Torque settings and sequence 1972 350 LT-1
Thread Starter
Intermediate
Joined: Apr 2018
Posts: 27
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Torque settings and sequence 1972 350 LT-1
I am replacing the rear main seal and oil pan gasket on my 1972 350 LT-1. In doing online research I am finding different answers for oil pan bolt torques and tightening sequences. I am finding torque ranges from 6.6 ft /lbs to 8 ft/lbs for the 1/4" X 20 bolts. I am finding 13.75 ft/lbs to 18 ft/lbs for the 5/16" X 18 bolts. Regarding the tightening sequence, I am finding some places say start in the middle with the 14" X 20 bolts and work your way out in a cross pattern and do the 4, 5/16" bolts last. Other places say tighten the 5/16" bolts first, then do the 1/4" X 20 bolts. Is there one correct way or are they all "good enough"? Thanks
Pro
Joined: May 2016
Posts: 708
Likes: 149
From: Minnesota
There is no set method. Don't overthink it. Tightening from the center out is always a good idea, and snug them well with a 1/4" drive ratchet (anything larger for these small bolts can give you a false impression that they aren't tight. I never torque an oil pan. Just tighten within reason and you can always go back after some time running it and give it a re-snug.
Of course, someone may chime in here and correct me, because this is the forum. This has worked for me on a dozen motors, though.
Of course, someone may chime in here and correct me, because this is the forum. This has worked for me on a dozen motors, though.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
Joe is right. Too many people try to make something out of nothing for small bolt torque values. I have seen long-handled torque wrenches snap more bolts than anything due to user error.
The safest way to torque those small bolts such as:
Valve Cover
Timing Cover
Oil Pan
Is to use a quarter inch drive ratchet (with extra long extension for the oil pan) and place the ratchet in the palm of the hand so the handle is not even used for torqueing. You can get the bolt plenty tight without the danger of snapping those heads off. A term to remember is: "Just A Little Past Snug".
The safest way to torque those small bolts such as:
Valve Cover
Timing Cover
Oil Pan
Is to use a quarter inch drive ratchet (with extra long extension for the oil pan) and place the ratchet in the palm of the hand so the handle is not even used for torqueing. You can get the bolt plenty tight without the danger of snapping those heads off. A term to remember is: "Just A Little Past Snug".
Thread Starter
Intermediate
Joined: Apr 2018
Posts: 27
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Thank you both for your replies. When I was much younger, (I'm 64 now) I never even thought of such things. I just tightened them up in a cross pattern a little at a time and had no issues. Now, that I'm trying to do it "right", I guess I'm making more out of it than necessary.
Race Director
Joined: May 2006
Posts: 18,648
Likes: 2,557
Hi Dave:
As the others said, no need to use a torque wrench on the pan bolts. It's all a matter of wrist feel, you dont want to put you whole forearm into tightening those bolts. Call me if you need help.
Mel
As the others said, no need to use a torque wrench on the pan bolts. It's all a matter of wrist feel, you dont want to put you whole forearm into tightening those bolts. Call me if you need help.
Mel
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,170
From: Hermosa
I don’t think it’s a bad idea to use a torque wrench. Mostly so you don’t over tighten them and you get a consistent torque on them all.
i use a 1/4” drive torque wrench calibrated in lb/inch’s.
If you overtorque even a bit it warps the pan rim under the bolt leading to a seep or leak.
i use a 1/4” drive torque wrench calibrated in lb/inch’s.
If you overtorque even a bit it warps the pan rim under the bolt leading to a seep or leak.
Racer
Joined: Sep 2011
Posts: 414
Likes: 55
From: Humboldt county Ca
Thank you both for your replies. When I was much younger, (I'm 64 now) I never even thought of such things. I just tightened them up in a cross pattern a little at a time and had no issues. Now, that I'm trying to do it "right", I guess I'm making more out of it than necessary.
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Race Director
Joined: Apr 2003
Posts: 19,345
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From: Tampa, Florida
If you haven't started ask yourself how right you want it to be..... There's a very nice one piece pan gasket out there, I coated mine on both sides with sealer. Not original correct but its a worthwhile to gasket to buy. Lay your pan down upside down and check the rail edge for straightness. Pound out any high/low spots. Paint it?
Thread Starter
Intermediate
Joined: Apr 2018
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I have the Fel Pro single piece gasket. I did check for straightness on the edge and pounded down any high spots at the bolt holes. The edge itself was flat. Reinstalled the new Fel Pro seal, bearing cap, oil pump/shaft and windage tray yesterday afternoon. Hope to finish up today. Thank you for your reply.
Racer
Joined: Sep 2011
Posts: 414
Likes: 55
From: Humboldt county Ca
I can tell you are a competent mechanic for such a young guy!
Best of luck and may the God of oil leaks never visit your garage.
Roy
Thread Starter
Intermediate
Joined: Apr 2018
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Thank you. It has been many years since working on an older car, so I was a little concerned about digging in to the underside of the engine. But I have to say how much I love being able to get back in there. It's also a great feeling of accomplishment to do this myself. To do this job forty years ago was nothing. It was just another day being a young kid. I never hesitated pulling the engine and doing a total rebuild on my 1966 Chevelle SS396 in 1972. Now, the pleasure of driving my Vette is equaled to working on it. I just wish I had a lift to get it in the air...lol. That would make it so much simpler.
Racer
Joined: Aug 2018
Posts: 266
Likes: 52
I always use a socket on a screw driver handle for large covers with many small bolts. With an oily gloved hand turning the screwdriver handle as tight as possible seems to get the consistent torque. The old american stuff is the most dofficult to get leak free because the pans and covers tend to warp easily. I remember doing an 80’s Oldsmobile valve cover 4 times before feeling satisfied.
Last edited by Greengear; Oct 28, 2018 at 01:23 PM.
Dr. Detroit
Joined: Mar 2012
Posts: 10,093
Likes: 4,017
From: New Braunfels Texas
Cinch the four corners up but do not tighten at first......jump around side to side from the center on the other bolts......pancake it out.....then tighten the four corners.
Jebby
Jebby