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j_tso
j_tso Reader
8/4/21 10:42 p.m.

In reply to frenchyd :

Z Car Garage link says this head is on a 3.2L Rebello engine, so it'll take 9000.

Peter Brock recounts the L24's vibration issues above 7000 in this Classic Motorsports article

malibuguy
malibuguy HalfDork
8/5/21 7:12 a.m.

I love how they kept it classic looking.  This is badass

people will buy it, but it obviously not going to be sold in the 1000s

If it were me, Id rock an NA RB fwiw

wspohn
wspohn SuperDork
8/5/21 11:02 a.m.

One issue I wonder about is why modern engines that can run for 200.000 miles with fuel injection (old days = more like 100,000 with cars with carbs that washed down the cylinder walls under choke) have pretty much completely switched to single width one row timing chains.

Yes, it saves some money and a small bit of weight, but a simplex chain wears more quickly than a duplex, so in an engine that will get higher miles put on it you choose the lesser chain that will be a maintenance pint for sure before the rest of the engine wears out.  Bean counters again?

Oh well, we have come a long way from a 1954 Healey I used to own which had the simplest tensioner (bar none at all) - a rubber ring that you installed under the chain on the large sprocket. You can guess how long those lasted.

frenchyd
frenchyd UltimaDork
8/5/21 11:25 a.m.

In reply to wspohn :

Manufactures don't want cars to last a lifetime. They want to motivate you to replace the car often.  10-15 new cars in your lifetime is their goal.  

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
8/5/21 11:32 a.m.
j_tso said:

In reply to frenchyd :

Z Car Garage link says this head is on a 3.2L Rebello engine, so it'll take 9000.

Peter Brock recounts the L24's vibration issues above 7000 in this Classic Motorsports article

IIRC, that issue was only in the very first 240Zs - as in, the first shipload in 1969.  Later cranks had revised counterweighting.

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
8/5/21 11:34 a.m.
wspohn said:

One issue I wonder about is why modern engines that can run for 200.000 miles with fuel injection (old days = more like 100,000 with cars with carbs that washed down the cylinder walls under choke) have pretty much completely switched to single width one row timing chains.

Yes, it saves some money and a small bit of weight, but a simplex chain wears more quickly than a duplex, so in an engine that will get higher miles put on it you choose the lesser chain that will be a maintenance pint for sure before the rest of the engine wears out.  Bean counters again?

Oh well, we have come a long way from a 1954 Healey I used to own which had the simplest tensioner (bar none at all) - a rubber ring that you installed under the chain on the large sprocket. You can guess how long those lasted.

Friction, size, weight.  Double row chains are also really, REALLY overkill for a DOHC engine with its light valves, light springs, and low lifts.

Toyota still uses large pitch chains, most everyone else has gone to 1/4" pitch give or take.  Those chains are the ones that have stretch issues, lots more pins and holes in plates to wear.

ShawnG
ShawnG UltimaDork
8/6/21 2:15 p.m.

Being that there are already DOHC Nissan I6 engines available, the only reason I could imagine someone spending money on this is if there were some rulebook restriction that mandated a stock block but any head you wanted.

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