335 head bolt problem

[Ralph wd45]

I will give, just a little history first. I took the heads off of my 335, and had the valves ground. When I was trying to install them, I had the first head bolt strip the threads out of the jug, before the torque wrench clicked at 95 lbs.I removed the head and verified that the jug stripped instead of the bolt threads stretching. I posted on this site, my intentions to use a helicoil, as a repair, and recieved several favorable comments on helicoils. I bought a helicoil kit, used the .531 drill bit, which was furnished with the kit, in a magnetic drill, to assure a straight drill job, and tapped the resulting hole, with the tap from the kit. When I screwed the helicoil in it bottomed out, with 2 threads still above the jug surface. I pulled the insert out and took another insert from the package, ground 2 threads off of the end without the tang, and screwed it in the jug, and it stopped just slightly recessed in the jug, the way I wanted, and was bottomed out. I broke off and removed the tang, and replaced the head, using new head bolts from tacoma screw. This time I went to harbor freight, and bought a new clicker torque wrench, just in case my old wrench was out of calibration, and maybe had caused the first bolt to strip. Well the first bolt I tightened was the repaired one, and at about 85lbs it stripped again, so I continued torqueing the rest of the head bolts to see what would happen. The result was 3 stripped holes, and all the rest at 95 lbs. When I removed the head this time, I found that the holes that stripped were blind holes, and the holes which held 95 lbs were drilled through to the water jacket. Each jug has 4 holes in a line, which, do not go thru. Any one know what I would hit if I tried to drill them deeper? Is there enough meat there to hold more threads?

 

[john in wa]

I do not know if this will help. My Manual says 95-100 ft-lbs with engine at operating temp. I also replaced all my bolts and it sounds like you did the same. I did strip the rear most bolt on the left hand side. i then chased it out with a metric tap the next size larger than what it was originally and installed a longer bolt. I also only torqued that bolt to around 85 ft-lbs.. I have been working this old 335 for 2 years like this and no leaks. Good Luck

 

[Joe Pro]

Fist off are you torquing them in the proper sequence and steps. You should follow a spiral sequence and start at about 50 ft lbs and work up in about ten or 15 pound increments.

But head bolt specs, have been sort of confusing to me. The IT manual says all tractors to be 90-100 ft pounds. My 4 star owners manual says i believe 70 - 75 and and I just looked and the 445 dealer shop manual says 70 - 75 for the head bolts. I have always torqued to about 95 but maybe the lesser would be ok? But torquing them in the proper sequence and the proper ft lb steps is also very impotant. You can not just set you wrench to 100 ft pounds and go to town you have to work up to that.

 

[Ralph wd45]

Yes JoePro! I did use the torquing sequence shown in my IT manual, that is why I refered to the first bolt(meaning first in the sequence). I have many engine overhauls behind me, and several older allis chalmer tractors. My IT manual calls for 95 to 100 ft lbs torque, with engine at operating temp, which is not realistic. The engine is always going to be cold, after not being ran since tear down.

 

[FordBronco]

Original M&M 335 Manual states that the cylinder head torque is (65-70)ft-lbs.

My old I&T Manual states to torque head to (75-80)ft-lbs cold, "which is 10ft-lbs over spec" so that the warm torque should be around (65-70)ft-lbs.

I believe that too much torque is being used.

Just my 2-cents worth.

Good Luck.

 

[john in wa]

FordBronco i may agree with you on the over torque. Pops said kid if you torque it to much you will strip the threads. he said, that is old soft cast and it wont handle that much torque. then he set there watching me torque it down to 95 shaking his head. i got lucky and only striped one. we also went rounds about valve adjustment. as i went by the book and he wanted me to do it his way.

 

[Anonymous-0]

No one has mentioned that the threads must be oiled.

 

[J.Wondergem]

That's what I don't like about the I&T manuals.

 

[Anonymous-0]

I had the same problem with mine in the wet holes where the threads had gotten rusted and pitted and the threads where no longer tight. I ended up going out to a 9/16 stud and putting some loctite sleeve retainer in them, I had no trouble putting the torque to them but I am not sure how well they will come out in the future if it needs bored.