I know this is a Mercedes forum, but I know there are a lot of other people here with vast knowledge of all makes.

On my Nissan 300ZX I am rebuilding the engine and I was wondering if it was necessary to resize the rods after replacing the rod bolts with ARP hardware. The rods are forged. I am not polishing the crank and all the bearings were fine, I am just going through it to freshened it up. Rings, bearings etc.

Sorry to post this here but I would like to ask people that are knowledgeable,
Steve

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1997 E320
1990 Nissan 300ZX Twin Turbo (Stage X+)

The rods shouldn't need work because you're replacing the rod bolts.

Sixto
91 300SE
87 300SDL
83 300SD

If the rod and cap are indexed by the bolts only and not a separate indexing scheme such as pins and mating holes, then resizing is recommended to be sure that the rod and cap assembly are abolutely round and not slightly off at the parting line.

Duke

Hi there,
I have had at least six Nissan products (4 280Z's and 2 PU's), and every one I've taken apart has shown no wear anywhere except the head. The blocks wear forever, and the cranks hold up well also. The only place I've seen any real problems is valve guides - they seem to wear enough to allow the stem seals to leak and cause oil consumption. They are replaceable, and I still have a set or two in the parts cabinet. New ones will hold a valve for a minute or two with a slight oil film, before allowing it to slide out. I think your twin turbo has a forged crankshaft and heavy duty rods. I suspect they are in fine shape, but it always is good practice to send them in to be checked for bend and torsion. I doubt they would need resized. You can check bearing crush to verify, though. My factory manual says they should have less than 0.05mm (0.002") per 100mm (3.94") bend or torsion. I would spend some time inspecting the head - make sure the valve seat inserts are in good shape and the guides are still serviceable. (less than .1 mm or 0.0039" clearance stem to guide) Check the head for warpage. Remember that with a turbo engine you don't want to rev the engine until oil pressure has built up to avoid destroying the turbo bearings, which are plain aluminum bushings. If you drive it hot and hard let it idle a bit to cool the turbos before shutoff. My cousin has a barrel of turbos that failed left from his airplane business, mostly due to inexperienced pilots failing to observe one or both of these simple rules.
Good luck with the rebuild/freshen up!
Richard Wooldridge
'82 300D/4.3L V6
Etc...