What should I do with this manifold?

[Jamesdorsey89]

Well, over the weekend I decided to see if I could find the exhaust leak I have heard around the front of the motor. I took the heat shield off and it revealed a HUGE crack in the manifold

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So I found a used 2g manifold that had been ported already. The guy was asking $90 for it which I was able to talk down to $70. Well I meet the guy to look at the manifold and there are some small cracks on the inside where all of the runners come together. So I ended up getting the manifold for $60. I didn't think that was to bad of a deal.

My question is, what should I do about these cracks? I have heard some types of welding make it more prone to break again. Which type of welding should I have done to it? I know how to weld, but I am guessing it is something different that MIG welding. Any recommendations would be greatly appreciated.

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[ramsack]

do you just skim over what people type and look for stuff to go off about? if you read it again carefully i said "minimal gains for non-high-hp cars".

nobody in here came to flame what the OP was doing we are just informing him he may lose a little spool, which is true, and that he may have to port the inlet to his turbo. i told him he should maybe not buy it, but i looked at the cracks more and they are just on the divider. they will likely never expand to the point where it will leak outside.

 

[paiutey]

Some manifolds look cracked but aren't actually cracked. I've noticed some manifolds have this "cast shell" that cracks and crumbles off. Just upgrade to a 2g manifold

 

[pj91gsx]

do you just skim over what people type and look for stuff to go off about? if you read it again carefully i said "minimal gains for non-high-hp cars".

nobody in here came to flame what the OP was doing we are just informing him he may lose a little spool, which is true, and that he may have to port the inlet to his turbo. i told him he should maybe not buy it, but i looked at the cracks more and they are just on the divider. they will likely never expand to the point where it will leak outside.

stick to your opinion ill stick to mine.

 

[Jamesdorsey89]

my manifold was cracked quite badly on the #4 runner and i thought it was warped because on #4 it would not sit flat on the head and there was oil inside there from the vc gasket leaking. went to put on a brand new manifold and it rocked back and forth on the head, so my head is warped and it still leaks just as bad.

This somewhat has me thinking. Something that I didn't mention that wasn't really related to the original post was that one of the bolts to the manifold was already snapped off! I just touched it with a socket wrench and it came right off...

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Now I am kind of thinking the worst... The head might not be warped though because none of the other bolts were hard to loosen. For the heck of it I was just trying to loosen them to see how hard they would be to take off. A little bit of PB Blaster and they came loose no problem. When the one bolt was already snapped before I even touched it, I figured the rest would be a nightmare to take out. But to my surprise they loosened with ease.

Any Ideas as to why that one would have snapped? The only thing I can think of is a warped head? I have never heard of the bolts breaking on their own though...

 

[ramsack]

the manifold is more likely to warp than a head, and with those cracks, the manifold is definitely warped. i would still check the surface at the head.

stick to your opinion ill stick to mine.

opinions don't help people looking for facts, nor do they usually represent truth. it is true that a bigger pipe will flow more, but there will be less velocity, which is what creates spool. if you can't get this i don't know how else to explain it. someone also welded cracks on the manifold i had, and they leaked anyway.

 

[pboglio]

when the air gets to that point of the manifold that divided doesnt make a difference because its all air pressure and heat. where do you get your theory?

for the OP i had good success with welding with a mig weld, gas cooled. I only welded the external area of the cracks. took a gring and cut into the cracks and filled it with weld.

I've run cut down dividers before, not good for spool. I've ported enough turbo's and manifolds to know what works, and what doesn't. This is the wrong kind of port job and seriously compromises the factory anti-reversion device. I've seen this English Racing port job and SBR's manifold and I always say the same thing, bad idea.

This has effectively turned the semi-divided manifold into a log manifold, which is a 50 year step backwards in technology. Way to go

 

[Jamesdorsey89]

I've run cut down dividers before, not good for spool. I've ported enough turbo's and manifolds to know what works, and what doesn't. This is the wrong kind of port job and seriously compromises the factory anti-reversion device. I've seen this English Racing port job and SBR's manifold and I always say the same thing, bad idea.

This has effectively turned the semi-divided manifold into a log manifold, which is a 50 year step backwards in technology. Way to go

As you would think, directing the flow perpendicular to the turbo inlet would be the best way to do it. I agree with what you are saying. Now will I notice it very much on my car, probably not, but the next manifold I buy will not be ported and I will be sure to leave the dividers when I port it myself!

 

[pboglio]

Think about this... boost is airpressure, in order for it to make airpressure the air volume must be pressing up against all the walls of the intercooler pipes and manifold. The air pressure in the exhaust is going to be the same way to spool that turbo. How much spool time do you think you would loose even if you logic was true?

To answer your question, if your really interested in facts. I went from hitting 18 psi at 4000 rpms on a manifold with the flow divider machined completely off. Then I went to a manifold that was ported the right way and dropped that spool number down to 2800 rpms, all on the same 14b. Credit goes to David Buschur for that well done port job that fixed things up nicely. So it was worth 1200 rpms worth of spool. Never in my life have I seen one single mod affect spool that badly.

No 14b on earth needs a port job that extreme.

 

[And_44]

I guess I was lucky and picked up a virgin unported 2g manifold with a very minor flake or a crack for just 20 bucks.....

 

[knochgoon24]

If you have the exhaust studs out, replace them with some SS ones. I had several broken ones, so I bought OEM replacement ones. I had a few of those get messed up, so I went and bought an SS kit from www.ssstuds.com and they're great. I never have to use PB Blaster or anti-seize. They come loose every time without pulling the stud out of the head.

 

[2qik4u]

the key to a good exhaust manifold is not only the divide or the flow numbers but how much heat it will retain also. thats why a cast manifold for most applications is the best way to go. now obviously not all manifolds can be made of cast due to alot of factors but if you can run cast i would!!! and when porting ANYTHING ive had alot more luck concentrating on smoothing airflow rather than just taking out a bunch of metal. ive actually seen people hurt their flow numbers by taking to much metal in the wrong areas and causing turbulance that reduced flow over "NEW" or "STOCK". when porting anything if you dont have a flow bench to use try using a big shop vaccum. it doesnt have to have huge negative pressure just has to pull alot of air volume. with the shop vac hooked to one end of the manifold stick a 1 1/2 foot long piece of kite string in the manifold holding one end. turn on the shop vac. if the string goes crazy you have air turbulance, if it runs straight in without alot or any flutter you have good flow "no turbulance". i took out less shavings than would fill a cigarette pack to port match and fully port and polish my 420a head and gained 50 cfm on the intake side and 30 cfm on the exhaust side. now another guy that i watched with his porting process on his 420a took out enough shavings to fill probably 2 to 2 1/2 cig packs and when all was said and done he had 7cfm gain on intake side but lost 18 cfm on the exhaust side. he just caused the air to run into itself and made it so turbulent that it just couldnt flow right. also word to the wise "you can only bend air 15 degrees at a time before running into turbulance". sorry bout the long post but thought it might help in the long run.

 

[pj91gsx]

To answer your question, if your really interested in facts. I went from hitting 18 psi at 4000 rpms on a manifold with the flow divider machined completely off. Then I went to a manifold that was ported the right way and dropped that spool number down to 2800 rpms, all on the same 14b. Credit goes to David Buschur for that well done port job that fixed things up nicely. So it was worth 1200 rpms worth of spool. Never in my life have I seen one single mod affect spool that badly.

No 14b on earth needs a port job that extreme.

3rd gear or 1st gear pull?

 

[2qik4u]

and just to answer one of the original questions..... when it comes to welding a cast manifold it is 'best' to weld it with a tig welder. the tig can be very highly controlled and the area affected by the heat from welding can be contained to a very small area. other things to consier are what filler rod you use too. if you use a high carbon rod the manifold will crack again cause it is brittle. if yu use a low carbon rod or something like silicon bronze you can have very good success welding cast. ive actually had very good luck using a 304 stainless steel filler rod when tig welding cast that is going to see heat cycles like our manifolds do. when you weld something you change the chemical properties of the area affected by the heat causeing it to become more brittle and less giving and that is why alot of welded cast manifolds out there have a fresh crack right next to where it was welded to be repaired from the first crack. hope this also helps!!! good luck!!! and guys find somewhere else to argue!!!! or back up what you are saying with a link to somewhere that supports what you are saying!!! you sound like my 3 and 4 yr old kids!!!!!

 

[Jamesdorsey89]

To 2qik4u:

Someone at my work mentioned welding a new divider in the manifold. I would just cut and contour the steel to the correct shape and have one of the guys in the prototype shot weld it up for me.

Or another thing I might do is get an after market manifold from the local part store for a 2nd gen. We have an account set up at a local parts store and get a pretty hefty discount. So I was thinking if I can get a decent deal on one of those, that I might just do that. I just don't know if there will be a huge difference between a cheap Chinese replica or the real OEM part. If anyone has experience with local part store manifolds for our cars let me know.

From everything that everyone is posting and talking to some of the engineers here at work, it has me wanting a manifold with the divider still intact. My only other option is just putting this one on and it will be a lot easier to replace next time when I take the stud out of the turbo.

No sure if anyone is interested in an update, but I got the power steering rack, manifold, turbo and radiator off last night. I wish I didn't have to take the radiator out because I then realized that I need a new one....

But on a good note, the exhaust manifold was cracked all the way around! So it looks like I should see a big difference in putting on the one I bought. I think I will just use the one without the dividers and down the road switch to something different. Right now I don't really want to spend more money so I will live with it for now. But here is a picture of the massive crack. The camera phone took better pictures of the manifold when it was in sunlight, not so much in this picture.

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[pboglio]

I hope your welder is prepared to do all this: Guidelines for Welding Cast Iron | Lincoln Electric

If not, you can add a blocked turbine inlet or wasted turbine wheel if any welding slag breaks loose to your parts bill.

I would 10x over install the ported one with the cut-down divider rather than a welded one. Then eventually just pick up a used 2g manifold and have someone port it and call it done. Do it right, do it once.