Inliners International Forums General Discussion Bench racing Recommendations needed

I want to epoxy a plenum divider in my intake manifold. Can anyone recommend an epoxy that will hold up to being in fuel.

Thanks in advance

JB weld works OK,DO not use the JB quick.
After a long period of use it starts to comes loose in small pieces,but so do the other epoxies.

What intake manifold do you want to put the divider in?

MBHD

If you are only doing the runners why Not make a small slot in the top& bottom and have someone Tack weld the divider in place.But If your plan is to divide the whole intake Then It mit be in your better interest to just weld it in.

The intake in question is a Clifford 4bbl for a Hudson. A crew running a Bonneville car have dyno findings that indicate significant hp gains when dividing the plenum. I'm going to try it.

Dany

If the Clifford intake for a Hudson engine is the same as for a 194-292, the plenum volume is way too big to make good torque.

I would try & fill up that plenum to take away some volume.

I devided my Clifford intake & to tell you the truth, I really did not notice much difference.

I made way more torque,, & I do mean wayyyyy more torque & HP with three side draft Webbers.

MBHD

Hank, did you divide the intake port with the divided manifold ? Is the Hudson port divided ?

Harry

I hate to sound dumb, but just what is a "divided plenum" on am inline six, with or without siamesed intake ports?

With respect to the plenum volume, is there a good "rule" for plenum volume for a given engine displacement and RPM range? Tomorrow I will measure the volume in the five-carb manifold that I am using on my 278-cu. in. 261. I was just looking at an intake manifold design book where the authors showed results with a very large plenum where the actual flow rate (or volumetric eficiency) would actually decrerase as rpm increased at some rpm ranges.

Turbo-6,,,,
I divided the standard 2/4 barrel Clifford intake manifold for a 194-292 Inline Chevy six.

Reason I did this is because the intake volume is so big, the intake air/fuel mixture enters the intake port @ such a low velosity it just kills your bottom end, well it did on my 250.

The Offy intake manifold made more power.
Well @ least more torque, & torque is what you need to make your vehicle move,,torque is king for the street.

MBHD

Hank, If the head port is not divided the valve that's open will draw from both manifold ports and the velocity will not increase ?

That is correct.
And if you divide the port in the cylinder head, the intake window gets too small to flow good.

Hank, If velocity does not increase why divide the intake manifold ?

A divided intake port has a choke area that will support a 292 at 6000 RPM and a 250 at 7000 RPM before VE will fall off, with a mach index of 0.54 and 0.46 respectfully.
air flow numbers with a divided head will support about 300+ HP

Just food for thought, Harry

Hank, If velocity does not increase why divide the intake manifold ?

A divided intake port has a choke area that will support a 292 at 6000 RPM and a 250 at 7000 RPM before VE will fall off, with a mach index of 0.54 and 0.46 respectfully.
air flow numbers with a divided head will support about 300+ HP

Just food for thought, Harry

I would like to see a picture of a divided cylinder head.
Also talk with this person to see what the cylinder head flowed.

MBHD

Hank
That was something that was done many years ago and some still divid the ports.I have a few dividers that were made from a templet( out of Alum).It came from a tech artical back In the early 70. I think Hot rod is the one that published it.They also split a clifford Intake clean back to the Carb.

O, I forgot about that, I have that article.
How does the cyl head flow with that divider?
Lousy,,, right??

MBHD

Honestly Hank
I never installed them. But My 2cent personaly Opion is If you divid the Port You should also widen the Port and along with taking at least .100 out of the top which is about half the gasket area in the top of the port.I have not had time to go back and cut the Sides of the Port But
I am pretty sure you can open the port at least .050 If not a little more.With Out having to do any Rewelding Or with getting into the water jacket.
That should get you back some Of the Lost air flow.I have enough cut up heads here ,Im sure i can find out Just How much could be removed. From
the sides Of the Ports.
I just need to get off my butt and find out.
But i feel between the two cuts It should make-up
what was filled in from the divider.
I also feel A shaped divider (meaning Shaped to the top and bottom of the Port would also Help the Air flow around the Valve guide, and down in the short turn radius where the divider meets the floor. Not Flat like That divider was made.

I will try a post a picture of my divided head,
it is shaped at the back near the valve pocket. I use the stock post so I have the best clamping force possible.
It does hurt flow about 20% but It increases velocity, mainly puts all the fuel for that port in that cylinder. As stated earlier the velocity is not so great as to hurt VE. High flow numbers are sometimes is not as important as keeping the fuel in suspension.
I feel that working with a stock head is a relative cheap way of trying to improve the performance of the engine, If you want an all out race engine you are wasting money and time just buy a kirby 12 port head, V8 hybrid, or 4 valve and be done.

HARRY

Well, with my findings with dividing the entire intake port ,the window gets too small, & when you open up to make up the difference,it's not worth the trouble.
You will get better benefits from a nice large short turn radius than opening up your intake port window size.

Using Larry's bolt in lump port or brazing in a lump port was a better way to go than to divide the entire intake port.

Like I told Larry, when I made upper bolt in lumps, you need to take up some volume towards the back of the port to increase the velosity..& to guide your intake charge in the bowl areas.

Dividing the port , just does not work good for a normally aspirated engine, you need to open up the intake port, then you need to open up/port match the intake manifold ,that will cause you to loose velosity.

MBHD

I have a question, does anyone out there have a problem with fuel distribution with a siamesed port? If so do you have carbs or fuel injection and the placement of them, also at what power level does this become a problem ?

Thanks, Harry

i have fuel distribution problems with the siamesed port.it has the biggest effect at idle. i am running multiport fuel injection, with 2 injectors per port @ a 45degree angle. at idle #1 cyl liked to grab all the fuel charge for both cyl 1 and 2. to correct it i now fire the injectors once per revolution and have split the harness so injector #1 fires 180 crank degrees off from #2 injector. that helped the idle. @ higher rpms, like 1500 and up it is not noticed.

turbo 6 do you run the divided ports with your setup? tom

Tom, yes I run divided ports now, was running siamesed ports but cylinder 1 and 6 were very lean in high boost-high HP range.

turbo 6, did you run dividers only to the intake or are you running the thru the intake also? are yours simular to the ones in the old hotrod article? tom

Tom, divided to within 1" of the bottom of the carbs, no fuel distribution problems now.
Dividers are of my own design they have wing shape back in the bowl area made from a castiron casting.

Harry