re-torquing heads after a rebuild

[pkboxer]

I just installed my rebuilt heads (R90/6)

-did the torquing in sequence and stages

-let it sit overnight, retorqued.

-set the valves.

-break in ride of 30 miles or so

-after cool down, checked valves before retorquing heads.

Valve clearance had just about closed up.

Normal??

How many miles before things stablize?

I set the valves on the loose side to be safer....

thoughts?

[Deleted User 62]

Normal, it will take a couple of heat cycles before things settle down. The Haynes manual recommends checking valve clearances after the initial startup run, and engine has completely cooled, and a retorque and valve adjustment again after 500 miles (800 km).

[ME 109]

We've all read many times about re-torquing heads.

Can't remember reading about the correct procedure for doing so?

Does one back off a head nut and torque it up again, or just apply the torque wrench at the highest value used in the initial torque sequence?

[dwerbil]

We've all read many times about re-torquing heads.

Can't remember reading about the correct procedure for doing so?

Does one back off a head nut and torque it up again, or just apply the torque wrench at the highest value used in the initial torque sequence?

There's a couple of step-up torques to the top torque setting (around 30).
During a routine valve clearance check up....if the feeler gauge shows bad mojo, I'll back-off all head nuts then re-torque to the specified (28 or 30?) torque. Then do the feeler gauge thing again and adjust valve clearances accordingly.

[ME 109]

There's a couple of step-up torques to the top torque setting (around 30).
During a routine valve clearance check up....if the feeler gauge shows bad mojo, I'll back-off all head nuts then re-torque to the specified (28 or 30?) torque. Then do the feeler gauge thing again and adjust valve clearances accordingly.

I think the top torque for my RS is 26.5 +3 ft. lb. starting at about 11 lb, then 17lb...

Also re-torquing involves re-setting rocker end play.

Can heads only loosen after initial torque, or can they tighten? In the past I've thought that if the heads only loosened, then re-applying the full torque value would have been sufficient.

[Motorhead]

I'd never torque over 25 ft lb

as my motor just came to 25,000 miles, I went to 25 from 23 ftlb as I had problems with my first BMW a 1974 made in 1973
when 25 ftlb pulled the long thread studs from the case

10 Ft Lb first

15 ft lb second

25 Ft Lb for final

to re-torque Lossen the nut a full 1/2 turn

[ME 109]

I
to re-torque Lossen the nut a full 1/2 turn

Just to clarify, is that a full half turn or half a full turn?
I seem to be discussing this elsewhere..........

[Motorhead]

Breaker bar or reverseing torque wrench 180 degrees................ loosen

[pkboxer]

Thanks all. So after this time I should be good for a few hunded miles (up to 500 or so)?

I'll try to keep an ear (or 2) on the valve noise and check sooner if they get too quiet.

And I'm assuming you lossen one nut and retorque it and then do the next.

Don't loosen all 6 and then retorque?

Do the top and bottom 2 tend to loosen? or is it just the 4 on the rockers?

I've been trying to wrap my brain around how this how break in takes up the valve lash but I just can't....

[robert]

As the new head gasket compresses after a few heat cycles, the heads move towards the cam and the lash goes away.