🔧 BUILD Upside-down M90 GTP build thread

[GTPpower]

Pulled the lim.

I think this weld alone fixed about 10 leaks.

 

[v6buicks]

Welding that pipe to the cast intake the way it is looks miserable. Do you have an oven or anything to preheat it with?

 

[GTPpower]

Welding that pipe to the cast intake the way it is looks miserable. Do you have an oven or anything to preheat it with?

Maybe I'm doing it wrong, but I don't really think that's necessary on aluminum. It gets so damn hot after only a few seconds of welding.

 

[v6buicks]

Maybe I'm doing it wrong, but I don't really think that's necessary on aluminum. It gets so damn hot after only a few seconds of welding.

Preheating it will not only help work out the impurities, but it will allow the temp to rise gradually versus being shocked with the torch. You also get the advantage of the whole part expanding at the same rate. This prevents cracking. It's always weird for me to think about this with aluminum because it's already such a heat sink by nature, but certain castings can change everything. I went down this rabbit hole when I converted my FWD manifold for RWD. I actually didn't even do the welding myself, so I'm just relaying what I was told. I handed it off to my work buddy who does this stuff pretty regularly. He still struggled like hell to weld it without leaks. Long story short: these manifold castings can be kind of a bitch. lol

Is the pipe counter sunk at all or is it just butting against the manifold? I think sinking it would make welding a lot easier too, but it would be a lot of work at this point.

 

[Turbocharged400sbc]

You can definitely tell you're improving. Times two on the preheat get yourself a map gas torch

 

[GTPpower]

I really don't think I'm any better, the welding area is just cleaned much better now. I'm removing material with the die grinder now versus just touching it with a wire brush last time.

 

[v6buicks]

I really don't think I'm any better, the welding area is just cleaned much better now. I'm removing material with the die grinder now versus just touching it with a wire brush last time.

Using a stainless brush that's used ONLY for cleaning aluminum is a good thing too. I've accidentally used my "everything else" welding brush on aluminum before and it's wild how much of a difference it made for the worse. If there's one thing I learned in welding school, it's that welding is pretty easy. It's prep and set-up that get you!

 

[GTPpower]

Yeah I have a brush that I only use on aluminum. It was just impossible to clean due to access.

 

[GTPpower]

Found 9 leaks in the blower hat. Got all those fixed and it's tight now. They were all either from trying to weld 1/2" plate with a 200 amp welder, or the anodized coating on the pipes.





Also, getting ready to test the lim for leaks again now that I rewelded it on the pipe connection.

 

[GTPpower]

Only two left in the lim, and they should be easy to fix. There might be something leaking on the throttle body though. I can't quite tell for sure yet.

 

[GTPpower]

So everything is fixed. But, there is a giant leak at the throttle body shaft. What am I to do with this?

 

[Mr_Roboto]

traditionally you would bush the shaft if it is really bad.

 

[Turbocharged400sbc]

not alot to do, the oem seals are negative pressure, if you flip em youll have vac leaks.

ive seem plastic nylon sleeves put under the throttle linkage cam to push inward on the seal lip so it cant burp under pressure easily

 

[GTPpower]

Can I switch to a different TB that would be better? N* or something?

 

[Turbocharged400sbc]

I believe most of the aftermarket LS style throttle bodies are pretty good for Boost I don't know about the OEM stuff they might be the same sealed bearing and simple viton Bellows type seals....

 

[Turbocharged400sbc]

high pressure throttle body shaft seal? - LS1TECH - Camaro and Firebird Forum Discussion

Forced Induction - high pressure throttle body shaft seal? - Does anyone know where to find some kind of high pressure throttle shaft seal for the stock Ls1 throttle body? Found out my seal is blowing tons of air out of it. I cant even find a replacement seal for it. Would another car have a...

ls1tech.com

 

[Turbocharged400sbc]

Are throttle body is pretty much the exact same setup right down to the 10 mm shaft size. You can probably do the exact same o-ring and flipping trick that he did

 

[GTPpower]

Nice! Looks like I'm going to take it apart this afternoon. Thank you much.

 

[Turbocharged400sbc]

no worries. its my duty to help slow folks

 

[Turbocharged400sbc]

im looking at this tb and it looks like you could use 3 old injector o rings stretched over the shaft.

i wonder if thats where he got those orings from lol

 

[GTPpower]

But wasn't one bigger than the other two?

 

[Turbocharged400sbc]

yeah thats probably a good point.

instead use a VC grommet with the 3 tits cutoff

 

[Turbocharged400sbc]

for the love of god man, just cobble it together

 

[GTPpower]

I'm about to be living in a boost leak free world!!!!

 

[Turbocharged400sbc]

bulshit.

your still gonna have boost leak past the tips of the rotors