Ever build your own intake... manifold?

[DirtyMJ]

IIRC, Teal did for a turbo setup or something. Or perhaps that was a header.




Anyways, cash is tight. Well, actually, it's not. It's just I can't seem to ever spend any real money on doing things the right way. Hence I tend to use the el-cheaponator route at DIY things that one really shouldn't. So, if this thread gets too freaky for you just hit the back button.


This is what I should be buying if I wasn't cheap:

http://www.jcwhitney.com/autoparts/...7/N-111+600002074+200728799/tf-Browse/s-10101

It isn't as pictured, it's actually built a little better and seems to have equal length runners and a dual pane setup. Or perhaps that's a different model. I almost picked one up used for a steal but some YJ guy with the big bucks swooped in and out-bid me. Well, 'swooped' doesn't exactly describe it, but you get the picture.


Now, you're probably wondering why I want a 4bbl intake? Well, it's to run propane. An Impco 425 for the record. Which is stupid. But a totally different story.


But enough of the irrelevent back sotry. Has anybody done anything this silly and seen reasonable results? I'm not expecting any real screamer on the performance here... If it WORKS I'd be happy enough.


My plan WAS to use 2x1.5x.188 HSS (or something like that, the ID matched the ports on the head) but my local steel yard doesn't seem to have it. And I'd rather not buy 20' at the price they want. Then I'd simply copy the stock intake design for the most part other than it would be eniterly HSS, odd geometry, and have the 4bbl carb pattern on it. The corners wouldn't be so nice, as I can't bend that stuff. But that's the price you've got to pay. If you look at the stock peice it's not like they did a great job of smoothing the corners (given my early renix eample).


So, abondoning that for the moment, I've decided to look into pipe/round tube. Which leads to a nasty problem in that it'll never match the rectangular ports on the intake. I thought about hogging out the ports a bit, to try to make them more or less round. But I'm pretty sure the casting isn't thick enough to do that in any sort of nice manner. So, given that this thing isn't going to work beatifully anyways, should I just try to match the ID size to being somewhere around the vertical size of the port? And just not worry about the poor flow characteristics that are inherent of doing this (I mean, it's gonna suck anyways!)? The advantage to round is that I can bend it with minimal deformation, which means that I can actually put fairly nice corners in it to a certain extent. And yeah, you can get those pre-fabbed tight radius 90*s too.


The other option is to take some HSS of the appropriate size on the horizontal dimension (1.5", 3/16 wall) and incorrect size on the other dimension (3") and make an angular cut along the top side of it, then weld a peice of FB over it to make a tube with a neck down. This would be alright, depending how well I can cut the angle in my chop saw. That and I wanted to minimize welds if possible as I know the inside of them isn't going to be perfect. But I am somewhat convinced it is my best option given that I don't really have many good ones.




So, thoughts? Feel free to call me an idiot. I'm well aware of my mental condition.

 

[Dr. Dyno]

Forget it. That manifold is for a 199, 232, or 258 engine up to 1980. I don't think it would be smog nazi compliant on a 4.0 and it's questionable whether it would even fit properly on a 4.0 head.

 

[j99xj]

I don't see how that manifold is any better than a 99+ or even a renix or HO.

 

[Flash]

Us the 99+ designed(dual plane) and cut a hole. weld in a 4 barrel plate. ............us the injector hole for some added NOS!:thumbup:

Flash.

 

[BLSXJ]

I plan on doing a simular project soon (next pay cheque) if you wait a few weeks I may be ableto help.

I was thinking about using tubing, but cutting it on the horizontal plane and adding filler pieces to create more of a "0" shape rather then a "o" shape

 

[Flash]

I plan on doing a simular project soon (next pay cheque) if you wait a few weeks I may be ableto help.

I was thinking about using tubing, but cutting it on the horizontal plane and adding filler pieces to create more of a "0" shape rather then a "o" shape

Why not just us the tubing"o" as desied and them just kinda smash it slight as it is fitted to the head"0"


Flash.

 

[JohnX]

Us the 99+ designed(dual plane) and cut a hole. weld in a 4 barrel plate. ............us the injector hole for some added NOS!:thumbup:

Flash.

This would be my suggestion too. I think it would be the cheapest and easiest to do by far.

 

[DirtyMJ]

Forget it. That manifold is for a 199, 232, or 258 engine up to 1980. I don't think it would be smog nazi compliant on a 4.0 and it's questionable whether it would even fit properly on a 4.0 head.

Umm. I'm pretty sure if it'll fit the 4.2/258 head on a YJ it'll fit a Renix 4.0 head. Seeing as the YJ guys throw the renix intakes on their heads to do a junkyard EFI swap. But, somebody can feel free to call me on that because I didn't do it - and like I said some YJ guy bought the manifold.

And who said ANYTHING about smog? Truck is a trailor princess without a trailor. IE, it's on borrowed time already before I will lose its tags. That and we don't have smog.

I don't see how that manifold is any better than a 99+ or even a renix or HO.

Read much? Apparently not.

Us the 99+ designed(dual plane) and cut a hole. weld in a 4 barrel plate.

Is it large enough? In the TB area? My renix intake isn't even close to being wide enough. It's rather irrelevent as I can't find such an intake this side of the border. At least, not for a price I'd pay.

plan on doing a simular project soon (next pay cheque) if you wait a few weeks I may be ableto help.

I was thinking about using tubing, but cutting it on the horizontal plane and adding filler pieces to create more of a "0" shape rather then a "o" shape

If you do that to the tubing I'll give you about a 10% chance of it not warping to all shat. But if you can pull it off do tell me. It would be interesting to try it.

 

[Flash]

DirtyMJ i really don't know sense i have only seen pic's of that manifold but it probably would hold a a small 4 barrle.............Hmmmm i can't think of it but its looks like a square box.........I what to say the flying toilet but that not it.....some one help with this:confused1

any ways it has a single throttle plate and can be adj from 500 cfm carb to 1000 this might be your best bet.


But in all honestly getting the fuel/air distribution to be equal in going to take a lot of manifold to be built and tested before there will be a worth while air/fuel flow.


When you have air running around in not so idea shapes and turns, there is no problem.........add fuel to that air and now you have fuel drooping out of the air on every turn and bend on the manifold and dripping raw fuel into the cylinder.

It sounds like a lot of fun. but it would take a lot more experience and knowledge than i have.:repair: :read: :flipoff:

flash.

 

[BLSXJ]

the trick too "squishing" the tubing will be to match the "circumfrence" but I will give it a try. Ill probly also try to make a port shaped mandrel to help with the transformation.

as far as "why" goes who cares why he/me wants to mount a 4brl carb on a 242!

 

[DirtyMJ]

DirtyMJ i really don't know sense i have only seen pic's of that manifold but it probably would hold a a small 4 barrle.............Hmmmm i can't think of it but its looks like a square box.........I what to say the flying toilet but that not it.....some one help with this:confused1

any ways it has a single throttle plate and can be adj from 500 cfm carb to 1000 this might be your best bet.


But in all honestly getting the fuel/air distribution to be equal in going to take a lot of manifold to be built and tested before there will be a worth while air/fuel flow.


When you have air running around in not so idea shapes and turns, there is no problem.........add fuel to that air and now you have fuel drooping out of the air on every turn and bend on the manifold and dripping raw fuel into the cylinder.

It sounds like a lot of fun. but it would take a lot more experience and knowledge than i have.:repair: :read: :flipoff:

flash.

I appreciate what help you can give. I took a look at the pictures of some of the newer (99+?) intakes and they possibly could be made to work - but at high risk of destorying something that will cost me at least $200 from a wrecker (yeah, we have sweet deals here). Hence it makes more sense to mess around with all of the extra steel I have lying around first.


The only reason I'm doing this is to run propane. As I said an Impco 425 4bbl. I didnt really elaborate on that and I'm sure most would have missed that that ment propane. Anyways, one of the few redeaming features or propane is it vapourizes at about -40~. So, it's really hard to create enough of a turbulence that it will actually cause the fuel to condense. The mixer design is also highly effecient at mixing the air/fuel before it enters the manifold meaning that as long as you're getting reasonably even flow to each port things should work alright.

 

[j99xj]

Read much? Apparently not.

What is that suppose to mean?

 

[DirtyMJ]

Yer missed the point of the thread.

 

[5-90]

Forget it. That manifold is for a 199, 232, or 258 engine up to 1980. I don't think it would be smog nazi compliant on a 4.0 and it's questionable whether it would even fit properly on a 4.0 head.

Moot point - he'll have to walk his propane mod past the Air Police anyhow. I'd considered converting to propane myself, but the California Air Police just give a flat "No" on pretty much any useful mods for transition vehicles like my RENIX (electronic controls, but pre-OBD. Like those damn fools know anything about how an engine runs anyhow...)

Almost forgot - Robert Bently Publishing, Scientific Design of Intake and Exhaust Systems. Don't have my copy yet, but it's on the "want list."

 

[Flash]

I appreciate what help you can give. I took a look at the pictures of some of the newer (99+?) intakes and they possibly could be made to work - but at high risk of destorying something that will cost me at least $200 from a wrecker (yeah, we have sweet deals here). Hence it makes more sense to mess around with all of the extra steel I have lying around first.


The only reason I'm doing this is to run propane. As I said an Impco 425 4bbl. I didnt really elaborate on that and I'm sure most would have missed that that ment propane. Anyways, one of the few redeaming features or propane is it vapourizes at about -40~. So, it's really hard to create enough of a turbulence that it will actually cause the fuel to condense. The mixer design is also highly effecient at mixing the air/fuel before it enters the manifold meaning that as long as you're getting reasonably even flow to each port things should work alright.

Sorry fogot about the propane being the fuelof choise on this projest!

and yes you are right it would have to be vary cold, cold to get fuel drop out!

Flash.

 

[j99xj]

Yer missed the point of the thread.

I didn't miss the point. I was making my own point. This is a forum you know.....

The point in my comment is that if your going to "copy the stock intake design" anyway that it would make better sense to modify an existing Jeep manifold to suit your needs. Take Flash's suggestion.

But if your the type that has more time than common sense, then go for it.

Have fun blowing up your engine with propane.

May I suggest investing in a fire extinguisher?

 

[Moab Systems]

If you have no smog stuff to worry about, I would say go for it, if nothing else, it will give you more experience with fabbing. What we did when we made our intake and headers for our slant six (EC4WDA jeep) was hammer the end of the tubing into the "squared" port shape of our flange. As for the intakes, I know several people that used a stock intake to modify to put the 4 barrel for our racing and have had good luck with it. To make our intaker we used stainless exhaust tubing. We bought the 180 degree bends so we had mandrels already formed....worked awesome. Good luck.

 

[Dingo509]

DirtyMJ i really don't know sense i have only seen pic's of that manifold but it probably would hold a a small 4 barrle.............Hmmmm i can't think of it but its looks like a square box.........I what to say the flying toilet but that not it.....some one help with this:confused1

Are you thinking of the Predator? Square box with an eagle on the side? It's actually a single barrel (if you can call it that). It only has one big square hole.

Ok one question. Do you have this propane injection carb already? I ask because if not there should be an easier way to do this. I have helped build an injected, blown 454 for a street rod and we used a GM 4-cylinder computer. Right under the scoop was 2 airvalves, NOT CARBS believe they where holley throttle bodies, no fuel control just 4 holes and throttle plates. Then under those but still on top of the blower was an aluminum plate with 16 injectors in it.

so why can't you just use the existing intake/throttle body and make a spacer (or use an existing throttle body spacer) and drill and tap a fitting into it for the propane?

I will admit that i know nothing of how propane systems operate so this may not work.

Dingo

 

[DirtyMJ]

I actually have a hord of propane parts from various vehicles. I have an impco 425 with equal sized primaries and secondaries (mechanically activated secondaries) which I had not origonally intended to use but would use if I was to build an intake myself. I also have an impco 300A; which is ment to be used in a dual fuel setup by being bolted to the top of a pre-existing carb. It has no throttle regulation of its own.

However, to make an adapter for it to the Renix/HO TB would require a bunch of time on the lathe and would create massive clearance issues (by by hood). I still consider it a viable option as I could get as much time on the lathe as I want in the next couple of weeks. But, that doesn't make it ideal as the Renix/HO manifold would need a lot of plugging (injector holes, bloody EGR, etc) which is a all well and good other than I'm not big on trying to weld aluminum with the SMAW. Block off plates could be made for some things, but it's still ugly. And there's that hood thing.


If anybody has a picture of a stocker intake modified to actually fit a 4 barrel I'd be interested.

 

[DirtyMJ]

Have fun blowing up your engine with propane.

So, it's gonna explode, eh?