I cut up a old x-over pipe I had left over as I need a flange and a short piece of pipe,I was modifing my Toyota turbo and needed to hook up a temp down pipe. I was surprised to see that the GM pipe was constructed of an inner and outter layer. The problem was that when it was bent from the factory the inner pipe did not bend with the outter pipe instead it folded inwards effectively pinching off the inner pipe !! It is blocked off at least 70%. Maybe mine was the only pipe that this happened to but somehow I doubt it, if anyone else has a old x over left laying around please cut it apart in the bend and have a look.
No wonder my EGT dropped and my power went up!

I cut up a old x-over pipe I had left over as I need a flange and a short piece of pipe,I was modifing my Toyota turbo and needed to hook up a temp down pipe. I was surprised to see that the GM pipe was constructed of an inner and outter layer. The problem was that when it was bent from the factory the inner pipe did not bend with the outter pipe instead it folded inwards effectively pinching off the inner pipe !! It is blocked off at least 70%. Maybe mine was the only pipe that this happened to but somehow I doubt it, if anyone else has a old x over left laying around please cut it apart in the bend and have a look.
No wonder my EGT dropped and my power went up!
As soon as I get mine swapped, I'll be happy to cut it open and let you know.
Mark

As promised here are the pics of the x-over pipe. I have since checked another truck by drilling a 1/8 hole and sticking a screw driver in and checked for depth. and it did not seem like this one was restricted.

what tha heck was gm friggin thinkin. had been contemplating a switch and after xmas i'll bump that up the 2 do list.

These pics of the x over make the downpipe look like it was ported and polished. If other pipes are like this no wonder some folks see such a "seat of the pants improvement"

I am surprised to. Good Info!

HOLY ****! I got a new flowmaster crossover sittin in the garage that I was contemplating getting rid of. Think I'll hang on to it and maybe even get it installed after seein this!

I just wish we hadn't heard all the nightmare stories about x-over replacement or this would be a no-brainer.

I wonder if you can sue GM to recoup the extra money you have been spending because of poor fuel mileage?

I cut up a old x-over pipe I had left over as I need a flange and a short piece of pipe,I was modifing my Toyota turbo and needed to hook up a temp down pipe. I was surprised to see that the GM pipe was constructed of an inner and outter layer. The problem was that when it was bent from the factory the inner pipe did not bend with the outter pipe instead it folded inwards effectively pinching off the inner pipe !! It is blocked off at least 70%. Maybe mine was the only pipe that this happened to but somehow I doubt it, if anyone else has a old x over left laying around please cut it apart in the bend and have a look.
No wonder my EGT dropped and my power went up!

This may be a stupid question but what is a homemade remote mounted PMD?

w_huisman, WHAT are you waiting for? the flowmaster kit is very nice, now i need to 'modify' the cat (and not the old one that sh*ts in my basement).

guybb3, it doesn't have to be that tough. you NEED to put penetrating oil on the bolts the night before you start work, you need a little patience before you break out the cut-off tool, sawz-all, blue wrench, etc., and you need an alternate vehicle to go to the parts store for the studs and nuts, etc.

You answered your own question...

w_huisman, WHAT are you waiting for?

you need a little patience before you break out the cut-off tool, sawz-all, blue wrench, etc...

It just doesn't sound like a lot of fun to me. However, if you ever make it out my direction, you are more than welcome to stop by and slap it on for me.

;)

You answered your own question...





It just doesn't sound like a lot of fun to me. However, if you ever make it out my direction, you are more than welcome to stop by and slap my new crossover on for me.

;)

Aww come on Wade..You takled your glow plug dilemma...The crossover can't be any worse than that, can it?

dbierman2001
The homemade remote mounted PMD, is just extending the existing harness and mounting the PMD on a heat sink, I soldiered and heatshrinked all my connections, then drilled and tapped a heat sink that I got at a local surplus store, all said and done I have a 10$ remote mounted PMD.

w_huisman
I have never had luck soaking bolts on exhaust prior to removal, it just seems to burn off. As for the cross over bolts, I think if you heat them first they will back out with little or no trouble, At least in my case they looked horrible and very thin due to rust. But they did come out with no trouble once the manifold was heated up (red) the trouble seems to happen when folks try to remove them cold and they snap off, that is when the troubles begin!

Has anyone else found a pinched off cross over yet??

Nick for X-over studs try some PB-Blaster, that stuff works miracles, better yet if you can find it try a Industrial supply house is something by Kano Corp. called Aero-Kroil we use it exclusively on jet hot gas path components/fasteners.

Also try shocking the fastener while appling torque, IIRC these are 6-pt nuts on the stud, get a deepwell socket (metric also IIRC) on end of extension/long breaker bar 1/2" reduced to 3/8" keeps you from overtorquing, (adapter usually gives before stud/nut rounds or breaks) and while applying steady but firm pressure rap the the breaker bar with a hammer to shock the threads of stud & nut, works like an impact but not as much force.

Key is steady even torque applied, you should be able to "feel" if you are appling too much force keep "rapping & wrenching" it should give, if you can't then you will probably need to seek more drastic measures like trying torch heating, or nut splitting, dremel tool is very handy in these situations it will cut but wheel is so small it doesn't get away from you like a big grinder or sawz-all would.

Once/if you get the nut off chase the threads with a die nut and liberally apply anti seize to the stud upon reassembly, torque to snug and a little more.

It has been my experience of fasteners exposed to heat, that design engineers set torque spec to that of what the material is capable of handling not necessarily the torque required to keep parts together, a mild torque and the heat it will be subjected to in this application will be plenty.

Two questions:

1. Are the holes in the manifold flange threaded?

2. Is there a gasket to replace between the manifold and the crossover?

Aww come on Wade..You takled your glow plug dilemma...The crossover can't be any worse than that, can it?

No, probably not. But I can handle something of that level of difficulty and frustration only once per year. Any more than that, and I get too crabby for the wife to put up with. ;)

Actually that info passed should have been for Wade not Nick,

You can do this not really as tough as it would seem, try the "rap & wrench" with penetrant, if the nuts come off you are in business, if they prove to be too stubborn, then take another stab at it later.

I guess I should have phrased my question a little different, what is a PMD?

Been to the glossary/acronym post in the FAQ ???, all is revealed there, I could tell you but that would be too easy. FAQ was initiated by moi, so it would be a handy reference for all, please use em.

I didn't know it was there, I will bookmark it and use it for sure, thanks.

I guess you'll have to point me to it, I can't seem to find it. I looked on the FAQ page.

I used to use PB-Blaster almost exclusively for that type of stuff. In the last year I came across 2 products I like better - Knocker Loose - loosened bolts in 15 min. that PB hadn't phased - available from Fastenal & Sea Foam Deep Creep - This I've had my best luck with ever when I can preheat.

Nick for X-over studs try some PB-Blaster, that stuff works miracles, better yet if you can find it try a Industrial supply house is something by Kano Corp. called Aero-Kroil we use it exclusively on jet hot gas path components/fasteners.

Also try shocking the fastener while appling torque, IIRC these are 6-pt nuts on the stud, get a deepwell socket (metric also IIRC) on end of extension/long breaker bar 1/2" reduced to 3/8" keeps you from overtorquing, (adapter usually gives before stud/nut rounds or breaks) and while applying steady but firm pressure rap the the breaker bar with a hammer to shock the threads of stud & nut, works like an impact but not as much force.

Key is steady even torque applied, you should be able to "feel" if you are appling too much force keep "rapping & wrenching" it should give, if you can't then you will probably need to seek more drastic measures like trying torch heating, or nut splitting, dremel tool is very handy in these situations it will cut but wheel is so small it doesn't get away from you like a big grinder or sawz-all would.

Once/if you get the nut off chase the threads with a die nut and liberally apply anti seize to the stud upon reassembly, torque to snug and a little more.

It has been my experience of fasteners exposed to heat, that design engineers set torque spec to that of what the material is capable of handling not necessarily the torque required to keep parts together, a mild torque and the heat it will be subjected to in this application will be plenty.

I guess you'll have to point me to it, I can't seem to find it. I looked on the FAQ page.


Doh ??? moment, don't worry I get them too,

Assuming you went to the locked sticky's for FAQ, right under header of Important General Threads is word Acronym and in blue just to the right of that is the link 2nd one on that list IIRC is definition, in retrospect it mite have been easier on my part to just tell you :eek: :eek: :eek: , but object here not just picking on you is to guide folks into using the FAQ.

I have to do this quarterly generally after an influx of new members joining up to the forum and not reading either the FAQ or the Welcome sticky to inform them of basic features we use in the 6.2 & 6.5 forums.

Admonishment here to the veterans here, why do I have to be the "bad guy" on this all the time; help a poor overworked moderator out :D :D :D


Since I've digressed this far off topic, for those of you that believe as I do, Merry Christmas, those of you from non Christian faiths, or non believers Happy Holidays.

I finally found it after about 30 minutes of searching, I was starting to feel like a real dumb a$$ because I couldn't find it.
It would have helped if you would have denoted that this particular thread you were directing me to was located in the 6.5 forum. I was looking in the FAQ that is located at the top of every page in the header. I also searched every forum for it until I stumbled onto it in the 6.5 forum.
Thanks for the workout.

Workouts are good for exercising the mind, sort of easy to draw a conclusion that someone posting a question in the 6.5 forum would look for answers about it in this forum, but I can also see where the confusion could quite easily occur, never considered that before as no one else reported it, but I and the other mods that hang here will make note of it. Thanks for the heads up.

No sweat Doc.

Checked my crossover over the weekend - it is OK (although I use that term loosely). Bolts came out fine - PB Blaster the night before.

Man I wish I would have seen this thread earlier. Funny posts. I would have helped you out TD. Anyway,

Those pictures are fantastic. Good info. Never in a million years would i have thought those are crimped like that. I am going to check mine right away.

Wade, sell me your crossover! My crossover bolts come out by hand with a rachet. But use some Aerol kroil...that stuff is amazing...I swear by it.


Good thread. Good info.

Kroil is definitely good stuff. Where do you buy it?

I get it direct from Kano Labratories:

PH. 615-833-4101

www.kanolabs.com (http://www.kanolabs.com)

BR 6.5 any hazmat shipping issues, I'm out and need some more. last time there was some flam liquid transport concerns

wow...... I will check my tonight since I have it off now.

BR 6.5 any hazmat shipping issues, I'm out and need some more. last time there was some flam liquid transport concerns

No. Not so far. I order it for a municipal maintance shop and have never had trouble. I am required by OSHA to have the MSD lists on hand at all times, but thats not any news there.

I will say, I have seen this stuff do amazing things. I use it on a daily basis almost. Its expensive, but worth it. It has saved me more than I have spent on it.

TD. most of the local HVAC supply houses stock Aero-Kroil up this way. Just need to find one that will sell to you, which shouldn't be a problem.

I just placed an order for some on the website. I made a 'ghost' business and PO in order to make it look official. I will let you know if they ship it or can the order.