[RWilson]

So, putting my top end back together after replacing head gaskets and reconditioning the heads (resurface and valve job). While tightening the RH side rocker shaft bolts, the front bolt broke off and I had to use an easy out on it. While waiting for a replacement bolt, I decided to do the LH side. This time I set my torque wrench at 15 ft. Lbs. and tightening each bolt from front to back. I then set to 20 lbs and repeated. Then 25. Then 30. This time the bolts turned more than I thought they should for just 5 extra lbs. my torque wrench was not clicking and I broke another bolt!!

What am I doing wrong here? I'm assuming the springs are compressing and the bolt is bottoming out, but how do I correct that from happening? I'm sure I'm just doing something stupid, but help is greatly appreciated!

 

[redtruck12]

Good for you for tackling this big job.
The first thing that jumps out at me is the mention of a torque wrench that you can set to 20 ,25,30, ft pounds? That is an exceptionally low setting. Numbers that low are usually measured in inch/pounds. 30 should not break a bolt of that size.
20 ft lbs is equivalent roughly a one hand turn with a standard wrench without any major effort so don't be fooled by a torque wrench that is set below its range of accuracy.
Secondly, there is likely a tightening procedure on the shaft bolts to draw it down equally.. Usually from the middle and working outward gradually
Check the rave for proper torque pattern.

 

[RWilson]

Thanks for the response. As far as the torque setting, I am sure it's 30 ft lbs (it's a 1/2 wrench that goes from 10-150 ft lbs). The rave just says to progressively tighten, not a specific order.

It feels like the bolt just keeps going until it bottoms out. Could the springs just keep compressing?

 

[gurunutkins]

Red truck x2
Rocker shaft bolts are indeed 30 ft lbs but you should be using a 3/8 drive torque wrench at the worst - the 1/2 inch torque wrench that works with a clicker is very inaccurate in the low readings. I wouldn't use a 1/2 inch drive torque wrench unless you have the expensive one with the electronic load cell. 30 ft lbs is 360 inch lbs which is the top end for a 1/4 inch drive torque wrench so I would go with a 3/8.
Also with the clicker type torque wrenches you need to undo the bolt on the end to adjust it and then tighten the bolt once its adjusted to the setting - if you dont tighten the bolt the clicker wont work properly.
good luck
Barri

 

[RWilson]

Okay, I'll try a smaller wrench. Do I have to order new bolts are can I find these at a local hardware store? I see no markings to tell me the grade...

I just wanted to make sure it didn't have to do with the springs compressing or lifters moving or something else as I have never done this before.

 

[gurunutkins]

Just remember that they are metric and are probably grade 5. Make sure that all of the push rods from the lifters to the rocker arms are in place on the balls at the back of the arm then tighten down against the springs. If its a new cam as well you should break it in at start with a high ZDDP additive in the oil.
cheers
Barri

 

[MetalMarine]

I bought this torque wrench. used it a few times already. works really good. well worth the $$ imo

craftsman digi-click torque wrench 3/8.

measures from 5 to 80 ft.lb. in .25 increments.

converts units from foot/pounds to Newton Meters (Nm), as well as into inch/pounds, and kg/cm. with a push of a button.

$80 plus $12 for a 3 year replacement warranty.

3/8-in Dr Digi Click Torque Wrench: Find High-Tech Wrenches at Sears

 

[RWilson]

I'm hoping it's just the fact I was using the wrong wrench... I just have a feeling it's something else, b\c this torque wrench has worked great previously at low settings (down to 15 ft. lbs)... well, at least I think it's worked well.

The bolts just seem to keep turning and turning, regardless of the amount of torque I apply. Is there a way I can check the valve springs that they were installed correctly by the machine shop after they did the valve job?

 

[PTSchram]

Do not replace with hardware store bolts.

The rocker shaft bolts are waisted to allow oil to flow around them.

As for the torque wrench, they are available in a dizzying array of capacities. A perfect example of the right tool for the job!

 

[RWilson]

Thanks PT - I'll make sure to order them from AB.

Still baffled by the torque wrench 'breaking' the bolts. All the examples & writeups I've seen on doing this work, they use a 1/2 torque wrench. I must have some gremlins in my system somewhere...

 

[Scot_Martin_]

I also busted a rocker shaft bolt for the same reason. Is the rocker shaft bolt replaceable on a 300tdi? I can't find the part anywhere. Anyone know where I can purchase rocker shaft bolts for a 300tdi?

 

[sierrafery]

Google out the part number from 13 Rockershaft - 300Tdi - Find Land Rover parts at LR Workshop and tighten them as it's recommended in the workshop manual...which means to 5Nm + 50 degrees and that's all for a rocker shaft pedestal bolt, nothing strange to bust a M8 bolt if you brutally "attack" it with a solid torque wrench