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 Post subject: Re: cross-flow slant?
PostPosted: Mon Jun 27, 2022 11:17 am 
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Turbo Slant 6
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CNC-Dude wrote:
Several bullet points that seem to always be overlooked when this topic pops up regarding OHC cylinder heads. One, how are you going to address the original cam tunnel in the block? Since the cam(s) are being relocated to the top of the engine, how are you going to block off oil flow that would go to the original camshaft? How will you drive the oil pump and distributor since they are driven by the camshaft in the block? And then, there are the complimentary items that will be required such as timing gears and chain or belt and likely chain and belt tensioner that will now be required along with a new timing cover to enclose the new chain/belt? The cylinder head is really just a small portion of the whole package to make the cylinder head function. Good project though, but keep plugging along.....

I think his design retains the stock cam location. It just converts to a crossflow head.

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 Post subject: Re: cross-flow slant?
PostPosted: Mon Jun 27, 2022 12:09 pm 
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Ahh... I think I see a dark line representing a pushrod now. Thanks....

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 Post subject: Re: cross-flow slant?
PostPosted: Fri Aug 26, 2022 6:18 pm 
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Car Model: 75 Dart stock slant, for now
I'm trying to figure out water and oiling jackets for the design, is this gasket labeled correctly? Unmarked are bolt holes.


Attachments:
slant gasket.jpg
slant gasket.jpg [ 37.35 KiB | Viewed 1083 times ]
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 Post subject: Re: cross-flow slant?
PostPosted: Sun Aug 28, 2022 2:16 pm 
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The bottom right hole is for oil. The middle right one is for a dowel. Otherwise, looks good.

Slant on,

Lou

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 Post subject: Re: cross-flow slant?
PostPosted: Sun Aug 28, 2022 9:14 pm 
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ProCycle wrote:
CNC-Dude wrote:
Several bullet points that seem to always be overlooked when this topic pops up regarding OHC cylinder heads. One, how are you going to address the original cam tunnel in the block? Since the cam(s) are being relocated to the top of the engine, how are you going to block off oil flow that would go to the original camshaft? How will you drive the oil pump and distributor since they are driven by the camshaft in the block? And then, there are the complimentary items that will be required such as timing gears and chain or belt and likely chain and belt tensioner that will now be required along with a new timing cover to enclose the new chain/belt? The cylinder head is really just a small portion of the whole package to make the cylinder head function. Good project though, but keep plugging along.....

I think his design retains the stock cam location. It just converts to a crossflow head.
The more I look at the Toyota 3TC, the more I like it. Its an adaptation of the 1950s Mopar valvetrain. I like it because there are enough motorheads who race them that the aftermarket is still producing billet T series billet heads, and rocker arms. If there was just one billet head made for a slant six that would be pretty cool - if it could use the T series valve train. One billet head is produced for $2,000. Maybe the T series camshaft is higher in the block than the slant six (might affect pushrod angles). The lifter galley on the T series is not open like on a slant six, the slant six can be more adaptive for pushrods - I think. The OEM T Series only produced 75 to 80 hp in the pushrod versions (there are OHC versions). In racing these 1.8 to 2.0 liter fours produce (I think) more than maybe any modified slant six I've heard of has produced. There was also a 4TC - I don't think it was for the U.S.A. market - might have been OHC. They are nifty pushrod motors.


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 Post subject: Re: cross-flow slant?
PostPosted: Sun Oct 09, 2022 5:08 pm 
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Call me stupid or call it devil's advocate or whatever/ but I don't really know what difference it would make on any given engine, whether intake and exhaust are on the same side as each other/ or on opposite sides of the head? I mean, the mixture has to go in, get closed into the cylinder by the intake valve closing, squeeze, blow then can't leave til the exhaust valve opens up for it to leave. If anything, the ability for the escaping exhaust to heat the intake, would be too big of advantage to lose by entering one side and leaving the opposite side.
Granted on a v type block there's no choice but to have intake and exhaust on opposite sides of the heads ..


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 Post subject: Re: cross-flow slant?
PostPosted: Mon Oct 10, 2022 3:36 am 
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Basically, there is more room for the int and exh port passages because they are not all right up against each other on the same side of the head. That extra space can give you better port flow since you have more freedom on port shape and size..

Lou

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 Post subject: Re: cross-flow slant?
PostPosted: Mon Oct 10, 2022 4:58 am 
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I would also think it's a bit more efficient since the air does not have to make a 180° U turn exiting the cylinder when the engine is running at speed.

I am not sure if there is a conclusive test to prove that, but it seems to make sense in my mind.

Greg

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 Post subject: Re: cross-flow slant?
PostPosted: Mon Oct 10, 2022 6:45 am 
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Don is not far from being correct thinking that cross flow heads are not a significant requirement, as long as the conversation is including carburetors or throttle body fuel injection. As the warmth provided by the exhaust manifold helps to heat the intake and that helps to keep the gasoline in suspension.
Add MPFI to the conversation, with the gasoline being injected at the back face of the intake valve and the fuel suspension issue is eliminated. It would also be advantageous to have the fuel rail and the injectors used with MPFI away from the hot environment of exhaust manifold. That is the main reason new two valve heads are of a cross flow design.
Lastly, when stepping up to performance 4 valve per cylinder designs, one would simply run out of room if all of the ports were on one side.
With respect to a newly designed slant six head. If designed as a cross flow head, unless the designer/manufacturer was also going to release a set of matching intake and exhaust headers, one should take care to match the existing intake and exhaust port spacing in the cross flow design so that the manifolds currently available still fit.

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 Post subject: Re: cross-flow slant?
PostPosted: Mon Oct 10, 2022 12:01 pm 
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I had a conversation the other day with someone who had a radical head that he'd spent a ton of money on. His final statement was it was a big disappointment because even at 3.500" the bore still impeded flow too much to make the project worthwhile. :oops:

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 Post subject: Re: cross-flow slant?
PostPosted: Mon Oct 10, 2022 12:46 pm 
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Supercharged

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Quote:
the bore still impeded flow too much


maybe stud mounted rockers or a redesign of the existing shaft mounted rocker arms that angled the valve stems so the valves moved away from the cylinder walls as they opened would be a project with a higher degree of success. if it was based on the existing slant head doing a 'canted valve' project would certainly be less expensive than designing-manufacturing a new cylinder head.

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 Post subject: Re: cross-flow slant?
PostPosted: Mon Oct 10, 2022 5:58 pm 
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Triple Duece Weber
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I agree with volaredon, I don't see the cross flow as needed.
I agree with Lou that the port design can and should be better with the crossflow.

Here is what I think we need and can use.
This would be a big seller.
An Aluminum head.
Swirl port chambers.
1.75 Intake valves.
1.50 exhaust valves.
Narrow stem valves, .200 taller than stock.
Larger intake and exhaust ports with improved shape and flow.
Late model small plugs.
Everything else stock spec to interchange.

My 2 cents worth.

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 Post subject: Re: cross-flow slant?
PostPosted: Tue Oct 11, 2022 6:17 am 
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Agreed, Stan. You can get a lot of flow out of a Slant head without making it cross flow. All we need is $100k and some time to get the project done...

Lou

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 Post subject: Re: cross-flow slant?
PostPosted: Tue Oct 11, 2022 5:56 pm 
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The reason a 2JZ can make so much power isn't the heads but the very strong block with high turbo boost.

The Jaguar 3.8 E type with the hemi heads has decent output for a '50s design but it is still rpm limited by the long stroke (basically the same as a 225 ). Factory race teams spent high dollars to get beyond 6,000 rpm. The strength of the XK6 was its torque - it was last used in a British military truck. Some have used titanium rods and billet cranks to get about 400 hp on a barely streetable E-type. The ancient block design really needed a "cradle", the blocks sometimes split when the crank flexes at high rpm.

I think a slant head head based on the Toyota 3TC hemi (itself based on 1950s Dodge hemi) could work, these only had about 75 hp from 1.8 liters, but race heads have produced 800 hp with a turbo. Billet 3TC heads are available for $2,000 - could be $3,000 for a slant six version.

My preferred slant six head would resemble the OEM head with an "improved" combustion chamber, raised and straightened intake ports - might need a remote air cleaner for hood clearance in some cars. I doubt if it would add more than 10 hp with a stock camshaft, but hopefully could tolerate higher compression on pump gas for more torque.

Many of us are impressed by a slant six with, say 185 hp. A nice head would be a novelty for most of us - who don't buy new cars and might spend the money for something cool that a grandson might inherit.


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 Post subject: Re: cross-flow slant?
PostPosted: Tue Nov 15, 2022 2:45 pm 
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Car Model: 75 Dart stock slant, for now
hyper_pak wrote:
Here is what I think we need and can use.
This would be a big seller.
An Aluminum head.
Swirl port chambers.
1.75 Intake valves.
1.50 exhaust valves.
Narrow stem valves, .200 taller than stock.
Larger intake and exhaust ports with improved shape and flow.
Late model small plugs.
Everything else stock spec to interchange.


Stock design with some major and minor changes

1. I do not know about how strong the head would be made out of aluminum, but I do know that I have made almost every section of wall thicker than stock slant wall.

2.I do not know how to design swirl port chambers in AutoCad

3. 1.75" intake valves, 1.50" exhaust

4. intake is 3.17"^2, exhaust is 1.70"^2

5. normal sized plugs, maybe 2 smaller plugs later

Looking for feedback of any kind.
Intake is the blue valve

Using rockers like the Ford Cammer OHC engine with an adjustable lash surface that can be swapped out for a cup or ball lash adjuster, this head can be SOHC, or pushrod driven


Attachments:
File comment: The Ports are angled 90 degrees to the deck surface because it reduces head weight and allows for injectors to be positioned at a better angle (shown in yellow) (Manifold is just a sketch)
2022-11-15 (5).png
2022-11-15 (5).png [ 92.08 KiB | Viewed 680 times ]
File comment: red ring is 3.5 diameter circle
FROGGG COMBUSTION CHAMBER.png
FROGGG COMBUSTION CHAMBER.png [ 145.97 KiB | Viewed 680 times ]
FROGGG EXHAUST.png
FROGGG EXHAUST.png [ 105.98 KiB | Viewed 680 times ]
FROGGG INTAKE.png
FROGGG INTAKE.png [ 118.23 KiB | Viewed 680 times ]
File comment: Basic design similar to stock
valve angle 10 degrees
Bottom of ports is 1.5" from the deck surface

FROGGG.png
FROGGG.png [ 129.82 KiB | Viewed 680 times ]
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