Hey there all.

 

I've recently bought a 1991 Twin Turbo Targa Top. Took her for MOT today which she passed :) but my mechanic suspects the bottom end bearings are just starting to knock.

 

I've rung the owner before the previous owner to see if he had any issues and he told me the noise has been there the entire time he owned it??? He took it to a Nissan garage and they told him the 300's suffer from 'cam bushes' which make a similar noise to big end bearings. Apparently its nothing to worry about and even when replaced it could soon come back.

 

The guy I spoke to has no reason to make anything up so I'm inclined to believe him, but I don't entirely believe the Nissan garage?!

 

Anyone else heard of these 'rattly camshaft bushes' as I really don't want to kill my newly acquired 300 :confused:

 

Any help much appreciated...

could be anything mate. sticking lifters is a possibility

you can get cam rattle this is due to the camshaft springs becoming weak. there is one in each of the two top camshafts behind the end caps. can you do a video clip of the noise as its bloody hard to diagnose a noise problem from a description.!!

 

there could be many factors that could give you a rattle/knocking. but somebody with more experience will be along shortly i would imagine.

the noise is only very faint. I doubt it'd come out on a video but Ill give it a go.

 

The main thing I was curious is if anyone has had any experience with noises of this type that don't cause problems?

 

If it is big ends they are only just starting to knock so wanna catch them early.

 

Cheers!

Just uploaded to videos. Can't really make it out a great deal.

 

 

 

Cheers...

The rattle only seems to be on light load. Its not there on idle, just as throttle is applied.

 

Could this still be cam springs rattle?

does it go away when it warm?

When I had my cambelt done the mechanic forgot to replace 1 of the 4 washers on the cooling fan, it was only about 1mm but enough to create an imbalance which I guess damaged the water pump in the process as it was wobbling when further inspected. Anyway in the end that's what caused the noise as the slightly wobbly fan was hitting the fanbelt when the engine was revved. Just one of those 1 in a million. :rolleyes:

lol, that must of bin a bit of an ass Z32KING...

 

and no it doesn't go away when shes warm pete...

 

I've just gone and got 1 pair of bearings out now anyway, may as well replace them to be sure. If the rattle is still there after then at least I know it won't be the big ends :)

Check your timimng as well if its over advanced you can get the noise you discribe.

 

Z32 King i very much dought the water from your car was damaged due to a missing washer.

More likely when the water pump belt was refitted and tensioned correctly the extra pressure on the puller just sent it on its way mate.

daz

Well by the looks the big end shells are knackered so its a good job I just decided to do it. Gonna order a new set from Honda tomorrow but apparently I have to check them all as with some cars they used different sizes? I don't see it myself but may as well check now Im there!

 

Hopefully this will solve the rattling! :-) It will take 4 days for the delivery though :(

your gonna get end shells from honda??????

Lol, doh. I used to have a Honda, not got used to this Nissan stuff yet! oops...:headvswal

pmsl, i thought id missed something then lol

I had a funny knock on a Z that no one could identify, turned out to be end float on the crank. So if you are doing the big ends check the mains too esp the main bearing wth the end float bearing part.

 

 

But I would replace the mains anyway as you are so close. The only one you cant do, if the engine is in the car is the rear main.

it's hard to hear in the video, but it sounds like worn VTC sprockets to me.

 

especially if the sound is there already for a long time.

Well the thing is I don't know if the previous owner is referring to the same rattle as me? I wouldn't of thought anyone would of even noticed unless listening for it but thankfully my mechanic did notice. He said it used to come and go so I don't know. Didn't want to take the risk.

 

Bit of an update, it would appear the big ends did have some wear. All being well we picked it up soon enough so to not have caused any lasting damage. Just waiting on some new shells to put them back in! :)

Well the thing is I don't know if the previous owner is referring to the same rattle as me? I wouldn't of thought anyone would of even noticed unless listening for it but thankfully my mechanic did notice. He said it used to come and go so I don't know. Didn't want to take the risk.

 

Bit of an update, it would appear the big ends did have some wear. All being well we picked it up soon enough so to not have caused any lasting damage. Just waiting on some new shells to put them back in! :)

 

And what were the mains like?

Just took the one out and it seems clean so will see what shes like with new big ends... :duffer:

Seeing as you are so close, as in another 15 minutes work, in my opinion you should look to make sure the rest are OK, but, your choice.

 

If, however, when you start it up and the noise is still there, and if it turns out to be mains/end float related who can you blame?

 

It probably is OK, but the word but can be a very big word.

 

A friend of mine had the same reasoning as you, (R33 GTR) when his engine let go a few weeks later he was sorry he didnt look while he had the chance. :-)