toyota 4 Age con rod bearing problems
toyota 4 Age con rod bearing problems
(OP)
Hi help needed with a run of bearing problems on Toyota 4 age engines, we build a high number of these engines without
problem but we are currently haveing a nightmare with Connecting rod bearings what we have is bearings which show classic fatigue problems but do not have a trail to explain the fatigue
we have used diffrent running clearances lubrication
oil pressure and flow also alternative bearing material
and manufacture even lowering compresion this is over
several engines any help or ideas will be gratefully recived
these failures occur in less than 200 miles.
Big Paul.
problem but we are currently haveing a nightmare with Connecting rod bearings what we have is bearings which show classic fatigue problems but do not have a trail to explain the fatigue
we have used diffrent running clearances lubrication
oil pressure and flow also alternative bearing material
and manufacture even lowering compresion this is over
several engines any help or ideas will be gratefully recived
these failures occur in less than 200 miles.
Big Paul.





RE: toyota 4 Age con rod bearing problems
RE: toyota 4 Age con rod bearing problems
272 duration cams on restricted side draft carbs 30mm
manadtory regulation. bearing used so far standard toyota
acl and clevite and fedral mogal (now no longer avalible)
rod one and two. mostley one.
Big Paul
RE: toyota 4 Age con rod bearing problems
RE: toyota 4 Age con rod bearing problems
Mike
RE: toyota 4 Age con rod bearing problems
Thanks for the replys, but this problem is there in standard
non machined cranks there no sign of particle contamination
ie lack of oil there is also little or no main bearing problem the max revs used is only 8100 the last engine that was pulled showed even cratering on all 4 cylindersand no journal damge.
as to balance they have to use std front damper they
are balanced spot on but it rare to have to do much correction
on any of the components I agree that it a rare problem with
4 age but its becoming an epidemic do any of you guys run the
cranks outside bottom limit. if we are running into a windage problem surely it would be showing on other engines?
we do not now have a technical dept that can help at the bearing manufactures so all that kind of insite has gone
RE: toyota 4 Age con rod bearing problems
Shaun TiedeULTRADYNE Arl,TX(stiede@ev1.net)
RE: toyota 4 Age con rod bearing problems
we are pretiy show its some kind of oil problem but pin pointing what is elusive.
RE: toyota 4 Age con rod bearing problems
Like I said, tough problem.
Rod
RE: toyota 4 Age con rod bearing problems
Bearing fatigue is most commonly caused by some sort of overload condition. Whether it is due to detonation, high combustion chamber pressures, or heavy engine loading during low RPM operation.
The symptoms of bearing fatigue and oil starvation are markedly different. I am having trouble following exactly which is the problem described. Maybe with a better description of the failure, we can get closer to a solution.
In any case, I’d start by doing a comparison between one of your successful builds, and one of the failing ones. Analyze all differences in materials, components, and assembly techniques for possible failure paths.
Good Luck, and keep us posted!
Bryan Carter
RE: toyota 4 Age con rod bearing problems
2 lessons:
1) make sure you can trust your tools
2)never lend your torque wrench to someone who'll drop it.
"I love deadlines. I love the whooshing noise they make as they go past." Douglas Adams
RE: toyota 4 Age con rod bearing problems
www.glaciervandervell.com/europe/ support/damage/default.htm
full bearing width or toward one edge? ever seen cavitation damage on a pump impeller?
what's your oil temp?
RE: toyota 4 Age con rod bearing problems
Dan, thanks for the link.
Paul, it is often near impossible to diagnose a bearing failure even when you have the engine in hand. I don't know how to do it but, posting a couple of photos could help. Also some oil temp/pres/flow etc. info.
Rod
RE: toyota 4 Age con rod bearing problems
rod one and two. mostley one.
Mike
RE: toyota 4 Age con rod bearing problems
RE: toyota 4 Age con rod bearing problems
Which bearing in the big end is showing distress? Both rod and cap, or just rod? On assembly how are you checking the clearances?
RE: toyota 4 Age con rod bearing problems
of the problems now, we carried out quite a number of deatail changes from Fliters to oil feed and return.
Paul.