Author Topic: Modified Stromberg intake ports?  (Read 879 times)

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Offline TurboFource

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Modified Stromberg intake ports?
« on: Saturday,November 14, 2020, 04:11:38 PM »
Based on pictures of other Stromberg heads it appears that the intake ports at the carb mounts on the spare head I got with my car, have been opened up a little over an 1/8" towards the front of the head on both inlets. Is this helpful mod that helps with flow bias in the siamesed intakes? Not sure if anything else has been done to this head as I currently have nothing to compare it to.
The more I do the more I find I need to do....

Offline jbcollier

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Re: Modified Stromberg intake ports?
« Reply #1 on: Saturday,November 14, 2020, 07:21:02 PM »
Photos?

The TC Weber, TC Stromberg and Renault crossflow heads all flow pretty well.  Can you make improvements?  Absolutely!  You need a flow bench and lots of experience though.  By all means smooth things out, match ports, etc.  Major porting?  Only if you know what you're doing.

One example is the port drop to the valve.  In as much as possible, you want the mix to flow straight at the valve head.  That way it flows around the valve head using the whole open area.  A classic mistake is to remove the port floor so the mix goes straight at the valve... sideways.  It "looks" more open but really you are now blowing the mix across the valve head and only utilizing half the available area.

Offline TurboFource

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Re: Modified Stromberg intake ports?
« Reply #2 on: Sunday,November 15, 2020, 03:44:44 AM »
My computer died so I am currently using an old iPad 2......  Not sure how to get photos from my iPhone to this thing.....or if it's even possible.
The more I do the more I find I need to do....

Offline BDA

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Re: Modified Stromberg intake ports?
« Reply #3 on: Sunday,November 15, 2020, 07:09:30 AM »
My computer died so I am currently using an old iPad 2......  Not sure how to get photos from my iPhone to this thing.....or if it's even possible.

Can’t you email them at least?

Offline jbcollier

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Re: Modified Stromberg intake ports?
« Reply #4 on: Sunday,November 15, 2020, 07:36:00 AM »
Does the iPad have a camera?

If not, email them to me and I'll post 'em.

j b c o l l i e r (at) s h a w (dot) c a

Offline TurboFource

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Re: Modified Stromberg intake ports?
« Reply #5 on: Sunday,November 15, 2020, 08:40:20 AM »
The iPad does have a camera..... :huh:

Will try it later.....didn't even think of that.... :confused:
The more I do the more I find I need to do....

Offline TurboFource

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Re: Modified Stromberg intake ports?
« Reply #6 on: Sunday,November 15, 2020, 11:37:37 AM »
Test pic.....
The more I do the more I find I need to do....

Offline Pfreen

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Re: Modified Stromberg intake ports?
« Reply #7 on: Sunday,November 15, 2020, 12:14:17 PM »
I assume the entrances to the head were modified to match the manifold that attaches to the head.  You definitely don't want it to be smaller.  Ideally, they should match ( as well as the gaskets) perfectly.

Offline TurboFource

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Re: Modified Stromberg intake ports?
« Reply #8 on: Sunday,November 15, 2020, 01:06:50 PM »
Are the gaskets egg shaped?
The more I do the more I find I need to do....

Offline Grumblebuns

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Re: Modified Stromberg intake ports?
« Reply #9 on: Sunday,November 15, 2020, 02:18:24 PM »
So, is the secondary throttle housing, the part that bolts to the head also modified to be egg shaped? Perhaps the previous owner was experimenting with porting.

From my limited understanding of porting, the opening to the head is cleaned up so that the edges matches the gasket on the carb outlet perfectly and the rest of the intake tract is ground and smoothed out to optimize air flow per the engine builders experience.   

Offline jbcollier

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Re: Modified Stromberg intake ports?
« Reply #10 on: Sunday,November 15, 2020, 03:27:26 PM »
Can't see any reason for that.

Offline TurboFource

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Re: Modified Stromberg intake ports?
« Reply #11 on: Sunday,November 15, 2020, 03:47:15 PM »
I don't have a spare intake that bolts to this head so I am not sure why this was done, unless it was done to try to overcome the flow bias that occurs in the siamesed port due to the firing order of the cylinders (and the resulting cam opening events)..... :confused:
The more I do the more I find I need to do....

Offline Pfreen

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Re: Modified Stromberg intake ports?
« Reply #12 on: Sunday,November 15, 2020, 06:35:39 PM »
I guess I am confused.  Is you car turbocharged?  I assumed it was.

Offline TurboFource

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Re: Modified Stromberg intake ports?
« Reply #13 on: Monday,November 16, 2020, 03:22:39 AM »
Pfreen,
It is turbocharged, this is on a spare head I got with the car.
The more I do the more I find I need to do....

Offline cwtech

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Re: Modified Stromberg intake ports?
« Reply #14 on: Monday,November 16, 2020, 06:39:33 AM »
I never noticed that while the head was in my possession. 

That head was not from a Europa (no groove for cam oil seal) and its history is unknown to me.

Is it possible that the flat surfaces were milled thinner for some reason? ...Or, did "core shift" occur when the head was cast? 

Since the flat surface is at an angle to the port, wouldn't that make the opening oval, as opposed to round?