Inlet flange torque

[Robski]

A real quick and easy one this one:

Does anybody know the torque figure for the inlet flanges on a Lycoming 0-320-E2D?

I can find that exhaust flange torque is listed as 40 inch pounds minimum but nothing specific for the inlet.

Thanks.

[mahlon_r]

!/4-20 fasteners are normally torques to 96-100 Inch pounds and 5/16 course fasteners are normally 205 inch pounds. Don't know where you got the 40 inch pound figure for the exhaust nuts but that is way to light in my opinion. I normally torque them until the crush washer is compressed real well.
Good Luck and Happy Thanksgiving,
Mahlon

[Robski]

Originally Posted by mahlon_r

Don't know where you got the 40 inch pound figure for the exhaust nuts

Lycoming service table of limits and torque value recommendations page 1-34 ref 906.

I know what you mean - the exhaust listing is a bit light but then again it is a minimum figure.

I will go with around 100 for the inlets

I think they have been waaaay over torqued at some point on my engine as all the inlet flanges are warped - one particularly so.
Just ordered 4 new ones - just don't want to warp them - hence the question.

Thanks for the reply.

[mahlon_r]

There are two different styles of inlet flanges based on weather you have the thick or thinner little flange on the intake pipe itself. If you have the thicker flange on the pipe with the thinner groove in the flange style flanges they get a little bent at the attachment. They still work but look warped. When you have the correct combination of pipe and flange the flange from the pipe is just about flush with the groove in the flange. But when they are miss matched the pipe can be loose in the flange with a thin style pipe and a thick style flange or the pipe flange will be way above the the flange parting surface in the case of a thick pipe flange and a thin groove flange. which I think you might have had had the later.
Good Luck,
Mahlon

[Robski]

Hi Mahlon.

I know what you mean but the pipe flanges do match the grooves in the mounting flanges. On the more straight ones all is pretty well flush. With the really warped one the original dimensions look like they match but nothing fits properly due to it being nowhere near flat.

New ones are the answer. Only issue is what colour to paint them: bright red to match the tubes and other engine details (push rod tubes, starter ring, rear accessory case, rocker covers), grey to match the main crankcase, or black to match the new cylinder barrels, mags etc.
Gotta love an engine that looks as cool as it runs.

[Toobuilder]

A few random thoughts:

The intake tube flange needs to be slightly proud of the retainer to seal...

A warped retainer can be brought back straight with a piece of crocus cloth/sandpaper on a flat surface like a tablesaw very easily...

Do yourself a favor and get the SDS flanges and be done with it forever.

[Robski]

Originally Posted by Toobuilder

A warped retainer can be brought back straight with a piece of crocus cloth/sandpaper on a flat surface like a tablesaw very easily...

Not the amount the bad one is warped! The other 3 possibly but then the recess in the retainer for the flange on the tube becomes uneven depth and not pulling the tube up square!

Originally Posted by Toobuilder

Do yourself a favor and get the SDS flanges and be done with it forever.

I am aware of that option but I'm in the UK and approval for it would cost money, take a ludicrous amount of time and have lots of irritating paperwork.

[larryMar]

Originally Posted by Robski

Lycoming service table of limits and torque value recommendations page 1-34 ref 906.

I know what you mean - the exhaust listing is a bit light but then again it is a minimum figure..

You are applying a cold torque. The exhaust obviously expands at 1500F.
Perhaps that is why.....?

[Toobuilder]

Originally Posted by Robski

Not the amount the bad one is warped! The other 3 possibly but then the recess in the retainer for the flange on the tube becomes uneven depth and not pulling the tube up square!...

The flanges can also be pressed straight without too much trouble. Then sanded flat. All that said, theres no real requirement for the recessed area to contact the flange perfectly flat. The seal (and the "squareness") is determined by the bottom of the flange-to-gasket contact. If the retainer is only clamping in 2 points, NBD.

Did not realize you needed "approval" for an engine accessory like the SDS flanges in the UK. That sucks!

[rv8ch]

Originally Posted by Robski

...I am aware of that option but I'm in the UK and approval for it would cost money, take a ludicrous amount of time and have lots of irritating paperwork.

Perhaps convince Van's to include it in their catalog - wouldn't that solve the problem?