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w58 vs n58 head question

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All L series 4 cyl. heads can be replaced by all other L series 4 cyl. heads.

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Both exist, both smog heads, not the greatest for flow, but if you're putting them on that camper, I doubt it will matter much.

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Remove the steel liners from your exhaust ports and just run it.

Too much flow for a stock motor.  It will be way worse than having the liners in.  Low compression in the hole will cause tumble and all sorts of other nastiness with those removed.

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I don't think so. It would flow about the same as a U67 head. Too much work for no gain on a stocker..

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I don't think so. It would flow about the same as a U67 head. Too much work for no gain on a stocker..

 

^

That.

 

Apples to apples-improve what ya have.

 

If wanting to upgrade, cruise the junk yards for an A87 head; hopefully finding a peanut.

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An A87 isn't an improvement over a W58 on an L20B.  SMALLER valves and ports.  Besides, you'd need a new exhaust manifold.

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Leave in. I've done this on a W58 closed chamber head. You have to remove the valves, and that's a lot of bother. First liner took me 45 min. the last was 15. The ports have pea sized bumps to support anf hold the liners away from the port surface so they aren't cooled and can get red hot from the exhaust. I split them lengthwise in several places and twisted then out with vicegriops. They are wrapped around the exhaust valve guid that protrudes into the port and are a pain to get out. Sounds easy, I assure you it is not.

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Never heard of an N58 head. Would be inclined to say it doesn't exist.

My 77 710 goon has one

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My 77 710 goon has one

Ok thanks all for the advise , i will leave it to the original state . since this engine sits in a camper , i don't need performance

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Never heard of an N58 head. Would be inclined to say it doesn't exist.

 

 

 

My 77 710 goon has one

 

 

Doesn't Jessie's goon have an N58? or was it an W53... some odd ball number.

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Old thread, but wanted to add I have an N58 head with an N58 stamped block. Was the stock engine in a '79 KC deluxe if that matters at all.

 

Exh mani was also stamped N58.

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W58 was used between '78 and '80 on all L20Bs. If it has a different head it was likely from an import engine from Japan. It was cheaper to put a low mileage import part on than to rebuild the stock one. I had a W58 closed chamber head I found in a wrecking yard... same thing.

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W58 was the most common, bur N56 - N58 showed up occasionally, particularly on early '78s built in 77.  While it's possible they are replacements, I have reason to think one was original to a '78 KHLA10.

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My 79 KCD has a W58 head.
I am 3rd owner,  it was all factory including A/C when I got it in 1987

 

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What is the best head for breathing that can be used on a 79 L20b ?
I had big valve heads on my VW Ghia, is there another OEM head with better flow than the W58 for the 79 L20b?

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1 hour ago, Goemon said:

What is the best head for breathing that can be used on a 79 L20b ?
I had big valve heads on my VW Ghia, is there another OEM head with better flow than the W58 for the 79 L20b?


219 or 912 is an oem head.

 

have at least 500 to 1000 bux to even try to buy one.

 

 

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The closed chamber W58 head is almost a 219 head, I am just not sure how well the round exhaust ports flow with that steel liner in there, they may flow just fine, I briefly had an L20b/w58 head in my work truck with a stock downdraft carb, it had lots of torque, it went right up the steep logging road hills in second without an issue, but I replaced it with the equivalent of a 219 head and dual SUs.

The W58 head has large valves and intake ports, but you need to find out if it is open or closed chamber.

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The W58 is alright. It's similar to the U67 for large valve and port size, but has round exhaust ports that have a thin steel liner in them. The liner is held away from the port wall and will glow hot from the exhaust heat. This is an ignition source to help burn off unburned hydrocarbons helped by the addition of air into the exhaust ports by the air pump. Myself, I would remove the exhaust valves and cut and pry the steel liners out. It will get slightly better flow at high RPMs but nothing radically noticeable.

 

I would slip the new manifold gasket onto the head and line it up with the bolt holes. Now scratch the gasket outline into the soft aluminum with a nail, or spray paint it. Remove the gasket and grind away any painted spots or inside the scratch line and blend and smooth back into the intake and exhaust ports at least an inch. Do the same with the aluminum intake and this will be harder... the cast iron exhaust manifold. When done and mated together the ports will line up smoothly and perfectly with the manifolds.

 

With the valves out smooth any sharp edges below the seat from the milling operation used to put them in and any casting flash. Do NOT hit or damage the valve seat face.

 

Chuck each valve in a drill and spin while holding sand paper to above and below the valve face. Round off the sharp edge smoothly  but do NOT damage the face itself. If a 3 angle valve job actually works why add more edges when you can smooth them like a trumpet horn for even smoother flow?

 

Smooth any sharp edges inside the combustion chamber with sand paper. Polish them as much as you like.

 

Index the spark plugs so that the ground strap is aligned and facing between the two valves and the plug facing the open chamber. The theory is that the fame has an easier time getting out and away from the plug. Does it work? beats me but cost nothing. Mark the insulator with a felt pen and using thin washers stack them till you get what you want with the plug tight.

 

With the plug torqued into the head inspect to see if any threads are sticking above the combustion chamber surface. If there are they can get hot and become an ignition source causing pinging under heavy load. Simply grind them down and smooth them.

 

Remove the air injection tubes inside the exhaust pipe that extend down into the exhaust ports almost to the valves. These inject air from the belt driven pump and the oxygen helps burn off any emissions. This removes a small restriction. Seal the exhaust manifold holes with pipe plugs.

 

Not one of the above is worth much but a tipping point can be reached where a lot of little things add up to something worthwhile. Plus these modifications NEVER go out of tune, they are built in.

 

 

 

 

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