Nyloc Nuts On CIS Runners to Head?

[SalParadise]

Been thinking before putting my CIS back on the engine.

Should I run Nyloc nuts over the washers instead of the regular factory nuts on this? I think it's a good idea, but it does scare me if I need to do some tweaks to the CIS with the engine in situ since there isn't a lot of room to get to these nuts once it's in.

Let me know what you guys think.

[Flat6pac]

I have the correct nuts, the split 12mm shoulder.
They are used, but correct.
In for sale. CIS intake locknuts
Bruce

[gazzerr]

I used Nylocs and no issues so far. Depends if you are stickler for the factory look or not I guess. Nylocs not strickly being re-usable would be the other drawback.

[SalParadise]

Thanks guys. I will probably go Nyloc - since I dropped the engine awhile ago I have learned that the only way to properly work on a 911 engine is to drop it - so getting Nylocs off when the engine is out is not a problem.

[pmax]

Nyloc nut on intake runner bolt.
Is this one reason not to use them ?

[proporsche]

Sal take an advice from Bruce Pmax..do not use nylon nuts .they are not made for this kind of job.You know, those Porsche dudes in factory use the 12mm for a good reason...
Ivan

[SalParadise]

Originally Posted by pmax

Nyloc nut on intake runner bolt.
Is this one reason not to use them ?

Yes, this is good advice - probably would pull the stud - I never thought of that. Thanks.

But then again they use all nylocs on the studs for the valve covers. Go figure. But there is a tremendous amount of access to these.

I guess I will just re-use the old nuts with washers. Properly torqued they will be as fine as they ever were.

[911pcars]

I'm unsure what that photo is demonstrating. Can you clarify?

Plain nuts are pretty much equivalent to Nylok nuts with worn out "Nylok" material. Yes?

Then again, plain nuts are available with a choice of metal characteristics while Nylok nuts may be plain Jane material. Thus, they shouldn't be used on any load bearing applications without further SAE/DIN reassurances.

Sherwood

[pmax]

The nut can't be removed from the stud.

On a related note, if anyone has any spare intake studs, I would like to buy 2 of them. Thanks !

[pmax]

Originally Posted by SalParadise

But then again they use all nylocs on the studs for the valve covers. Go figure. But there is a tremendous amount of access to these.

Yeah, that many locking nuts on the non-weight bearing valve cover seems like overkill to me.

[911pcars]

Originally Posted by pmax

Yeah, that many locking nuts on the non-weight bearing valve cover seems like overkill to me.

Tightening valve cover nuts to an M8 fastener specification (18 ft.lbs./27 Nm) is not recommended for this application. The valve cover can distort and/or the gasket distorts. In either case, a leak may develop. Suggest a lower spec, like 6 ft.lbs.

If a regular nut is installed at that lower torque spec, that's insufficient torque to create the needed metal tension. As a result, it may/will back off and possibly cause an oil leak. A fresh Nylok nut will remain in the position tightened, enough to compress the gasket and contain the oil.

Sherwood

[juanbenae]

I use nylocks on my carb manifolds to the heads. easier to get at with carbs I guess.

ive had a number of valve cover studs back out over the years & simply put a drop of locktite on the stud, reinstalled and backed the nylock off the next day for a fresh one. it's not like the stud is lost forever max. cinch up a pair of nuts on the other end of the stud, put sacrificial nuts in a vice, back off the stuck nylock. mail it over and ill remove it for ya and send it back.

[pmax]

Originally Posted by juanbenae

put sacrificial nuts in a vice

Got it.

[911pcars]

Tight access to intake manifold nuts can be made easier by sourcing M8 nuts with a 12mm hex instead of the typical 13mm size used by Germans.

Sherwood

[911pcars]

Originally Posted by pmax

The nut can't be removed from the stud.

On a related note, if anyone has any spare intake studs, I would like to buy 2 of them. Thanks !

In lieu of replacing studs that are probably still usable, practice removing frozen nuts. It's a handy skill when removing heat exchanger fasteners. Very fun.



Can also try "double-nutting" one end to grip in a bench vise. Apply penetrating solvent to the stuck nut, then go for it. Heat and slicing are also effective options, especially if you want to avoid destroying/snapping the stud (e.g. in a cylinder head). That's more fun.

Sherwood

[gazzerr]

I seem to remember ordering the nuts with the Porsche part number and that's what they sent me. I just figured it was the modern replacement for the split 12mm. Hopefully they won't ever get stuck on me.

[pmax]

Great stuff, Sherwood. Learn something all the time on this forum from the experts.

Luckily, these intake studs are only $3 genuine Porsche, can you believe it. I'll order 2 of these new shiny ones plus some copper washers that somehow one always forgets to buy and practice on the old, which has seen better days !

Cylinder Head Stud (intake, M8 X 25mm, 12 required, sold per each) Part #: 999-062-008-02-OEM $3.00

[juanbenae]

that, you can afford apparently.

[911pcars]

Originally Posted by juanbenae

that, you can afford apparently.

Every slippery slope has a beginning. Careful.