Head Install

I did it again! I installed the head and though I had all the pushrods lined up with the rockers. After I finished torquing the head an intake pushrod jumped out of it's socket. I was able to get it back on the rocker, but seems something got bent. Probably intake valve! So how do others make sure all the pushrods are aligned. :?: Thanks

I begin by pulling one exhaust rocker spindle and arm out of the head. Then I turn the engine untill three pusrods are down and the one that goes to the missing arm is up. Then when you set the head in place it will go all the way down to the gasket and it is easy to make sure the three installed arms are engaging the pusrods correctly. After the head is tightened down then I rotate the engine a turn and re-install the last rocker arm. I started doing that years ago after bending a valve and breaking the guide when I had a pushrod out of place. Jim

OH ugh Comoz! Peel head allowed easy spindle removal but Trixie Combat we put 4 spindles in last month was a freaking terror to drive home and turn to align to covers. I'm sure I'll have to check in on bad luck Trixie and sure don't want to handle the spindle trauma again. Oh yes we heated head to need gloves to handle. Alas I too know the sound of a push rod shot off lifer seat on first turn check - but didn't injure anything but my mood of self worth.

My only reason to remove spindles now is to grind off enough from rocker ends the push rods just slip past first time every time. Then zip tie each pair to help jam in head.

Then I zip tie head over barrel using bolts in head stead thread and the spindle covers. Diddle gasket/sealant drop head lightly on barrel.

Then stretch rubber bans over the head hooked to rocker ends to put some down pressure on them so each placed push rod stays put - work my way around then double check and settle head to start bolts then remove bands and carry on.

I will no longer use synthetic thread in engine especially head as I found the temps melt it to either mash down thinner than its original impression or leaves gaps from semi melt contraction. Cotton of silk thank you.

I must have had my head on and off 5 times during rebuild. I never had any trouble lining up the rods. Used the Hemmings DVD method. Rubber band the rockers all the way up. Install push rods up past the rocker arms and rubber band in place. Install head on barrel with motor in frame after gasket and goop. Drop rods down on cam followers by cutting rubber bands. Remove rocker arm rubber bands. Slowly fish push rods around to seat in rocker sockets and keep rockers down on rods. Commence tightening head bolts making sure the rods are still in their sockets as you go. Rotate engine as you go to make sure rods are seated. It helps to have 2 people.

I haven't done lots of engines, but it seemed to work for me, it's pretty much what the workshop manual uses. Much easier with motor out of frame.

Dave
69S

Getting the head on is tricky and there are many hints and tip to do this but validating the position of the pushrod ends in the rockers is simply a matter of procedure.

I have alway had to check, bring the head down a little,(at this point put number 1 bolt in place using it to facilitate the process) recheck the pushrod ends in the rockers, bring it down a little more, re-recheck the pushrod ends in the rockers and repeat till all the way home.
In this instance you really learn the meaning of "never assume".

pvisseriii said:

Getting the head on is tricky and there are many hints and tip to do this but validating the position of the pushrod ends in the rockers is simply a matter of procedure.

I have alway had to check, bring the head down a little,(at this point put number 1 bolt in place using it to facilitate the process) recheck the pushrod ends in the rockers, bring it down a little more, re-recheck the pushrod ends in the rockers and repeat till all the way home.
In this instance you really learn the meaning of "never assume".

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Well Pete I will tell you exactly how I did it so maybe it will never happen to you,

I started out with rubber bands on the rockers and the pistons halfway up on the exhaust stroke of the left cylinder. This was my bike and I was just doing a quick head replacement with a rebuilt head. Since it was a Mk3 I didn't want to remove the chaincase and deal with the gasket. It had new mushroom tappets and they were all the way up.

So I slid the head into place and dropped the pushrods into the holes and played with them until I was sure they were seated in the lifters. Then I lowered the head and made sure all the rocker arms were engaged with a light and a little hook.

I slowly snugged up the bolts and watched the left hand exhaust valve open as I expected. Once the head was in contact with the gasket I carefully pushed the kickstarter down with my hand and watched as the exhaust valve moved toward closed. Unfortunately the bottom of that pushrod was setting on the edge of the lifter so the valve did not close all the way and as the intake on that cylinder opened it caught the edge of the exhaust valve and pushed it forward and a small piece of the new cast valve guide popped out of the exhaust port and landed on the bench.

There is the possibility that had I been turning the crank directly and watching for valve clearance I may have caught it before damage but I like the feeling of the head solidly home on the gasket before I start tightening things. Jim

I've repeatedly used the "bit of rag" method successfully over a dozen times.

Set up the cam to where the position is such that a single cam follower is rising or falling. Loosen all rocker adjusters a couple of turns.

Flip the head upside-down on the bench, insert all 4 pushrods, then stuff thin strips of rag in the pushrod tunnels, with the ends hanging out about 4"

Stick the ends in the exhaust ports and screw in the finned exhaust retainer nuts part way to hold the strips clear of the head surface area.

Install the head by carefully tipping it in place then rotating it front-to-bak as you lower it all the way down to where the "active" pushrod makes contact.

Install the 4 main outer head bolts and finger-tighten as much as possible.

Pull the strips of cloth and check all rocker positions on pushrod ends with a flashlight through the exhaust rockerbox holes.

Install remaining bolts and cross-torque by the book.

So how do you know that the pushrods are seated correctly in the lifters [cam followers]. It is easy to tell if they are seated in the rockers because you can see them. Where I have seen problems is the other end of the pushrod.

Did you get your cam yet? Jim

I've been using zip ties to keep the pushrods in the head and that works great. I cut the zip ties once pushrods situated over tunnel and ready torque head. I seems to have missed getting the pushrods situated on the rocker arms correctly. If the adjusters are fully backed off will the clear the pushrods then tighten as you torque to seat till you're ready to set clearance?

I just did this and can't remember, but I did back the adjusters out all the way and it seems that there will still be tension on one or more pushrods depending on where your motor is on it's stroke. I also had one pushrod hang up and it snapped into place. I didn't check to see if anything bent, but everything appeared to go in it's place and adjust ok. Now I'll have to check compression as soon as I am able. I think Jim's way would be the safest and overall easiest method.

comnoz said:

So how do you know that the pushrods are seated correctly in the lifters [cam followers]. It is easy to tell if they are seated in the rockers because you can see them. Where I have seen problems is the other end of the pushrod.

Did you get your cam yet? Jim

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The pushrods always fall into place (for me, so far, without fail). Narrowness of the tunnels seems to insure this.

No cam yet, but expecting it in plenty of time as I haven't yet started to wash & prep the bottom end parts yet anyway. In fact, I still need to go get a couple of buckets of Agitene to re-fill my parts wash sink...

Yes, you will always have tension on at least one pushrod even if the adjusters are backed all the way out, unless that rocker arm is removed. Jim

comnoz said:

Yes, you will always have tension on at least one pushrod even if the adjusters are backed all the way out, unless that rocker arm is removed. Jim

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Figured that would be the case!

Quote
The pushrods always fall into place (for me, so far, without fail). Narrowness of the tunnels seems to insure this.

I have found that is not always the case. I tore one down recently that had one pushrod that had ridden on the edge of the cup on the camfollower for many miles. There was an arch shaped groove cut in the bottom ball of the pushrod where it had been riding and the side of the pusrod had serious wear from rubbing against the other pushrod. The lash adjuster on that valve was backed off farther than the rest. It had not been apart for years. Jim

Right, adjusters being way off are a tell-tale that all is not well.