torquing new head down, rocker arm just snaped

metsfan3321 · Post by **metsfan3321** » Sun Oct 26, 2014 6:47 pm

so I was torqueing the new head down and one rocker arm just snapped. I have no clue why or how this happened. I know the number one piston was at top dead center and the valves on the number one cylinder were both closed before I put the head on. Whast weird is I was tightening a head bolt that was no where near the rocker that snapped.. is there a good right up on here on how to replace the rockers? I no the head has to come back off.... thank guys

T.Hanson · Post by **T.Hanson** » Sun Oct 26, 2014 9:43 pm

You say," New head," as in factory assembly, or casting that received the cams, valves,...assembled by,...return to builder ?

Very odd, unless stress cracked or somehow involved in wrench contact. But, if it's busted,...out she goes. My experience with heads learned the proper tools are very necessary. "Making do," with improvisations is both time consuming and risky. To the point, head builders build heads.

GripGreg · Post by **GripGreg** » Sun Oct 26, 2014 11:10 pm

Remember, if it's a NEW head, it was never on a car before.
Maybe it's under warranty?
I hope you know the sequence to tighten down a head goes in three tightening sequences?
And, there's a particular spacing to use? It isn't 'just tightened'. Do you have a book?
Greg

metsfan3321 · Post by **metsfan3321** » Mon Oct 27, 2014 5:03 pm

it wasn't a new head. sorry I wasn't clear on that. I purchased it used on ebay. its just weird that the rocker snapped as I was torqueing a bolt no were near the rocker that snapped. I am a technician at a dealer and I have torqued tons of heads and this never happened. all I can think is that it was on it way out and decided to go. is there a good write up on here in order how to replace the rockers and the shafts....? alldata was a lil confusing.

bizz · Post by **bizz** » Tue Oct 28, 2014 5:11 am

Head's gotta come off

http://www.firstfives.org/faq/cylinder_ ... ad_faq.htm

Mike W. · Post by **Mike W.** » Tue Oct 28, 2014 10:50 pm

It had to have been out of time, just torquing it wouldn't put any load or stress on the rocker. I know you think you had it right, but it had to be out of time. Sorry.

metsfan3321 · Post by **metsfan3321** » Wed Oct 29, 2014 5:12 pm

mike.... when the head was on the bench I made sure the valves for the number one cylinder had just closed as I spun the cam nut.. thought that was right....

Mike W. · Post by **Mike W.** » Wed Oct 29, 2014 9:19 pm

Put the cam sprocket on and make sure. But there shouldn't be anything to make contact or do anything to the rocker, nothing should change as you torque it down. Loosening the adjusting nut doesn't hurt either but shouldn't be needed. Look at the valves and the pistons before you bolt it up.

Falkenberg · Post by **Falkenberg** » Thu Oct 30, 2014 4:35 am

It should be easy to see if there is a piston on TDC and a valve open on a certain cylinder. The head will not even settle on the block when you put it in position.