A&Q about 350Z
Q:
as it says...is it a complete waste of time rebuilding bottom end with new rings, bearings etc without honing bores, getting tolerances checked etc?
Is it vital? or just recommended?
What kinda costs are we looking at for getting bottom end bits checked over, and bores honed?
looking more and more like its not worth the effort.
My 9A has done around 150K, mechanic said big ends are rumbling a bit, I intended to do them relatively quickly, and change teh other bits while i'm there, thought it couldn't be 'bad'.
Or is it worth me changing just the big ends?
more confused than ever...
Dave
A:
absolutely pointless rebuilding without gapping the rings correctly and not honing the bores. if you dont hone the bores the rings wont bed in properly.
A:
Thats seems the consensus from people i've spoken to so far tbh.
So, is it worth me slipping new big ends in?
tbh the engine seems fine to me, but i'm no expert.
A:
It really depends on what your plans are for the engine, but if the big ends are rumbling its deffo time to investigate.
A:
has it had a recent rebuild? if not then the chances are at 150k miles the bore will be sufficiently worn to make the only real option a rebore with new pistons and rings.
if your going to do it you should do it right! ;)
A:
New rings = honing. If you can reuse the originals (get the block measured and check the ring gaps) then a glaze buster should do it though honing isn't very expensive anyway. But as Pol says at 150K it probably need boring. If yours will run a while longer I'd look at sourcing another bottom end and getting it rebuilt - don't be tempted to pay a bit more for a 'runner' unless you know it's good. Far better long term to get a real cheapy and know it's right.
barkstar
A:
as above, if you are going to rebuild and engine, then everything needs measuring to see whether clearances are within spec. this way you know EXACTLY what does and more importantly doesn`t need replacing. after all, if it ain`t broke don`t fix it.
my 9a block that i`m nearly ready to install didn`t need anything replacing even wiht 107k on the engine. i have however put new rings in and deglazed it. realistically i could have done with some new pistons because the originals were running at max tolerance, but its not going to make mega power, and more importantly i haven`t got the money for new pistons (why are they so bloody expensive for vws but cheap for everything else??).
but as above, defo try to source another engine to build, then you can just swap them over in a weekend, rather than taking the car off the road for a forttnight
A:
Fair play guys, you've made my mind up.
I may see if its worth slipping in new big ends only and no further (Seems easy enough from Haynes, crank can stay in place...), I want to change my sump anyway (its had a few run-ins with the black top!)
i'm going to go with the route of just keeping an eye out for another bottom end for a decent price.
Mine is running fine, in fact its running brilliantly aside from using a bit of oil and a slight rumble from below (apparently, sounds fine to me). I wanted to 'prevent', before anything happens!
Next question I guess is whats a reasonable price for a 9A Bottom end? Have found a 64K 9A bottom end for £300 but that seems a hell of a lot compared to the £380 I paid for the whole passat with MOT last year that donated my existing engine! Esp since I would want to rebuild it anyway.
A:
has it had a recent rebuild? if not then the chances are at 150k miles the bore will be sufficiently worn to make the only real option a rebore with new pistons and rings.
if your going to do it you should do it right! ;)
My 16v had over 140k on it and bores were not even at bottom limit of tolerance. (0.0005-0.001"" down on standard size to be exact).
They were measured by an expert so no errors occured
A:
i paid £300 for a 9a complete just over a year ago, it had 107k, must have come from a passat, it didn`t look like it had been abused at all when i inspected it