Dewedging throttle body

[tez]

I've got a couple of questions about dewedging the throttle body. Me and Chris tried it tonight, and ran into a couple of problems.

I got as far as taking the wedges off, but you can't really get the rivet gun square on to the holes. Chris gave it a go on his, and one of them wasn't sealing properly so he had to drill it out (knackering the throttle plate in the process). Is there a way to do this without taking the throttle plate out?

Also, is there a knack to getting the screws out of the centre spindle? I tried on mine with a view to getting the plate out and putting the rivets in with a bit more access, but I can't get a proper grip on the screws. I don't want to round them off, so have been a bit cautious.

Cheers!

[PeteG40]

you just need a rivet gun with a deep nozzle.

[Chris_J]

I'm going to make an alu plate up to replace the wedged one. For some reason, the rivets feel pikey to me and wasn't really 100% on doing it.

I think you should have another go at removing the spindle screws and I'll get a plate made up for you  

[tez]

Cheers Pete, seems I've got you to thank for saving my charger before it destroyed itself too!

Fair enough Chris, I'm going to give it a go with some better screwdriver heads. Going to be fun if I round them off though!

Let me know what you decide about going 51mm with it...

[Chris_J]

Cool, will do. If I do go 51mm, it will be on Saf's spare one, as I'll want to be able to return to stock of course

Was thinking about it before, it may not be worth doing on my setup. Would be much better combined with a GT inlet, smaller pulleys and ported charger.

Since you're running a stage 4, toothies and various other engine mods, I think you'll certainly notice the difference.

Either way, I'll see what I can sort wrt machining.

[PeteG40]

the flat throttle plates (without wedges) can be bought from maxrpm and bartek.

When i de-wedged one I used dome headed allen bolts and nyloc nuts with more loctite (safety first)

[Justin14100]

I could make up some 45mm chamfered throttle plates if people are interested?

[hayesey]

I did mine with liquid metal eventually.  Used rivets at first but decided liquid metal would be better.  Put a countersink on both sides of the holes first so that when the liquid metal hardens, it's cross section is hourglass shaped.

It's very, very hard to make a new throttle plate that seals properly and doesn't stick.  They have an unusual opposing chamfer on the edges.  I heard stories of PSD spending hours and hours with wet&dry paper trying to get each one right when they did 51mm throttle bodies, and even these still stick slightly open when they should be closed sometimes.

[Chris_J]

Measuring the plate with a vernier, it seems that they are not quite perfectly round anyway.  Only 1/10th of a millimeter variance around it's circumference, but not quite perfect all the same.

Like you mention Hayes, when I saw this I was worried about getting a propper seal without sticking. I've got access to a lathe this week, so I will have a go at turning some and see what they're like.

As a failsafe, I'll try your liquid metal trick.

[Justin14100]

They're elliptical and not just a round disk - Steve started with a 2" disk according to the guys who did them for him (the guys I went to about getting some more phase 2 toothies done) I've worked out what the original chamfered angle is and cut mine to it.

[Justin14100]

Also, I'm quite sceptical about what the seal has anything to do with the idle sticking, unless somehow the throttle actually gets jammed open it shouldn't make a difference. I've had some original bodies that have a seal worse than the 51mm bodies I make.

[hayesey]

possible yours are made better than the PSD ones were? 

[Chris_J]

Eliptical, seriously!!? That seems mental that they would machine them into that shape 

Sounds like my turned ones won't work then, bugger.

Sounds like I'll be putting the original back, unless you're making some up 

[tez]

Justin, how much are we talking for a 51mm body if I send you my standard one (currently minus wedges)

[Justin14100]

It has to be elliptical to seal, if you think about it - it doesn't shut at 90 degrees to the opening so it measures 51mm(or 45 for that matter) along the shaft but it is longer against the other axis. The angle it shuts at is what defines the chamfered edge angle.