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*photos* cracked crankcase- strainer nut overtorqued

Posted: 21 Mar 2013, 15:04
by 81AirCooled
If stupidity hurt I'd have a cracking headache. I decided to do an oil change today and as the sump bolt must have been rounded off by a previous owner I drain via the strainer like I did last time.

The torque wrench was set up correctly but I didn't notice the click, thought "13 nm seems a lot" as I kept on tightening until there was an almighty crack and the nut had split.

Have I possibly damaged the oil sump or will simply changing the strainer, nut etc etc do the job? As an aside is fresh oil much thinner than old stuff as it's dripping quite "nicely" from the rocker cover or pushrod tube seals on one side

Soooo stupid

Re: Oil strainer nut overtightened - bang!

Posted: 21 Mar 2013, 18:09
by sarran1955
Hello,

Do you mean one of the 6 domed nuts, that go round the plate with copper washers underneath,

If so do you think the stud has pulled loose..

Photos will help..

Cordialement,


Re: Oil strainer nut overtightened - bang!

Posted: 21 Mar 2013, 18:13
by Plasticman
^^^ he knows but i personally wouldnt use a t wrench to do those up. feel is what you want feeel.
mm

Re: Oil strainer nut overtightened - bang!

Posted: 21 Mar 2013, 18:28
by 81AirCooled
Hi Sarran, it's not this one http://www.justkampers.com/vw-t25-parts ... 000cc.html

its the one with the thread inside that screws onto the stud in the sump I'll have to drop the 3.5 litres of new oil (€40 for 5l ) and check it out. Everything is still tight and there's no obvious leak around there but I'll hopefully get to it at the weekend. Having a bit of an issue trying to source a new nut before I get under her again.

Re: Oil strainer nut overtightened - bang!

Posted: 21 Mar 2013, 18:42
by AdrianC
Ah, the false sense of security of a torque wrench. 13nm = 10lb-ft = "nip it up a bit gently"... 1/4" ratchet just fine, if not nutspinner.

The nut itself visibly split, and it's one of six holding the cover on?

TBH, I'd just lob a new nut on and see if it leaks... It's almost certainly a bog standard thread, so if you've got a "spare nuts tub", then have a rummage through that, otherwise pull one of the other six off and walk it down to a local half-way decent fastener supplier's desk.

(then fix the drain plug properly for next time)

Re: Oil strainer nut overtightened - bang!

Posted: 21 Mar 2013, 18:58
by sarran1955
Hello,

Well at least we now know what torque will break the thing..

Try Serial kombi:

http://en.serial-kombi.com/

Pretty good for T3 in Europa.. less postage..

Collect your oil in a clean basin, and de cant with a funnel back into an oil can..

Waste not...want not..

Cordialement,


Re: Oil strainer nut overtightened - bang!

Posted: 21 Mar 2013, 19:27
by 81AirCooled
Yes Adrian it's the cover nut and the top has basically erupted open. On this picture you can see the strainer plate is held on by one cover nut attached to a stud in the centre of the plate. Got one http://www.vwheritage.com/vw_spares_Nut ... try_GB.htm That's not my engine btw even mine is a bit cleaner than that.

Image

Thanks for the tip with the oil John, simple I know but after the botch I've managed today even the simple things come hard.

Re: Oil strainer nut overtightened - bang!

Posted: 22 Mar 2013, 13:20
by CovKid
As a rough guide, out in the field, if you don't have a torque wrench and no idea of how one relates to pressure needed, if you use only your last three fingers and don't use your whole your hand on the average socket set wrench, thats around 10lb-15lb. I wouldn't use much more than that on a sump plug. Three fingers really limits how much pressure you can put on a bolt/nut. Not many things around an engine need massive tightening, its just when you come to suspension and running gear that you need to make sure things are tight and give it some welly.

Four fingers only is around 20lb-25lb. In the early days I used a torque wrench constantly (particularly when building race-tuned bug engines) but after a while you start to 'feel' the right pressure and no longer need one. Hope that helps.

Re: Oil strainer nut overtightened - bang!

Posted: 22 Mar 2013, 17:28
by sarran1955
Hello,

You see.... a picture is worth a thousand words....

OK.. if it's not leaking, then put off the job for a bit..

Give you time to put the thinking cap on...

There are ( so I am told) more ways of killing a pig other than drowning it in boiling custard..

I'm playing VW this weekend, and will have a think...

Cordialement,


Re: Oil strainer nut overtightened - bang!

Posted: 22 Mar 2013, 19:09
by Allanw
sarran1955 wrote:
There are ( so I am told) more ways of killing a pig other than drowning it in boiling custard..

. Really. Must remember that.

Re: Oil strainer nut overtightened - bang!

Posted: 28 Mar 2013, 12:02
by 81AirCooled
Freezing temperatures and the fact I haven't go the spare part mean I'l lbe putting the job another week. Oh spring, where art thou?

Re: Oil strainer nut overtightened - bang!

Posted: 28 Mar 2013, 21:14
by sarran1955
Helo,

Hey .. its not leaking..

Get some kilometers before the next oil change..

Easter weekend....

Drive... hook up... chill out...

Its a VW thing...

If its sunny on sunday I'll be on the slopes...

Cordialement,


Re: *updated w/photos* Oil strainer nut overtightened

Posted: 21 Apr 2013, 19:38
by 81AirCooled
So after making a total hash of the oil change I noticed an oil leak on the left side. Assuming it was the pushrod tube seals and the thinner cleaner oil I changed them and 10 minutes later and a warm engine I could see oil was still pouring out - 1st photo

Looking at photo 2 I think the seals are ok but theres alot of oil leaking into that grove on top of the sump. Also after replacing the strainer nut and tightening it correctly their is now a leak from there also, but not as bad as that pictured.

Assuming I've knackered the stud or even the sump - is it possible to change the sump on a CU and what kind of job is it? There's supposedly one here http://www.justkampers.com/deep-sump-aluminium.html but it's nothing like the original and I can't see how the original is removed. Any advice is greatly appreciated

Image
oil1 by RushWolf, on Flickr

Image
oil2 by RushWolf, on Flickr

Re: *updated w/photos* Oil strainer nut overtightened

Posted: 21 Apr 2013, 20:48
by 81AirCooled
Found this short explanation -

"From what I remember during the brief time I spent poking around type IVs the problem is not stripping the bolt but overtorquing it, as the topside of it has an eye that a case bolt passes through to hold it up into place. When overtightened you are pulling down on this case bolt and can crack the boss inside the case that it threads into. The 2L has a reinforced area for this but I have heard it can still happen if you don't like reading torque specs. Regardless, you should be able to look at the threads on the bolt and in the nut and see if anything is going on there. You may be able to clean them up. I suppose it is possible the eye at the top of the bolt broke and is allowing it to spin, doesn't sound plausible but who knows? As far as a deep sump goes I have no idea how they attach to the bottom. I've never built a type I without one but they must mount differently. Either way before you sneak around this problem you aught to figure out what the cause is so that it doesn't bite you in the ass down the road."

So in other words I've fooked my crankcase?

Re: *updated w/photos* Oil strainer nut overtightened

Posted: 22 Apr 2013, 10:42
by 81AirCooled
This pretty much confirms my worst fears. http://www.thesamba.com/vw/forum/viewto ... sc&start=0 The photos on that thread matched with those of my oil leak point to a cracked crankcase. There's no crack visible on the photo but it must be there.

Excuse me now while I stick my head in a barrel of boiling water, after spending 500 euros getting through the MOT last month I'm feeling a little down.