In my opinion this is not correct. The Cummins shop manual give a Torque Plus Angle Spec for head bolts. And also gives a spec for head bolt length to be sure they have not yielded.OK Guys ,I thought I saw on this site that somebody says torque the head bolts to 125 & stop. Is this correct ?
My Cummins 4B series engines use 14 head bolt cap screws. Two of my Cummins Parts Manuals show these cap screws as follows;Thanx Paul, I'm doing it "By the Book" but it says to tighten all capscrews to 66ft-lb, then tighten the " long capscrews only" to 89ft-lb . There are 3 lengths of capscrews . I'm not sure about tightening the middle length screws to the 89ft-lb or just the 4 longest screws. Any help , Thank you.
In my Cummins book Bulletin 3666087-02 printed 10/99 for both 3.9 and 5.9,
It talks about a medium length capscrew of a max length of 4.807, page 2-11, I'm guessing it applies to someting else besides cyl head cap screws, but it's listed in the cylinder head group? Its not listed in the crank group either.
Your right, the long bolts are for the Rocker Pedestals/ head bolts. I have my pedestal bolts in bags with each pedestal and thus did not count them with the head bolts. Open mouth, put foot in ha ha.I've got 18 bolts total . 4-long ones in the rocker pedestals , 10- medium length ones (between valve covers & they go thru the head kind of behind the exh ports ) and 4- short ones right next to the exh ports . So I'm not sure Cummins wants me to torque the 4 long & 10 medium bolts to the higher torque setting or just the 4 long bolts only.
hi paul any chance you could eme that jpg pick of the head sequence? i cant read it on the site maybe if you e it to me direct it would come through betterI Stopped and talked with the service manager of Cummins while up north this afternoon.
While I was with him, he looked at 8 Cummins Service Manuals for the 3.9 and the 3.9/5.9.
Not one showed the Torque Tightening Sequence for a 3.9 engine. In all cases the manuals showed the 5.9 head sequence as illustration. So, we have nothing at this time that shows the proper tightening sequence for a 4B Series 3.9 Engine Head ! He suggested to use the 5.9 tightening sequence as a guide on the proper sequence and then tighten the corresponding head bolt positions as close as possible.
The picture is a photocopy he made for me taken from a 1985 4B Series 3.9 Shop Manual. Note that the head shown in that manual is still a 5.9 head. The remarkable thing is the torque specs given in the 1985 3.9 Manual (Bulletin Number 3810206-01) ! You can see in the picture that the torque specs are all given in Foot Pounds ONLY, not Torque Plus Angle. And also remarkable is that ALL head bolts are torqued to 92 foot pounds. The service manager told me that in the
1990's (he forgot the exact year) the torque changed from Torque Only to Torque Plus Angle.
Further the present manuals have an error ! They show the short bolts only getting 66 foot pounds + 90 degrees rotation, and the rest getting 89 foot pounds + 90 degrees rotation. The error is that ALL bolts need to be torqued to 89 foot pounds + 90 degrees rotation. He said the final step was left out by accident and if you dont bring the short bolts up to 89 foot pounds + 90 degrees rotation, you have a head that is not evenly torqued and probably will blow a head gasket on the short bolt side. This does make sense and is in keeping with the torque specs given in the pictures of 92 foot pounds for ' ALL ' head bolts.
Now, digressing, somewhere out there in the world is a shop manual with the proper head torque sequence and torque specs. We need to find that to verify, back up if you will, the information I learned today. What I believe we need is for some of you guys to visit your local Cummins and Try to get a Photocopy of the Torque Sequence and Torque Specs, both for the old engines and newer where Torque Plus Angle is used. I live very remote and have no other Cummins to visit.
PLEASE !! dont kill the messenger. I am just bringing forward info I learned today at Cummins.
Harry; PM me with your regular email address. I dont know how to attach pictures to PM's. If anyone else requests these 2 pictures, would you go ahead and send them out. I am on a 24.4K dial up, pictures take me forever. Thank Youhi paul any chance you could eme that jpg pick of the head sequence? i cant read it on the site maybe if you e it to me direct it would come through better
and is the 92 lbs + 90 degrees right?