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One step forward, two back - Main Bearing Cap not locked

Posted: Thu May 10, 2012 12:13 am
by Bensdexta
Whilst refitting the sump oil strainer, I peered up through the hole into the engine. I noticed that one of the locking tabs on the centre main bearing cap was not bent over. :(

I am loosing faith in the shop that did my engine - what else haven't they done? Did they do up the cap bolt to the correct torque? :evil:

What should I do?
-- Bend over the tab with a mole grip through the strainer hole and hope for the best?
-- Check the torque on the offending bolt, then bend over the tab?
-- Drop the sump and check all the bolts, tabs and have a general look around the bottom end?

One other curiosity: The locking tabs on the bolts that hold on the rear crankshaft balance weight seem to have been welded to the bolt heads. Is this a normal practice?

Looks like it was done sometime ago as the bolts don't look new, unlike the bolts on the front balance weight, which are shiny & new, but have no welding, the tabs are just bent over.

Advice appreciated
TIA

Re: One step forward, two back - Main Bearing Cap not locked

Posted: Thu May 10, 2012 10:58 am
by russelm
Its got to be worth checking at least the ones you can get at.

As for the counterweights, was the crank ground?

I know that when mine was done they could not grind the crank with the weights fitted as they overhang part of the crank area.

I guess a blob of weld on the bolts will make them more secure but the tabs should do a pretty good job on their own, I sort of wonder if they were ever removed!

As many know, I trust nobody on such things and hence do them myself :cry:

Re: One step forward, two back - Main Bearing Cap not locked

Posted: Thu May 10, 2012 11:44 am
by Bensdexta
russelm wrote:Its got to be worth checking at least the ones you can get at.
As for the counterweights, was the crank ground?
I know that when mine was done they could not grind the crank with the weights fitted as they overhang part of the crank area.
I guess a blob of weld on the bolts will make them more secure but the tabs should do a pretty good job on their own, I sort of wonder if they were ever removed!
As many know, I trust nobody on such things and hence do them myself :cry:
I suspect also that the rear balance weight hasn't been removed so maybe the crankshaft wasn't reground, though I was led to believe it was, but who knows it was 3 years ago now.

My main concern is that nothing should fly apart and wreck the engine.

Thanks for your advice

Re: One step forward, two back - Main Bearing Cap not locked

Posted: Thu May 10, 2012 8:31 pm
by marcusgs
Hi,

Think I would whip the sump off and check them all mate if it was mine....

For peace of mind if nothing else.

Re: One step forward, two back - Main Bearing Cap not locked

Posted: Sat May 12, 2012 8:53 am
by tom lad
+1 mate sorry

Re: One step forward, two back - Main Bearing Cap not locked

Posted: Sat May 12, 2012 12:08 pm
by Bensdexta
I checked the torque for the unlocked cap bolt. It was up to spec, 122Nm (90ft.lbs)

Will checking the torque on all the other bolts mean replacing their locking tabs (as they have been bent)? Can the cap bolts be reused or must they be checked for stretch?

TIA

Re: One step forward, two back - Main Bearing Cap not locked

Posted: Sat May 12, 2012 12:21 pm
by Tubal Cain
In my experience it was only the bottom end bolts that we examined for stretch and in some cases replaced after 10,000 running hours. I would say that you are safe to use the original bolts as the forces acting on the crankshaft bearing caps differ from those on the bottom ends.

Gerald