Build your own 3.4 crossover pipe - Page 2

Jason4X4 · 11-24-2008, 11:12 AM

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mt_goat · 01-17-2009, 09:07 AM

Some of us have had a problem with the crossover wrapping. Apparently it allows the metal to get too hot and causes the pipe to crack. This is probably made much worse by using too much overlap with the wrap and or supercharging the engine. Ceramic coating seems to be a better option.

Pic of my crossover failure, note the flaking of the metal, this was inside too resulting in the pipe thickeness decreasing more and more until a crack developed (or that's my theory anyway) It was very thin where it got too hot, it must have been very close to molten because it scaled over and got flaky like molten steel gets. Some would confuse this for rusting out, but I'm sure it wasn't from rust. I was careful to always run the engine for a while after washing the truck to evaparate any water from the wrap.

neoworm0 · 01-17-2009, 09:29 AM

Mt. Goat, have you heard of anyone who has had thier xover ceramic coated and having it crack? I had mined ceramic coated but I'm wondering now if I should just try to beef up that joint before I go ahead and put my motor in. This problem seems to be getting more common.

Opinions?

mt_goat · 01-17-2009, 09:43 AM

Quote:

Originally Posted by neoworm0

Mt. Goat, have you heard of anyone who has had thier xover ceramic coated and having it crack? I had mined ceramic coated but I'm wondering now if I should just try to beef up that joint before I go ahead and put my motor in. This problem seems to be getting more common.

Opinions?

I can't remember anyone having a failure with a ceramic coating. At least make sure you support the crossover with a brace at the bell housing, something like this:

And put a flex coupling after that (before the cat).

**Lysmachia** · 01-28-2009, 06:12 PM

Getting ready to do this. Man it is so exciting to finally get my 3.4 in there!

mt_goat · 01-29-2009, 05:09 AM

Go Molly go

904_runner · 02-25-2009, 05:59 PM

NICE!!!!

Im about to start one i think...
Glad i found this thread.

spanish-road · 02-25-2009, 08:50 PM

I know that heat wrap would damage the pipe and welds, since it would cause mass build-up of heat.

904_runner · 03-17-2009, 08:19 PM

Okay so with that being said how many people used the wrap over it??

Would you recommend it or not???
Im going to start mine real soon

mt_goat · 03-18-2009, 05:14 AM

Quote:

Originally Posted by 904_runner

Okay so with that being said how many people used the wrap over it??

Would you recommend it or not???
Im going to start mine real soon

Just spend the extra $40 or so and get it ceramic coated.

okie81 · 03-18-2009, 07:28 AM

Quote:

Originally Posted by 904_runner

Okay so with that being said how many people used the wrap over it??

Would you recommend it or not???
Im going to start mine real soon

As stated above, wrapping get's things hot. I tried header wrap; no bueno.

slcpunk74 · 03-23-2009, 09:37 PM

So is it not possible to use the log style exhaust manifolds with a Y under the trans? Just curious because Im getting ready to start my swap.

neoworm0 · 03-23-2009, 09:51 PM

By log do you mean "stock"? If so. Yes it is. You need to buy headers.

slcpunk74 · 03-23-2009, 10:04 PM

damn! well i guess the prerunner will just be that much more fun.

904_runner · 03-23-2009, 10:06 PM

Got mine done.. remember guys to sort of tuck that exhaust flange close to the transmission so it doesn't interfer with the frame.. ill have to modify mine some how in order to get this done...

I did get it done though..
Thanks for the write up!

slcpunk74 · 03-23-2009, 10:09 PM

sorry to hijack but are the downey 95.5+ tacoma headers the ones I want?

Looks good 904

mt_goat · 03-24-2009, 05:45 AM

Quote:

Originally Posted by slcpunk74

So is it not possible to use the log style exhaust manifolds with a Y under the trans? Just curious because Im getting ready to start my swap.

Those of us with 4wd wanted to avoid a cross-over below, that may get hit on the trail. Also that makes it harder to keep the front O2 sensor in the proper spot, if you care about that.

Also crossing over below the tranny means you'll have one bank of hot exhaust running down by your brake and fuel lines.

slcpunk74 · 03-24-2009, 06:58 AM

If trail clearance is the only problem and those lines I think Im ok. I can figure somethin out for it.

Gravehunter · 05-18-2009, 08:06 AM

Getting ready do this swap: It would seem to me the easiest way would be to cut the flanges off and just run each side down from the manifolds and then run the right side over to the left side and out the back. Most trucks with V-8's do it that way. If there is room to run a pipe down on the right side with headers then theres got to be room to do it with the stock manifolds. I don't care about a cross over pipe running across to the other side since it won't be a hardcore offroad truck or anything.
Then theres no crossover pipe at all!

I'm not seeing a reason not to do it this way. Anyone see a problem with it?

thefallman · 05-19-2009, 12:04 AM

As MtGoat said earlier this makes positioning the O2 Sensors front or rear in proper position nearly impossible as it moves the junction farther away from the manifolds and allows exhaust gases to cool more before hitting the Cat which will mean the Cat will very likely not function properly and u may very well end up throwing O2 sensor Codes because of this. I have heard of this being a problem in the past. do i know any specific instances, no i cant say. What i can say is that my O2 sensors are positioned EXACTLY the same distance from the manifolds as the ones on the stock install are. And i have never had a O2 sensor code thrown EVEN with a 2.5 inch high flow CAT along with the rest of the exhaust which is all 2.5 as well including magnaflow muffler which sounds awesome

vital22re · 05-19-2009, 01:04 AM

when i did my swap in feb this year i pulled a 3.4 from a 96 chopped the crossover flipped it and got the factory heat shield to fit. My truck was cali so it had 2 o2's i replaced both with ones from the 96, added a magna flow cat and 2 1/4 piping all the way back to a magnaflow muffler. no codes no probs.

Gravehunter · 05-19-2009, 01:15 AM

mmmm... ok, i didn't know the position of the O2 was so particular.
I'm comfortable doing the cross over mod myself, just thought it would be easier and better not to. Sounds like to much of a risk. Crossover mod it is.
Thanks for the info.

Edit: What are the guys that are putting in the headers doing? Some may be crossing over, others may be running duals out the back from each side, so i'd think this would be a problem for them as well.?

thefallman · 05-19-2009, 09:58 AM

i don't know of any set of headers that don't cross over at some point. some separate again for duals out the back of the truck after this point but i don't know of any that are completely separate all the way out the back. I believe u have to use an O2 sensor eliminator kit with Downeys headers. But you might talk to Downey about that

Gravehunter · 05-19-2009, 10:30 AM

Downey said if you use there crossover kit all the 02 sensors stay in the same place.

If they have room you'd think i would?(muffler shop running it out of my stock manifolds. ?

thefallman · 05-21-2009, 11:59 PM

just never have liked the idea of a exhaust pipe being the lower then drivelines or other things on my truck too easy to smash it would seem

01-17-2009, 09:07 AM	#27 (permalink)
mt_goat Contributing Member Join Date: Nov 2002 Location: Oklahoma State Posts: 8,919	Some of us have had a problem with the crossover wrapping. Apparently it allows the metal to get too hot and causes the pipe to crack. This is probably made much worse by using too much overlap with the wrap and or supercharging the engine. Ceramic coating seems to be a better option. Pic of my crossover failure, note the flaking of the metal, this was inside too resulting in the pipe thickeness decreasing more and more until a crack developed (or that's my theory anyway) It was very thin where it got too hot, it must have been very close to molten because it scaled over and got flaky like molten steel gets. Some would confuse this for rusting out, but I'm sure it wasn't from rust. I was careful to always run the engine for a while after washing the truck to evaparate any water from the wrap. __________________ ~Dale~ 93 4X4 ext-cab, auto, SR5, 3.4 V6, supercharged, 2.1" pulley, URD fuel mods, Aquamist WI, IPT valve body mod, dual cases, 4" superlift front, Alcan springs rear, 33 BFG MT, ARB locked front & rear, 5.29 US Gears, RB 1" Body Lift, 1.5" ball joint spacers, manual hubs, TJM T-17, Warn m8000. Last edited by mt_goat; 01-17-2009 at 09:50 AM.

01-17-2009, 09:29 AM	#28 (permalink)
neoworm0 Registered User Join Date: Jan 2005 Location: North Vancouver, BC Posts: 604	Mt. Goat, have you heard of anyone who has had thier xover ceramic coated and having it crack? I had mined ceramic coated but I'm wondering now if I should just try to beef up that joint before I go ahead and put my motor in. This problem seems to be getting more common. Opinions? __________________ 1995 Toyota PU SR5. 2000 3.4l V6 and a few other mods. my album: http://www.yotatech.com/album.php?albumid=101 my SAS: http://picasaweb.google.com/areinhol...eat=directlink www.overlandcanada.ca www.alltracwagon.net

01-29-2009, 05:09 AM	#31 (permalink)
mt_goat Contributing Member Join Date: Nov 2002 Location: Oklahoma State Posts: 8,919	Go Molly go __________________ ~Dale~ 93 4X4 ext-cab, auto, SR5, 3.4 V6, supercharged, 2.1" pulley, URD fuel mods, Aquamist WI, IPT valve body mod, dual cases, 4" superlift front, Alcan springs rear, 33 BFG MT, ARB locked front & rear, 5.29 US Gears, RB 1" Body Lift, 1.5" ball joint spacers, manual hubs, TJM T-17, Warn m8000.

02-25-2009, 05:59 PM	#32 (permalink)
904_runner Registered User Join Date: Mar 2008 Location: Chico, California Posts: 3,782	NICE!!!! Im about to start one i think... Glad i found this thread. __________________ Mike 1990 4runner: 3.4 swapped, 5-speed, sas'd, Rear leaf swap, Locked, 5.29's, 39.5" iroks on Beadlocks, Armor'd Longfields, Duals coming soon: My build thread http://www.yotatech.com/f152/904_run...thread-158746/ http://www.treadlightly.org/ http://www.pirate4x4.com/tech/billav...ery/index.html

02-25-2009, 08:50 PM	#33 (permalink)
spanish-road Registered User Join Date: Mar 2007 Location: Fairbanks Ak Posts: 1,097	I know that heat wrap would damage the pipe and welds, since it would cause mass build-up of heat. __________________ What I don't get is why pay someone to work on your vehicle? 1991 toyota pickup extcab- 22re 31x10.5x15 bone stock except for the RV cam and tires.

03-17-2009, 08:19 PM	#34 (permalink)
904_runner Registered User Join Date: Mar 2008 Location: Chico, California Posts: 3,782	Okay so with that being said how many people used the wrap over it?? Would you recommend it or not??? Im going to start mine real soon __________________ Mike 1990 4runner: 3.4 swapped, 5-speed, sas'd, Rear leaf swap, Locked, 5.29's, 39.5" iroks on Beadlocks, Armor'd Longfields, Duals coming soon: My build thread http://www.yotatech.com/f152/904_run...thread-158746/ http://www.treadlightly.org/ http://www.pirate4x4.com/tech/billav...ery/index.html

03-23-2009, 09:37 PM	#37 (permalink)
slcpunk74 Registered User Join Date: Oct 2008 Location: SL,UT Posts: 125	So is it not possible to use the log style exhaust manifolds with a Y under the trans? Just curious because Im getting ready to start my swap. __________________ 1994 yoda jd fab lt front,62" deaver back,full glass, and kings. 1997 xj the DD/prerunner 1974 bronco 5.8 EFI 4r70w np205 "IN PROGRESS" With the navigation arrow pointed straight at Ihop Aunt Jamaima really likes me cause my syrup is so hot!

03-23-2009, 09:51 PM	#38 (permalink)
neoworm0 Registered User Join Date: Jan 2005 Location: North Vancouver, BC Posts: 604	By log do you mean "stock"? If so. Yes it is. You need to buy headers. __________________ 1995 Toyota PU SR5. 2000 3.4l V6 and a few other mods. my album: http://www.yotatech.com/album.php?albumid=101 my SAS: http://picasaweb.google.com/areinhol...eat=directlink www.overlandcanada.ca www.alltracwagon.net

03-23-2009, 10:04 PM	#39 (permalink)
slcpunk74 Registered User Join Date: Oct 2008 Location: SL,UT Posts: 125	damn! well i guess the prerunner will just be that much more fun. __________________ 1994 yoda jd fab lt front,62" deaver back,full glass, and kings. 1997 xj the DD/prerunner 1974 bronco 5.8 EFI 4r70w np205 "IN PROGRESS" With the navigation arrow pointed straight at Ihop Aunt Jamaima really likes me cause my syrup is so hot!

03-23-2009, 10:06 PM	#40 (permalink)
904_runner Registered User Join Date: Mar 2008 Location: Chico, California Posts: 3,782	Got mine done.. remember guys to sort of tuck that exhaust flange close to the transmission so it doesn't interfer with the frame.. ill have to modify mine some how in order to get this done... I did get it done though.. Thanks for the write up! __________________ Mike 1990 4runner: 3.4 swapped, 5-speed, sas'd, Rear leaf swap, Locked, 5.29's, 39.5" iroks on Beadlocks, Armor'd Longfields, Duals coming soon: My build thread http://www.yotatech.com/f152/904_run...thread-158746/ http://www.treadlightly.org/ http://www.pirate4x4.com/tech/billav...ery/index.html

03-23-2009, 10:09 PM	#41 (permalink)
slcpunk74 Registered User Join Date: Oct 2008 Location: SL,UT Posts: 125	sorry to hijack but are the downey 95.5+ tacoma headers the ones I want? Looks good 904 __________________ 1994 yoda jd fab lt front,62" deaver back,full glass, and kings. 1997 xj the DD/prerunner 1974 bronco 5.8 EFI 4r70w np205 "IN PROGRESS" With the navigation arrow pointed straight at Ihop Aunt Jamaima really likes me cause my syrup is so hot!

03-24-2009, 06:58 AM	#43 (permalink)
slcpunk74 Registered User Join Date: Oct 2008 Location: SL,UT Posts: 125	If trail clearance is the only problem and those lines I think Im ok. I can figure somethin out for it. __________________ 1994 yoda jd fab lt front,62" deaver back,full glass, and kings. 1997 xj the DD/prerunner 1974 bronco 5.8 EFI 4r70w np205 "IN PROGRESS" With the navigation arrow pointed straight at Ihop Aunt Jamaima really likes me cause my syrup is so hot!

05-18-2009, 08:06 AM	#44 (permalink)
Gravehunter Registered User Join Date: Jul 2008 Posts: 62	Getting ready do this swap: It would seem to me the easiest way would be to cut the flanges off and just run each side down from the manifolds and then run the right side over to the left side and out the back. Most trucks with V-8's do it that way. If there is room to run a pipe down on the right side with headers then theres got to be room to do it with the stock manifolds. I don't care about a cross over pipe running across to the other side since it won't be a hardcore offroad truck or anything. Then theres no crossover pipe at all! I'm not seeing a reason not to do it this way. Anyone see a problem with it? __________________ . . . 1990 Toyota pickup. Ext cab, 4x4 with a 3.4 auto swap. Cragar Soft 8's, 33/10.50-15 BFG's. 2" body lift.

05-19-2009, 12:04 AM	#45 (permalink)
thefallman Registered User Join Date: Jun 2006 Location: Walla Walla, WA Posts: 550	As MtGoat said earlier this makes positioning the O2 Sensors front or rear in proper position nearly impossible as it moves the junction farther away from the manifolds and allows exhaust gases to cool more before hitting the Cat which will mean the Cat will very likely not function properly and u may very well end up throwing O2 sensor Codes because of this. I have heard of this being a problem in the past. do i know any specific instances, no i cant say. What i can say is that my O2 sensors are positioned EXACTLY the same distance from the manifolds as the ones on the stock install are. And i have never had a O2 sensor code thrown EVEN with a 2.5 inch high flow CAT along with the rest of the exhaust which is all 2.5 as well including magnaflow muffler which sounds awesome __________________ ~Brian GETTING FIXED 89 Ex-Cab 3.4 Conv. T100 Auto Tranny ~Phoenix 94 Ex-Cab 22re 5spd Came with parts truck. Doesnt run yet. 90 4runner 3.0 Auto (Wifes Toy) 92 4runner 3.0 Auto (Currently With Blown Engine) (New 3.4 Swap i think)

05-19-2009, 01:04 AM	#46 (permalink)
vital22re Registered User Join Date: Feb 2006 Location: kirkland washington Posts: 682	when i did my swap in feb this year i pulled a 3.4 from a 96 chopped the crossover flipped it and got the factory heat shield to fit. My truck was cali so it had 2 o2's i replaced both with ones from the 96, added a magna flow cat and 2 1/4 piping all the way back to a magnaflow muffler. no codes no probs. __________________ 92 toyota truck 3.4 5spd 4.56 gears magna flow cat and muffler2 1/4 piping isr mod to intake 1.5 bjsfront add a leafs and 2inch lift shackles rear rancho shocks all around sitting on 265/75/r16 nitto terra grapplers

05-19-2009, 01:15 AM	#47 (permalink)
Gravehunter Registered User Join Date: Jul 2008 Posts: 62	mmmm... ok, i didn't know the position of the O2 was so particular. I'm comfortable doing the cross over mod myself, just thought it would be easier and better not to. Sounds like to much of a risk. Crossover mod it is. Thanks for the info. Edit: What are the guys that are putting in the headers doing? Some may be crossing over, others may be running duals out the back from each side, so i'd think this would be a problem for them as well.? __________________ . . . 1990 Toyota pickup. Ext cab, 4x4 with a 3.4 auto swap. Cragar Soft 8's, 33/10.50-15 BFG's. 2" body lift. Last edited by Gravehunter; 05-19-2009 at 02:34 AM.

05-19-2009, 09:58 AM	#48 (permalink)
thefallman Registered User Join Date: Jun 2006 Location: Walla Walla, WA Posts: 550	i don't know of any set of headers that don't cross over at some point. some separate again for duals out the back of the truck after this point but i don't know of any that are completely separate all the way out the back. I believe u have to use an O2 sensor eliminator kit with Downeys headers. But you might talk to Downey about that __________________ ~Brian GETTING FIXED 89 Ex-Cab 3.4 Conv. T100 Auto Tranny ~Phoenix 94 Ex-Cab 22re 5spd Came with parts truck. Doesnt run yet. 90 4runner 3.0 Auto (Wifes Toy) 92 4runner 3.0 Auto (Currently With Blown Engine) (New 3.4 Swap i think)

05-19-2009, 10:30 AM	#49 (permalink)
Gravehunter Registered User Join Date: Jul 2008 Posts: 62	Downey said if you use there crossover kit all the 02 sensors stay in the same place. If they have room you'd think i would?(muffler shop running it out of my stock manifolds. ? __________________ . . . 1990 Toyota pickup. Ext cab, 4x4 with a 3.4 auto swap. Cragar Soft 8's, 33/10.50-15 BFG's. 2" body lift.

05-21-2009, 11:59 PM	#50 (permalink)
thefallman Registered User Join Date: Jun 2006 Location: Walla Walla, WA Posts: 550	just never have liked the idea of a exhaust pipe being the lower then drivelines or other things on my truck too easy to smash it would seem __________________ ~Brian GETTING FIXED 89 Ex-Cab 3.4 Conv. T100 Auto Tranny ~Phoenix 94 Ex-Cab 22re 5spd Came with parts truck. Doesnt run yet. 90 4runner 3.0 Auto (Wifes Toy) 92 4runner 3.0 Auto (Currently With Blown Engine) (New 3.4 Swap i think)

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