Budget 100x71 Build

[cal 67]

Good info! Thanks!

[cal 67]

I was outside just staring at the heads last night, trying to figure my plan of attack. I wanted some bronze seats, but it'll be very labor-intensive to get em done. Steel 44x38 seats will get installed with dummy guides that can be easily tapped back out. I spoke with Anthony Chicca last night, and he helped me with my numbers. I'ma aim for 89% at the seat, and about 3/4" below. Then, I'll taper to 90%.

Manley offers TIV valves that use the modern LS groove instead of the weak 3-groove valves, so I have a titanium retainer/keeper option that I used for my other high revving project. PAC sells all the components. Then I can use Stateside duals, which only are about 270 lbs @ .550".

Milled a bunch of mounting blocks yesterday, just to have.

[cal 67]

I milled one head yesterday to mock. I'm somewhat concerned about the removal of the bracing that keeps the rocker assembly rigid. I may end up welding rods to brace the rocker box. I won't be using much spring pressure, but it still concerns me.

The tops studs will be 175mm and the lowers 150mm. Since I'll have M12/M10 inserts in the case, and no more lower bracing on the head to worry about, I'll raise my torque values between 30 and 35 lb-ft. In place of factory nuts, I'll likely use M14 12-point nuts with a 17,7mm flange and a thick, narrow washer underneath. On top, I'll use my normal wide washers.

I think the next step will be an actual mock-up. I know the barrels need about 5mm of shortening, but I'll get to it after I verify clearances. I sometimes just do the math and shorten before a mock-up, but I'm in no rush.

Disappointed about the P cam I was going to use. Measured .391" at the cam instead of the advertised .410" and about .020 less duration. I know some lift is lost from the copy process, but that's a ton. It makes the cam a lot smaller. I'll step up to a "wilder" cam to compensate. Maybe the Q cam...

Btw, I have a set of nos 100mm pistons for sale in the FS section.

[Clatter]

Whoo! Now my brain is really getting bent..!

I always thought the lower four head studs went clear to the floor of the rocker box area to help keep the pushrods from trying to push the heads off.
Might be interesting to see if you could measure a loss of lift at the valve vs. having the stock lower studs..
Always thought the reason the lower four tends to come loose wasn't just that they were longer,
But that the pushrods are flailing away working them loose.

Are you sure there's enough meat there to keep the heads sealed up?

Is this done to keep the studs shorter?

Seen five and six studs, but never this mod before.
Looks like i need to go and study some heads a little more..

Sweet build.
Love it.

[cal 67]

Whoo! Now my brain is really getting bent..!

I always thought the lower four head studs went clear to the floor of the rocker box area to help keep the pushrods from trying to push the heads off.
Might be interesting to see if you could measure a loss of lift at the valve vs. having the stock lower studs..
Always thought the reason the lower four tends to come loose wasn't just that they were longer,
But that the pushrods are flailing away working them loose.

Are you sure there's enough meat there to keep the heads sealed up?

Is this done to keep the studs shorter?

Seen five and six studs, but never this mod before.
Looks like i need to go and study some heads a little more..

Sweet build.
Love it.

Evening Clatter. I posted this elsewhere and Raby said that he's done it, and it worked well for him using some kind of Porsche studs. I stole this directly from Autocraft/Pauter heads. They both bolt directly to the chamber wall. I figure studs come loose because the heads are not rigid enough, so the stud does not stretch adequately. Those lower studs also see "secondhand cooling", after the tops of the barrels get cooled by much colder air. That coupled with them being longer makes the layout less than favorable IMO...

The head's webbing is responsible for the rocker area remaining rigid. The studs' mounting in the rocker box seems more of a practical thing. By milling away some of the webbing, I do realize that I've made issues for the rocker stability. I have a plan: reinforcing the lost webbing. Actually, some of the bridging didn't even terminate at the chamber wall, so I doubt it did much. At least now I'll have full support all the way to the largest fin. Everything in red is getting welded.

The chambers are also way too big. Used the CB calculator and with a 65cc chamber, I'd get about 9.0:1 at best. I'ma fill in those dead spots on the sides of the plugs, add a 3/4 funnel around the exhaust like new Type 1 heads have. I need about 11.0:1 minimum to have decent psi.

Btw, the chamber wall is .500" thick. I haven't thinned it really, so I figure I can only improve clamping by going this route.

[wreck]

I spoke to Jonathon ,(I think it was ) . He was very canid with the mistakes they had made with the new 2lt 914 castings . the main thing that he said they made a mistake with was not making a modern combustion chamber and just copying the factory head without upgrading it .

Can you image a new type 4 head with modern chambers and a longer short turn on the exhaust port for the prices they've for those heads now . Stick a head like that on a 2lt type 4 with a good cam and exhaust etc and it would wipe the floor with most type 1's

[cal 67]

I spoke to Jonathon ,(I think it was ) . He was very canid with the mistakes they had made with the new 2lt 914 castings . the main thing that he said they made a mistake with was not making a modern combustion chamber and just copying the factory head without upgrading it .

Can you image a new type 4 head with modern chambers and a longer short turn on the exhaust port for the prices they've for those heads now . Stick a head like that on a 2lt type 4 with a good cam and exhaust etc and it would wipe the floor with most type 1's

Well there's Remmele's CU head.... I have a set for my main engine, but they're in Sweden now

I don't see the exhaust port length as a hindrance much. The header becomes an extension of that. Only the sealing ring bothers me.

[cal 67]

Got some air horns 3D printed for my 48 IDFs. They can withstand over 200°F.

Gonna turn some guides down tomorrow for a .000 machine fit, or a slip fit when heads are heated. They'll be temporary to install the seats.

[twodollardoug]

Nice.

[DRED]

Nice production, in several lenght! good idea..

[cal 67]

Jobs today: turn down time sert's flange so I don't need to counterbore my case. I also tapped my heads' stud passages for plugs since I won't be passing them through the rocker box. To accurately tap straight and centered, I used a tight-fitting locating pin, pulled the pin, and centered a 1/4 NPT tap.

I'm an idiot! only machined eight time serts instead of 16! Enough to complete one side. Loctite for larger hardware was used inside the threads to hold them still for expanding with the special tool, and a ring of silicone at the top threads on the insert for oil leaks.

Tried to exchange for a Q cam today, but it needs to get ground, because there are none on the shelf. I'll get it at the start of the year.

[cal 67]

Walked in, and some NOS rod bearings showed up

[Clatter]

Love it. Watching every little detail.

I feel better seeing you're welding reinforcement in between fins like that; not that i would know.
On the 'downstream' side of cooling air, they shouldn't add heat much at all, unlike some welding you see done to heads.
Are you going to be welding in any other reinforcement to help seal the cylinder?

Blank canvas for the artist these bare castings..
Can't wait to see what you do with the chambers.

Rare to see someone insert head studs on a type 4.
I'd almost be more inclined to insert the rocker studs.

[cal 67]

Love it. Watching every little detail.

I feel better seeing you're welding reinforcement in between fins like that; not that i would know.
On the 'downstream' side of cooling air, they shouldn't add heat much at all, unlike some welding you see done to heads.
Are you going to be welding in any other reinforcement to help seal the cylinder?

Blank canvas for the artist these bare castings..
Can't wait to see what you do with the chambers.

Rare to see someone insert head studs on a type 4.
I'd almost be more inclined to insert the rocker studs.

Won't be running enough pressure to warrant it. I think I'll be 270#@.550". Stateside duals are being used.

No other welding provisions. Shrinking the chambers should reinforce some areas alone. It's only 100 bore. Think (hope) it'll be fine. Got the other eight inserts in last night. Finna go cut-down a dummy 44 and 38 valve now for chamber porting. Not exactly sure how the chambers will end up. That plug is very high up. Wish it were closer to the center...

As for cooling, not too concerned. I used to stress about it, but in my experience, everything runs cool if you chill on spring pressure and you cut down on friction. May not cool exactly even, but it'll live a relatively decent life.

Thinking about making some spring-loaded T4 pushrods tubes.... I know that the head doesn't have a stop, and the assembly is meant to float, but I think I have a clever way of solving that, while making some tubes that can suit my narrower engine width. I could also just chop some stockers and maybe reweld.

[subtaf]

Love the experimentation and your work with this build.
I'm following along closely as I'd like to build a slightly down tuned version of this with a stroke around ~76mm (can always be talked into more) and peak hp a bit over 6000rpm. Shooting for 180~200hp.
With the infilling required in the chambers do you think starting with a basic 2L AMC head would require much the same amount of work or are the intake ports far smaller?
Keep the posts & photos coming please.