PSA: IMO, the torque spec for the block drains is wrong!
#46
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Mate of mine once worked on an off shore oil platform. It had a crane on a pillar for lifting supplies and machinery off barges 100ft below on the water. The crane pillar was held down by some VERY LARGE BOLTS into the deck. Part of regular maintenance was to check the nuts on the BIG bolts. Seems they did it wrong, just applied specified torque without any loosening...over and over and over. One day the crane was lifting a large load off a barge, and the nuts just went elastic, and pulled off. The driver rode the crane 140ft to the water, and got away with a broken arm or similar. The threads on the bolts still looked servicable apparently.
I did have trouble the first time I pulled the block drains , but it was more a question of getting the wrench pull at the right angle. They were pretty tight, but they went in looser, and dont leak.
jp 83 Euro S AT 56k
I did have trouble the first time I pulled the block drains , but it was more a question of getting the wrench pull at the right angle. They were pretty tight, but they went in looser, and dont leak.
jp 83 Euro S AT 56k
#47
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M22 - 60Nm
M20 - 50Nm
The idea of tightening a crush washer to 60Nm is odd enough, what makes this extra bazaar is the 22mm is the old style without the helicoil insert. Why would tightening a drain plug into bare aluminum threads be higher than the one with the insert?
WSM Volume I
Page 10-05
#48
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A little visual aid might serve as a good reminder to not torque the block drain plugs too much:
Block drain plug, seriously deformed crush washer, and new crush washer:
![](https://lh3.googleusercontent.com/-vul0yiQdoB8/VyDSVRxvl2I/AAAAAAAAqoM/QrTTf3RsrJo9x4GRA7MbtD0Q8GHxcWsfgCCo/s800/2016-04-C1-0034.jpg)
The crush washer wasn't crushed as much as it was totally reformed.
I had to unscrew it from the drain plug. It didn't leak, though, and provided a few years of trouble-free service.
![](https://lh3.googleusercontent.com/-P892IpKHTTQ/VyDSVjaR5EI/AAAAAAAAqoM/gBuQhirdtNY0M49CwsGZIYm8jhIBMq2JwCCo/s800/2016-04-C1-0036.jpg)
Block drain plug, seriously deformed crush washer, and new crush washer:
![](https://lh3.googleusercontent.com/-vul0yiQdoB8/VyDSVRxvl2I/AAAAAAAAqoM/QrTTf3RsrJo9x4GRA7MbtD0Q8GHxcWsfgCCo/s800/2016-04-C1-0034.jpg)
The crush washer wasn't crushed as much as it was totally reformed.
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
![](https://lh3.googleusercontent.com/-P892IpKHTTQ/VyDSVjaR5EI/AAAAAAAAqoM/gBuQhirdtNY0M49CwsGZIYm8jhIBMq2JwCCo/s800/2016-04-C1-0036.jpg)
![](https://lh3.googleusercontent.com/-sMnUF7K0wbM/VyDSWKNxvxI/AAAAAAAAqoM/AUTGq6GhPZYrSX_ViqAcYZY0v33PqGgBQCCo/s800/2016-04-C1-0037.jpg)
#49
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Doesn't even look like the same part. Maybe it's not!
"Gotta make sure this doesn't come loose" is often the thought right before screwing things up.
I keep blue loctite handy to satisfy that impulse.
"Gotta make sure this doesn't come loose" is often the thought right before screwing things up.
I keep blue loctite handy to satisfy that impulse.
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jcorenman (07-20-2020)
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We (my shop) torque everything, except screws. From the 5mm hardware to the biggest threaded fasteners in the transmission, we torque it. I own 11 different torque wrenches....at work, alone. Of those, I actively use 7 of them....two different calibrations of inch pounds, two different calibrations of 3/8"', two different calibrations of 1/2", and one 3/4" one.
I can probably can get within 15 foot lbs on 8mm and 10mm hardware (always too tight), but after about 100 foot pounds, I can't get close. It's easier to just grab a torque wrench and use it for everything, for both Grant and myself.
BTW Dave: Completely agree with you on the block drains.
I can probably can get within 15 foot lbs on 8mm and 10mm hardware (always too tight), but after about 100 foot pounds, I can't get close. It's easier to just grab a torque wrench and use it for everything, for both Grant and myself.
BTW Dave: Completely agree with you on the block drains.
#51
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Interesting discussion. I just drained my coolant this past weekend and reinstalled the plugs to torque spec (per WSM) with some anti-seize. I was paranoid about pulling the plugs out as they felt tight when I tried to remove and I was not the last one to put them in. I used the torque wrench in reverse at torque spec to try and ensure I did not break these bolts. - they came right out at or around the WSM torque ( assuming reverse reading is valid?)
Before I put coolant in, maybe I will remove again and re torque or hand torque to lower setting, with another new set of crush washers as advised - to ensure they will come out again next time.
Good thing I did not read the links here on broken bolt drains first. Sometimes too much reading leads to not enough doing - especially for us rookies.
Before I put coolant in, maybe I will remove again and re torque or hand torque to lower setting, with another new set of crush washers as advised - to ensure they will come out again next time.
Good thing I did not read the links here on broken bolt drains first. Sometimes too much reading leads to not enough doing - especially for us rookies.
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Bump.
It's been over a year since this was on the front page and we've lots of new folks getting coolant on their faces.
It's been over a year since this was on the front page and we've lots of new folks getting coolant on their faces.
#53
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Just did my block drains a few days ago. Took the coolant bath. New crush washers and replaced plugs with 26Ft Lb. The removal torque was significantly higher, assuming due to long term fitment.
I torqued all the important stuff on the front engine job. Got the new pinch bolt on flex bumped up to 66 Ft Lbs. Checked the rear one before removal, and I could see someone had been in there. It was right up to mid-60 so I left it alone.
Only thing I didn't torque was the crank bolt, which is important, and I will go back and torque it when I get to the shop with the right tool. I just used my 24" breaker with a pipe over it. I should be 'close' to book on that.
BTW, putting anything, including white seal tape changes the torque value.
I torqued all the important stuff on the front engine job. Got the new pinch bolt on flex bumped up to 66 Ft Lbs. Checked the rear one before removal, and I could see someone had been in there. It was right up to mid-60 so I left it alone.
Only thing I didn't torque was the crank bolt, which is important, and I will go back and torque it when I get to the shop with the right tool. I just used my 24" breaker with a pipe over it. I should be 'close' to book on that.
BTW, putting anything, including white seal tape changes the torque value.
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The block drains will seal at 26 n-m (19 ft-lbs) without distorting the crush washers.
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Bump for C19 shelterers draining coolant themselves for the first time.
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dr bob (04-29-2020)
#56
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Nice Dave !
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Decided to freshen the coolant in 1978 US #0021 today, may have come across a rationale for the original torque spec being 26 ft-lbs. M12x16 hex head bolts. I torqued them to 19. ![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
![](https://webfiles.uci.edu/redwards/public/%230021%20engine%20block%20drain%20bolts%20M12%20x%2016%207-19-20.jpg)
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Confused Rob I am. Didn’t we cover this: https://rennlist.com/forums/928-foru...l#post12265692
Wait... you postulate that the spec is due to using a M12 Hex-head bolt (which would be a 19mm hex-head) rather than the small-head drain plugs (M12 with 13mm head?)
Wait... you postulate that the spec is due to using a M12 Hex-head bolt (which would be a 19mm hex-head) rather than the small-head drain plugs (M12 with 13mm head?)
#59
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Yes, this very early block has these bigass 19 mm-head M12 bolts (the driver' side drain is close to the boss for the lower bellhousing bolt and the clutch hardline is right in the way, was a PITA to get at), so maybe they switched to the smaller bolt heads for clearance reasons? Just a WAG.
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Interesting discussion on torque wrenches.
I have 3 different torque wrenches, small, medium, large, and use them on every torque-able bolt/nut without fail using the factory specs. I do it only because I don't trust myself and believe in using the proper tool for the job - which my arm by itself is not.
The only time I've had a problem using them, was with 928 oil pan gaskets. With that said, I'll be ordering Greg's new pan gaskets so I can finally use a torque wrench properly during their installation.
As a side-note, I'm always a wreck while installing brand-new spark plugs - those crush washers always seem to take forever while waiting for the click of the wrench!
I have 3 different torque wrenches, small, medium, large, and use them on every torque-able bolt/nut without fail using the factory specs. I do it only because I don't trust myself and believe in using the proper tool for the job - which my arm by itself is not.
The only time I've had a problem using them, was with 928 oil pan gaskets. With that said, I'll be ordering Greg's new pan gaskets so I can finally use a torque wrench properly during their installation.
As a side-note, I'm always a wreck while installing brand-new spark plugs - those crush washers always seem to take forever while waiting for the click of the wrench!