I am assembling my engine now on its' second rebuild in 40 years. I did the first rebuilt in 1970 when I was sixteen and, as you can imagine, learned alot, but made alot of mistakes along the way, which caused some damage. when I sent my engine to George King III in Connecticutt to be rebuilt, the pan needed extensive straightening on a KRW jig, due to my overtightening of the block and hogshead to pan bolts and the bottom access door to pan bolts, which caused the pan lips around each bolt to distort and protrude into the soft gasket. George had to beat the bulging areas around each hole flat.

This time around I am going to be more careful and not tighten the 1/2" bolts as tight as possible, but instead, will be using a torque wrench to tighten them gradually and uniformly. I will be using a layer of Ultra Black on each side of the gasket, so care must be taken to apply enough torque to seal the gasket and tighten the bolt sufficiently without causing the area around each bolt to distort and be pressed down into the softer gasket.

Question: What is the proper torque for the 1/2" bolts securing the engine parts to the pan without distorting the pan. I installed the bottom access door to the pan and went around about six times, gradually tightening each bolt about 2.5 foot lbs. per pass until reaching 15 foot lbs. with a good seal with ultra Black oozing out all around and no visible distortion around the bolt heads. Do you think 15 foot lbs. is about right? If not, how much should be used? I don't want the bolts to vibrate out from not being tightened enough but there does appear to be a superb seal. Thank you. Jim Patrick

I'm moving this thread back to the top in the hopes that someone with the answer may have missed it the first time around. I still need an answer as to whether or not 15 foot lbs is enough torque because I am ready to install the engine block to the pan and want to use enough torque to sufficiently tighten the bolts, but not so much as to distort the pan by bulging the areas around each pan bolt hole up into the soft gasket. I'll appreciate the help. Jim Patrick

Tighten them until snug. Then advance the castle nut until the next cotter pin location aligns. The amount of torque would not be measurable. To ensure no leakage, use a good sealant such as "The Right Stuff".

I use lock washers and tighten them snug. Don't have to mess with the cotter pins and should they need tightening,just do it.

I use an about six or seven inch end wrench or ratchet and tighten them to just past snug. Sometimes I go to the trouble of castle nuts and cotter pins and sometimes I just use lock washers and regular nuts. I do like to re-tighten them after about a hundred miles.
W2

15-foot pounds would be way more then enough i would think

Thank you. It sounds as if I used just about the right amount of torque on the access pan bolts, which, by the way, are not 1/2", but more like 5/16" or so. It takes a 1/2" wrench to turn the bolt and I was not thinking about the actual bolt size but instead was thinking about the wrench I just used. I have a real good seal on the bottom pan access door thanks to the Ultra Black, which will, no doubt serve as a form of thread seal and help to keep the bolts in place until I remove them. I will also use 10 to 15 ft./lbs. of torque on the engine block to pan bolts as well. Thanks again. Jim Patrick

Those 1/2" heads are on 5/16" dia. bolts, which is the determinant for torque.



Rubber/steel washers from Home Debt or elsewhere are good for sealing and shaking, but I don't always have them on hand when assembling.

rdr

Thank you Ralph. Now, THAT'S what I'm talkin' about. Your chart shows 12 ft/lbs for the 5/16" bolt (slightly less than what I used, but tolerable). Great! I'm gonna print it out and use it in my shop so I won't twist off or over tighten grade 2 bolts anymore.

Due to the unique circumstances of the soft pan, I will, however, still only use about 15 ft/lbs on the 3/8" engine block and hogshead to pan bolts so as not to distort the pan lips. Jim Patrick

Ralph's chart is for coarse thread fasteners. IIRC the bolts on the pan are 5/16"-24, meaning, ignoring friction, that for the same torque as applied to a 5/16"-18 fastener, you'll get 1/3 more clamping force.

Which means that 15 ft lbs is way too much torque.

Seth: 5/16"-24 is the same as SAE (fine thread) which calls for 12 ft. lbs. which is in the infield of the ballpark. I'm just happy that I stopped at 15. My main concern is that I don't distort the pan lip and it appears that 15 ft.lbs. is just enough to avoid distortion of the pan and which is what I plan to use on the 3/8" SAE engine and hogshead bolts, which, in the above chart calls for 20 ft/lbs. but I would be concerned that, that much torque might start distorting the pan. Jim Patrick

"calls for" means the maximum recommended torque for that fastener. It doesn't mean that in every application where the fastener is used, should it be tightened that much.

Oh, and the chart is still for coarse threaded fasteners (UNC).

SAE stands for Society of Automotive Engineers and where it says SAE, it means the Society of Automotive Engineers designated Grade of fastener.

UNF (Unified National Fine) threads are mentioned nowhere. I never quite understood where UNF threads somehow got called SAE threads.

I have been Purchasing Manager for Mulberry Railcar Repair Company for thirty years and one of the things I order is barrels of Grade 2, Grade 5 and Grade 8, N.C. and SAE threaded bolts and nuts for the railcars we repair and since 1980, whenever I order course thread bolts , they are ordered with the designation N.C. (National Course) and fine threaded bolts are ordered by using the designation SAE. Just to be sure, I called my supplier, "Pyramid Fasteners" and was told that "Yes, SAE is automatically considered fine threads", which I'm glad she said, for I'd hate to think I had been ordering the wrong thing the wrong way, all these years. LOL! Jim Patrick

Well, I'm glad you are getting the right bolts from your supplier, course (sic) or otherwise. LOL!

Seth