Make your own throttle plate?

So now that I have a metal lathe, I have a few ideas I want to play around with. One of them is a bored out thtottle body. Its a popular mod to have a stock jeep 4.0 TB bored out to 62mm to match the opening in the intake. But the cost of these bored TB's are crazy. Now that I can do it myself, I want to.
The actual boring of the TB will not be the hard part. The throttle plate will be. Has anyone ever made one? Most I have seen have had a ever so slight taper on each edge of the blade, I'm guessing to account for the blade setting a few degrees at a angle instead of perfectly flat. How would you even do that? Slow carefull work with a fine hand file I'm thinking?

Or does anyone know of a OEM throttle body with a 62mm plate I could find in a junkyard?

how about 65 and possibly turn it down the 3mm you need? i can think of one or two of those off-hand, though i don't know if the fastener locations on the plate will match the shaft of your TB.

Can I borrow your lathe? Possibly for a year or two? J/K - I have pulled off some cool Jeep mods before. My favorite Jeep project was a 2003 Rubicon - loads of nifty mods, including a switch to enable the locking diff's in 2HI and 4HI. This gives it the ability to run fast up the sandy hills in the desert without the low gear ratio causing a loss of traction.

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Originally Posted by RobertISaar

how about 65 and possibly turn it down the 3mm you need? i can think of one or two of those off-hand, though i don't know if the fastener locations on the plate will match the shaft of your TB.

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That thought crossed my mind also, find one slightly bigger and turn it down.
I guess the only way to tell if it would work would be to try it. New holes can be drilled easy, I had to do that on the 75mm blade I have in my vortec TB I have on my cherokee. The stock blade has that deflector rivited to it, but I found the throttle blade from a late model northstar engine is the same size, but with no deflector. I just had to drill 2 new holes. The throttle shaft covers up the old holes and causes no issues.
What should I look for at the junkyard?

the oldsmobile 3.5(shortstar) has a 65mm TB, popular to swap the entire unit onto 60V6 engines with an adapter, should see plenty of those in a junkyard with blown headgaskets.

not sure how well it would work, but the 04 to 06ish 3500 has a DBW throttle at 65mm. not sure how easy it would be to pull the plate out.

a google search shows a lot of interesting 65mm applications, especially some older stuff should your yard not have any newer vehicles(the ones local to me have a lot of mid to late 90s stuff, not much outside of that).

a search for 62mm throttle body also shows a lot of interesting stuff.

http://www.jeepsunlimited.com/forums...ich-one-to-get

dakota 4.7 are apparently 65-68mm.

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Originally Posted by JeepsAndGuns

So now that I have a metal lathe, I have a few ideas I want to play around with. One of them is a bored out thtottle body. Its a popular mod to have a stock jeep 4.0 TB bored out to 62mm to match the opening in the intake. But the cost of these bored TB's are crazy. Now that I can do it myself, I want to.
The actual boring of the TB will not be the hard part. The throttle plate will be. Has anyone ever made one? Most I have seen have had a ever so slight taper on each edge of the blade, I'm guessing to account for the blade setting a few degrees at a angle instead of perfectly flat. How would you even do that? Slow carefull work with a fine hand file I'm thinking?

Or does anyone know of a OEM throttle body with a 62mm plate I could find in a junkyard?

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You are correct , the basic outer diameter is easy to get to , it's the slight taper to fit the bore and not bind when opened and closed that is the trick. Also , be sure to account for temperature when you final fit the blade , if you finish in a shop that is 70 degrees , I can gaurantee it will bind once the engine is at a lower temperature ,say in a colder climate or winter.

I like to start with a blank that is slightly oversized and file it to what I want . Remember "Feel, File , and Form to Fit" .

TOM

Quote:

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Originally Posted by RobertISaar

the oldsmobile 3.5(shortstar) has a 65mm TB, popular to swap the entire unit onto 60V6 engines with an adapter, should see plenty of those in a junkyard with blown headgaskets.

not sure how well it would work, but the 04 to 06ish 3500 has a DBW throttle at 65mm. not sure how easy it would be to pull the plate out.

a google search shows a lot of interesting 65mm applications, especially some older stuff should your yard not have any newer vehicles(the ones local to me have a lot of mid to late 90s stuff, not much outside of that).

a search for 62mm throttle body also shows a lot of interesting stuff.

http://www.jeepsunlimited.com/forums...ich-one-to-get

dakota 4.7 are apparently 65-68mm.

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That gives me a few things to look for next time I go to the yard. Usally its hard to find anything newer than the early 2000's at the one I go to the most (pull a part)

Here's some usful information if your going to build some throttle plates. From EFIhardware.com

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EFI HARDWARE PRODUCE 6° THROTTLE PLATES

In the past, 12° throttle plates were the industry standard. The problem with 12° throttle plates, is that as the plates are moved off the closed position, the change in airflow is huge. It makes it very difficult to drive smoothly at lower throttle openings.

At EFI Hardware, we only use 6° throttle plates. This improves off idle and cruise driveability making your vehicle far more enjoyable to drive.

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That's a bit if a red herring. So what if the actual opening is twice as much at a defined throttle position? We drive by feel so we will only open the throttle enough for the amount of acceleration we want.

Wet to the junkyard this morning. Found one of the shortstars, pulled the plate out of it (charged me a whopping $0.50...lol) Didnt see any of the other above mentioned vehicles.
Brought it home and thought I would test fit it to the shaft, its too thick. The original blade is .063 thick, the shortstar one is .080, its also 64mm. mounting holes are also real close, just a few hits with a small round file would make it fit.
I think I figured out a way to hold it while turning it down, but I am not sure what to do about the thickness. I'm not seeing a easy way to make the slot wider.

I am going through the same thing, different unit. The Eaton M90 supercharger on the 3800 series 2 L67 engine has rebuild kits and individual parts available. My boost bypass rotating butterfly valve has abnormal wear on one side. It looks like something was pulling on the rotating shaft that connects to the vac diaphragm. I have seen only one for sale on ebay and they wanted $65 for it. To the junkyard I shall go.

I've also got a lathe/mill in my shop and have wondered this myself though I have yet to try it. Usually easier to just make an adapter and transplant another TB.
Keep thread updated if you figure out a way,I always figured when I give it a try I would just transplant another plate if I had too.


Nameless send me a pm,I have to go back thru my rebuilt m90 to fix a screwup and wasn't going to use the bypass on the motor/vehicle it's going in.
If I can figure out a way to block the hole than you can have mine.
The bypass shaft and plate are both ceramic coated (poorly since it was used as practice but it's fine).
I've got to pull apart another stock M90 to pilfer a rotor as well,it still has the bypass valve in it also.
Just gotta find a plug big enough for the hole.

I thought about swapping on another TB. But I have yet to find one that looked doable without too much work to make it not worth it.
I have seen a writeup where someone modded a 65mm ford V8 TB onto the 4.0, but the stuff he had to go through to do it was not worth it to me.

I looked at the shortstar TB when I pulled it for the plate, as the thought of swapping the whole TB crossed my mind. But its so oddly and differently shaped, I dont think it would be easy to swap on.

Ok, here is a thought I had while looking at the shaft in my TB, it may be a very bad idea. What about removing the top half of the shaft? The shaft is 3/8in. If I remove the top half, the bottom is 1/8 thick. Is that safe? Would that weaken the shaft too much? I dont want to run the risk of the throttle shaft breaking. Doing that would make it easy to bolt on this shaft.

i want to say it's been done in the 60V6 world before without issues.

i've seen aftermarket ones that claim xx more CFM = ZOMG MORE MMS WIT DA SAME SIZE BECAUSE HAF TEH SHAFT IS GONE.

I dont care about a tiny little bit of cfm from halfing the shaft, I'm more concerned about saftey. I dont want to theaft to be too weak and risk it breaking and going WOT. I have a manual trans so all I would have to do is push in the clutch real quick, but then the engine would redline if I didnt shut it off just as quick.
This TB I have is just a extra one I have, so I may play with it and see how it feels.

Yeah,i've halfshafted them before,really common when you do the restrictor plate mod for some folks on the vortecs.
just make sure you cut off the side that doesn't have the threads :mad1: