My 620 build thread.

[J's 620]

When the cam gets back to me I’ll have to get some measurements. I’m curious to see what kind of lift and duration it will actually have and how they achieved that. I’ll post up pics as well

[datzenmike]

Cam makers show lift and duration at 0.050" lift whereas Nissan just specifies absolute lift, lobe - base circle. The L20B cam is 0.413" valve lift and 248⁰duration. I would love to know what an L20B cam is at 0.050" lift but it will be less than those numbers. By grinding down the base circle the duration and lift are increased. I have an Isky cam marked L -0.490  09 7101 It has 0.480" total lift. I just measured it

[Stoffregen Motorsports]

On 8/24/2020 at 7:11 AM, banzai510(hainz) said:

Delta Cams were never right the ones I got.  I NEVER USED THEM.

Cal Cams has all the modern L series cams. At least they should, but they may be proprietary and you may need to buy through Rebello.

 

I don't think Isky has designed a new cam for the L motor since the 80's.

[J's 620]

So if my delta comes back as a real turd go with an isky or a cal cams through to robello? I really just want a slight increase in lift and duration over stock, nothing crazy it’s still a street truck. 
I asked for a 272 grind for a bit more top end to compete on the freeways. It’s a 4 spd 
 

[datzenmike]

With the 4.11 differential and stock tires...

 

@ 60 that's 3,400 RPMs

@ 65 that's 3,700

@ 70 that's just under 4,000

 

If the cam starts to really work above 4K you may not be able to use it.

[J's 620]

19 hours ago, datzenmike said:

With the 4.11 differential and stock tires...

 

@ 60 that's 3,400 RPMs

@ 65 that's 3,700

@ 70 that's just under 4,000

 

If the cam starts to really work above 4K you may not be able to use it.

I kinda remember the guy saying the range was 2000-5000 rpm on the cam. I’ll call today and confirm that.

 My tire size is 205/70/15

[J's 620]

The 272 grind is supposed to be a mild cam

[J's 620]

Oh and mike, my truck doesn’t have a tach, so I never know what my rpms are and my speedo seems to be less accurate the faster I go. 

[banzai510(hainz)]

yeah call him and say what I sad about the cams I bought.  You want lift also and make sure to grind it and measure it and times 1.4891.5 or your not buying it.

 

hope you have thicker lash pads and maybe taller retainers

[J's 620]

9 minutes ago, banzai510(hainz) said:

yeah call him and say what I sad about the cams I bought.  You want lift also and make sure to grind it and measure it and times 1.4891.5 or your not buying it.

 

hope you have thicker lash pads and maybe taller retainers

Thanks hainz, I will tell him exactly what you’ve been saying. I’m counting on the shop to get the lash pads and retainers, I just don’t know where to get those items. 
 I’m going to drop by today and check on the progress, and show them the coolant passages to drill into the head for the particular manifold I will now be running. It’s from an 80’ 720. 

[J's 620]

Is there anything they need to know about drilling those coolant passage holes? Any do’s/dont’s???

[J's 620]

so here’s what I was told over the phone. 
 The 272 is a 218 duration at .050, 435 lift. 
no need for taller lash pads or retainers, 1800 and up on rpm.

 It’s a mild cam, the next one up needs stiffer springs, so the 272 will allow me to re use all my current components. I will have the shop verify these numbers or I won’t buy that cam. 

[banzai510(hainz)]

the head coollant passage I just take a intake gasket and drill a 1/4  inch hole enough to pass water thru there.

However if one lives in a hot climate I would leave the head alone and keep it solid and one don't have to worry about water leaks from that again. One just has to plug the water out let under the fuel pump. Most people just cut the rubber line and but a bolt in there and clamp it

 

 

I have a 460lift 270 Schneider and really this should have come stock in datsuns  minues the valve last its about 450 if that on lift.

Notice the 1/4 inch water passage I drilled U67 head

Edited August 28, 2020 by banzai510(hainz)

[J's 620]

I live in east idaho, we get both extremes, cold and hot, I think for winter it would be better to have coolant flow through that manifold to warm up easier. 

[J's 620]

I see some evidence of cavitation in my front cover. 

[J's 620]

It actually looks worse in person, the picture down plays the depth in some areas.

[J's 620]

Timing guides and the tensioner. The grooves are maybe 1/8” deep, slightly more than that possibly.

[Stoffregen Motorsports]

The timing cover doesn't look bad at all. As long as there aren't any holes in it, I'd run it. New coolant will help keep the porosity from getting worse.

 

Obviously you're replacing the timing chain guides and tensioner, right?

[J's 620]

18 minutes ago, Stoffregen Motorsports said:

The timing cover doesn't look bad at all. As long as there aren't any holes in it, I'd run it. New coolant will help keep the porosity from getting worse.

 

Obviously you're replacing the timing chain guides and tensioner, right?

I was hoping it was still good to use, there are no holes. Besides I wouldn’t expect to find a front cover these days.

 ITM brand is what my timing set is. I’m replacing all the components. I’m already there might as well. 

[J's 620]

I’m basically ready for the head to come back from the shop, I want to get it running again. 

[banzai510(hainz)]

Somebody might have a timing cover.

 

maybe you could JB weld the pits but that's me. and I acutua;ly had a hole it was so tiny and water in the oil pan once it pressurized up

[datzenmike]

On 8/28/2020 at 8:12 AM, J's 620 said:

so here’s what I was told over the phone. 
 The 272 is a 218 duration at .050, 435 lift. 
no need for taller lash pads or retainers, 1800 and up on rpm.

 It’s a mild cam, the next one up needs stiffer springs, so the 272 will allow me to re use all my current components. I will have the shop verify these numbers or I won’t buy that cam. 

 

Stock duration is 248 but I doubt it's measured at the standard 0.050" lift most cam makers do. Someone needs to have an L cam measured so we are comparing apples to apples.

[J's 620]

I was looking at my water pumps today and realized I have a different water pump altogether then what I want to run now.

 

[J's 620]

The one on the left : it’s what I was running before I tore it apart, I beleive it’s a 240z pump but not sure. 
 The one on the right: it’s what I plan on using. It’s this part # (pic below)

[J's 620]

this is the ‘S10’ water pump pulley I was running with that water pump that I think was for a 240z. It’s bolt holes are way off for the AW9009.