Just bought a 521

[demo243]

Thinking back on it too... My L20b originally had DCOM 40s on it. I swapped to Mikuni 44s after one of the Weber mounting ears broke off. Its been a while, but i do recall the car having better mid-top end power w/ the 44s... but thats was only on the butt dyno.

[demo243]

Found the cam I was running as well - 

Comp Cam's # 79-131-6 Grind # 280S . 
2000-6000rpm; Adv. Dur. 280 Int./Exh.; Valve Lift .460 Int

Just for reference. 

I think 40's will be fine - My buddy B^2 is running 40's on his L20b and one of the Cali Guys ran 40's on his L20b, but both were "stock" engines. 

With the work your planning I would just do some research and double check, since 45s may suit your engine better.

Edited January 12, 2021 by demo243

[mainer311]

Cool, thanks for all the info.

[mainer311]

1 hour ago, datzenmike said:

 

The 200mm Roadster clutch is TALL. I have a 240mm pressure plate out back and should weigh it. It's THIN!!! I'd be curious to their weights.

 

Interesting. Taller than a stock 521 pressure plate? I wonder to use for the throwout bearing sleeve?

 

@d.p Didn't you just install a roadster "heavy duty" pressure plate? If so, what throwout bearing sleeve did you use?

Edited January 12, 2021 by mainer311

[datzenmike]

I think the housing is, it's the diaphragm fingers that matter for housing length and should be same as stock L16 200mm. I can go back out and measure the highest part of the body and also the diaphragm finger height. I seems like a pancake to me. Maybe a I'm off. Should go compare it to a 225mm first.

.

[datzenmike]

Well I don't have a Roadster PP so I don't know. I thought the 240mm was thinner but can't see much difference between it and a 225mm. Found 3, 240mm so there's probably 3 flywheels laying around somewhere. I do have one wheel picked out with the scalloped back so around 21 pounds. I know I have a heavier 29 pound one.

[mainer311]

Yeah, the 29-30lb ones are just flat across the front and back. 

[datzenmike]

Advantageous for small engines or heavier vehicles that need stored kinetic energy.

[Stoffregen Motorsports]

Yes, the roadster clutch uses a short throwout bearing collar. I think a 280ZX or something had the right length collar.

 

There's an old thread on here somewhere that has pics of all the different length collars.

[banzai510(hainz)]

roadster clutch is same demensional specs a 510 /521 but with the 650KG clamping force  so use that T.O bearing/collar set up.   The Exedy ones sold now thru classic Roadsters or what ever are 600Kg but at a good price(150$) as thel Roadster- 20111 part number is $$$$out of sight now if you can find them (besides in my garage still in the box).

 

the 225mm has a stage 1 Daiken/exedy  and common part but its like a leg crushing 750KG which I don't think is needed esp on a daily driver.  I assume use the Datsun 620 truck set up  would work. T.O bearing collar as they list them for these what I seen.

[mainer311]

Yes, I think I’m settling on the Exedy NSC581, 600kg, 200mm. Exedy and Daikin are the same company, so I’m not worried about NOS or quality.

[Stoffregen Motorsports]

I don't think the height of the Roadster clutch is the same as the 510 clutch. I am pretty sure the Roadster clutch is much taller.

 

Am I wrong? That wouldn't be a first.

[datzenmike]

1 hour ago, banzai510(hainz) said:

 if you can find them (besides in my garage still in the box).

 

Hainz can you weigh it for me.

[d.p]

1 hour ago, mainer311 said:

Yes, I think I’m settling on the Exedy NSC581, 600kg, 200mm. Exedy and Daikin are the same company, so I’m not worried about NOS or quality.

 

Same one I got no?  

[banzai510(hainz)]

1 hour ago, Stoffregen Motorsports said:

I don't think the height of the Roadster clutch is the same as the 510 clutch. I am pretty sure the Roadster clutch is much taller.

 

Am I wrong? That wouldn't be a first.

they the same and installed with the 510/521 t/O bearing/collar set up. its in the old How to Modifly and race your Datsun book.

stock 510/521 is a 2 rivet  roadster 3 rivet is how one coud tell. but otherwise the same

stock 510 350KG

roadster 650KG  both 200mm

 

other model cars I am not as much a expert on the clutches

Edited January 14, 2021 by banzai510(hainz)

[mainer311]

28 minutes ago, d.p said:

 

Same one I got no?  

 

I asked you that a few posts back. I believe it's the one that you got. What bearing collar did you end up using?

[d.p]

28 minutes ago, mainer311 said:

 

I asked you that a few posts back. I believe it's the one that you got. What bearing collar did you end up using?

 

The one that came out of my 4speed which is the stock 521 as far as I know.   Used the 4 speed fork as well if that helps. 

Edited January 14, 2021 by d.p

[mainer311]

Well, my block and head were dropped off at the machine shop yesterday. The guy quoted me $625 for everything, which I thought was fair. He quickly checked the block and head, and they were both almost completely flat. Hopefully he can just lightly skim both and away we go. 

 

And I know it's in good hands, since his R32 GTR and imported 180sx were sitting in the shop, along with a pair of Lamborghini heads on the bench.

 

Depending on how much he takes off, should I install the cam tower shims? I measured the shims at .016-.017"

[banzai510(hainz)]

shims were sold at .015      I think.

http://shop.silver-seal.com/storefrontCommerce/itemDetail.do?item-id=17850&order-quantity=1&item-index=0&customer-item=591000&order-uom=EA&warehouse-id=25&item-number=591000

 

I think even partsgeek had these.

https://www.partsgeek.com/catalog/1971/nissan/510/engine_mechanical/cylinder_head_spacer_shim.html

 

if you do a slight cut maybe you don't need to add the shims it up to you.

 

I just know the bolt going in the head to hold the cam towers on  onluy want like 10-13 pounds. and can strip ez so be careful.  I had to have one helicoiled. if worse Keensert.

Edited January 15, 2021 by banzai510(hainz)

[mainer311]

1 hour ago, banzai510(hainz) said:

If you do a slight cut maybe you don't need to add the shims it up to you.

 

I just know the bolt going in the head to hold the cam towers on  onluy want like 10-13 pounds. and can strip ez so be careful.  I had to have one helicoiled. if worse Keensert.

Noted. I have the shims already,  but would rather not use them if I don’t have to.

 

I have the L series rebuild book, so I’ll refer to that for torque specs.

[mainer311]

Will a 720 3-hole alternator bracket fit on an L20b? My short block didn't come with one, and I need it. 

 

Found this one on ebay:

https://www.ebay.com/itm/1983-1989-Nissan-Datsun-720-D21-Hardbody-Truck-Z24-Alternator-Mounting-Bracket/184604671590?hash=item2afb4bbe66:g:ytgAAOSwGgdf76Ne

[datzenmike]

 

Yes it will fit. It positions the alternator very slightly higher. It was one of the reasons I put one on my 620 when I put the larger diameter 50/60 amp alternator on it. You might need a slightly shorter belt.

[banzai510(hainz)]

Mainer

also about the shims was foer the head being cut but uping the chain to a higher number cheats it  as being the same or chain stretch.

[d.p]

11 hours ago, mainer311 said:

Will a 720 3-hole alternator bracket fit on an L20b? My short block didn't come with one, and I need it. 

 

Found this one on ebay:

https://www.ebay.com/itm/1983-1989-Nissan-Datsun-720-D21-Hardbody-Truck-Z24-Alternator-Mounting-Bracket/184604671590?hash=item2afb4bbe66:g:ytgAAOSwGgdf76Ne

 

FWIW I have that same bracket on my l20 and with the 200SX alternator its a tight fit right up against the zerk fitting on the passenger control arm IIRC.

[mainer311]

47 minutes ago, banzai510(hainz) said:

Mainer

also about the shims was foer the head being cut but uping the chain to a higher number cheats it  as being the same or chain stretch.

 

Yeah, I know, but then you run out of adjustment later if it's needed. I have no idea what my cam specs are (duration in particular) and I'm running flat tops, so I'm already concerned about piston/valve clearance.

 

41 minutes ago, d.p said:

 

FWIW I have that same bracket on my l20 and with the 200SX alternator its a tight fit right up against the zerk fitting on the passenger control arm IIRC.

 

Zerk on top of the steering idler, I believe. I have the 50 amp 510 alternator which is probably the same. Tight fit for sure. Too far in either direction and you hit something.