best head

[sdsurf]

ok two scenarios.

 

I have a U67 head, 210 head, and closed chamber A87.

 

Which head is best on

 

A) L-16

 

B) L20b

[hang_510]

too many variables to say what is best.

 

best for ?

whadaya want out of it? torque? HP? speed? mileage? _______???

[Phlebmaster]

The closed chamber A87 head is good on either an L16 or an L20.

 

The U67 is good on an L20, but will lower your compression on an L16.

 

The 210 head....don't know much about them. Came stock on an L16 so it would be an ok head for the L16. I think the 210 head will drive up your compression if you put it on an L20...but not sure. Small ports and valves make this head less desirable.

 

:D

[pl521sss]

best head ever, hmmmmm:rolleyes:

Can't remember her name

 

oh wait, cylinder head :D

never mind

 

on stock L16 and 4 speed

219 cylinder head with matching SU carb is a rocket

 

In your case, A87 over 210

Although, I've seen closed chamber 210 but can't remember the valve size.

[Phlebmaster]

Can you post pics of your head...s? :lol:

 

I want to see the intake/exhaust ports and the valves.

[datzenmike]

U-67 on an L20B for most power/torque... A-87 closed chamber not as good. The added compression 8.9 is outweighed by smaller ports and valves, open chamber a little less. 210 least powerful but good for economy. Oddly enough years ago I put an L16 head on my L20B because the Nissan dealer told me it could not be done, and my L20B head was out being surfaced. Ran fine, no ping but maybe the gas in the '70s was better. The head came from a Canadian '68 510 so I assume it was a 210. The compression works out to 9.2

 

The 210 head is stock on the L16 (so we know how lame that is) An A-87 head has very slightly larger valves and intake ports and would breath better. A closed chamber would provide better compression at 8.39. The open chamber A-87 AND the U-67 would have a compression of 7.86. The U-67 would have the best breathing potential with the largest ports and valves but poor compression. Milling aprox. 0.80mm from the open chamber A-87 or the U 67 head should bring the compression up to about 8.4

 

L16.... A-87 closed chamber head is good, milled U-67 head better.

L20B.. U-67 head

 

Just an opinion.

Edited February 25, 2009 by datzenmike

[sdsurf]

excellent... question #2

 

In taking my head to a machine shop (bare, no pistons, crank, etc) what am I asking for? magnaflux? boil it? Bore cylinders? I want to get the block prepped to rebuild the best way possible

 

And if I take the head in, U67, what do I need to ask? Should I leave it intact? valves and cam?

 

Thanks for your help

[Phlebmaster]

excellent... question #2

 

In taking my head to a machine shop (bare, no pistons, crank, etc) what am I asking for? magnaflux? boil it? Bore cylinders?

 

And if I take the head in, U67, what do I need to ask? Should I leave it intact? valves and cam?

 

Thanks for your help

 

What?? You have all of that in your head? lol

 

JK! :D

[datzenmike]

excellent... question #2

 

In taking my head to a machine shop (bare, no pistons, crank, etc) what am I asking for? magnaflux? boil it? Bore cylinders? I want to get the block prepped to rebuild the best way possible

 

And if I take the head in, U67, what do I need to ask? Should I leave it intact? valves and cam?

 

Thanks for your help

 

The block: For an L16 I would keep it simple otherwise a lot of money will be spent to bring the power up to that of an L20B. If this is the case, why not use a stock L20B that has 10-15 more hp to start with? If you have a bare block, power wash it with lots of soap and dry thoroughly. Measure the cylinder bores. If it isn't too worn you can re-use your pistons which saves money on new oversize ones and having the block over bored. If it doesn't need over boring then don't. Increasing the bore by 1mm or about 40 thou adds about 40cc of displacement to the motor or a 1/40th increase. If the L16 makes about 90 hp that's an increase of only 2.25 hp not worth the cost and bother of pistons and boring. I would guess close to a hundred dollars per hp.

 

If you do need new pistons get the smallest oversize and take them to whoever is doing the boring. He will bore to match the piston. Just because it says 30 over does not mean it will fit a 30 over block. They must be measured and the block bored to give the proper fit.

 

 

The head: Remove everything but the cam towers. If the shop can't mill without taking the towers off try somewhere else. The cam towers that support the cam have been align bored and if removed this critical alignment can be lost. Do some homework and decide how much you want to remove from the head. Any head material removed will will lower the cam closer to the crank, effectively introducing slack into the timing chain. Too much will alter the cam timing. Something to think about and what to do to correct it..

[sdsurf]

Ok I am going to build the L20b. So I should wash it completely? I was thinking of new rings, bearings, etc. I think the pistons are good. Should I keep the pistons, rods and crank and just replace bearings and rings?

 

For the head I want to take the bare minimum off. I don't want to mess with it that much. Should I replace the valves or use what I have.

 

I will post pics tonight...

 

This thread is coming from wonderful L.A. County Jury Duty

[Phlebmaster]

Ok I am going to build the L20b. So I should wash it completely? I was thinking of new rings, bearings, etc. I think the pistons are good. Should I keep the pistons, rods and crank and just replace bearings and rings?

 

For the head I want to take the bare minimum off. I don't want to mess with it that much. Should I replace the valves or use what I have.

 

I will post pics tonight...

 

This thread is coming from wonderful L.A. County Jury Duty

 

You want to make sure you don't put any part back in that you are not sure about. You don't have to go overboard, but don't take any chances if you are putting in that much work. Just use your common sense with the engine parts...look them over.

[datzenmike]

The block: For an L16 I would keep it simple otherwise a lot of money will be spent to bring the power up to that of an L20B. If this is the case, why not use a stock L20B that has 10-15 more hp to start with? If you have a bare block, power wash it with lots of soap and dry thoroughly. Measure the cylinder bores. If it isn't too worn you can re-use your pistons which saves money on new oversize ones and having the block over bored. If it doesn't need over boring then don't. Increasing the bore by 1mm or about 40 thou adds about 40cc of displacement to the motor or a 1/40th increase. If the L16 makes about 90 hp that's an increase of only 2.25 hp not worth the cost and bother of pistons and boring. I would guess close to a hundred dollars per hp.

 

If you do need new pistons get the smallest oversize and take them to whoever is doing the boring. He will bore to match the piston. Just because it says 30 over does not mean it will fit a 30 over block. They must be measured and the block bored to give the proper fit.

 

 

Just substitute L20B in place of L16 in the text. Measure the cylinder wear to know if you need to go oversize. Hope that you don't and just replace the rings and bearings.

 

Stock valves are ok. Replace with larger only if the seats need replacing anyway, and you can afford it all. Check guide wear and replace the guide seals to prevent excess oil burning.

[pl521sss]

The head: Remove everything but the cam towers. The cam towers that support the cam have been align bored and if removed this critical alignment can be lost. .

 

 

I did not know that, what happens if removed and marked where they go back, is that ok? So using cam towers from other engine may not line up correctly? Like cam towers from L28 with spray bar used on L4 cylinder head. Yikes, sounds like there's some homework I need to do.

 

Sdsurf, Make sure if the shop gets you engine kit that they are of good quality or trusted name brand. We had cast iron oil pump instead of the cast aluminum that came with the kit. Also the freeze plug, go for the bronze instead of the steel. If they tell you what you need, you might save some money to get it yourself and shop around online.

Bring the crank too while your at it. They can inspect that and clean it when they steam clean the engine.

Prepare to spend several hundred dollars on a budget engine rebuild.

[hang_510]

Measure the cylinder wear to know if you need to go oversize.

Check guide wear and replace the guide seals to prevent excess oil burning.

 

measure 3X, pay once :D

 

 

at a good head shop ;) you shouldnt have to say much...

i had the towers removed and aligned.

 

if the cond is unknown/questionable, plan on replacing the guides and seats... cuz its off!

 

mark the rockers and lash caps so they go back on the same lobe

 

 

BEFORE you spend any money on the L20, confirm there are no cracks on the deck surface, esp between #2 & #3.

[datzenmike]

Removing towers may be unavoidable so mark with center punch one dot for 1 two for 2 and so on. When installing put the cam back in then finish tightening the bolts. This will help align them. You should be able to turn the oiled cam by hand when done.

[hang_510]

I did not know that, what happens if removed and marked where they go back, is that ok?

So using cam towers from other engine may not line up correctly? Like cam towers from L28 with spray bar used on L4 cylinder head. Yikes, sounds like there's some homework I need to do.

 

likely be OK reinstalling the OG towers and cam.

verify the cam rotates freely w/o ANY interference...:blink:

 

new cam / L28 towers = get it aligned

Edited February 26, 2009 by hang_510
i type slower than mike

[sdsurf]

Ok this is the L20b:

 

after cleaning

 

#1

 

#4

 

Crankshaft

 

Springs in pan at disassembly

 

washer in pan at disassembly

[pl521sss]

Ok this is the L20b:

 

Crankshaft

 

 

Springs in pan at disassembly

 

 

washer in pan at disassembly

 

 

Looks like the valve was hitting the pistons.

How about the cylinder head?

 

Use plastigage to check bearing clearances and such.

 

http://www.ehow.com/how_2142943_use-plastigage-measure-clearances.html

[hang_510]

Looks like the valve was hitting the pistons.

 

both!

0.50 bored over?

looks like a good starting point.

 

 

the spring is from the tensioner.

[sdsurf]

both!

0.50 bored over?

looks like a good starting point.

 

 

the spring is from the tensioner.

 

I don't know if it is already bored. got this engine from the J/Y. Is that the 0.50 stamp on the piston?

[sdsurf]

U67 head

 

cam

 

valves

 

#1

 

#2

 

#3

 

#4

[hang_510]

Is that the 0.50 stamp on the piston?

my guess.

and it seems the pistons may have had reliefs cut into them. (nice felpro "no retorque" imprint :lol: )

 

for a JY motor it looks damn good!!!

[littlekeeley]

 

 

:D:D:D:D:D:D:D:D:D:D:D:D

[sdsurf]

 

 

:D:D:D:D:D:D:D:D:D:D:D:D

 

????? How does this help to determine if the head I have is good?

[datzenmike]

Someone re-built with oversize by the look of it and for what ever reason the chain broke (though I have never heard of this happening) or maybe the cam sprocket came off... something, and the tensioner fell out. Cam stopped and the pistons hit.

 

If you look at #1, it seems the valve hit in more than one spot. How? it's likely bent.

 

 

That's two springs in there, so this has happened at least twice.

 

 

This looks like a washer from under one of the head bolts. Plus ground up Teflon from the tensioner and guides.

 

 

The oversize pistons show it was rebuilt so the tensioner springs and washer would have to be since then. The valves were likely damaged so they have been replaced OR the head was replaced. The red RTV sealant is likely from the timing cover being removed to fix the chain/guides/tensioner?