"Oh crap!" or "that was a lucky break" ?

[richardthestag]

Assembling my block tonight. All goes well until one big end nut doesn't torque to 45ft/lb

Replaced the nut and just about got it there! Hmmm

Next rod same thing. Only this time and at about 35-40 the con rod bolt sheered.

I will replace two bolts and nuts mentioned above. All others are nice and tight at 45ft lb. so should i go and replace the lot? Have i been unlucky?

The con rods were new at last rebuild 17 years and 30k miles ago.

image.jpg

[stagmuffin]

could be fatigued at that age considering the work done ! I think I would replace them without a doubt ,got to be cheaper alternative than sleepless nights waiting for the others to let go .
steve
ps I would also get your torque wrench calibration checked.

[richardthestag]

could be fatigued at that age considering the work done ! I think I would replace them without a doubt ,got to be cheaper alternative than sleepless nights waiting for the others to let go .
steve
ps I would also get your torque wrench calibration checked.

Heading that direction.

Torque wrench has been tested against another before i started. I have no reason to believe that it is at fault. How do you calibrate? Engineering shop?

Cheers

Richard

[milothedog]

I agree with Steve about the T/wrench, they were calibrated every 6 months at work as a part of our IS0 9001 accreditation, many failed and needed adjusting and these were expensive, professional ones. (Norbar, Britool & Facom)

With the bolts I would replace them purely for piece of mind, never had a problem with any B/End bolts breaking (and I've done many over the years) on anything but seeing as you have had a problem I would do it so I could sleep at night

Ian

[milothedog]

Heading that direction.

Torque wrench has been tested against another before i started. I have no reason to believe that it is at fault. How do you calibrate? Engineering shop?

Cheers

Richard

Richard, a decent tool supplier should be able to test for you and if it's good quality make adjust it and issue a certificate for it.

Ian

If you want it testing and can't find anywhere, I have a mate in Mitcham in Surrey who can do it if you get down this way.

[Staggard]

could be fatigued at that age considering the work done ! I think I would replace them without a doubt ,got to be cheaper alternative than sleepless nights waiting for the others to let go .
steve
ps I would also get your torque wrench calibration checked.

I am with Steve on this one

[71Stag]

I was certainly under the impression that you should replace them on a rebuild
Bruce

[stagmuffin]

don't know who would do calibration Richard ,I do a lot of work for the underground and they have calibrated test stations for their wrenches and im able to check mine against them. but if you had verification against a couple of wrenches with yours im sure if they are close ( within a couple of ft. pounds ) it would be ok. I just rebuilt my daughters mgf k series on Saturday head gasket failure ,where have we heard of that before lol and I had to convert from newton metres to ft. pounds to tighten the head down but then it was only about 15.7 ft. lbs. and then had to revert to turning the bolts thru 180 degrees twice and job done soon wont need torque wrenches at all on moderns !!
Steve

[ChasR]

The Passat PD diesel engines are the same Steve. Almost everything on those engines you tighten to a certain low torque and then angle tighten in stages.

[wilf]

IMHO, very false economy to rebuild an engine and not replace all the bolts with good quality items.

[richardthestag]

I think i am suffering from a ****e but brand new ratchet torque wrench that i used when i first rebuilt the engine. Only after i knackered threads in the heads did i get calibration checked at lower torque and found it to be better used as a hammer.

I would almost certainly have used it for the bottom end!

I replaced it with one of this type for low torque settings. It is spot on for the cam caps

image.jpg

I use it to loosely calibrate against my quality ratchet torque wrench and have found both to be the same as each other from 50 upto 150 ft lb. tighten with ratchet torque wrench and then check with scale wrench and find the reading to be the same. Not scientific but it is going to be good for a couple of ft lb accuracy.

it is also used for anything under 50ft lb as the ratchet drive will not go that low.

[mjb67]

I heard recently that torque wrenches are only really accurate in the higher 80% of their range, which would be consistent with yours being out at lower torques. So it might not be too ****e.

[milothedog]

I heard recently that torque wrenches are only really accurate in the higher 80% of their range, which would be consistent with yours being out at lower torques. So it might not be too ****e.

Not true, it comes down to what you pay for one and how it's maintained, a decent one will come with a calibration certificate and the tool should be rechecked (calibrated) every six months.

Ian

[GDPR]

IMHO, very false economy to rebuild an engine and not replace all the bolts with good quality items.

I would tend to agree Wilf, but unfortunately a lot of supposed good quality bolts from current suppliers turn out to be chocolate - unless you have got genuine OEM spares, it's difficult to tell what you have

[wilf]

That thought did wander through my mind after I posted. Was why I edited to add "good quality new bolts". Do ARP make any for Stags?