3.0 TDV6 broken crankshaft / engine rebuild

**Fabsky** · 29th December 2022, 08:17 PM

Ok, now two words about the work that has been done.

In general, despite the failure of the engine, the block was not damaged and was within the specification tolerance.
However, work has been done to refresh the surface, such as:
- cylinder honing
- resurface of the block decks
- grinding / re-honing the tunnel bore for new bearings.

I decided to use bearing shells from King Bearings because of the much larger oil delivery hole.
As for the oil clearance on the main shaft, they oscillate between 0.050, 0.058 and 0.060mm

IMG-1490.jpg

**Jeffoir** · 29th December 2022, 10:37 PM

Seasons Greetings Fab,
once again, you’re commitment is extremely impressive.
well done and thank you.
looking forward to learning more.
best wishes for 2033
jeff

**discomatt69** · 30th December 2022, 05:44 AM

Originally Posted by Jeffoir

Seasons Greetings Fab,
once again, you’re commitment is extremely impressive.
well done and thank you.
looking forward to learning more.
best wishes for 2033
jeff

MMM what about the next 10 years?
Best wishes with the build in 2023 as well

**Fabsky** · 1st January 2023, 09:48 PM

Welcome everyone in the New Year. I hope it brings the best to everyone 🤘

**Fabsky** · 2nd January 2023, 05:22 PM

And my joy of rebuilding the engine was gone like a soap bubble...
During the next stage of the final assembly of the engine, I noticed a micro crack on the block near the ear where it is directly bolted timing belt idler pulley.
The ear does not bear the slightest traces of impact and the frontal plane is perfectly flat. The only thing that comes to my mind is that maybe this crack was caused by vibrations or the screw that holds the wheel was tightened with too much force during the timing belt replacement?
Is there anyone who can advise me if welding from the inside (inner left and right corners) will solve the problem?
Or maybe some other solution?
I will be grateful for any suggestions.

1.jpg 2.jpg 3.jpg 4.jpg 5.jpg

**BradC** · 2nd January 2023, 05:50 PM

I can't find any info on welding CGI (I was going to say reliably welding, but I've turned up pretty much nothing).

Edit after the post by Graeme below. I'd be more tempted to Braze it up. The only other repair process I'm familiar with for Iron is stitching, but that's a sod of a spot.

Have to say I'm gutted for you at this point. This might be one of those cases where you need to seek advice from a an old (read as "experienced") engine builder or machinist with experience with Iron.

**Graeme** · 2nd January 2023, 07:01 PM

Welding consumable research for compacted graphite cast iron | SpringerLink

The article is dated 1991 so hopefully more current information is available.

**Fattima** · 2nd January 2023, 07:37 PM

I've had a cast iron engine block welded up in the past, so it can be done. Engine was assembled (Lotus engine) and had an accident on the dyno causing damage. As stated a good engine builder should be able to recommend someone, sadly the guy I used has passed away.

**haydent** · 3rd January 2023, 07:30 AM

Originally Posted by Fabsky

And my joy of rebuilding the engine was gone like a soap bubble...
During the next stage of the final assembly of the engine, I noticed a micro crack on the block near the ear where it is directly bolted timing belt idler pulley.
The ear does not bear the slightest traces of impact and the frontal plane is perfectly flat. The only thing that comes to my mind is that maybe this crack was caused by vibrations or the screw that holds the wheel was tightened with too much force during the timing belt replacement?
Is there anyone who can advise me if welding from the inside (inner left and right corners) will solve the problem?
Or maybe some other solution?
I will be grateful for any suggestions.

1.jpg 2.jpg 3.jpg 4.jpg 5.jpg

you would think for it to crack there the lower bolt would stop the top tab flexing back that way...

i tried to find a good image in the manual of what mounts on there but couldnt, does the idler mount into all four bolt holes ?

**Graeme** · 3rd January 2023, 11:51 AM

Isn't that the bolt hole for the cambelt idler pulley that would be pulled upwards by the belt?

I would be looking at fabricating a plate that bolts under the heads of the top bolt and the 2 idler pulley bolts below to make a triangle. The cover would probably have to be modified for clearance but that should provide support for the top bolt without trying to weld the cracks.

Edit: The idler pulley bolts are well recessed so can't simply bolt a plate under those.
What's the use of the hole directly below the top hole and is it threaded? A bespoke bolt for the centre idler pulley could allow a brace to the hole below if it is usable.

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