Quantcast
RWD - header pipe to exhaust manifold studs (a WTF question)

Volvo RWD 200 Forum

INDEX FOR 10/2017(CURRENT) INDEX FOR 2/2012 200 INDEX [<<]  [>>]

 VIEW    REPLY TO THIS MESSAGE    PRINT   SAVE   A    A 

header pipe to exhaust manifold studs (a WTF question) 200 1988

I'm replacing the header pipe on my '88 244 DL.

I have replaced the header pipe two times previously. Both times the manifold studs at the header pipe came out with the nuts. So I purchased new manifold studs from IPD but they turn out to be for the valve head not the head pipe.

I have found that whenever possible to replace nuts with stainless steel threaded together with anti-sieze. The SS nuts and bolts from the header pipe to cat came out nicely.

The manifold stud nuts took some wrestling to get off with PB Blaster and time. This time the studs did not come out.

I took the old nuts that secure the header pipe to exhaust manifold studs to the hardware store and they match 3/8-16 thread.
I buy SS 3/8-16 thread.

I get under the car and the new SS bolts will not thread onto the studs.

WTF?

I wire brush and wipe down with brake cleaner the studs. That does not help.
I find even the old nuts do not thread on easily but will thread on if I use a socket.
Is this wear and tear on the old studs AND nuts that have changed the profile of the threads?
Am I now committed to changing out the studs?

I went back to the hardware store and checked the original nuts on all the closest metric bolts and nada. The original nut still only threads onto the 3/8-16 bolt.
I double checked all the new SS nuts and they were the same 3/8-16 thread.

In addition, and this does not impact getting the new SS nuts threaded on but, staring at the studs I see the the threaded diameter gets smaller before it reaches the manifold flange.
No I am not seeing the blank knuckle stop.
It is as if the threads go from 3/8-16 down to something else.
Could that happen if someone tightened down with a coarse threaded nut over a fine threaded stud. Or is this OEM?
--
1988 244 DL; B230F; LH-2.2; Manual 5-speed (M47)

 





[about brickboard ads]

THREADED THREADED EXPANDED FLAT PRINT ALL
MESSAGES IN THIS THREAD

New header pipe to exhaust manifold studs (a WTF question) [200][1988]
posted by  tbb2  on Mon Jul 31 17:37 CST 2017 >

[about brickboard ads]

Cut and paste link:

<< < > >>


Users marked in green are currently online.

©Jarrod Stenberg 1997-2016. All material except where indicated.


Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.

All participants agree to these terms.
Powered by Denizen - Custom Software for Enthusiasts