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madkayaker
Pro sparkey Pro Welder
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Depends on the condition and what you plan to do with the engine. If there warm then defiantly and if you planed to keep the engine for a while I would. If its a car your turning over/ letting the wife drive then no as something else will die/ hit first
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Only if they were worn, otherwise just the small end bearings.
mike os
just a little insane.....
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depends on the cost...and the overall state, not bought BE's for a while, but if not too much £££ why would you not change
If the rings are gone then what reason do we have to assume everything else in the "wear chain" is still good? ( small, big and main) they all supposedly have the same service life... ie i need a reson to justify not changing, rather than one to change
personally whenever i have stripped an engine (unless following a failure shortly after a rebuild or top end on a 2t) i have always done as i was taught & replaced all service bearings & seals. To me it is just not worth the grief of another dismantle to replace a part i should hav done first time
If the rings are gone then what reason do we have to assume everything else in the "wear chain" is still good? ( small, big and main) they all supposedly have the same service life... ie i need a reson to justify not changing, rather than one to change
personally whenever i have stripped an engine (unless following a failure shortly after a rebuild or top end on a 2t) i have always done as i was taught & replaced all service bearings & seals. To me it is just not worth the grief of another dismantle to replace a part i should hav done first time
As a seasoned engine builder / racing car constructor - my view!
Having removed the conrods /pistons to do the rings then it is only common sense to replace the big end bearings. You have access and a set is not that expensive and a good precautionary measure unless they have recently been replaced for another reason
Having removed the conrods /pistons to do the rings then it is only common sense to replace the big end bearings. You have access and a set is not that expensive and a good precautionary measure unless they have recently been replaced for another reason
Flathead_Dave
Member
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I'd also replace the big end nuts/bolts.
the snooper
getting older by the day
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why ? they are not stretch bolts
mike os
just a little insane.....
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certainly if it is high mileage, or known to be an issue
Flathead_Dave
Member
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It was always considered standard practice when I started,and I've done it ever since.
All bolts stretch or deform when torqued up.In the first factory workshop manuals I used,instead of a torque figure for bigends,they gave amount of bolt stretch.You measured the bolt length with a micrometer,then checked as you tightened it up.
I work on the principle,if it's not worth a set of bolts,it's not worth my time rebuilding it.I expect engines to be bullet proof,not time bombs,waiting for a missed gear.
ronan
Member
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+1 , an older mechanic told me to always replace the big end nuts and bolts , they are subject to high stresses and aren't expensive when you consider the price of a knackered engine.
People don't bother now , if an engine needs any sort of work like that its dumped and a new one put in.
wheresmejumper
Banned
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you have to draw the line somewhere though.should depend on cost, use and availabilty.
i cant see the point of replacing everything in a 93 carina E leanburn used to tow a dog trailer.
i cant see the point of replacing everything in a 93 carina E leanburn used to tow a dog trailer.
Pete.
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The factory manual for my bike says to replace the big end bolts if you remove the rods, but I don't know anybody anywhere who has actually done it, even on high-powered turbocharged ones, drag-raced ones, landspeed ones - no-one changes them. Some have been stripped dozens of times with bolts re-used. It's not always necessary.
brightspark
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if an engine ran for over one hundred thousand miles on original nuts and bolts on the crank why suddenly that its been stripped and rebuilt the said nuts and bolts would or could fail ???as they would be torqued up to the same pressure as before 
anyone any thoughts on why??
anyone any thoughts on why??
Shox Dr
Chief Engineer to Carlos Fandango
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Not wanting to take this thread any further off the OP's original question.
I would rather rebuild* an engine than fit a recon or indeed new. The reason been I will have built it myself. I guess it's a case of not trusting anyone to anything correctly these days
*subject to costs/use/expected use and life span
mike os
just a little insane.....
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... untill you are sat on the hard shoulder of the m6 at 3am, in the rain, waiting for recovery
wheresmejumper
Banned
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i would be perfectly happy to drive home my carina with a knocking bottom end.
the question asked was about changing bearings after all....
even if it did end up scrap
the question asked was about changing bearings after all....
even if it did end up scrap
