Questions Regarding Siamesed Intake Ports (9 Port Head)

General engine tech -- Drag Racing to Circle Track

Moderator: Team

PackardV8
Guru
Guru
Posts: 5039
Joined: Sun Jul 30, 2006 2:03 pm

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by PackardV8 » Sat Apr 01, 2017 9:35 pm

pamotorman wrote:how does the second engine cool because it is seeing all the heated air from the front engine ??
If you've ever ridden a naked bike in street clothes, the pants cuffs will beat your ankles raw; there's a cyclone going on down at cylinder level.
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering

wyrmrider
Guru
Guru
Posts: 6932
Joined: Thu Jan 10, 2013 10:52 pm

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by wyrmrider » Sat Apr 01, 2017 9:59 pm

oil coolers

Truckedup
Guru
Guru
Posts: 1354
Joined: Mon Jan 21, 2013 2:41 pm

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by Truckedup » Sun Apr 02, 2017 6:44 am

wyrmrider wrote:oil coolers
Nope.....The engine only runs for about 30-40 seconds at full throttle....The oil never gets that warm even with trying to get heat into the engines before each run...The rear engine cools ok for short duration racing as Jack mentions...Except for the engine machine work,I built it in my shop of horrors using a old lathe and mostly hand held tools, I was a construction electrician not a mechanic :D ...............All the time and money so my rider wearing animal skins can cling to an oily vibrating machine propelled by fire that may have an engine seize any any time, locking the rear tire ,and tossing off the rider at 170 mph if he doesn't pull in the clutch lever fast enough...
Naked frame LSR bikes, dressed in animal hides clinging to machines propelled by fire...

enigma57
Guru
Guru
Posts: 1216
Joined: Sun Oct 07, 2007 11:59 pm
Location: Galt's Gulch

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by enigma57 » Sun Apr 02, 2017 6:50 am

Thanks, guys! Excellent info here. I have read over and greatly appreciate each and every one of your posts. Just trying to answer all comments in as few posts as I can here. Have made a note to self regarding 292 cam core, as well.

And yes, I will keep my options open. That includes running Mikuni or 1-3/4" or 2" SU carbs in lieu of Weber DCOE's and either modifying the DCOE intake I have here or building my own from scratch if need be.

I am at the point just now where I need to finish mocking up the 292 engine in my chassis. I have the 292 short block in my car (still needs to be rebuilt). I am using a '57 V-8 bellhousing and side mounts to locate it in the chassis whilst I fab the front engine mounts. Once I have this done, I can fit a head to the short block and see exactly where my interference points are (right now, looks like master cylinder and steering column will have clearance issues with sidedraught intake and DCOE carbs). I have approximated them, but need to finish front mounts, bolt on a cylinder head and trial fit the intake and carbs to get this right on the money.

This is all on hold until I finish income taxes. Should be done with taxes this coming week.

Best regards to all,

Harry

Truckedup
Guru
Guru
Posts: 1354
Joined: Mon Jan 21, 2013 2:41 pm

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by Truckedup » Sun Apr 02, 2017 7:42 am

Harry, some guys run down draft carbs because of the steering column interference....I think on a street engine it may come down to what carbs you can afford and how they look and perform at lower speeds...With extra power trying to twist the long crankshaft, a proper harmonic damper is important..The first several years of the 292 had a forged crank, then cast after that...The later cranks with more counterweights are supposedly better...But all the cranks when prepared properly can handle 500 HP from what they say...
Naked frame LSR bikes, dressed in animal hides clinging to machines propelled by fire...

PackardV8
Guru
Guru
Posts: 5039
Joined: Sun Jul 30, 2006 2:03 pm

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by PackardV8 » Sun Apr 02, 2017 2:49 pm

a 292 Chevy inline 6 that will be built for max torque and redlined at 5,000 RPMs due to long stroke.
Did some trial fitting and preliminary measuring today. This sidedraught intake setup is going to be a challenge to package in my '57 engine bay due to clearance issues with master cylinder and steering column. . . The car is original thus far and I don't want to butcher it
.I'm guilty as anyone on this thread, but let's bring it back to a reality check. It's a sub-5,000-RPM street car and keeping the engine compartment looking stock is more important than max horsepower carb and intake design, so is us reminding him about 500+horsepower crank and damper concerns or his
I will see if I can work out a way to take advantage of tuned length for 3rd (or possibly even 2nd) harmonic.
really anything other than pleasant Sunday afternoon bench racing? Not that's a bad thing. ;>)

Best advice so far:
Roc - 2) Don't overthink it.
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering

enigma57
Guru
Guru
Posts: 1216
Joined: Sun Oct 07, 2007 11:59 pm
Location: Galt's Gulch

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by enigma57 » Sun Apr 02, 2017 8:10 pm

Pretty wild weather here in Texas earlier today. Everything from flooding and high winds to hail and tornadoes. We had around 4-1/2" of rain here between 7:00 AM and 2:00 PM.

Worst of the storms seem to have passed through here for now and we have electric again. Just stepped outside to make sure we don't have any trees nor fences blown down. So far, so good. Water has run off, road into town looks passable and roof looks OK. Much to be grateful for. Many weren't as fortunate. Especially in East Texas and Louisiana as these storms have moved in that direction.

Our family will keep all affected in our thoughts and in our prayers.

G-d bless,

Harry and Family

enigma57
Guru
Guru
Posts: 1216
Joined: Sun Oct 07, 2007 11:59 pm
Location: Galt's Gulch

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by enigma57 » Sun Apr 02, 2017 8:35 pm

:D Thanks, guys! I am looking at those issues, as well. Regarding carbs...... Simplest solution for what I intend to do with this car and engine would be to just locate a good single carb intake such as the AussieSpeed 4bbl intake, drop a well prepped 600 Holley double pumper on it and sort out jetting and power valves. That's the easy way to do it.

I just enjoy tinkering with Webers and multiple carbs, though. Have a crusty old Offenhauser triple 1bbl log type intake here I could set up with 3 Weber 34 ICH carbs on straight (non-progressive) throttle linkage. That intake setup should (just) carry the 292 to 5,000 RPMs redline and run well on the road after sorting out jetting.

But that's too easy. I enjoy a challenge. So may do something altogether different (Mikunis? SUs?) depending on how much clearance I have to master cylinder and steering column once I have front engine mounts done and bolt on a cylinder head for trial fitting.

Regarding tuned length...... If I were running EFI, I could take some mandrel bends of correct diameter and fab up a long runner intake that turns 90 degrees and passes over the valve cover to passenger side of engine compartment and set it up with ITBs at upstream end, but place injectors closer to back side of intake valves. But carbs are my thing and with carbs, I believe throttle response would be better if I keep them closer to back side of intake valve. So will look at it from the perspective of carbs, what I can package in the '57 engine bay and what will run well.

Might add...... With Dan's EMC engine, we found on exhaust side that the 'too large, too short', unequal length off the shelf Hot Heads street rod headers that outperformed the high tech merge collector headers Dan spent so much time and effort on priour to the 2011 EMC...... Had very nearly equal volume to headers having theoretical correct primary size and length, when averaged out. This being with both sets of headers run on same engine through what I called the 'motor home' (very long, muffled) exhaust system at EMC...... Which acts quite a bit differently than if you are running open headers at the track with correct diameter, equal length primaries and correct collector diameter and length. We also found correct diameter and length collectors...... If extended by multiples (meaning collector length and volume are doubled, or tripled or quadrupled)...... Not to adversely affect power.

So I am wondering if the same principle...... These DCOE intake runners being larger and shorter than optimal CSA and tuned length for this particular application...... But having very nearly equal volume (and similar resonance signature?) to correct diameter and length for a 12-port head and isolated runner setup (between throttle blades and back side of intake valves)...... Might allow for a rather crude 'tuned length' with this siamesed intake design? Seems velocity through the siamesed intake ports will suffer no matter what, but mightn't 'tuned length' (or more correctly, similar resonance signature) be achieved through equal overall volume to optimal? Just wondering.

:shock: "Don't overthink it." Guilty as charged, Your Honour. Yes, I was the 7 year old kid in grammar school who when our teacher said we were 'up the creek without a paddle'...... Asked why that would be a problem? Because if we wanted to go up the creek, we were already there. And if we wanted to go down the creek, we could simply let the current carry us downstream. No paddle needed.

Thanks for your thoughts on this,

Harry
Last edited by enigma57 on Sun Apr 02, 2017 8:40 pm, edited 1 time in total.

peejay
Guru
Guru
Posts: 1213
Joined: Tue Aug 10, 2010 9:16 pm

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by peejay » Sun Apr 02, 2017 8:38 pm

roc wrote:Hi Harry, three humble comments:

1) Enjoy and have fun with your 292". I admire you for getting off the V8 beaten path.
2) Don't overthink it.
3) I've never seen an inline-six which firing order isn't 1-5-3-6-2-4 (or equivalent if numbered backwards).
153624 backwards is also 153624 :)

Geoff2
Expert
Expert
Posts: 583
Joined: Mon Nov 09, 2015 4:36 pm
Location: Australia

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by Geoff2 » Mon Apr 03, 2017 6:30 am

With a max rpm of 5700, normally aspirated, HP is going to be limited; I think you need to worry less about tuned lengths & more about carb type & size selection to optimise torque. This is going to be a torque engine more so than a high rpm hp engine. Camshaft selection is also going to require careful selection, optimising torque, not hp.
As I said in an earlier post, I think 40 DCOE Webers would work the best. ANY 4bbl barrel manifold will be a poor choice because of the long runner lengths for the end cylinders & short runner lengths for the inner cyls. You could never get optimum jetting for all cyls, some rich, some lean, compromising HP.

enigma57
Guru
Guru
Posts: 1216
Joined: Sun Oct 07, 2007 11:59 pm
Location: Galt's Gulch

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by enigma57 » Mon Apr 03, 2017 6:49 am

Agree 100%, Geoff. This inline 6 engine will run 3 carburettors to aid fuel distribution. If I have the room, it will be 40 DCOEs with 28mm to 30mm chokes. If I cannot clear master cylinder and steering column with DCOEs, will either run 3 Mikunis or SUs...... Or will come up with a 3 carb intake setup that will do what I want whilst clearing the master cylinder and steering column, as well.

Appreciate your comments and perspective.

Many thanks,

Harry

roc
Pro
Pro
Posts: 433
Joined: Sun Sep 02, 2012 9:41 pm
Location: Columbus, IN

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by roc » Mon Apr 03, 2017 7:15 am

peejay wrote:
roc wrote:Hi Harry, three humble comments:

1) Enjoy and have fun with your 292". I admire you for getting off the V8 beaten path.
2) Don't overthink it.
3) I've never seen an inline-six which firing order isn't 1-5-3-6-2-4 (or equivalent if numbered backwards).
153624 backwards is also 153624 :)
Just as racecar backwards is.. racecar! :lol:

enigma57
Guru
Guru
Posts: 1216
Joined: Sun Oct 07, 2007 11:59 pm
Location: Galt's Gulch

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by enigma57 » Thu May 18, 2017 5:47 am

Apologies for being so long in posting an update, guys. Finished mocking up engine mounts in my '57 Chevy and put a bare head on 292 block so I could trial fit sidedraught intake. As I suspected, the master cylinder and steering column interfere with DCOE carbs on this intake and there is no room for even short trumpets and an air box.

A friend in Brazil who posts here suggested making a log type plenum, bolting it to the DCOE sidedraught mounting flange and mounting the 3 DCNF downdraught carbs atop it. This is a good idea. Straightforward design and I gave it serious consideration. However, I wish to keep the function of the intake manifold's separated ports and with the siamesed headport situation of the Chevy inline 6 thrown into the works as well...... I cannot quantify (functionally) where effective plenum and intake runner for each carb begin and end, really. So was concerned about the additional plenum volume of a common plenum 20" long and its effect on throttle response off idle to mid-range (this is primarily a street car). I suspect that with the divided runners and siamesd headports...... Effective intake runner length and plenum volume (in the running engine) are dynamic rather than static. A function of firing order, intake valve closing event, etc. Possibly affected by exhaust valve opening event, exhaust system design and RPMs, as well.

So I decided to convert one of the Brazilian sidedraught intakes to accept 3 Weber 42 DCNF downdraught carburettors I have here. Center to center distance between DCNF throttle bores is closer (46mm) than that of DCOE carbs (90mm)...... So in order to position each 1/2" thick carb mounting flange where it will intersect the diverging intake ports...... DCNF carbs end up in center of 5" wide sidedraught intake....... Resulting in runners being too short to my way of thinking and carbs being so close to head and rocker cover as to make access to mixture adjusting screws problematic (only way they would fit at all is to place float bowls outboard, which results in mixture screws being inboard).

Plan B...... Modify 1 sidedraught intake as noted above. Blank off original mounting flanges of modified intake. Then reverse it and bolt it to the other (unmodified) sidedraught intake I have here (each intake is a mirror image of the other). Unmodified sidedraught intake inboard. Modified intake outboard. This will result in a 2-piece downdraught intake having longer runners that should 'just' clear my master cylinder and steering column.

Getting started. After having powder coating sandblasted off the intake to be modified, I picked up 3 DCNF carb mounting flanges off E-bay. Contacted machinist who made them and sent him cardboard templates of filler plugs (for triangular spaces between runners that I will need welded in to fill that space before carb mounting flanges are welded on). And for the blanking plates to close what were originally the intake openings into the siamesed headports.

After I had the carb mounting flanges and filler plugs in hand...... Hand fitted the plugs to the intake (triangular pieces filling gap between ports at DCOE flange are an interference fit)......

Image

Image

Image

Image

After doing initial fit up at the house here, sent intake to my friend Nick at Smithberg Racing for welding and machining. NIck and I had the honour of being team members on Dan Miller's and Gene Adams' EMC effort. My wife reminded me that I am now the same age (69) as was Dan when he passed. And if I intend to get my '57 on the road again in a couple of years and have some fun driving it, I had better get to work.

As you can see, Nick is doing a great job bringing my dream to fruition......

Image

Image

Image

Image

Image

You will notice that I left an outboard extension of the small plenum beneath each carburettor, rather than shortening the intake to a point flush with the outboard edge of the throttle bores. The old Crower U-fab (log manifold) intakes had similar plenum extensions and I believe their purpose was to dampen somewhat the reversion and pulsing effects beneath the throttle bores.

Ready for final welding now. After I have intake back, will make a small balance tube interconnecting all 3 mini-plenums (for better idle quality, will not be large enough to make this a common plenum design). Will also make a water manifold to heat base of plenums beneath carbs (for better atomization and drivability).

Will let you know how this is proceeding.

Thanks to all for your ideas and comments,

Harry

1989TransAm
Guru
Guru
Posts: 4868
Joined: Thu Feb 15, 2007 8:43 pm
Location: Cypress, California

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by 1989TransAm » Fri May 19, 2017 11:50 pm

Darn Harry, the pictures went away.

enigma57
Guru
Guru
Posts: 1216
Joined: Sun Oct 07, 2007 11:59 pm
Location: Galt's Gulch

Re: Questions Regarding Siamesed Intake Ports (9 Port Head)

Post by enigma57 » Sat May 20, 2017 2:29 am

Sorry you're having trouble viewing them, Allen. I'm not very good with computers. Especially posting photos from E-mail or from files downloaded to hard drive. I just logged on and can see them, although images in the first batch that my wife took (in post above) are so big only a portion of each image is visible here.

I'll send you an E-mail with a file of the first batch my wife took and forward you the photos Nick sent me via E-mail this past week. If you have a way to post them here in case others are having trouble seeing them as well, I would be much obliged.

Best regards,

Harry

Post Reply