Hi, just changing out the rocker cover gaskets today, and thought I'd see if by chance my headbolts have been replaced.

I think maybe they might of been, there is nothing in the service history to say they have been done.

About the best photo I could get, deffo seems a male multiple spine bolt head to me

Zoomed in on photo. Internal Torx, so not new.

The shadow on the bolt head makes it hard to say based on the photo. Get a closer look it's easy to tell in person.

Not sure if this is any better, the bolt was deffo a male headed end, not a female torx

It was deffo like the top one

Yep, that's the updated bolt. Check both banks, and also take a look at the tips of the camshaft lobes for wear.

Dude you hit the lottery. Def a new bolt. Nice going.

Not sure if this shows anything, I've changed a few cams in my Ford days, I couldn't feel any ridges on the ends, and also checked the cam adjusters for play, they were solid. Car just passed 70k

I'm not convinced. Perhaps use a small screwdriver to pick around to feel if the Torx is internal or external.

Yep that's what I did, it was deffo a male torx head, I wasn't sure if the updated ones were male or female ended

You're looking pretty good

If you can, turn the engine over by hand and check all the tips of the lobes up close. The crank bolt is a standard metric size, maybe 32 or 36mm I don't remember. Make sure to turn it clockwise. What I see in the pic looks good so far.

What's going to happen if you manually turn it CCW?

It's always good practice to turn the engine in the direction it runs. The theory is that if turned backwards the timing chain slack will move to the opposite bank, away from the tensioner side of the engine. Some engines use a ratcheting tensioner that once tight, cannot go back. Or, the side without the tensioner now having all the slack can skip a tooth on the chain or belt and become out of time.

If there's slack in the timing chain. What happens when you throttle lift at 7K RPM at load then get back on WOT several times at a race track?
Does this theory apply to the M156? Timing chain routing, guide, tensioner etc below for reference.

I heard if you turn the crank backwards it will suck like when you put the hose on the other side of a shop vac.

Maybe Jasonoff is into that kind of thing.

As the camshafts got so low inertia they will decrease in rpm instantly due to friction on the lobes, so there will never be any problem hitting throttle on or off.
BUT!
Turning slowly backward will make the slack on the wrong side, i dunno if there´s any problem, but with worn out lockplates in camgears they maybe wouldn´t lock as they should, and maybe cause a problem.

lol thought the same, but look at where the shadow from the access hole. The light source is in the upper left and the shadow off the head is in the lower right... therefore external.

Thanks for all the feedback