Datsun 620 High Comp Engine Swap

[Beastlikethat1]

So I'm going to be buying an engine and trans for a nice price soon. The setup is L16 head with Z24 block with flat top pistons and a "mild" cam. Twin Mikuni carbs. 5 spd inlcuded. One of my main questions is what the compression ratio may be on this engine?

[datzenmike]

I can't see why anyone would put the smallest L head (210) there is on an engine that has a 50% larger displacement. I know of no 89mm flattop pistons that will fit the Z24... the closest being those from a KA24E but they have a 2.8cc dish in them. For argument sake a Z24 with KA pistons and 210 head would have a compression of 12.57... a ludicrous amount and poor breathing to boot.

 

You would be infinitely better off with an open chamber U67 head...... 11.24. Larger ports and valves. Slightly better than L16 cam, or swap your 'mild' one in.

[flatcat19]

Sounds like too good of a deal. *wink, wink*

 

 

 

Have you ever seen this engine run? No? Pass.

[datzenmike]

I suspect the seller doesn't know what he has or this is suffering from 'specification drift'.

[2wheel-lee]

The carbs are of good value of the overall deal is good. Though I recall finding parts for those carbs can be a bit difficult, so hope they're in good shape. Heck, if the price is right, i'd buy it for the carbs and manifold alone. 

[flatcat19]

I suspect the seller doesn't know what he has or this is suffering from 'specification drift'.

 

 

Seller may know exactly what he has....which is why it is being sold for a "good price."

 

 

One man's junk...

[Beastlikethat1]

http://imgur.com/a/B4kue

Here's pics of it, you guys are much more of experts than I am! So a L16 head seems a little crazy on this block?

[Beastlikethat1]

Also I want to note I have a full L20B engine from my 1977 620, would that head make a better swap onto this block I'm guessing? What compression would we be talking then?

[datzenmike]

http://imgur.com/a/B4kue

Here's pics of it, you guys are much more of experts than I am! So a L16 head seems a little crazy on this block?

 

Look between the #1 and #2 spark plugs down along the bottom of the head. If L16 head, it will say MADE IN JAPAN 210.

 

I have doubts this is a Z24 block. The block ID will be top edge just below the head on the carb side between the carbs... kind of hard to get at. If this is a Z series I expect it will say it's a Z22. 

 

Also, look above the starter at top of the block where it meets the head. If an L series block it will have a dip stick located here. Look just behind the handle there will be a flat boss and on it, it will say L20B.

 

 

Also I want to note I have a full L20B engine from my 1977 620, would that head make a better swap onto this block I'm guessing? What compression would we be talking then?

 

Already answered....

 

You would be infinitely better off with an open chamber U67 head...... 11.24. Larger ports and valves. Slightly better than L16 cam, or swap your 'mild' one in.

 

Again, look between the 1 and 2 spark plug. A '77 should say MADE IN JAPAN U67

[Crashtd420]

What is your end goal?

What's wrong with your L20?

And what head is on it?

 

I assume the z24 is what the 5 spd transmission fits... do you know what transmission model is?

 

Maybe use the head from your l20, and steal the cam and rockers out of the l16 head..... and hope the carbs aren't as bad as they look.

 

 

And the 210 is just the least desirable head, on the l20 I think the compression increases is about .4, if I remember a stock l20 had a cr of 9.5 to 1..

but if it has a cam maybe it's had some porting done...

 

Alot of ifs with that purchase.

[2wheel-lee]

Did I mention that I want those carbs? ;) I don't even have a use for them! lol Maybe I'd find one. 

[banzai510(hainz)]

that is a Motorsport manifold carb set up. Nice big long runners.  thats 500$ right there

[Crashtd420]

All depends on the actual asking price...

Could be worth it for the parts...

[Stoffregen Motorsports]

Dude, buy that engine now. Don't wait until it's gone. Those carbs and manifold are highly sought after for vintage racing guys. The red stickers on the carbs alone could be worth something.

 

I don't even own a Datsun anymore and I want that intake setup. How much? I'll buy it right now.

[datzenmike]

Stock L20B compression is.... 8.4

 

With closed chamber head..... 8.9

 

With 210 head......................... 9.23 (not that you would want to... )

[flatcat19]

L20B, guessing.

 

 

The Z24 is taller than the L20B, Z20, Z22. Welding will have to be done to the cover to fit head and block height.

[datzenmike]

Can't see the front cover very well.




Not seeing the Z series dip stick here. Might have already been moved to the other side? For what it's worth if this was a Z24 it would have a 240mm clutch and flywheel. The 240mm pressure plate has 9 bolts holding it on this one only has 6. I suppose a lighter clutch could have been used.


Will have to wait for more pictures.

[Beastlikethat1]

Here you guys go, sorry it took so long to get more pics. http://imgur.com/a/2Da0X

[datzenmike]

 

W53 is likely a closed chamber head.

I think this is a Z series block. The L series are stamped on the top edge of the block above the and just below the head.... where that heater hose is. If a Z series engine, it's stamped on the other top side between cylinder 2 and 3.

 

Can you get a picture of the front of the engine?? 

 

If you do not have a ,that hose must be closed off so there is no flow.

[flatcat19]

What the hell is up with the plumbing fixture?

[datzenmike]

If running without a heater the head fitting should be removed and plugged. The return hose cut short and a large bolt and gear clamp used to seal it. 

[distributorguy]

???

Run a hose from the head port to the port by the lower radiator hose.  Leave them connected.  This helps cool the rear of the engine.  Otherwise cylinder #4 tends to get hotter and the mixture goes lean on the rear cylinders.  This can end up with you having problems burning an exhaust valve in cylinders 3/4.  The heater helps circulate hot coolant out of the rear of the head quickly, and puts it back to the water pump input.  By pulling more coolant through your head you'll have less overheating issues.  Its critical, like turning on your heater when the engine runs hot.  Only this way, you don't get hot and the head won't develop hot spots where water flow diminishes in the rear of the head.  

[datzenmike]

So what happens if you have your heater connected and it's shut off for the summer????? You're going to burn out the valves???? All Datsuns heaters are shut off in the summer.

 

Never connect around the heater as it has a shut off valve. If you do this, a huge amount of hot water is circulated directly back into the engine without any cooling what ever. A full open thermostat probably moves this amount of water. Bypassing the heater just increases the cooling load on the radiator. Specially in warm weather.

[distributorguy]

You want to get heat out of the engine, and you want your engine to be relatively the same internal temp front to back.  Not installing a bypass hose from the head, especially when its so easy to hook up, is just lazy.  It IS beneficial.  Plugging ports just helps to allow hot spots and worse - trapped air in the head.  Circulation is your friend.  

[datzenmike]

That hose isn't intended for that... it's for the heater only. All Datsun heaters have a shut off valve when not needed in the summer so there is no flow through the pipe. You are not taking heat out of the engine you are putting it right back in and by-passing the radiator. Now the radiator has even more work to do on less flow and in the summer heat.

 

I have turned the heater on during over heating in the summer and it does drop the gauge slightly.