UEL JDL catless headers crooked flange
 

Recently installed a JDL catless UEL header and was supplied with these instructions when I contacted JDL about the flanges not being flush with a glass surface.

"Jay,

It is not uncommon when placing both flanges on something like a piece of glass to see some variation from side to side between flanges. These headers are not rigid in a manner that will prevent them from pulling to the heads correctly when being torqued. This will also have no adverse effect with added stress. Once the header has been heat cycled a few times everything will settle into place and it is a good idea to re-check your torque. The important part is making sure that the proper torque sequence is used during this stage of install. We prefer the OEM gaskets for the header to heads over the multi-layer steel ones as they are more forgiving to improper install/torque variations.

The header needs to be lifted to the heads and the center nuts run on by hand. Just hand tighten them, then move on to the outer nuts. Once the header is closed up to the heads hand tight you will begin the actual torque sequence which is as follows:

-Start with center nuts (does not matter which bank), torque to 25lb/ft.
-Move to outer nuts and torque to 25lb/ft. in a criss-cross method bank to bank.
-Once all 6 have been torqued, start at the center nuts again and torque to 35lb/ft.
-Move to the outer nuts and torque to 35lb/ft. in a criss-cross method bank to bank
-You can run through all 6 again if you like just to be certain you didn't miss one.
-Then proceed to your outlet flange, it is your preference which 2-bolt gasket you use but the supplied gasket will be more forgiving to improper seating compared to the steel layers OEM gasket.

Best regards,

JDL Auto Design Team"

I would like to say that JDL has been super helpful, and their customer service is amazing, but was wondering if I torqued the headers over the recommended 22ft/lbs that it could cause problems? Did a data log on OFT and found my LTFT to be around +-5%.

I would go with JDL's recommendation. Tightening things like this to the correct torque isn't as critical as you would think by reading these forums.

That's for sure........:thumbsup:

During my 70 year wrenching career, I have tightened tens of thousands of bolts and nuts and never used a torque wrench (except on head bolts).


humfrz

Do you have the version with the braided flex joints? They should allow enough movement to pull the flanges flat when you torque down the bolts.

I once tighetened header bolts to torque specs. 2 days later I smelled a lot of exhaust in the cabin. Nevertheless one of the nuts was missing. Just flat out gone. The others were kind of loose too. Just tighten them as much as you can and till it feels good. Make sure you do it when the car is cold though, otherwise you risk breaking something off.

Never again

use fresh gaskets, i like the grimmspeed

Went back under the car and everything was tight and couldn’t find leaks, I guess it’s just normal