back to Roy to be exchanged for new heads with no step. In the meantime I ordered some stage 2 heads from Steve Tims, so that I can get this thing together this lifetime. SD

[roymofoco]

I am having testing done right now from an source outside the VW community. This will insure that the results are 100% unbiased. I have the initial findings already and they are very positive. The heads are being tested using a method that eliminates many of the variables of a car or a standard dyno. I will be publishing all the findings when the testing is completed.