Ok I have a question for those who only have built or build manifolds for a living. Sorry I have to specify, it seems everyone is a professional welder in here.

After fully welding the collector, I tacked on the rest of the runners with 4 spot welds, then tacked the runners to the head flange. I got everything where I wanted them just right, so I broke down the setup and started welding. The runners were welded up on the bench separately, then tack mounted back up again for one last fit. The runners and head flange seem very easy to get around and weld together. My problem starts with the collector. There doesn't seem enough space to get the tungsten in there.

My question is how do I go about welding the runners to complete the manifold. Do I start to weld one runner at a time all the way around, then mount the runner to the head flange? Do I weld to head flange first then completely weld to collector. Both techniques will leave me with the last runner that goes to the collector, this will cause problems since I cant get all around the last runner when it comes time to weld it the collector. I hear people sticking out their tungsten 2-3 inches out to get to this last part, but how is that going to weld without the gas so far away?

How do you go about doing it?

 

Make all the runners. Put 1 or 2 tacks to the head flage and collector. Weld as much as you can of each runner while the whole manifold is assembled preferably in your fixture/jig. Then break off each runner one by one and finish them up. Figure out the order of welding them on (if not a ram horn, if it is I do 1&4 first then 2 and 3). And weld each runner on one at a time this way you can get around everyone fairly easily at the collector and the last one is just a little hard. Depending on your collector angle and where the cut is places you can weld the seams up around the base of the pipe to each runner at the collector joint. If wide extend your tungsten out a bit and weld small areas at a time in difficult spots allowing for pre and alot of post flow to cover the tight areas. Every time you make a part you learn something new,figure something out or it gets easier to do. If you aren't your not focusing hard enough.

 

Thanx for the advice! Its a little difficult trying to weld at the collector, but I will take your advice and pre-plan on which runners gets welded first to the collector. I will start with the tightest one that way the it will leave the looser bends, and make things easier to maneuver the tungsten in for the last weld.

 

They make many types of torches, including ones with flexible heads or pencil torches. I have yet to TIG weld, but maybe this is a time to use such a torch?

 

That's the fun part of making manifolds. You have to first decide when all 4 are tacked on which would be the easiest to get to, then weld that one last. Then get creative with your tungsten and pull it out as far as needed to get into the tight spots. A little tip, if it is super tight I will even remove the cup or even remove the lense and use a standard collet setup because it's smaller... But what about gas coverage...? I use my back purge line as my main gas feed. I attach it however I can to the manifold so it is supplying enough gas to the area... Works great!

 

Great idea on the back purge line. I will have to try that!

 

keep in mind argon is heavier than air, use this to your advantage. When doing tricky spots in tight places, i pull the tungsten out of the cup by maybe 1/2 inch, then turn up the gas flow at the tank (~25 cfm). I position pieces of scrap metal around the area im working in. when starting I open the gas valve on my torch all the way up and let the argon "pool" around what im welding, then I dial the argon back at the torch to normal levels, maybe a little extra (~15 cfm) and weld like normal, maybe a little quicker than normal, and in short bursts. This has always worked well for me since i dont have a back purge setup.

 

Don't forget that Argon is not the only indert gas either. Weight relative to atmosphere is important depending on what you are trying to accomplish.

 

I've used a tungsten coming straight out of the torch with no cup, basically welding with a 4 inch tungsten. Turn off the gas to the torch, and use the purge line with a gas lens attached to it (plug the center hole or the gas will flow out of it instead of the screen). I use that to supply argon to local areas I simply can't reach othrewise.

I work basically the same way as EdsGTI ... weld as much as you can on the fixture. You really should be using a fixture to locate the turbo flange, otherwise after heating up a few runners, everything moves and your last few runners won't fit for ****.

ETc ...

 

Great info guys! I am undertaking two manifolds this weekend for the first time. She be interesting. Any pics of you guys mid process of doing these manifolds?

 

I am doing a run of 5 of the same manifold next week, vw 20v, vband precision top mount with 38mm mvs.

I am starting monday though with fall nationals being this weekend. So I can take some pictures.

I have done the purge line to it as well, You have to be very careful if you remove the cup and just have a gas lense unprotected by the ceramic.

If you touch that it explodes during welding lol.

When I first started years ago I didnt realize how much things moved and would tack everything thinking that I could weld them on the bench. Even if everything is 100% flat and not even a few thou gap it will still rotate, pull, turn brake other tacks when you begin to weld from one spot.

You HAVE to weld most of the runner (75+%) while in the jig, the same rules apply, weld the most out in the open runners and then once they are almost completely root passed pull them off (dead blow hammer and a chisel works for me after slicing the tacks with an angle grinder) and get to the rest of the other runners that were hidden by the runners you just pulled off.

Another big point, never tack in stupid places that you cant fit your grinder or access, because having to really pound on your setup to get it apart will also distort everything.

I completely weld the collector, mill the flange and everything before I even put it on the jig to get started making the runners because with some of these small engine bays rotating the flanges doesnt always allow for a simple cut on the finish machined product and if you mill it at another angle your clearance may no longer be there. I remachine other companies manifolds who use belt sanders often, not because belt sanding doenst work well, but people forget that if they are sanding in one specific spot all day the back plenum on the sander will wear a groove and start to sand worse than if it was warped from welding.

When I got my used wet/dry heavy duty kalamazoo sander I had to take almost 1/4" off of the entire plenum and re heat treat it because it was so warped, It took almost 2 hours with a insert face mill on a cnc machine because the main portion was so hard we had to move slow.

 

^^ Any pix yet?

 

disagree whole heartedly about welding runners in the fixture. Holding the ends builds up stresses in the runners that can cause problems later. I usually just tack each joint in at least 8-10 places to ensure it doesn't move during welding then do all the runner welding on the bench. If something does happen to warp (usually only happens if the joint doesn't fit perfect) I just cut and refit the runner. It's worth the extra time to me to know there are no stresses in the runner itself. Of course however flanges are always bolted down, guess I'm a hypocrit lol.

 

ive always fitted everything and tacked it all together with at least 3 tacks on all the runner joints and then go ahead and pull the runners off, weld them all up on the bench and then tack it all back together and weld the collector and head flange on. and every time the runners distort some so it never lines back up they way it orignally did when the whole manifold was tacked together.

so a couple of u are saying that if u weld the majority of the runner joints in ur jig and then pull them off as need to access the other runners and then finish all the runners on the bench (the parts u could not get to) then it wont distort much at all?


mike

 

To reduce the possible problems associated with welding the runners, I actually will completely weld each runner before starting the next one. This basically reduces the problem to one runner at a time instead of welding them all and having 4 that don't fit that have to be changed. Idk, I could be wrong but just seems like the right way to me.

 

Everyone has there own way to do it. but i will make one runner strong enough to hold the turbo for fitment if i don't have a jig. Then i build the whole thing and weld as much as i can while it's together. then i break off only the ones i need to and finish weld the whole thing.

I don't think there a wrong way just w/e your preference is.

I have caught myself when i first started building manifolds where i couldn't finish a weld. Never will i let that happen again.