Rocker shaft bolt, stretch type?

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jenand40
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Rocker shaft bolt, stretch type?

Post by jenand40 »

Building up my 4 litre engine, again, and have just fitted the stretch head bolts, that was a concern torquing them up to 25nm and then turning 90 deg + 90 deg but all done now.
When I came to fit the rocker shaft bolts one of them just sheared off as I was doing it up hand tight, luckily managed to get the broken end out okay. When I examined the bolts I noticed that they were of the same design as the cylinder head stretch bolts. I thought that the rocker shaft bolts were reusable? Am I right?
If I am wrong let it be a warning to others not to reuse them.
Anyway will have to order 8 off new bolts tomorrow.



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ChrisJC
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Post by ChrisJC »

They are reusable. I think they look the same so there is room for oil to pass between the bolt and the pedestal to reach the rocker shaft.

Chris.
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DEVONMAN
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Post by DEVONMAN »

I had exactly the same happen with a rocker post bolt. I never figured out why it sheared when lightly reinstalling it. I imagine it was fatigue at the necking point.
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


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unstable load
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Post by unstable load »

ChrisJC wrote:They are reusable. I think they look the same so there is room for oil to pass between the bolt and the pedestal to reach the rocker shaft..
Correct.
I had a rocker shaft bolt shear on my Land Rover when I did the head and it turned out it had an old partial fracture that failed on torquing.
Cheers,
John

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