dj55b

iTrader: (2)

Hey guys,

Here's my little dilema, I have a powder coated intake manifold, and would like to add a couple more fuel injectors. Now i could waste that nice finish on the manifold, and weld in the bungs, but thats such a waste of a good powder coated manifold.

So i had to expand my options a bit, and thought if i machine a custom bung, and drill the holes on the upper part of the manifold on a mill and get a very tight fitment on there, slap a bit of JB weld or Loctite Weld.

Here's a shot of the Intake in question:

David Hayes

iTrader: (6)

How about drilling a hole and then cutting in some threads with a NPT tap? With this you could just screw in the injector bung without any need for JB Weld or Loctite.

http://www.toolsusa.com/asp/item_det...ode=GoogleBase

Here are metric to NPT adapters:

http://www.sealconusa.com/encnpthub.htm

I think they sell them at Home Depot and Ace Hardware

dj55b

iTrader: (2)

I have thought about this too, but I'm not sure it will work out too good. The insert that I'm making will need to be beveled on the side the is going inside the manifold and I'm not too sure how much thickness I have to play around with.

I would like to have them positioned right above where it says "Racing Beat" on the manifold shooting downstream. Also I was thinking of making one billet piece that goes to both sides and then just drilling and tapping the ends to have the fuel rail bolt on to it as oppose to drilling and tapping the manifold to keep the flow inside as good as possible.

David Hayes

iTrader: (6)

I dunno, seems like your best bet is to weld them on and have the UIM re-powder coated. Wouldn't be over $50 would it?

PvillKnight7

iTrader: (16)

JB weld is fine.

dj55b

iTrader: (2)

It's not about cost, I can do the welding and powder coating myself . But that, powder color is no longer available, and taking out powder coating is a pain in the butt.

I did forget to mention that it will be boosted too later on in its life but no more than 12 psi or so.

dj55b

iTrader: (2)

It's not about cost, I can do the welding and powder coating myself . But that, powder color is no longer available, and taking out powder coating is a pain in the butt.

I did forget to mention that it will be boosted too later on in its life but no more than 12 psi or so.

fritts

iTrader: (5)

You have got to be kidding. JB weld, Loctite? Weld it, do it right or you will have issues. Fuel leaks are dangerous and if it came apart you could easily start a fire being over the top of the exhaust manifold.

Chuck Norris FB

+1

PvillKnight7

iTrader: (16)

JB weld is fine. It's used to seal PP intake sleeves. I know it can handle joining some non-structural aluminum because I've used it and seen it used by others on custom intake manifolds. There is another bonding agent called devcon that has similar applications to JB weld.

Here's the specs on JB weld:
http://jbweld.net/products/jbweld.php

500F continuous.

The key to a good, strong, long-lasting bond is in the prep work. Make sure the surfaces are free of contaminants like and paint and oil by using acetone and course sandpaper to prep the surfaces.

It's also good practice to keep one of those small kitchen type fire extinguishers behind the passenger seat. You never know what might go wrong on a 20+ year old car.

dj55b

iTrader: (2)

Well i think i figured out what I'm going to do, I think that I'm going to grab an aluminum dowel turn it down and drill it to fit the injectors and put a lip on it. Then i'm going to make an insert that sits over that lip with another hole in it that will hold an m8 bolt or something so that insert is going to look like an "8" figure with one hole larger than the other. I'll still seal the injector insert with jb weld though.

I'll get a few pictures going soon, but I should start manufacturing the parts tomorrow if I get a chance. I have to finish welding a set of headers first.

Then all I need to do is figure out what to do with the fuel rail now.

PvillKnight7

iTrader: (16)

If you have these awesome fab skills, your creative, and have access to machine tools what do you need us for?

fritts

iTrader: (5)

No matter what you use to justify its use it is not best practice and can fail. Look at it this way would you consider a PP motor a long life motor.

dj55b

iTrader: (2)

because a little insight now and then never hurts.

dj55b

iTrader: (2)

then what would you suggest that I seal them with? Just high temp silicone?

fritts

iTrader: (5)

Tig them in. Its just powder coat. Aesthetics should always follow function

levelzero

iTrader: (1)

Freeze fit them.

Drill/ream the holes in the manifold to size. Machine the bungs 0.003" over. Place the bungs in the freezer and heat the manifold to 300*c (which should be safe for the powder depending on brand). Tap the bungs into place. Once thawed they shouldn't move. There are a couple production engines that do it this way for the cam gears. 0.003" might be too much but it's typically what I use. There are formulas out there to calculate shrinkage for free fitting though.

You can also use green loctite. It's used to hole cylinder liners in and is virtually impossible to break once set.

dj55b

iTrader: (2)

I hope that I can maybe do this, I'm having issues that the insert always wants to angle when I'm putting it in as it not equal levels. Here's a few shot of it so far. The hole size is 1/2"

I already made some inserts for it also, but I think that I'm going to have to made them about 1/4" longer for it to sit properly or just take a 1" mill bit and take out a bit off the top so the insert sits better which might also help locate it in the hole better.

levelzero

iTrader: (1)

You could make the insert longer and taper the end. A 3* taper should be more then enough. The drawback to this method is having to grind out the insert from inside the manifold.

dj55b

iTrader: (2)

Ya i think that I might have to do something like this.

dj55b

iTrader: (2)

Decided to keep the same inserts that I had, but just used some loctite 638 on it. Seems to be holding up decently right now. Still need to make the retaining parts for it.

dj55b

iTrader: (2)

the function is the same, its just the approch to it.

David Hayes

iTrader: (6)

Post up some pics. I am interested to see how it all turns out.

dj55b

iTrader: (2)

I'll get some pictures later on tonight. I didn't sleep last night working on the intake. And to make matters worse, I have to modify every fitting that i bought for my fuel pump as nobody carried what I needed.

So i still need to finish up the plate that holds both of those injectors bungs in, and also I'll be making my fuel rail today. I'm buying a chunk of 1x1/5x5" 6061 aluminum and machining it to fit. The ends will be tapped with 1/4" NPT and then get the -6an plumbing routed.

dj55b

iTrader: (2)

well day 2 of no sleep lol ... just starting my fuel rail, its sitting on the lathe now finished machining the ends so they're square now. Drilling the holes is alway fun though to make sure it ends up as close as possible to center on the other side. Its 5" long, I've done 12" before and worked so it shouldn't be as bad.

One a second note, after running a heat gun for quite a while on the loctited parts, I grinded the excess stickout with a die grinders and all smoothed out from the inside. If it survived the harsh grinding I'm sure it'll survive on the engine. I just hope there is no vaccum leaks out of there.

I'll get pictures once I have a bit more done, things are still looking a bit rough and crude.