Folowing my recent post about my T5 engine trying to eat itself, I have now had time to get it out of the car and take it apart.

On Saturday I had the rocker cover off and found nothing untoward other than swarf in the oil. Last night the block came out and I whipped the sump off to be greeted by this little collection of items:


Volvo snapped conrod

It appears one of the rod bolts unscrewed by itself leaving the other to shear in pretty short order. That left the crank to beat the rest of the rod into submission. The two halves of the big end don't exactly line up any more! There is a small hole in the sump where the filter screws on (hence the dumping of oil when I stopped) and on closer inspection the side of the block is also cracked where the rod has tried to make a break for freedom.

No idea how or why this would happen unless the bolts got stretched leaving them loose, but the engine is rev-limited at the standard level so that doesn't seem likely. Maybe I'm just unlucky!

At least new engines are cheap...

JB Weld?

That hasn't gone well has it!

How cheap is a T5 engine then?? (Speaking as a man without an engine at the moment!)

Mike

yikes!

quote:

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Originally posted by Guinness
How cheap is a T5 engine then??

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Thanks for that Ben.

Although sorry for you for the problems, I was rather looking forward to the post mortem!


Cheers,
James

Its a common problem with the 850 t5 engine to throw a rod around 100.000 miles mark

Now retrieved the rest of it:


Volvo snapped conrod 2

If it's a common problem, is there a remedy I should do before fitting the new engine (it'll inevitable have 100k+ on it)? Whip sump off and re-torque rod bolts?

if its definitely a problem with the rod bolt, rather than just retorquing them, i'd replace them with lovely new ones

That'll make a loverly paperweight

Its common for rods to break with more boost, theyre inherently the weakest point of the engine, but ive never heard of one going like that.

Ill b whipping the sump off mine and chucking a set of ARPs in it before I head for 7300rpm. Having seen that Id be tempted to do it regardless.

quote:

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Originally posted by alistairolsen
Ill b whipping the sump off mine and chucking a set of ARPs in it before I head for 7300rpm. Having seen that Id be tempted to do it regardless.

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ab-sa-blumin-lutely a set of of arp's seems cheap insurance considering your photos,

feel a group buy coming on if someone can find a source, maybe sweden

i think youll find the volvo bolts are pretty good spec , certainly on the redblocks .

IIRC the the whiteblocks only use the highest spec ARP bolt because they are drilled for the bigger ARP bolts , youll be stuck with some expensive ARPs that are no better .

its not especially common for teh early engines to throw rods at 100k - its more common for the bearing to destroy itself and then do what its done by either throwing a rod or knackering the crank .

heavy duty bearings are a necessity .

i can tell ya where to get some ARPS from aswell .

two sources .

1) TTV racing in the UK
2) Rsportinternational in the US .

ive dealt with both companies and both are reputable .

heavy duty bearings? Slightly different mettalurgy?

better quality aswell .

there still having problems on the dyno at dunston with new 5 pots shaggin bearings up !!

you have just answered my post with the same reply bearing goes rod breaks hence they throw rods this info comes from a ex volvo tech that works with us