eastsideauto
Full Access Member
The 3 small bolts that hold the ip to the gear. What do they torque at?
small ip gear bolts
- Thread starter eastsideauto
- Start date
icanfixall
Official GMM hand model
25 ft lbs is the torque on those. they are a 12 point 5/16 hex head. Same as the rear universal joint bolts. BTW you can buy those at Nappa in a u-joint repair kit for our trucks. they are a special heat treated bolt so don't worry about the seemingly high torque value...
eastsideauto
Full Access Member
Glad you replied.....I read somewhere that the torque spec was only 7ft/lb
icanfixall
Official GMM hand model
I don't know where you found the 7 lbs torque but... Had you used that things would have "changed" quickly for you. There is increditable twisting torque applied there because of the force needed to turn the pump to make the pressure needed to pop open an injecter. I know there is a large drive pin but its still a lot of load on that gear.
eastsideauto
Full Access Member
I read it in Mel's fuel injection servicing article.
That is correct. 7 ft-pounds is what my book says, and to be honest, when I tighten them I use a little wrench about 3 inches long, and just press down on it as hard as I can with my thumb. I've NEVER had a problem. There is very LITTLE force transmitted to the IP, and these bolts don't do much more than hold the gear on. Yes, there is a lot of presure being delivered to the injectors, but such is the wonder of hydrualics. Consider that you can jack up a 5 ton truck with a bottle jack and about 16 foot pounds of presure on a 1 foot long handle and you get the idea. To be honest, 25 foot pounds sounds scary to me on a bolt that size.
A 1/4-20 grade 2 bolt can only handle 6 foot-pounds of torque as per...
Read more: Standard Bolt Torque Specifications | eHow.com http://www.ehow.com/list_7579651_standard-bolt-torque-specifications.html#ixzz2776dTxda
A 1/4-20 grade 2 bolt can only handle 6 foot-pounds of torque as per...
Read more: Standard Bolt Torque Specifications | eHow.com http://www.ehow.com/list_7579651_standard-bolt-torque-specifications.html#ixzz2776dTxda
icanfixall
Official GMM hand model
This drive bolt is a specially made and heat treated bolt. Thats why it can handle that torque. I have the International Navistar Engine Shop Manual. It clearly says the injection pump drive gear bolts torque is 25 ft lbs. I too was skeptical about this too so I tested it. My finding were the number was correct. I recall Mel telling me how he installed injection pumps when he did my Moose pump at the 2009 ralley. We talked about his thumb pressure he uses. We both felt he was doing what was needed but thats not to say others could or would have the same feel that he has. Reasons given and its true... Nobody else has removed or installed as many pumps as Mel has and therefore he has developed a particular feel for the torque. Is it really important to use a torque wrench.. Yes it is unless you have developed a feel for torque by hand pressure and a small wrench. Now ask yourself if the torque wrench you have is actually reading correct. Is it off high or low by 1%....
My thoughts are if you have no real experiance and really want the torque to be "close" to what you want or need... Use a torque wrench thats been calibrated once a year. Most torque wrenches have directions telling you to drop the pressure and don't store it with pressure on the spring. My 40 year old Craftsman click type wrench instructions tell me to set it for 10 lbs during storage. Never leave it higher than that. Care of a click type torque wrench is as important as the torque value your asking of it. I tipically use a torque wrench on the head bolts. The rods and the mains mostly. The front and back of the crank gets the same care when tightening too. But very seldom does anything else get torqued down on my engines. I have developed that "feel" for most bolts. I have never torqued the valve cover bolts or the water pump bolts. I just have a feel and don't see the need for torqueing those bolts.
When I install an injection pump I use brakeclean to clean out the drive gear threaded holes and on the three bolts. Then a small drop of blue loctite is on the threads just as insurance. In the past we have seen posting about a drive bolt that broke or backed out... What a mess that makes in the gears and the aluminum housing. If these bolts loosen up and shear off your really lucky if they just drop down into the oil pan and not end up in the gears of the cam or crank.
My thoughts are if you have no real experiance and really want the torque to be "close" to what you want or need... Use a torque wrench thats been calibrated once a year. Most torque wrenches have directions telling you to drop the pressure and don't store it with pressure on the spring. My 40 year old Craftsman click type wrench instructions tell me to set it for 10 lbs during storage. Never leave it higher than that. Care of a click type torque wrench is as important as the torque value your asking of it. I tipically use a torque wrench on the head bolts. The rods and the mains mostly. The front and back of the crank gets the same care when tightening too. But very seldom does anything else get torqued down on my engines. I have developed that "feel" for most bolts. I have never torqued the valve cover bolts or the water pump bolts. I just have a feel and don't see the need for torqueing those bolts. When I install an injection pump I use brakeclean to clean out the drive gear threaded holes and on the three bolts. Then a small drop of blue loctite is on the threads just as insurance. In the past we have seen posting about a drive bolt that broke or backed out... What a mess that makes in the gears and the aluminum housing. If these bolts loosen up and shear off your really lucky if they just drop down into the oil pan and not end up in the gears of the cam or crank.
If your book says 25 Gary, I'm fine with that. I will have to check my 94' CD and see if it is any different than my 83' engine book because I am curious now. Helm is not above making a mistake either.
icanfixall
Official GMM hand model
Mel.. I felt just like you about 25 lbs. Thats why I tested it. My findings were its going to torque up at 25 lbs without stretch that breaks the bolts. I really was surprised at this too.
