8mm rod bolts and racing

[Kronoss]

I'm trying to locate a set of the elusive L24 rods with the 9mm rod bolts (bolts would be upgraded to ARP) but so far no luck.

Plan B is to run the more common 8mm L24 rods with ARP bolts.

Plan C...machine the 8MM rod to accept a 9mm bolt...but I feel this would actually be weakening the rod.

Would the "plan B" ARP 8mm rods live in a race motor with a 7500 RPM redline? (with an occasional "war emergency" blip to 8000 RPM).

Carrillo/Pauter are not a financial option at this time.

–Thanks for any feedback

[Pir0San]

If I remember correctly, the only block that came with the 9mm rod bolts was the 260Z p30.

[Carl Beck]

TSO72-102

From 8mm to 9mm rod bolts:

Starting at Engine Serial Number: L24-096181

Found in 240-Z's produced from 04/72 around HLS30 77xxx

The rod bolt distance - measurement center to center - changed from 62mm to 63mm.

FWIW,

Carl B.

Carl Beck

Clearwater, FL

http://ZHome.com

[rzola]

1973 240 engines had 9mm bolts.

[zcarnut]

I'm trying to locate a set of the elusive L24 rods with the 9mm rod bolts (bolts would be upgraded to ARP) but so far no luck….

Contact Roger Schmidt at the Z Barn http://www.zbarn.com/. He has several sets of L24 9mm rods available.

… From 8mm to 9mm rod bolts:

Starting at Engine Serial Number: L24-096181

Found in 240-Z's produced from 04/72 around HLS30 77xxx

In addition to the [late production] 1972 and 1973 240Z’s, the 9mm L24 rods were also used in the four cylinder L16 engines (from 1973 and up) and in the 1977-80 L24E engine used in the Datsun 810. Do not bother trying to find a Maxima L24E engine (1981-84) as Nissan went back to 8mm rod bolts when they changed the crankshaft for the 1st gen Maxima.

[texasz]

I'm trying to locate a set of the elusive L24 rods with the 9mm rod bolts (bolts would be upgraded to ARP) but so far no luck.

Plan B is to run the more common 8mm L24 rods with ARP bolts.

Plan C...machine the 8MM rod to accept a 9mm bolt...but I feel this would actually be weakening the rod.

Would the "plan B" ARP 8mm rods live in a race motor with a 7500 RPM redline? (with an occasional "war emergency" blip to 8000 RPM).

Carrillo/Pauter are not a financial option at this time.

–Thanks for any feedback

Yes, plan B would be alright...though I would still look for plan A if you have a little time.

[Pir0San]

If I remember correctly, the only block that came with the 9mm rod bolts was the 260Z p30.

oops, I don't know what I was thinking.

[Arne]

I'd watch Craigslist for your area. Don't watch for the rods, look for people trying to dump '73 L24s. I've seen intact '73 L24 engines from free to $100 or so.

[Phred]

Years ago (pre ARP), I Installed 9mm rod bolts in sveral sets of 8mm rods. As an engine machinist, I had all the proper drills, reamers, and milling machine to duplicate the factory fit. Later when ARP came out with good 8mm bolt kits, I used many of these on stock to race engines. I never had one fail. Special note: All these rods were resized after changing bolts. Also, at minimum, these rods were balanced, and the race rods were lightened and shotpeened. Last time I checked, the 9mm bolts were still available:

9mm bolt 12109-N0110

9mm nut 12112-N0101

Kronoss,

For your medium performance race /street engine, I'd go for the ARP 8mm bolts. Simple install, no need to change rods, no special machine work required, peace of mind when revs climb. I would still highly recommend giving these to your engine machinist, with your new rod bearings, and have them resized to .002 clearance. If the engine is to be raced more than street driven, shoot for .0025 clr.

Phred

[S30ZT]

I'd watch Craigslist for your area. Don't watch for the rods, look for people trying to dump '73 L24s. I've seen intact '73 L24 engines from free to $100 or so.

Scored my '73 L24 the other day for $25. The week before I almost bought a '73 parts car for $150. Both found on craigslist :classic: