Exhaust header torqued down but two threads are not showing

[tjo]

Originally Posted by rv7charlie

Maybe an engineer should jump in here...
Charlie

OK, I will. This is correct:

Originally Posted by rvbuilder2002

First thing is to understand what the actual requirement is, and why...

1. The requirement is not for 2 threads it is only one.

2. The requirement is for when using self locking nuts. To assure that enough of the threaded portion of the fastener shank penetrates through the self locking feature of the nut to assure that it develops the proper prevailing torque to keep the nut in place.

The nuts for attaching the exhaust system are not self locking nuts so the rule does not apply. Lock washers are used for the locking/safety function.

As long as the threads of the nut are fully engaged with threads on the stud (which it appears to be), you are good to go.

If you personally don't like it, you could remove and reinstall with a light washer, but that will require new lock washers as well (internal tooth lock washers are single use only).

Tim

[JonJay]

Originally Posted by rvbuilder2002

Excuse me for sounding a bit snarky, but this is the point in the story (and it repeats it self over over over here and on other internet forums) where the poor builder has to choose from all of the well intended advice in an on line forum.
He does choose, and attempts to do some work he knows nothing about (and was totally un-needed). He then ends up spending a bunch of money having someone who does know what they are doing, repair the threads in their cyl head that are now damaged.

It was a question asked about what would be the harm. I take it, the harm of putting in the next size stud could, potentially, be driving it into the head farther than intended ruining the threads?
Sorry you took it as advice, rather than a question, as it was worded. We all appreciate your experience and knowledge, snarkiness aside. I know you. Your not that snarky

PS - under the guidance of a very well known local RV mechanic (you know him) this is exactly what we did to correct an issue on the 0320 on my Bucker. Just sayin.....

PS-PS - this is one reason why I don't show up on here as much anymore.... to much jumping on people without reading what was said.....

[rvbuilder2002]

Originally Posted by JonJay

It was a question asked about what would be the harm. I take it, the harm of putting in the next size stud could, potentially, be driving it into the head farther than intended ruining the threads?
Sorry you took it as advice, rather than a question, as it was worded. We all appreciate your experience and knowledge, snarkiness aside. I know you. Your not that snarky

PS - under the guidance of a very well known local RV mechanic (you know him) this is exactly what we did to correct an issue on the 0320 on my Bucker. Just sayin.....

PS-PS - this is one reason why I don't show up on here as much anymore.... to much jumping on people without reading what was said.....

Please don't jump to the conclusion that I was singling you out Jon. I wasn't.
My comment was to the whole vibe of the thread in general.
My main point was to get people to analyze whether there really is anything wrong with the OP's installation (I say there is not), and if not, is it worth the risk (at the very least the wasted effort) to change the studs if it is not really needed?

[JonJay]

Originally Posted by rvbuilder2002

Please don't jump to the conclusion that I was singling you out Jon. I wasn't.
My comment was to the whole vibe of the thread in general.
My main point was to get people to analyze whether there really is anything wrong with the OP's installation (I say there is not), and if not, is it worth the risk (at the very least the wasted effort) to change the studs if it is not really needed?

No offense taken Scott. Your too good of a guy. Sorry I concluded incorrectly.
Nobody wants anybody to do any extra work for no reason, let alone damage something out of ignorance from a suggestion in a forum.

Carry on, and again, thank you for continuing to chime in.

[jrs14855]

Originally Posted by A2Jake

1st, Need a better picture, at a lower angle.

Most likley, remove the flat washer, install brass nuts, DONE !

From the picture, my attention would be more focused on, if that is a spark plug lead routed thru and touching the exhaust pipe

If the engine has much time, inexperienced persons removing those studs will most likely result in??

Enjoy

never heard of brass nuts on Lyc exhaust.
Plus one on removing flat washer and proceed. I have never used the flat washer on Lyc exhaust on EAB, never a problem.

[lndwarrior]

My final solution - was to do exactly what I was supposed to do in the first place.

I realized I had torqued the bolts to the stud torque setting of 40 in. Lbs and not the recommended torque for the 5/16" nuts - 204 in. Lbs. (As per my copy of the overhaul manual for my engine). When I did do this all bolts had more than one thread showing.

I appreciate all of the comments on my question. I think a big part of the learning process is to learn the wrong way to do things, so the right way gets impressed into your brain. After this I believe I will always remember the difference between torquing the studs and torquing the nuts - and the correct values for both!

Thank you all for the responses.
Gary

[RV7A Flyer]

Originally Posted by lndwarrior

My final solution - was to do exactly what I was supposed to do in the first place.

I realized I had torqued the bolts to the stud torque setting of 40 in. Lbs and not the recommended torque for the 5/16" nuts - 204 in. Lbs. (As per my copy of the overhaul manual for my engine). When I did do this all bolts had more than one thread showing.

Whose exhaust is this? If it's Vetterman, don't his instructions call for something like *120* in-lbs?

If it's not a Vetterman exhaust...then "never mind".

[lndwarrior]

Originally Posted by RV7A Flyer

Whose exhaust is this? If it's Vetterman, don't his instructions call for something like *120* in-lbs?

If it's not a Vetterman exhaust...then "never mind".

Nope, not a vetterman.

[Walt]

Originally Posted by RV7A Flyer

Whose exhaust is this? If it's Vetterman, don't his instructions call for something like *120* in-lbs?

If it's not a Vetterman exhaust...then "never mind".

Vetterman used to show those low numbers, I believe they've revised their documents to show the correct higher torque of 180-200.

[RV7A Flyer]

Originally Posted by Walt

Vetterman used to show those low numbers, I believe they've revised their documents to show the correct higher torque of 200.

I know they showed somewhat lower numbers originally (maybe something like 100-110) and then revised their documents to slightly higher numbers (120-140 or something like that).

I haven't seen one showing torques that high (and if it exists, I'd like to, because mine are torqued at the 120-140 or whatever it said value).

ETA: His site shows

What is the correct torque on the exhaust flange bolts?
We recommend 140 to 180 inch pounds.

I'm pretty sure that's crept up from what is stated in the paperwork I have, so I'll have to double-check this at upcoming annual. (Again reminding me why I'm less-than-thrilled with various vendors ways of communicating changes...this is just stuck way down on the website somewhere...nothing like word-of-mouth on the internet to communicate changes to critical systems, eh? )