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L20B Head and cam choice


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So, here's my dilemma. I've got a L20B in my 520. It was constantly burning oil, like really severe on start-up. I pulled the W-58 head off and found about a 1/4 teaspoon of fresh oil in every piston dish. Looking further into the head after pulling a couple of valves I discovered a few cracks around the valve guides. This head is junk which is too bad because it was a closed chamber W58, which I understand is rare??

I bought a complete rebuilt 1600 with a faux SSS head, meaning it's a 210 casting with 1.65 intake and 1.30 exhaust valves with closed chambers. It has a Shadbolt 445 cam in it ready to go. I also got a Shadbolt 651 cam with the motor. 

My question is, do I run the 445 cam or the 651? I also have a brand new U20 cam out of my W58 head. I'm not really sure what a U20 is, but those are the numbers on it. I should also mention I am running Mikuni R1 carbs with a Bogg Bros. intake and a Hitachi dizzy.The truck ran really good with the W58 head and carbs, however I was gonna kill every mosquito in BC with the smoke.

Any help is greatly appreciated!

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Just rebuild the W58 head(new guides, ect.), as your exhaust manifold is made for round port exhaust, and the 210 head has small intake ports which are always going to be small, it's like trying to breath thru a straw, sure you can sit on the couch and breath, but it won't work on a jog around the block.

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Just rebuild the W58 head(new guides, ect.), as your exhaust manifold is made for round port exhaust, and the 210 head has small intake ports which are always going to be small, it's like trying to breath thru a straw, sure you can sit on the couch and breath, but it won't work on a jog around the block.

Well the head is cracked, so I can't rebuild it. My 210 has 1 3/8" intake runners, and my exhaust manifold is square port.

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The 210 head is just a generic L16 head and is not even close to an L16/18 SSS head. Someone may have put larger intakes in it and they may have made the port openings larger at the gasket but it won't be larger all the way to the valve like the 219 / 912 SSS head. There was a 210 with closed combustion chamber, quite rare but the vast majority were open 'semi closed' (a term that makes little sense as it either is or it isn't)

 

Please post a picture of this 210 head's combustion chamber.

 

 

 

An equal amount of oil on each piston would seem to indicate an equal amount of cause. The chances of valve cracks being equal on all four are very remote.

 

It's more likely the valve seals are all bad or even missing.

 

Over filling of the oil could whip up an oil fog that would be sucked out the crankcase vent pipe to the PCV and into the intake. Take a look at your intake... does it have oil in it? At the same time the rings would be overloaded with oil and it would enter the combustion chamber directly.

 

When the L20B was installed did you swap the L16 oil pan onto the L20B??? What dip stick???? Maybe it has more oil in it that you think.

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dont know the specs on the cams but the head shoule work fine for your needs since is been worked. Doing that to a l16 210 herad is alot of work but it is a 38cc combustion chamber.

I have a W53 with 1.65 and 1.30 exhaust . Its fine.

 

I think if the head is bad that you have fix the L20 block just put the head on there and see what happens.

 

I would not go bac to a L16 unless your just out of motors.

 

On safe side I would pick the smaller of the cams. BUT SINCE 520/521s are lower geared maybe pick the longer duration cam and set to 2 or 3 on sprocket to advance and get power sooner

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The 210 head is going to bump the L20B's compression too high... it will ping. In addition the head is an L16 head for a 1.6 liter engine with 1.30 exhaust valves. It won't breath as well as an L20B head. The W58 had 1.38" exhausts and larger ports.

 

Find the cause of the oil and stick both cams in the W58 head and try them. Pick the one you like.   

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I've run many engines with high compression on the street, and always been able to tune out any pre-ignition.

You just have to ballance the timing, fuel grade, and fair/fuel ratio to get around it.

 

If you are stuck in the mud thinking you have to time an engine to factory specifications, you are not a tuner, or even a mechanic.

 

Hi mikey !

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The 210 head is just a generic L16 head and is not even close to an L16/18 SSS head. Someone may have put larger intakes in it and they may have made the port openings larger at the gasket but it won't be larger all the way to the valve like the 219 / 912 SSS head. There was a 210 with closed combustion chamber, quite rare but the vast majority were open 'semi closed' (a term that makes little sense as it either is or it isn't)

 

Please post a picture of this 210 head's combustion chamber.

 

 

 

An equal amount of oil on each piston would seem to indicate an equal amount of cause. The chances of valve cracks being equal on all four are very remote.

 

It's more likely the valve seals are all bad or even missing.

 

Over filling of the oil could whip up an oil fog that would be sucked out the crankcase vent pipe to the PCV and into the intake. Take a look at your intake... does it have oil in it? At the same time the rings would be overloaded with oil and it would enter the combustion chamber directly.

 

When the L20B was installed did you swap the L16 oil pan onto the L20B??? What dip stick???? Maybe it has more oil in it that you think.

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Valve seals where new and were all in place. I'm sure I never over filled the oil. It took around 4 quarts if I remember right. I don't have a pvc suction hooked up to my intake as I am running Mikunis on a Bogg intake. I'm running the block pipe to atmosphere.

Pictures are coming.

My 210 head is definately closed chamber.

Is the U20 cam any good that came out of the W58, which looks to be a closed chamber head also.

Thanks everyone,..and yes, pix are coming.

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The U20 number is used on several L20B parts. The crank for instance has it cast into one of the throws.

 

The L20B cam is almost identical to the Japan L16/18SSS cam.

 

L20B with closed chamber 210 head (estimated 38cc) is only 9.3 compression, lower than I thought.

 

 

 


I've run many engines with high compression on the street, and always been able to tune out any pre-ignition.
You just have to ballance the timing, fuel grade, and fair/fuel ratio to get around it.
 
 

 

I think I said it was too high and will ping. Not that you couldn't/shouldn't run it. It should go without saying that there are many remedies for pinging but not pinging in the first place works too.

 

 

 


If you are stuck in the mud thinking you have to time an engine to factory specifications, you are not a tuner, or even a mechanic.

 

Hi mikey !

 

...and you, are simply a dick for saying that, ....... Gordo.

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IMG_7236_zpsepqcynaj.jpg

 

210 closed chamber head... not something you see often. They weren't used on N Am. Datsuns. Must be from an import engine. Hang onto that one.

 

IMG_7238_zpsecargb6e.jpg
 
 
 
Not seeing cracks. That line on the right is just casting flash from the molding process. I think you'll find the oil is probably getting past the rings or seals are on wrong or missing. .
.

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i WOULD RUN THAT HEAD IF IT WAS GOOD. YOULL BE FINE .

if tha cam is already set up and correct lash pads installed dont be changing th cams as the geometry might be set different.

 

U20 is just a casting number.

 

L20 cam is just a L16SSS cam not big deal. If the 445 cam is installed alsready run that

 

 

dont be fucking swapping stuff around. If that shadbolt is installed and is set up just bolt it on. Dont sound like you have a bunch of different size lash pads running around for you to be swapping stuff in Out thinking you going to get massive HP swings.

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I bought a complete rebuilt 1600 with a faux SSS head, meaning it's a 210 casting with 1.65 intake and 1.30 exhaust valves with closed chambers.

 

The 219/912 heads were 1.50" intake and 1.38" exhaust. But I hear ya. The 9 can look like a 0 or an 8 and a 5 like a 3 at a glance.

 

The 219/912 also has a 41cc combustion chamber, the 210 closed chamber is supposed to be close to the 210 open around 37 or 38cc.

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Both my heads are closed chamber. The W58 and the 210 head. The W58 has 1.65 intake and 1.38 exhaust valves. The 210 has 1.65 intakes and 1.30 exhaust valves. I'm putting the 210 head on tonight with the 445 cam......stay tuned. I will let you know what transpires.

I am running the cam sprocket on #2 hole also.

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Truck runs awesome nice and loapy, nice throttle response,but.....still burns oil goddamitt!!!

Coming apart .....again. Rings this time. If not, everything is for sale!

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  • 3 weeks later...

Well it's been a week since I tore into my motor to solve the oil burning problem. Everything is back together and the problem is solved!!

I honed the cylinders and replaced the rings and bearings. I am running the 210 head with the Shadbolt 445 cam on #2 sprocket  hole and it runs like a top!! No more oil burner!!! 

My truck should be on the road in about a week. It's interior time next, some odds and ends, then time to enjoy driving my 520 around. Thanks again everyone for your input and opinions. It was a great deal of help for me being new to the Datsun world. I think I finally have these things figured out.

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