ihz big end bearings

[bigdee]

just wondering if i should replace big end bearings on my 1hz 80 series 94 model .its up to 400,000klms and i'm fitting a safari turbo kit and the sump has to come off to fit return oil line anyway, motor is running fine and has reasonably good oil pressure and wonder whether to upset it would cause any problems, if so what brand of bearings should i fit,any advice would be good.

[4runner2.8]

wouldnt hurt but 1hz's are not knowen to have big end failure, it was the 1hdt, factory turbos that had the problem. im about to fit a turbo to mine with 370 000km and i dont think ill bother, but im not looking forward to pulling the sump off thoe cos i reckon it will be stuck on there real good.

[Z()LTAN]

you can perform whats called a bearing roll, where you can actually replace all big end and main bearings by rolling out the old bearings and rolling in the new ones, without removing anything but the sump and bearing caps.

The crank can stay in place, all you need to do is loosen the fan belts so there is a bit of crank play to slide the bearings in and out.

This is a commonly performed task, but should only be undertaken by one who has sufficient knowledge

good luck

[goannaoffroad]

You can't replace the main bearings in a 1HZ without removing the engine as the bottom of the block is a bearing girdle which means there are'nt
individual main bearing caps . But if you have the sump off have a look at the rod caps, check for any that show signs of discolouration from heat due to poor lubrication, grab hold of them at the bottom of there stroke and see if you can get any movement by pushing up or pulling down or by twisting.If all seems ok just remove one cap and inspect the bearing and crank journal. look for excessive grooves ,pitting etc if all is ok refit the bearing and cap to correct tension .As a general rule of thumb if one is ok they all are as their all feed the same oil at the same pressure at the same time.
Good luck with your project.

[fj45iris]

My opinion differs a bit,we fitted a kit to a 1hz only had done 260,000kms and the owner wasn't keen on doing the mains and bigends, he didn't get away with it for long and within three months he had spun a bearing, might be due to his driving style or other mods which i won't mention but it is probably something i would recommend if you are less than 80 and have a right foot.
Can be done in frame, not recommended for a short fused head.
My motto is normally if it ain't broke don't fix it but there are always an exception to a rule

[peeko22]

i would defenitely recomend replacing the big end bearings. my cruiser has done 420,000 and my crankshaft is now F***ed its cheaper for me now to replace the engine. $4500 tio fix (which i dont have).do it or you will regret like i have .

[bigdee]

thanks for the input whats a good brand of bearing if they show signs of wear and should i go to the trouble of using plastigauge when fitting the new ones to check clearances or just bang em in thanks

[goannaoffroad]

Genuine Toyota are a good bearing .I'd plastigauge one old bearing to see if it's within tolerence if it is put new bearing's straight in.
The only thing you have to really worry about in a 1HZ is surface cracks on the bearing journals they usualy start around the oil feed hole and can be hard to spot they are caused by fatigue and will chew bearings out,so look long and hard at the crank and the old bearings before doing any thing else.

[scottmcguinness172]

we put acl bearings in guerd87's motor rebuild give him a pm he will tell u

[bigdee]

if the crank has cracks at oil feed holes what do u do put it back together and wait till i lose oil pressure as it could go for awhile like that if the plastiguage measures over size do i put a new bearing in and see if it measures up alright if the old ones measure up and look alright do i leave them in.thanks darren

[sniper]

IMO it is alot safer just to do the bearings, you will sleep better at night

Every 100k

[Z()LTAN]

its pretty cheap...














in comparison to you know what...

[fj45iris]

if you have dramas with clearances you would have to pull the crank to do it right, u can't just put oversize bearings in, u have to grind the crank oversize and match the bearings to suit. If you are goin to the trouble of checking u should be prepared to do whats necessary cos by disturbing it you could make things worse by introducing foreign particles etc. hopefully a set of new bearings flexigauge alright

[goannaoffroad]

If the crank has any sign of cracks or scores you remove it and have it either machined or replaced. When ever I'm rebuilding one of these or any turbo diesel I get the crank crack tested .
When I'm checking an oil clearance on a crank journal I platigauge the old bearing and if that is under the max' limit it will be fine with new bearings.
There is no point buying and fitting new bearings until you know the crank journals are to tolerance and measuring an existing bearing with plastigauge is the easiest way to do this.If a bearing is buggered the journal is to.

[dow50r]

I would leave it if you havnt got white metal in the filter...its not worth half doing just because the pan is off...

[dumbdunce]

I would leave it if you havnt got white metal in the filter...its not worth half doing just because the pan is off...

I disagree. although it's true a 1HZ is unlikely to ever spit the big ends, taking off the sump is by far the hardest part of the job, and the parts are cheap. might as well do it while the pan is off.