Hi

 

I am considering buying a '92 twin turbo auto with 50k miles that has 'done' its big ends.

 

What are the implications?

 

New set of shells and off you go......or replacement egine?

 

Is the 300zx prone to bearing failure?

 

Regards

Johnb

Depends on the price you are getting the car for and if its worth the hassle getting it doneJust got mine done-Hell of a lot of trouble and expense,not really knowing if thats the extent of the problem,you could have the crankshaft damaged you wont know till the engines out.

If i could go back in time i wouldnt have got the car ive got now.

But its sorted now so fingers crossed!

New set of shells at 50k?

 

Bottom ends are usually quite strong on these engines. I'd be wary about that one.

The parts totalled about 160 quid and about 700 labour.If you can do it yourself then great but just think about he expense if the crankshafts knackered

New set of shells at 50k?

 

Bottom ends are usually quite strong on these engines. I'd be wary about that one.

 

doesnt matter how low mileage is-if you believe the mileage :rolleyes: and it only take the oil to get low and bye bye bearings

Hi

 

I am considering buying a '92 twin turbo auto with 50k miles that has 'done' its big ends.

 

What are the implications?

 

New set of shells and off you go......or replacement egine?

 

Is the 300zx prone to bearing failure?

 

Regards

Johnb

 

I take it you mean the one on Autotrader? I was going for that one but it dissapeared, I assumed sold, but now its back (I've since found a nice NA that I want more).

If you're lucky it might just be a £30 bearing you could change yourself if you drop the subframe and take apart the sump (graham_foley69 on here has done the same thing recently and it sounds like he ended up with a bargain). On the other hand you may need a new crank or the existing one reground and a few more bearings which means £££.

When I hear big ends and bottom ends, I get chills down my spine. I have had so much bad luck with my Supra with bottom and big ends, its very expensive job.

it depends how far gone they are, my s13 big ends went,but they are famous for it, dont know about the 300, anyone know? if theyve only just started rattling it aint so bad, although its still an engine out job, but if theyre left then my understanding is they seize onto the crankshaft, thus fvcking it good and proper.

it depends how far gone they are, my s13 big ends went,but they are famous for it, dont know about the 300, anyone know? if theyve only just started rattling it aint so bad, although its still an engine out job, but if theyre left then my understanding is they seize onto the crankshaft, thus fvcking it good and proper.

 

Spot on :)

 

if it's just a slight knock then it's usually just a bearing as Jacks has said, what normally happens is the bearings get spun meaning that both half's of the shell weld together and then to the crank, a damaged crank is not a problem but what is a problem is the damaged rod as rods can only be changed through the top of the block which is heads off and basically a full engine rebuild

Genrally 300s dont have big end problems unlike the s13 .But if changed sooner rather than later u can save the crank from getting scored .Sometimes a light score on the crank can be pollished out insitu and new sheels fitted .On a s13 ca18det engine this can be done with engine in by lowering front cross member to get the sump clear of crossmember not sure on vg30dett.When the get realy bad the sheel can spin inside the big end journal and its game over.If the crank has never been ground the shells should have std stamped on them ,if its had a grind you will need oversize shells.

Genrally 300s dont have big end problems unlike the s13 .But if changed sooner rather than later u can save the crank from getting scored .Sometimes a light score on the crank can be pollished out insitu and new sheels fitted .On a s13 ca18det engine this can be done with engine in by lowering front cross member to get the sump clear of crossmember not sure on vg30dett.When the get realy bad the sheel can spin inside the big end journal and its game over.If the crank has never been ground the shells should have std stamped on them ,if its had a grind you will need oversize shells.

 

the bearings can be done in situ on the vg30de

Bearing problems are not common on the 300zx, a low oil pressure reading is usually a sign of a faulty oil pressure sender.

 

The only point I would replace the bearings is when there is a profound knocking on the bottom end!