Are ARP bolts needed in LZ2.3 big bore?

[Hix1985]

Hello guys,

 

Just got my L20b apart and looking for a machine shop to bore it out, if anyone knows of anyone good machine shop in Ohio that has machined a Datsun engine will take the help.

 

 need to know if ARP bolts for rod, head and main studs are really needed? the engine will only make at top 140Hp. its all most $300 for all them just trying to save money where I can.

 

Thanks

 

PS. I know is a thin wall on L20b and I should use A z22 or z20; however, living on Ohio does not give me much options the closes block is over 8hr drive one way. and it took me months just to find l20b.

[Stoffregen Motorsports]

L20B block bores are too thin at 89mm. You will need a Z20 or Z22 block, preferably a Z20 block as the Z22 has steam holes that can be bored into. When I have a shop bore those blocks, I have them spread the bores out to avoid hitting the steam holes.

 

Don't need studs. L28 Turbo head bolts are fine. Actually, any OEM head bolt with a circle stamped into the top is fine.

 

I hate using head studs. They make removal and installation of the head a PITA.

 

I lust looked on car-part.com and I found  Z22 blocks and complete engines. Couldn't find a listing for a Z20 though. Most are in western states, but shipping on a complete engine is usually only about $100-$200.

[flatcat19]

What he said...bore to big to be strong enough to last.

 

 

280zx non-turbo, 81-83, has 86mm flat tops.

Combine that with a U67 head for a good time.

 

Another easy option, oversized L18 pistons with a closed chamber head(W53, A87).

 

There are more options of things to do with an L20B, but given your location, the ones listed above will be more logical/viable.

Both sets of those pistons should be able to be found on eBay, RockAuto, or through local parts house.

[datzenmike]

The L20B should take a 4mm bore increase. That's only 2mm all the way round. 2mm is only 80 thou. (0.080") Naturally the larger the over bore the more the risk, but I've never heard that the L20B has a 'thin' wall. L20B's are generally a good block and not known for casting shifts. That said, I searched out a Z22 block for my project. If this is your only block get the '86mm flattops or a 1mm oversize L20B piston. Or find a Z22 crank and pistons and bore to 87mm and make this a 2.2 liter engine. 

.  

[Hix1985]

The cost of the engine and shipping Im look around $400 to $500 just for the engine :geek:

the parts I got for the build 

 

l20b engine

 

z22 crank shaft

 

KA24E  pistons 

 

U60 Head that needs rockers, cam, lash pads, springs. valves.

 

R1 carbs still need to get the intake manifold

 

I really want LZ2.3, I guess I will keep looking for Z22  or z20 block, but if I don't fine one by the end of July I will take the chance on l20b  It will only be a weekend driver.

 

Is there a set up where you can get the cam, rockers and spring, lash pads in a kit? I can find anything

[datzenmike]

I think the easiest is just get everything from another head. Or another head, and you then have a spare. Port it out, relieve the valve shrouding and have it shaved to keep the compression up. U67 would be my choice but best to run the stand alone '78-'80 intake that does not bolt to the exhaust. You will need to drill two 3/8" holes in the head just below the intake ports for coolant for the runners and pipe it down to the lower rad inlet to the water pump. I just recently did this to my U67 head..

[Hix1985]

I think the easiest is just get everything from another head. Or another head, and you then have a spare. Port it out, relieve the valve shrouding and have it shaved to keep the compression up. U67 would be my choice but best to run the stand alone '78-'80 intake that does not bolt to the exhaust. You will need to drill two 3/8" holes in the head just below the intake ports for coolant for the runners and pipe it down to the lower rad inlet to the water pump. I just recently did this to my U67 head..

 

ok thanks I got a W58 head I can take all the parts from, but is the cam the same in W58 as U60 or U67? and I thought the U60 and U67 are the same head?

 

any Chance you have Photos showing right were you drilled and how you piped it down?

[Stoffregen Motorsports]

The L20B should take a 4mm bore increase. That's only 2mm all the way round. 2mm is only 80 thou. (0.080") Naturally the larger the over bore the more the risk, but I've never heard that the L20B has a 'thin' wall. L20B's are generally a good block and not known for casting shifts. That said, I searched out a Z22 block for my project. If this is your only block get the '86mm flattops or a 1mm oversize L20B piston. Or find a Z22 crank and pistons and bore to 87mm and make this a 2.2 liter engine. 

.  

The difference in cylinder wall thickness between a L20B and Z20 block is significant. Boring the L20B to 89mm  not only leaves you with a flexy bore, but even in the honing process it's too thin to hold its shape.

[datzenmike]

ok thanks I got a W58 head I can take all the parts from, but is the cam the same in W58 as U60 or U67? and I thought the U60 and U67 are the same head?

 

any Chance you have Photos showing right were you drilled and how you piped it down?

 

The L20B cams are the same or if there are any differences very slight. 

 

Most L20B intake/exhaust gaskets simply have the holes in them already rather than having two different ones. I just slipped the gasket in place and inked the head through the hole. Remove the gasket and drill the holes. No special sealer required just the gasket. 

 

The intake will have a water outlet tube below the carb front slightly on the valve cover side. This must be connected to the by-pass outlet hose from the thermostat housing. On late L20Bs and L16/18 the metal line down to the rad return hose already has a Y in it for this.

[Hix1985]

The L20B cams are the same or if there are any differences very slight. 

 

Most L20B intake/exhaust gaskets simply have the holes in them already rather than having two different ones. I just slipped the gasket in place and inked the head through the hole. Remove the gasket and drill the holes. No special sealer required just the gasket. 

 

The intake will have a water outlet tube below the carb front slightly on the valve cover side. This must be connected to the by-pass outlet hose from the thermostat housing. On late L20Bs and L16/18 the metal line down to the rad return hose already has a Y in it for this.

Sweet that does not seem that hard to do thanks!

[datzenmike]

L16/18 had it this way and the '78-'80 L20Bs, but for some reason Nissan started the L20B in '74/'75 with the co-joined intake/exhaust set up. Initially it might warm up the intake and air faster and this would give better emission control, but I think it would run much hotter on warm days. The coolant flow from the head warms on cold days but also draws off  radiant heat from the exhaust when warmed up and specially on very hot days. Having the intake air temp closely controlled over a wide range of conditions keeps performance, emissions and economy consistent.  

[Hix1985]

L20B block bores are too thin at 89mm. You will need a Z20 or Z22 block, preferably a Z20 block as the Z22 has steam holes that can be bored into. When I have a shop bore those blocks, I have them spread the bores out to avoid hitting the steam holes.

 

Don't need studs. L28 Turbo head bolts are fine. Actually, any OEM head bolt with a circle stamped into the top is fine.

 

I hate using head studs. They make removal and installation of the head a PITA.

 

I lust looked on car-part.com and I found  Z22 blocks and complete engines. Couldn't find a listing for a Z20 though. Most are in western states, but shipping on a complete engine is usually only about $100-$200.

 

Thanks I never looked at car-part.com and found a completed engine about 3hr drive from me. Getting it tomorrow they did not know what to ask for it so we came up with $150.00!   :thumbup:  that is really good for E-cost,  the guy was shocked that they had that old of a truck still on the lot.  

[Stoffregen Motorsports]

Awesome that you found one. car-part.com is a database not a company so you can be sure that the listings there are pretty accurate. It's the first place I look when trying to find a used part.

[scooter]

I have main studs and head studs in mine, I chose to do that to get rid of 30 year old fatigued fasteners. Probably overkill. On the the other hand if your using stock rods get them shot peened and arp bolted. If you do head mods you can get the big bore 2.3 to pull up to 7500 :)

 

My z22 block was thick, it's thick at 89mm, it will probably go 90 but I'll sonic test it before doing that. One guy on here has an early L20b block bored to 89mm, but it's also filled with concrete.

 

I think the next ones gonna be a 2.1, 89 mil bore and l20b crank for some more revs

[510SSS]

Not entirely true I have seen 89mm bore l20b's hold together fine, it just depends on if you upgrade you're cooling system to compensate for the heat, and you precisely caliper all of your cylinder diameters to make sure they are not out of round, you don't even need a torque plate if you built it properly.

[Stoffregen Motorsports]

Not so in my experience. A risk worth taking for a home builder? Maybe, but I would never willingly use a L20B block and bore it to 89mm on a customer's job. There's too much bore flex when you bore that block to 89mm. Bore flex causes uneven ring and piston contact, blow-by, premature wear of pistons and rings, etc.

 

It's not the overheating that concerns me. Sure, that can be compensated for.

[scooter]

Mines made out of a z22 block and doesnt run hot at all. Whatabout doing a partial block fill with an l20b, sonic check it and run a oil cooler to compensate for the half filled block?

[bilzbobaggins]

Will the concrete clog my coolant filter?

[datzenmike]

The 89mm bore will work or it won't. Concrete won't save it.

[scooter]

So with the head studs, im using a shitty fel pro composite gasket made for a z24, i did mill the head and the block clean.

No head gasket issues with 12.3:1 compression combined with a 75 shot of nitrous. So far so good

[nad015]

Many have done 89mm bored L20b in Aus.

And yes they are super thin, I've heard people say 1 in 6 blocks checked are thick enough, then half grout filled.

 

I'm pretty sure people only do it because they needed to use the l20b block because of Motorsport class rules, or road car engineering laws and z blocks here are super rare, z22 and z20 engines would be near impossible to find. Z24 engines would be a little more common , but even then are real old now and thin on the ground.

 

L18 blocks are also taken to 89mm, with the same process(and usually have l20b cranks or z22,z24 cranks installed) that's a big job but as the block need line boring because the crank has bigger mains.

[Stoffregen Motorsports]

I've built those L18's before. Lots of work to get the crank in there and then the rod to stroke ratio is horrible, but they are fun to drive...

[datzenmike]

Yeah like a Z24 crank in an L20B. (they don't fit easily either) There's a reason that the deck heights are raised.

[RoadRace]

if the question is to bore to 89 or not - why bother. seriously, not a lot of power available there for an extra mm or so of bore (if any) - seems kinda redundant. Combustion chambers should just be un-shrouded like mentioned earlier.  risk vs reward conversation should include intended use.

 

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[510SSS]

Ive got a Set of ARP rod bolts still in package for sale if you need some for you're build. I'm no expert either, but with a 2.3 the increased torque could very well put increased stress on the rod bolts over stock, ARP is probably advised, I used em on mine and it's only a 2.1 ltr.