L20B Head dilemmas; Rebuild? Swap? Cam?

[KlassicMotion]

So I knew my head gasket was seeping, but I was tuning my carb today with the vacuum gauge and the reading tells me I may have burnt or sticking valves, or maybe it's just a head gasket....

 

Bottom line, I've got to swap out the gasket.  My dilemma is;

Do I just have a shop go through the W58 head and put it back on?

Or do I put a cam in it when I do it? 

Or do I build my A87 peanut head with a cam and put it on?

 

If my calculations are correct, the A87 should bump the compression ratio from 8.4:1 to 8.9:1.

 

Are there any issues running a peanut head?

 

Does anyone have advice what is a good street/performance cam?

 

Or does anyone have the specs to the factory W58 cam so I can compare it to some other grinds on the market?

[flatcat19]

Run the peanut if you have it and it's solid.

 

Spend your money on that, not the W58.

[Zeusimo]

What Motor Is This Going On?

One Thing To Check Out Is If The Head Has Ever Been Shaved

If It Has Shim The Towers While You Have The Head Out

 

I Have A Penut Head A87 Standard L20b Camshaft

A87 Sounds Better For Daily Driving Because Of The Smaller Ports

 

If You Get An Aftermarket Camshaft You Need Various Things

Correct Size Lash Pads

Stiffer Springs

And Correct Height Hats (Motorsports Still Has These)

[flatcat19]

Have to add...

You probably have the big combined intake/exhaust manifold clusterfuck.

 

While all is unbolted, you might want to change it all out.

The earlier L20Bs came with a separate intake and exhaust. 

 

A87 c/c plus a different intake and exhaust manifold will give you a bit more punch.

[flatcat19]

What Motor Is This Going On?

 

 

It says in the title of the thread.

[KlassicMotion]

To clearify:

 

1980 L20B

Top-end performance header

2" exhaust

Weber 38 DGES

Matchbox dizzy

280zx trans

 

[flatcat19]

you're set.

 

Make sure your peanut is dialed.

Slap it on.

 

 

Sexy motor!

[cruznude]

your motor looks real good.  Looks like you've really put the time into it.  Where did you get your header and how much was it?

[wayno]

It is likely a round port header, if it is, then I would stick with the round port head(W58), if your header is square port, they I would likely go with the A87 head depending on the valve sizes, the A87 head came in a few different configurations, which one configuration was basically a 219 version(big valves/big intake holes/closed chamber).

If you have a small valve A87 head, then the W58 head is likely the better choice, as it has big valves.

 

It really depends on what type of header it is, round port use the W58, square port, use a square port head.

 

Another thing to keep in mind about cams, the more radical the cam, the less torque you have, so if you have a really radical cam, you have to keep your RPMs up just to get started, as you rob torque to gain HP.

[datzenmike]

'75 to '77 L20B had the U67 heads (some very early may have had A87s it's not clear) and these did not have the coolant holes for the intakes. Instead, the intake was bolted to the exhaust manifold and the heat from that used to warm and vaporize the fuel air.

 

Later '78-'80 L20Bs used a W58 head with coolant flow in the manifold to both warm and cool the intake for much better control of the intake air. The manifolds were separate to reduce overheating of the intake in hot weather.

 

Stock U67 and W58  cams were identical for trucks and cars. I have an L18 A87 head... the part number is different than the L20B cam. Could be close. L16 cams have way less lift than L20Bs

 

The W58 head has round exhaust ports.... the U67 (also an L20B head) and the A87 are square. Not that good to run a square port head on a round L20B exhaust manifold, it might leak. A round port head into a square port manifold is better.

 

Closed chamber heads have combustion chambers that are smaller than the piston below it. In places the piston comes to TDC with nothing above it but the flat head surface and is separated only by the thickness of the crushed head gasket material. The air caught in this quench or pinch area is violently squeezed out into the open area causing extreme turbulence. This assures that there are no rich (cool) or lean (hot) areas and the mixture is homogenized. The combustion chamber runs 'cooler'  or to look at it another way does not have hot spots that lead to early pre ignition. Other results are more efficient burn and more power for less.

 

As a rule, a closed chamber head will run with more compression without pinging than an open chamber head.

 

The L series closed chamber head will up the L20B compression to about 8.9 and compression increased always makes a motor more efficient. Think gunpowder in the open just fizzes and makes a cloud of smoke but confined in a tight paper tube makes a huge bang. Same with gas and air.... there is a larger more sudden explosion that pushes down on the piston. In addition the burn time is decreased and the combustion chamber smaller so there is less time and less surface area for heat to be absorbed by the motor. More heat to expand the gasses and do more work. Very roughly a one point increase from 8.5 to 9.5 compression adds about 4% more power. For a stock L20B that's only 3-4 hp. Very roughly. But this isn't completely free... you have to deal with pre ignition.

 

I'm with wayno. Run with what you know and have. W58... it fits and works.

[banzai510(hainz)]

clean looking set up you got

 

I hope the PVC and the fuel vaper hoses going to the fender are correct.

 

You but spacers on the Champion radiator? I have 1 3 core also but havent instlled it yet. Looks like one needs a spacer as the top tank butts right up the the core support. My stock Modine have a huge space(gap) from radiator to the core support.

 

 

yes let up know what header you have as Top End only sold squareport headers so I assume you would put a square port head on there.

 

Persoanlly I dont think nothing wrong with the Round port heads myself. as they do have bigger intake ports compared to the A87/W53 (1.25). Howere they are open chamber and have a desieling proplem with reg gas.

 

If you can afford a cam and rockers do it but its expensive. otherwise just run the stock stuff. PS I love the 38/38.

 

 

Change the head gasket yourself.

[KlassicMotion]

your motor looks real good.  Looks like you've really put the time into it.  Where did you get your header and how much was it?

 

Thanks.  There is a lot more time to put into it, but it's getting there.  The header is a Top-end Performance square port.  I can't remember if I got it off eBay, or off their website.  It was probably eBay, since I hate their website.  Read my next response below before you buy one.

 

It is likely a round port header, if it is, then I would stick with the round port head(W58), if your header is square port, they I would likely go with the A87 head depending on the valve sizes, the A87 head came in a few different configurations, which one configuration was basically a 219 version(big valves/big intake holes/closed chamber).

If you have a small valve A87 head, then the W58 head is likely the better choice, as it has big valves.

 

It really depends on what type of header it is, round port use the W58, square port, use a square port head.

 

Another thing to keep in mind about cams, the more radical the cam, the less torque you have, so if you have a really radical cam, you have to keep your RPMs up just to get started, as you rob torque to gain HP.

 

It is actually the square port header..... Before anyone gets their panties in a bunch, I thoroughly experimented with the setup first.  I tried a few different gaskets, studied them on square and round port heads, then I Gasket matched the header to the gasket itself.  It may not be a perfect fit, but at most, there is only maybe 3% "restriction".  I ended up using the Felpro gasket *MS22801* for the round port L20b.

 

 

First off let me rant on the quality of the Top-End header.....  It came to me as pretty much junk.  Who ever welded the primary tubes into the flange did not get full penetration, but they obvoiusly tried to cover it up by adding more weld.  The ports were tiny.  So I took my carbide bit and cleaned them up and re-welded the areas that did not get full penetration.  Next was the flange itself.  Again, who ever welded the header obviously had some pretty sloppy welds, because they took a grinder to the flange and totally warped it.  There was no way, even with a thick header gasket that it was going to seal.  So I took it to my machine shop and had it planed back to true.

 

Anyone considering this header should be ready to re-work it, or take it to someone to have it re-worked. 

 

That being said, It now runs great.  With a little work, I wouldn't be affraid to run this header on a round port head..... Oh yeah, there is one other issue:  The collector; they give you a reducer pipe to reduce the collector from 2.5" to 2".  That's cool, but the pitman arm hits the collector right where the one slides over the other....I had to take a torch and a hammer and re shape the collector so the pitman are has room....  I'd still buy this header over some of the other ones on the market.   

 

When I pull the head off, I will take a picture of the gasket overlay on the head versus the header.

 

 

 

'75 to '77 L20B.....

 

Great info.  Thanks Mike.  Just FYI, I have done my own research, so 90% I knew, but I like the regergitation of info on here for when the next person is searching for the same answers.

 

So you guys are confirming what I already believed that the W58 really isn't that bad of a head, aside from the open chamber.  Personally, the steel sleeves inside the exhaust port don't bother me either.  As far as I can see, they are smooth and unrestricted (good flow) and who cares if they burn off some unburnt carbon.  That just means a cleaner tail pipe. 

[KlassicMotion]

clean looking set up you got

 

I hope the PVC and the fuel vaper hoses going to the fender are correct.

 

You but spacers on the Champion radiator? I have 1 3 core also but havent instlled it yet. Looks like one needs a spacer as the top tank butts right up the the core support. My stock Modine have a huge space(gap) from radiator to the core support.

 

 

yes let up know what header you have as Top End only sold squareport headers so I assume you would put a square port head on there.

 

Persoanlly I dont think nothing wrong with the Round port heads myself. as they do have bigger intake ports compared to the A87/W53 (1.25). Howere they are open chamber and have a desieling proplem with reg gas.

 

If you can afford a cam and rockers do it but its expensive. otherwise just run the stock stuff. PS I love the 38/38.

 

 

Change the head gasket yourself.

 

I had to teach myself about the L series PCV system.  Once I understood it, its a great system in theory.  So I did my utmost to make sure I adapted it correctly to the the Weber 38.  I wish more guys would try to understand the system and work to incorportate into their builds.  I cringe when I see or hear guys talking about getting rid of the system.  Having owned Minis and Sprite/Midgets, I know the importance of getting gasses out of the engine block.  There is a big difference in revs when you have an A series engine with no crank case ventilation, versus one that has or a PCV system or just multiple vents.

 

Radiator:  I had intended to Post a thread on my install..... I will do one now and post the link.....

****Added****

http://community.ratsun.net/topic/56540-champion-aluminum-radiator-meets-510-this-is-my-install/

[wayno]

If you have a square port header, I would use a square port head, I realize that the W58 will work, as I ran one on my square port header for over 6 months until my head was completed, but eventually it will leak.

Will it leak before you have issues with the header itself, well that is a good question, as I have never had one of these headers(top end) last more than 3 years without having to be repaired, mine always go bad where the 4 tubes come together, and I always cut the tube off about where the tubes are welded on the inside, re-weld them, and then weld it back together.

I have done this repair at least 3 times over the years, so it's not a big issue to me, other than having to tear the whole thing down to get that POS out of there to repair it.

I personally don't know about 510 fitment, but these headers work well in a 521, except for the quality of course.

I still have one left(top end), but I bought a better quality long tube header out of a 521(so I know it fits) for the next header failure.

 

There is nothing wrong with a W58 head, it has the big ports and valves, it just isn't a good performance head, but how many of us really run our engines up to 6000+rpms daily, not many, so it should work just fine if that is the way you choose to go.

[KlassicMotion]

This is the A87 I bought.  It looks like it does have the water ports...  I've got it in storage at the momment, so I can't messure the valves, but they look pretty large in the pictures.....

 

[datzenmike]

The only head I know of without the water cooled intakes IS the U67. The W58 breathes just fine at normal use RPMs. The liners may start to get in the way restriction wise if revved way beyond normal or if a better breathing cam with more carb is added. I have removed liners in a W58 (closed chamber) before but never ran it and I doubt you would notice it anyway.

[KlassicMotion]

I hate doing things twice, but I'm leaning in the direction of fixing what I've got for now... And building a better head later down the line.....

 

Ultimately I'd like to put something in the car that pulls 150-200hp.  Just not sure what route to go, or how much I want to spend.  I like the idea of keeping an L series in the car.....

[datzenmike]

Then 150 is going to cost you. LZ24 will get you close with cam multi-carbs.

[KlassicMotion]

Then 150 is going to cost you. LZ24 will get you close with cam multi-carbs.

 

Those aren't the words I wanted to hear!..... Fine, I will stick with the L20B setup I have for now.  Simple and straight forward.  I will get started pulling the head today during nap time.  We'll see what I find, that may change things.

[wayno]

The only head I know of without the water cooled intakes IS the U67. The W58 breathes just fine at normal use RPMs. The liners may start to get in the way restriction wise if revved way beyond normal or if a better breathing cam with more carb is added. I have removed liners in a W58 (closed chamber) before but never ran it and I doubt you would notice it anyway.

 

I have had to drill holes for the water passages for my SU intake manifolds in one my hybrid W53 heads, all the others have had the holes, including the open chamber W53 head I have, the reason I know this is because the holes I drill are smaller than the holes that are stock, strange that the one did not have the holes.

Maybe it was 2 of the W53 heads out of the 4 I have that had to be drilled, seems like I had to do it more than once.

 

Those aren't the words I wanted to hear!..... Fine, I will stick with the L20B setup I have for now.  Simple and straight forward.  I will get started pulling the head today during nap time.  We'll see what I find, that may change things.

If you have to rebuild a head, I would rebuild the A87 head myself.

[Sealik]

My K14 intake had the coolant holes....whereas the 'holes' in the U67 head were MIA.

I just drilled them out with a 3/8 bit

[KlassicMotion]

I'm assuming the head bolts are of the reusable type, versus the one time use head bolts.

[wayno]

I'm assuming the head bolts are of the reusable type, versus the one time use head bolts.

 

They are re-usable,  just clean them up good, if you can, chase the block threads with a tap also.

[KlassicMotion]

Good deal. 

I'd have the head off, but the cam sprocket bolt is on tight, and my garage is under my son's bedroom, who is sleeping right now, so no impact.  I guess I will tackle it in the morning.

[banzai510(hainz)]

if you have a later L motor there is 2 knobs on the center cam. put a big adjustable on it turn the motor till the Wrench locks up on the head bolt loosen the sprocket bolt then turn head back to TDC and loosen up everything

Like in my Vid I explain this