Inliners International Forums General Discussion Engines Tech- Hogging out fact 1bbl to 2bbl - TurboJED

In my quest for more CFM's of flow, I decided to try and hogg out my factory intake instead of buying a Offenhau$er. After all, this was mostly free. A big thanks to good bud, Jesse Greening (www.greeningautocompany.com) for expertise and equipment. I have a few pics of the process.

Milling the carb adapter flat and opening the hole to a 2bbl.


Started to hogg out the 1bbl. notice the 1bbl sleeve. I uncovered some cavities, that I will fill with JB weld


Opened up and carb adapter mounted


Blasted and painted



I also made a plate to block off the exhaust / intake heat transfer hole.

Looks good. It's great that you have access to a mill. I spend most of my time at the shop on the mill and lathe making/modifying parts for engines. I wouldn't have built my Jimmy if those machines weren't available.

Ron

I agree with Ron. It looks good and a bud with a mill is a good bud! Do you plan on running any heat to the carb?

No heat to the carb. I will be installing it just like the factory setup was but, without the exhaust damper and with a plate between the two.

Oh, you are telling me. Without his mill, there is no shot at this. This is embarrassing, but I cannot believe I was actually thinking about milling it down with low grit sandpaper and a palm sander. Then, trying to cut out the hole with a damn hole saw! ignorant.

Jesse is an amazing fabricator. Big ups to him.

Great pics! How deep did you go before you discovered the 'sleeve' in the intake? Have any pics from before you started milling the intake?

Here is one, the carb mounting surface is raised about 1/32", so I took it down until it was completely flat.

Do you plan on sealing up the open (old exh) ports on the sides? This would streamline flow.

Looks nice, good job! Tom

Very nice work. Looks like it belongs there. Not a clunky mod. I don't know if it would be a good idea to fill what's left of the old 'stove' - though it would concentrate the heat on the floor where pooling can occur. That said, leaving it as-is maximizes the hot surface area . . .

tonight i tried to fill the cavities with JB weld. It was very messy. The two cavities connect and I had JB weld running out. After taping off one side, it went well. It is hard to tell by the pictures but the cavities you see are on a totally different level than the actual intake runners. I am a little nervous about the temp getting too high, but JB Weld says its good for up to 600deg. So, we'll see.

You can machine the entire cavity out leaving only the outside walls. This will leave you with two holes in the bottom that are very simple to braze shut, this gives you enough area to adapt even a four barrel and it will allow you to round the entry to the 1-2,5-6 runners. Then intake can be bolted back to a stock exhaust manifold or used with headers. I have used a belt sander to get a flat surface to bolt an alum adapter plate I make from 1 1/2 or 2 inch thick alum. Using the thicker alum block allows you to drill passages around the outside for additional water heat if you drive in very cold weather. This project can be done with a belt sander and a drill press and a few carbide burrs if you don't have a mill.

big bill,
How was the performance of one of your modified stock intakes? Did they work well with a 2bbl/4bbl? How did they compare to any of the aftermarket 2bbl/4bbl intakes?
Thanks,
JP

I think they work very well on a street machine with a four barrel. I am using one currently on my car, built it about eight years ago. Total investment is usually $25.00 or less plus your time. I have never dyno one to compare but if you want to do it yourself and don't wish to pop for an after market unit then have at it. Some guys just enjoy making there own like we did back in the day when the aftermarket arena wasn't as large as it is now. Keep in mind that all those guys you read about that originated the parts you buy today started out making a part because they couldn't or wouldn't go out and buy it. Some even got lucky and became famous others just had a sense of acomplishment that they did it themselves.

IMHO a 2 bbl. is a win, but nothing larger.
Any 4 bbl. needs a very tall transition piece to re-direct the flow into the manifold, and the area of the throat has to be larger than the manifold's cross-section.
A Holley 390 4 bbl. with 1-7/16" throttle bores has to be necked down to a single 2-7/8" opening to avoid restriction - the manifold isn't big enough.
Even making the entry point an ellipse 2" wide by 3-1/2" long only moves the restriction away from the transition, since the manifold runner is way too small.
This is why adding a 2nd carburetor works: it only feeds the adjacent cylinder pairs, not the whole row of 6.

One thing to do before you put in the JB Weld, is to use a mig welder in the areas you are applying the JB Weld,, using a mig welder let the wire weld to the intake & leave the wire in the welded areas & cut off the too long of wire,then apply the JB Weld,,, this will allow the JB to grab onto something ( the wire ) & not break loose & possibly go into your engine.

Hope that makes some sort of sense?

MBHD

Hank, it does. I did one half the other night and JB weld is some amazing stuff. It conformed to the mold of the cavities really well. Inside the cavities are a lot of irregular shapes and crevices. I believe/hope that the JB will hold.

That is good Boucher.

I would not use the JB quick weld, I my experience, it would not stick as good ,more so when fuel gets to it.

Maybe on the instructions it says not to use w/fuel?

I used JB weld a lot of times for my 2 stroke porting & reshaping of the transfer ports boost ports but mostly for the reed cage & intake area right after the carb. I used it for racing when I used to race motorcycles @ Willow springs.The fastest track in the West.I was not the fastest though, but I did win a championship w/JB weld.

MBHD

235/261 version for large base Rochester 2G:

The key is going to be keeping the heat riser block-off plate from burning/eroding away. If you can do that the filled port should survive. I have seen similar thin block-off shims fail and burn up the epoxy on the other side. As long as you have the mill why don't you take .062" off the face of the heat riser and use a 1/16 stainless shim block-off plate. That way you will be safe and avoid a teardown hassle to repair it in the future. A little red silicone hi-temp sealer would be good insurance too.

Good luck with the project. Let us know how it works.

(This is the smallest size, 100 pixels)
CurtB,
When you open your pics up there is a button at the bottom of the photo, if you hover your cursor over it, it says, "copy the code to post this photo in a forum"
When you click on this button, it gives you several size options and three different link codes that you can copy/paste into the forum. You want to copy/paste the bottom-most link code directly into your post. The image that this link-setup generates is a clickable thumbnail so clicking on the images will take the viewer to your photo album for a bigger view.

G'luck
-Stephen

Panic
You cut it out to the out side wall which leaves it almost square then where you left the bolt bosses you cut them down to almost nothing. Now you have room to round the runner passages and to polish everything up. Then you make your alum adapter that I mentioned Taper from the outside of the carb openings to the new manifold opening and install it with the longest bolts possible. I never depend on a plate to seal off the manifold I always braze the holes left in the bottom shut.
This will produce a street manifold that will handle a four barrel and have good torque. I may not make the all out horse power that a clifford will at high RPMS but if properly done you will be amazed. I tow my roadster behind my sedan at highway speeds with no problem. Many people on this board have seen it several hundred miles from home and some have followed it at speeds in excess of 70 mph while towing the roadster. I am not claiming this to be the super best you can get, but it does work well if done right.

Thanks for the IT lesson.

How do you think this type of a spacer will cause the engine to react? It seems like a mini tunnel ram, almost. Looks about 2 inches or more high. Does any one care to hazard a guess?

Curt B. - wow, that is nice. I like how you do it in Canada.

Anyone care to comment on the above mentioned 2 barrel adapter for the 235?

hey Boucher, nice work... a year ago i was thinking of doing the same but did not have the resources...