Just bought a 521

[datzenmike]

Just now, datzenmike said:

Nothing wrong with Felpro HGs for stock applications and they are economically priced. Were $21 CDN about 20 years ago and $29 now. If VR are 'better' but you are paying the same then that's just wrong. If VR considers Felpro an equal then just go directly to Felpro.

Used to work in a town that had a Champion spark plug factory. Guys I worked with had all worked there. When the assembly line changed to a different brand the only difference was the printing on the porcelain. A lot of shit is that way with the higher quality plugs getting more after production quality control rejection.

[mainer311]

Posting this again here, since some of you aren’t on Facebook. The Nismo head gasket blocks off the front water bypass. Should I modify the head gasket, or leave it blocked off?

 

 

[datzenmike]

Tell me more about what the purpose of the by pass is for.

[mainer311]

37 minutes ago, datzenmike said:

Tell me more about what the purpose of the by pass is for.

Hah! I was hoping you would tell me! As far as I can tell, it looks like a direct path of coolant from the head to recirc back into the water pump inlet. I shined a flashlight into the block, and it’s completely separated from the water jacket, which means that the coolant has to come from the head. 
 

It seems that blocking it off would force more water to exit either via the heater core, or the thermostat outlet.

[datzenmike]

I have fit an L head onto a Z24 block and first noticed that bulge with the hole. It's not used on the Z24 block so I drilled it out and added some JB to better support the head gasket. The water pump pushes water in on the right side of the block. From there it has to push up into the head and between the cylinders from right to left side.

 

Perhaps there is more than enough holes into the head and it is almost over cooled so this hole draws some away and across the front cylinder and into the thermostat housing. The Nismo HG would close this and give maximum cooling up into and through the head. Just a guess.

 

L28 racers drill and tap coolant holes on the left side of the head, join them and connect to the thermostat housing. Gotta figure the rear cylinders have to push hot coolant all the way to the front of the head to get out, so they are going to run hotter. This is what I like about the coolant in the intake runners... there's two places for the hot water to get out of the head without having to go all the way to the front.  

[mainer311]

Yeah, that’s my guess too. I’ll probably just leave it blocked off. I’d run those intake ports, but won’t be able to with DCOE 40’s.

[mainer311]

So close, yet so far. Painted the block a medium grey. Should go well with the plans I have for the valve cover.

 

[Charlie69]

That looks good!

[mainer311]

Anyone know what the proper oil clearance on the mains is? Went out to the garage during lunch and installed 2, 3, and 4 main caps with some plastigage and got just under 0.002”

 

[Stoffregen Motorsports]

Under .002" is pretty tight for an L motor. Usually they are around .022" to .028". Plastigage is not the most accurate method for checking clearances, and it could be off by a couple tenths of a thou. If they are all the same and the crank spins freely, go for it.

 

Do you know how to set the thrust clearance?

[mainer311]

20 minutes ago, Stoffregen Motorsports said:

Under .002" is pretty tight for an L motor. Usually they are around .022" to .028". Plastigage is not the most accurate method for checking clearances, and it could be off by a couple tenths of a thou. If they are all the same and the crank spins freely, go for it.

 

Do you know how to set the thrust clearance?

 

.022-.028"?? Do you mean .0022-.0028"?

 

Yeah, I already adjusted the thrust. The #3 bearings were actually too thick and I couldn't even drop the crank in. I lapped them on some 800 grit sandpaper and was able to open them up a bit.

[Stoffregen Motorsports]

Yes, the important decimal point got moved...

 

You sanded the front side of the thrust bearing, right?

[mainer311]

36 minutes ago, Stoffregen Motorsports said:

Yes, the important decimal point got moved...

 

You sanded the front side of the thrust bearing, right?

 

Both sides equally I'd say.

[mainer311]

Well, there’s $1100 worth of Pierce Manifold goodness showing up in about a week. I called them up and they custom jetted a pair of DCOE 40’s how I wanted them. Great people to work with.

[Crashtd420]

3 hours ago, mainer311 said:

Well, there’s $1100 worth of Pierce Manifold goodness showing up in about a week. I called them up and they custom jetted a pair of DCOE 40’s how I wanted them. Great people to work with.

Did you get the intake from them too?

I have always entertained the idea of adding a 2nd weber but I've done so much work to make my single work.. 

 

I ask because i saw a 521 specific manifold for dual 40s being offered as well as a couple others which I never saw available before.... of course no pictures on the website of the one I wanted to see.... I'm just glad to see more new things available for these old trucks.... 

[mainer311]

1 hour ago, Crashtd420 said:

Did you get the intake from them too?

I did. I got the K667 kit, which comes with the manifold for a 620, plus the linkage. So, I guess I didn’t get the 521 specific manifold. My guess is that the runners on the 521 manifold are much smaller in diameter on the head side, since all 521’s ran the 210 heads with tiny ports. The manifold I got (MT-0037-C) does have a picture. It’s a 2-piece unit, and the guy on the phone went and grabbed one and measured it for me. It’s exactly 38mm (1.5”) which is the same as the ports on my head.

[Crashtd420]

39 minutes ago, mainer311 said:

I did. I got the K667 kit, which comes with the manifold for a 620, plus the linkage. So, I guess I didn’t get the 521 specific manifold. My guess is that the runners on the 521 manifold are much smaller in diameter on the head side, since all 521’s ran the 210 heads with tiny ports. The manifold I got (MT-0037-C) does have a picture. It’s a 2-piece unit, and the guy on the phone went and grabbed one and measured it for me. It’s exactly 38mm (1.5”) which is the same as the ports on my head.

That would make sense.... 

[banzai510(hainz)]

 DUALS!!!!

Edited March 17, 2021 by banzai510(hainz)

[Stoffregen Motorsports]

On 3/16/2021 at 8:54 AM, mainer311 said:

 

Both sides equally I'd say.

I normally only sand the front side.

[mainer311]

3 hours ago, banzai510(hainz) said:

 DUALS!!!!

Yeah, dual 40’s.

[mainer311]

It’s starting to get real. I threw a thin Apex HG on the block, plopped the head on, and checked valve clearance on #1 after setting the lash and timing all up. Good news is I didn’t have any contact, but I still want to check it with some playdoh or something to see how much I really have.
 

[datzenmike]

Flattop and larger diameter intakes are a worry.

[mainer311]

13 minutes ago, datzenmike said:

Flattop and larger diameter intakes are a worry.

They’re only 1mm larger.

[mainer311]

@banzai510(hainz)These Nismo head gaskets are measuring 88.6mm diameter.

 

[Draker]

That timing chain inspection cover is super snazzy.