SBC Oil Pump Bolt Torque - Page 2

BillK · 03-16-2016, 10:46 PM

Dave,
Probably too late now but the factory spec is 65 lb ft. The bolt is almost identical to a short head bolt so it makes sense that the torque would be close.

Bolt charts are ok for "generic" fasteners but most engine fasteners are designed for a specific use and the factory torque specs should be used if available.

I have probably done a hundred of them and never have had the issue you mentioned with the bolt crushing the pump. I really think it would be a good idea to get your torque wrench checked or at least compare it to another one. If it is one of the Snap On wrenches with the little knob on the side I have had two of them start sticking and not releasing properly. One was a 3/8 and the other a 1/2" drive. I have replace both of them with "traditional" Snap On wrenches, I just could not trust them

Just my opinon,

Dave Gantz · 03-17-2016, 09:47 PM

Looks to be a bad casting. Two shots of each the new and old pump. The shot looking down through the bolt hole of the old pump (sort of) shows the casting to be thinner on one side of the bolt hole. (Core shift?) That's were the casting crushed. The block, heads and the pump all say, "Mexico" on them, so I guess the pump is original to this crate motor. http://s978.photobucket.com/user/Pic...%20Pump?sort=3 I couldn't upload to the site. Said they were too big, and I don't have a clue how to compress them.
Thanks for that info, Bill. I, of course, just put it back together today. I used 55#.
Thanks, everyone, for the help.

Ed Wright · 03-18-2016, 09:44 AM

Not many threads in the main cap for the oil pump bolt. I have had to helicoil a couple of caps for guys. I'm not comfortable with 65lbs on that bolt. I'm not a professional engine builder, just been screwing my own junk together for 55 years, and helped a few other guys with theirs. Easily over 100 engines. Have seen guys kill the rear main using too long bolts. Might want to watch that if your new at this.

Rich Biebel · 03-18-2016, 10:31 AM

Junk casting...

If you don't use a hardened washer under the bolt or nut if it's a stud the casting can do exactly what you have shown in your picture.

Old Small block Chevy heads used to do the same thing.

Poor casting material.....head bolts with no washers...

Short head bolt bosses on 461 heads often split and had broken sections just like that pump...

The factory used to even weld repair some heads and blocks with minor imperfections like that.

Ed Wright · 03-18-2016, 03:43 PM

I agree with Rich, a hardened washer should be the normal thing to do.

03-16-2016, 10:46 PM	#11
BillK Member Join Date: Nov 2005 Location: Waldorf Md Posts: 230 Likes: 12 Liked 30 Times in 17 Posts	Re: SBC Oil Pump Bolt Torque Dave, Probably too late now but the factory spec is 65 lb ft. The bolt is almost identical to a short head bolt so it makes sense that the torque would be close. Bolt charts are ok for "generic" fasteners but most engine fasteners are designed for a specific use and the factory torque specs should be used if available. I have probably done a hundred of them and never have had the issue you mentioned with the bolt crushing the pump. I really think it would be a good idea to get your torque wrench checked or at least compare it to another one. If it is one of the Snap On wrenches with the little knob on the side I have had two of them start sticking and not releasing properly. One was a 3/8 and the other a 1/2" drive. I have replace both of them with "traditional" Snap On wrenches, I just could not trust them Just my opinon, __________________ Bill Koustenis

03-17-2016, 09:47 PM	#12
Dave Gantz Senior Member Join Date: Nov 2005 Location: Verrry South Jersey Posts: 537 Likes: 134 Liked 251 Times in 125 Posts	Re: SBC Oil Pump Bolt Torque Looks to be a bad casting. Two shots of each the new and old pump. The shot looking down through the bolt hole of the old pump (sort of) shows the casting to be thinner on one side of the bolt hole. (Core shift?) That's were the casting crushed. The block, heads and the pump all say, "Mexico" on them, so I guess the pump is original to this crate motor. http://s978.photobucket.com/user/Pic...%20Pump?sort=3 I couldn't upload to the site. Said they were too big, and I don't have a clue how to compress them. Thanks for that info, Bill. I, of course, just put it back together today. I used 55#. Thanks, everyone, for the help.

03-18-2016, 09:44 AM	#13
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: SBC Oil Pump Bolt Torque Not many threads in the main cap for the oil pump bolt. I have had to helicoil a couple of caps for guys. I'm not comfortable with 65lbs on that bolt. I'm not a professional engine builder, just been screwing my own junk together for 55 years, and helped a few other guys with theirs. Easily over 100 engines. Have seen guys kill the rear main using too long bolts. Might want to watch that if your new at this. __________________ Ed Wright 4156 SS/JA

03-18-2016, 10:31 AM	#14
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,314 Likes: 25 Liked 544 Times in 213 Posts	Re: SBC Oil Pump Bolt Torque Junk casting... If you don't use a hardened washer under the bolt or nut if it's a stud the casting can do exactly what you have shown in your picture. Old Small block Chevy heads used to do the same thing. Poor casting material.....head bolts with no washers... Short head bolt bosses on 461 heads often split and had broken sections just like that pump... The factory used to even weld repair some heads and blocks with minor imperfections like that. __________________ Rich Biebel S/C 1479 Stock 147R

03-18-2016, 03:43 PM	#15
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: SBC Oil Pump Bolt Torque I agree with Rich, a hardened washer should be the normal thing to do. __________________ Ed Wright 4156 SS/JA