I looked through the FSM and on the inter webs and I've come up empty.

I disassembled my Twins to port the waste gate and now wish to know the torque specs to reassemble. Specifically, what is the torque specs for the 4 bolts from the exhaust housing to the central manifold? If someone knows what page in the FSM, that would be great as well.

Thanks!

 

It's in the 'C' section of the fsm with the engine rebuild stuff. Iirc, I've used 35 ft lb.

 

Thanks, I'll go with that.

 

BTW, I dug through Section C assembly a few times and see no specs for actual twins assembly. Just mounting to the engine exhaust manifold.

Maybe Mazda never expected folks to tear them apart eh?

 

Make sure you use some anti-seize on them too.

God knows that if you ever have to remove them in the future, you don't want to be breaking the hardware and go through some fits of cursing.

I went there a few times with some FD's I've worked on... I dread working on another FD for that one reason.
One FD in particular, I thought about setting it on fire because nearly every nut and bolt that I touched broke off. I literally cried myself to sleep that night in pure anger and frustration.

 

+1 on the anti seize, I seriously use that stuff on almost everything

 

Haha, that would be me with my old miata. The prior owner drove it in the winter. Every bolt underneath was replaced as I sheared half them off. I was debating antiseeze or not. It's so hot there I didn't know if it would even survive.

My FD was CA car till I bought it and I haven't had to fight a single bolt since I started wrenching on it!

 

OP--just to clarify: the 10mm bolts & studs are approx 35ft lbs.; the 8mm bolts thru the turbine housings and center (common) section are gonna be about 19-->24ft lbs max.

cptpain: good call on the anti-seize. I recommend the copper formulation and it does work. I've been using the same exhaust manifold and turbo hardware for 10+ years without incident--read NO broken studs and I've reused the hardware several times. (And there are some advantages to being a CA resident.) If a nut or bolt doesn't feel like it 'pulls up' right when torqued, then inspect and/or change it.

The iconel studs that the factory uses are the best heat stretch resistant material that I've used; however, they are not as hard as, say a grade 8 bolts, and will break if over torqued and/or will gall easily (similar to stainless) if you don't lube them before use or disassembly.

 

Thanks for the clarification, looks like I have to loosen and retorque to 25.

 

How do you even get a torque wrench in there? Some of them I can only get to it with a wrench.

 

Crow feet

 

Oh ok, so you'll have to use some kinda formula to calculate the setting on the torque wrench right?

 

Yeap

Torque Wrench Adapter Extended Calculation - Engineers Edge

The problem now is, I don't have a torque wrench that is accurate less than 25 ft lb. I need yet another tool!

 

BTW, I'm planning to drop the engine back in Nov 9th with some friends as well as do my 5th gear synchro. Feel free to join us if you don't mind driving up to Gurnee.

 

The big 1/2" wrench I have is pretty good with anything above 20lb/ft, but I have a 3/8" one that does things in lb/inch that I use for anything less than 20lb/ft and in tight spaces.

Hmm it is tempting to make a drive up, I might if my car is running by then.

 

They're hard to find, but the specs are in the service manual.


Exhaust studs to block: 22-26 ft lbs
Exhaust manifold to block: 48-57 ft lbs

Studs into manifold: Big=12-17 ft lbs, Small=8-12 NM

Nuts for turbochargers: 6 Big=32-42 ft lbs, 1 Small=16-21 ft lbs, center bolts 28=38ft lbs

Downpipe nuts: 28-38 ft lbs

 

awesome, than I am all set at 35. Thanks Smokey!