Push Rods Jam Together at Head Installation

Hello all. The first time I installed my Commando cylinder head it went very smoothly. Last two times now the two p rods right are good until I try and seat the head. I lift the head in place tilting it back (in situ), and it easily drops down. I make sure rods are seated in lifters, and when I align rockers to p rods head drops nicely into place. Then w/out torquing all the way my rods are jammed together on the right side. I removed the rocker spindle and arm to see better and both rods are jammed. I then jiggle and tap and free them and lift the head off where it is now.
New set of Prods, all straight. What the heck am I doing wrong here? Should I leave the rocker off until I have affirmed movement next time?

robertv said:

Hello all. The first time I installed my Commando cylinder head it went very smoothly. Last two times now the two p rods right are good until I try and seat the head. I lift the head in place tilting it back (in situ), and it easily drops down. I make sure rods are seated in lifters, and when I align rockers to p rods head drops nicely into place. Then w/out torquing all the way my rods are jammed together on the right side. I removed the rocker spindle and arm to see better and both rods are jammed. I then jiggle and tap and free them and lift the head off where it is now.
New set of Prods, all straight. What the heck am I doing wrong here? Should I leave the rocker off until I have affirmed movement next time?

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Lifters are all moving up and down nicely.

I tried it once again today, for if nothing else I am tenacious. A little grease in the rod cups and placed the head. Made sure my P-rods were located in the lifters and then the rockers. Carefully. As I did this, the head dropped down naturally.
I tightened the head with outer four bolts carefully, not fully. I spun the engine and heard a snap! I have experienced this before with VWs. Means the P rod was on the side of the lifter, and had now dropped in. I could spin the motor and rockers operated all the valves. Ok. Tightened it down w/o crushing the gasket completely, and same thing. It would no longer spin, and the right P rods were jammed. I am stumped on this. Any help would be appreciated. I removed the head and checked all rods. Straight. I assured that all lifters were working. Thanks.

I just did this a few months ago for the first time, so I'm no expert. I pushed the push rods up into the head as far as they will go, then lowered the head down letting the push rods drop naturally into the lifters. Getting the push rods to engage the rockers was a bit of a trouble but lifting the head a bit eventually got everything aligned.

It's a "look before you leap" thing

All rockers must be installed - don't try to install them after the head is on!

The tappet end of the pushrods generally fall into place by themselves.

You can see all four top cups if you look through the exhaust side. Takes some maneuvering of your head to see them. I loosen the adjusters all the way. Then one rocker at a time, get the ball in the cup, hold the adjuster end of the rockers up and lower the head. Then finger tighten the adjusters. Being able to freely move the rocker up and down really helps as does getting them all in place with the head about 1/8" to 1/4" from sitting down. Then put the front center bolt in and snug it down and take a final look at all four cups.

marshg246 said:

It's a "look before you leap" thing

All rockers must be installed - don't try to install them after the head is on!

The tappet end of the pushrods generally fall into place by themselves.

You can see all four top cups if you look through the exhaust side. Takes some maneuvering of your head to see them. I loosen the adjusters all the way. Then one rocker at a time, get the ball in the cup, hold the adjuster end of the rockers up and lower the head. Then finger tighten the adjusters. Being able to freely move the rocker up and down really helps as does getting them all in place with the head about 1/8" to 1/4" from sitting down. Then put the front center bolt in and snug it down and take a final look at all four cups.

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I appreciate your reply. I will apply your advice next attempted install. Thanks.

There is a very easy way to install the head/pushrods.

Bring pistons up to TDC. Then simply place a short piece of 3/8" rubber tube between the head & cylinders near the exhaust ports when you're lowering the head. This will hold the head up about 1/2" off the cylinders. Now you can easily see both the intake and exhaust rocker ends and rotate them down onto the pushrod ends. You will need a screwdriver to hold the pushrods in place one at a time while doing this. When all the rocker tips are located on the pushrods - remove the rubber tube and lower down the head. Without the rubber tube you can't see the rocker ends where they should meet the pushrods - you're blind and you will miss without the rubber tubing. With the rubber tubing its very easy. I discovered this technique when reinstalling the head on my spintron over and over all day to test lifter materials. It works great. Without the rubber tube its a huge PIA.

I use wood shims on top of the barrel perimeter fins instead of rubber tubing. Same idea as what jseng1 describes though. I also use the small diameter picks and hooks like those Harbor Freight and other hardware places sell to move the push rods around if I have to. Doing the head is probably 10 times more fussing around with the engine in the frame. Of course it's not convenient to remove the engine just to do the head. I'm just saying.

Another useful addition is rubber bands, inlet to exhaust rocker adjusters. You can then push the rocker down to engage push rod and when you let go the band holds the rocker onto the push rod

when everything seems OK and I'm ready for the tightening of the center head bolt to start the head down. I spin the P rods and poke them to spin them, and you can feel if the P rods are in place. Grease seems to help or assembly lube as it is very tacky.

I sincerely thank you all for your tips. Come the weekend I will try again. Another member here whose message I saved gave me some insight also. In my first go which was successful a few months back, I had not backed off the adjusters before placing the head. Now they are backed all the way out. I think that once I engage the push rods, I should screw the adjusters down closer to adjustment spec. Then the P rods will have top and bottom contact and the valves will move when I spin the motor a bit. Better held in place that way. 3/8 rubber hose. OK. I finally got the 850 running quite nicely. Just trying to correct a minor oil seep. I sincerely appreciate those of you who give tips to a new Norton owner. I always did that with VW customers over the years. After all, it is not rocket science. Cheers.

Another tip I've come across, though not tried myself yet, is to pull out the front isolastic bolt to permit front of engine to rotate downward...gives a few inches more clearance at top of head/frame while fitting head. Obviously a floor or scissor jack under engine is needed.

Success! Thankyou all for your tips. My pushrods not seating properly on the lifters was the problem. This time I kept the head up using a shim between head and cylinders. This allowed me to spin and center the pushrods more easily.
When shims removed, the head dropped into place. I am pretty fast now at head removal and placement. And next time, I will pay close attention to pr placement. Thanks again for your tips. Robert