By the way the adjusters have been fully backed off and are not hitting.
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Mailman’s XS2 a full on restoration
- Thread starter Mailman
- Start date
Even with the adjusters backed all the way out, the rockers will still push against the cam. You're looking at "normal operations" there Bob.
I’m not sure I understand. I had everything ready to assemble. The cam all gooped up with assembly grease, Yamabond on the mating surfaces , then when I tried to set the rocker cover on it wouldn’t sit down flush on the head. Then when I turned the crank it started lifting it up like you saw. I pulled it all apart and cleaned the Yamabond off and wiped off all the grease, then put it back together and made the film you saw.
Are you saying that if I just start cranking down the bolts everything will be alright? That just seems like that would damage something.
Are you saying that if I just start cranking down the bolts everything will be alright? That just seems like that would damage something.
With one cylinder at TDC on compression stroke, the other is at valve overlap with exhaust closing and intake opening. They'll push the rockers.... trust me.
With the adjusters backed off, they won't push as much, but they'll still push slightly.
With the adjusters backed off, they won't push as much, but they'll still push slightly.
Just crankin.em down may create tight loose spots. To torque in sequence would work.
So you had the same situation? When you sat your rocker cover on, it didn’t lay flat all the way around? And you had to tighten the bolts to pull it down flush?
Correct.
I’m just trying to wrap my head around this. Thats always the way it is then?
Ok just read your post . I’ll do it.
Ok just read your post . I’ll do it.
tight interference friction fit
The cam is lifting the rocker cover because the cam lobes are pushing UP on the rockers and the rockers are pushing DOWN on the valves - but there is nothing to hold the cam cover down - and so that is normal.
Once you install the head bolts and head acorn nuts to hold the cam cover onto the cylinder head - all should be OK.
Once you install the head bolts and head acorn nuts to hold the cam cover onto the cylinder head - all should be OK.
I've never experienced this issue on the ones I've put back together but I have the adjusters backed waaaay off. The cover sits down on there OK and you can wiggle all 4 rockers and feel some play in them. Well, lots of play in the 2 on the cylinder that's at TDC on it's compression stroke, but also a little bit on the other cylinder.
Of course you'll see the cover lift if you crank the motor through full revolutions like you did in your video, because of what Pete said.
Of course you'll see the cover lift if you crank the motor through full revolutions like you did in your video, because of what Pete said.
With the SG I just finished, the left rockers "just" touched when I put the rocker box on. You could easily push it flat by hand.... but there wasn't any play in 'em... they were definitely starting to open the valves. The adjusters were back off till they were "about" flush...
I think if you back the screws off even more, the top of the valve stem will go into the screw hole a little bit. Like I said, I've never encountered this, but many of my re-assemblies were with heads that had the elephant foot adjuster screws installed. With those, you grind the rockers back so they will retract enough.
Ok guys, I’m gonna trust you. I did already have all the adjusters backed off all the way flush before I started. This just feels so counter intuitive, like I’m forcing it. I shall take it slow and in sequence.
Tomorrow, I’m outa the garage for today.
Thanks for the input guys!
Tomorrow, I’m outa the garage for today.
Thanks for the input guys!
It just dawned on me what you’re saying. Back them off beyond flush! Will do!
Remember that the rockers will likely be a bit stiffer because of the new o-rings you’ve installed on them and so they wont pivot as easily as when everything was worn-in (before the rebuild). As 5T pointed out, you likely would need to back the screws WAY out to totally prevent contact with the valves.
Anyhow - I suggest that you fasten things down and then rotate the crank veeeerrrryyyyyy slowly to ensure that nothing is hitting enything else as she goes around.
Anyhow - I suggest that you fasten things down and then rotate the crank veeeerrrryyyyyy slowly to ensure that nothing is hitting enything else as she goes around.
Fwiw... you could just as easily leave the adjusters removed. No reason why you couldn't install 'em after you torque the head. I never really worried about the little bit of pressure. I've done 4 cyl. engines where it's unavoidable. At least 1 cyl will have a valve almost fully open. As long as you tighten evenly, it won't hurt anything,
Yes - if you think about the engine cycle and what is happening when, an inline 4 or 6 will always have at least one valve under some pressure from a rocker arm.
Between the facts that most cars have hydraulic lifters (which can often collapse when not running) and the weight of a big car cylinder head pushing down, you sort of don’t notice that a valve is being pushed open as you bolt down the head.
