VCCA Home Forums GENERAL DISCUSSION What did you do with your vehicle today? Not so good day with my '36 truck.

I've been trying to get the head back on my '36 1-1/2 ton truck. I had the head torqued in place a couple of days ago then realized I had not installed the drain tube from the head to the crankcase. I backed the bolts out to lift the head about 1/4 inch and installed the tube.
I started the torque sequence and advanced in 10 lb. steps. When I started the final round from 50 to 60 ft./lbs., the #3 bolt did not reach 60 lbs. with considerably more rotation than required for #s 1 and 2. I advanced to # 4 and had the same result, too much rotation. I concluded that I was stretching the bolts so I stopped. After several calls looking for new, correct bolts, with no luck. I bought new grade 8 bolts and assumed I was ready for my final battle with the head. When I got to the 50 - 60 ft./lb round of the torque sequence, I had the same experience at bolt #3. Too much rotation.
I have concluded that I am pulling the threads from the block and not stretching bolts, as previously thought. I was so disheartened that I left the shop without further investigation. I feel sure that #4 bolt suffered from the same ailment. How many more?? What do I do to figure out which holes need repair so that I can do them all at one time?
I went to my buddy's house and borrowed his Heli Coil kit. My Son called for an update and suggested a repair system called Time-Sert. I checked it out and ordered the kit.
I have a few days to regroup before starting the repair.
Shall I continue the torquing to find any additional threads that have been compromised? Yes, I oiled the threads. HELP!!

Mike

If you are pulling some of the threads in the block I would think it prudent to do the lot rather than do 1 or 2 then have to lift the head again to do more. I have used helicoils with success in most cases but have not used Time-Sert and imagine they would be just as successful providing they go in with the same hole centre.
Tony

Maybe just for kicks you should get your torque wrench checked as well and if necessary calibrated?

cabby,
I think you are on to something. I posed my problem to the morning coffee guys today. A couple of them are working mechanics. I had 2 immediate offers of loaned torque wrenches.
It got me thinking about the adjustment on my Craftsman wrench and that it was not acting right. I will report back.

Mike

Hi Mike,

Sorry to hear about the setback. As always you are doing a good job thinking through all the solutions and alternatives.

Here are a couple of thoughts to consider.

Do you really need to go to 60 ft lbs? Is 50 or 55 enough for that engine? 60 is above the recommended torque for a 1/2-13 Grade 2 bolt. In this case the limitation is the threads in the block. Were they intended to handle that much bolt tension?

Even though you are using Grade 8 bolts you will only have the same clamp force as a lower grade bolt at the same torque. It is clamp force that keeps the head and block together.

I keep my beam torque wrench to use in these situations especially if I think my click wrenches are not working correctly. Beam wrenches do not go out of calibration unless you do something to reduce the cross section of the beam. Sometimes the pointer will get bent out of position but you can easily make it read 0.

I use an old beam style wrench too. You can really detect too much rotation with it.

You might also consider the oiled vs. non-oiled bolt torque. There was a discussion on that in another thread. Not sure what the exact outcome was but all the charts I have viewed show the oiled torque at considerable less than oiled. The diacussion was regarding the bolts however i would think it would apply to the block threads also.