Does anyone happen to know the intake/exhaust manifolds' bolt/stud size? Diameter, thread pitch, and length? For example--8mm--1.25 x 25mm, or 10mm--1.25 x 25mm.

 

Thanks

John

On what motor?

Sorry, realized I didn't put the engine about one minute after I posted. Toyota 4K-C...although I "think" all of the K series used the same size bolts?

If you are replacing them, I wonder if its worth using hex cap head screws. I always found them to be a pain in the butt to get with the socket wrench, an alen key might be easier?

10 x 1.25

10 x 1.25. Thanks.

 

I have always had an issue with the fasteners coming loose so I thought I might try Stage 8 fasteners this time around:

 

http://store.stage8.com/p/6925-toyota-fj-cruiser-locking-header-nut-kit?pp=96&sort_selection=recommended

 

They look like they might be a pain to both install and remove but...might be worth it.

Good idea....but, I can for 1 see you having issues fitting them on the bolts which mount both the inlet and ex manifolds (4 of the 6) and 2 accessing the centre lower 2 under the manifolds.

 

If you are replacing them, I wonder if its worth using hex cap head screws. I always found them to be a pain in the butt to get with the socket wrench, an alen key might be easier?

 

Being an alloy head you're much better off using studs rather than bolts as you run the risk of stripping out the holes in the head. You're right in the fact you can get a lot more torque on an Allen key cap screw....but that only increases the chances of the above. Been there, done that!

 

You should be able to get a decent mount out of the original studs and nuts, with the aid of some lock tight. If not the next best option would be "cone lock" nuts, but be prepared to swap out studs each time you remove them as they can eat up the thread a bit on removal.