Cupped Washers for Turbo Exhaust Manifold

MarioDrivesaBrick · 03-10-2021, 01:51 PM

Hi all,

I am installing a 90+ manifold on a B21FT, and I am trying to decide what hardware to put on the car. It looks like the car has non locking nuts with washers. I can't tell if they are the stock cupped washers or not. My question is, are the cupped washers seen here, what people use between the turbo manifold and the nut? And if so, what nuts do you use with them, because it looks like you cannot use a flanged locking nut like this, because the flange is large than the recessed area for the nut in the washer?

Or do people just say the hell with it and just use normal locking flanged nuts with no washers.

Thanks for the help!

Ursan · 03-10-2021, 02:00 PM

I've used these with good result.

https://www.mcmaster.com/wedge-lock-washers

Stiggy Pop · 03-10-2021, 02:06 PM

I have always used the OE turbo studs, OE turbo cup washers, and new copper coated locking nuts every time it's assembled. 100% success rate, never had one move and never had one seize.

hiperfauto · 03-10-2021, 02:07 PM

The 419401 washers are specified for turbo applications as well as the push rod engines going back to B18.

The recessed area faces the manifold, not the nut. If you look closely, the washer is stamped UT which means 'out' in Swedish.

Copper coated steel lock nuts like this are what most people use. The washer is curved so the flanged lock nut doesn't do much.

FYI, I have the nuts and cupped washers in stock.

bobxyz · 03-10-2021, 04:14 PM

I've always assumed that the cupped washers, with manifold contact just on the edge of the cup, allow the manifold to move around a bit (over many heat cycles) if it's stressed. IIRC, there are 7 big holes and 1 smaller locating hole in the manifold.

MarioDrivesaBrick · 03-10-2021, 05:01 PM

Great, thank you all for the information. I'll have to pick up some fresh hardware, maybe from Eric.

dalek · 04-03-2021, 11:17 AM

Quote:

Originally Posted by hiperfauto

The 419401 washers are specified for turbo applications as well as the push rod engines going back to B18.

The recessed area faces the manifold, not the nut. If you look closely, the washer is stamped UT which means 'out' in Swedish.

Copper coated steel lock nuts like this are what most people use. The washer is curved so the flanged lock nut doesn't do much.

FYI, I have the nuts and cupped washers in stock.

Those copper coated nuts look stock for VWs.

03-10-2021, 01:51 PM	#1
MarioDrivesaBrick Board Member Join Date: Jun 2016 Location: Santa Barbara, CA	Cupped Washers for Turbo Exhaust Manifold Hi all, I am installing a 90+ manifold on a B21FT, and I am trying to decide what hardware to put on the car. It looks like the car has non locking nuts with washers. I can't tell if they are the stock cupped washers or not. My question is, are the cupped washers seen here, what people use between the turbo manifold and the nut? And if so, what nuts do you use with them, because it looks like you cannot use a flanged locking nut like this, because the flange is large than the recessed area for the nut in the washer? Or do people just say the hell with it and just use normal locking flanged nuts with no washers. Thanks for the help!

03-10-2021, 02:06 PM	#3
Stiggy Pop Board Member Join Date: Feb 2011 Location: Granville, MA	I have always used the OE turbo studs, OE turbo cup washers, and new copper coated locking nuts every time it's assembled. 100% success rate, never had one move and never had one seize. __________________ '79 242 943 pickup

03-10-2021, 02:07 PM	#4
hiperfauto The Librarian Join Date: Nov 2011 Location: So Cal	The 419401 washers are specified for turbo applications as well as the push rod engines going back to B18. The recessed area faces the manifold, not the nut. If you look closely, the washer is stamped UT which means 'out' in Swedish. Copper coated steel lock nuts like this are what most people use. The washer is curved so the flanged lock nut doesn't do much. FYI, I have the nuts and cupped washers in stock. __________________ 240 Alcantara Shift Boot Cover (164 & 72- 140 too) Rare, Race & R-Sports Parts Colored B/S Brake Hoses 140/160 and more Volvo Advertising Stuff -

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

03-10-2021, 04:14 PM	#5
bobxyz Board Member Join Date: Aug 2014 Location: Boulder CO	I've always assumed that the cupped washers, with manifold contact just on the edge of the cup, allow the manifold to move around a bit (over many heat cycles) if it's stressed. IIRC, there are 7 big holes and 1 smaller locating hole in the manifold.

03-10-2021, 05:01 PM	#6
MarioDrivesaBrick Board Member Join Date: Jun 2016 Location: Santa Barbara, CA	Great, thank you all for the information. I'll have to pick up some fresh hardware, maybe from Eric.