A87 peanut on a L20b

[jon521]

So I have heard and read a few different things on closechambers on a stock L20b. My plan is to have my A87 close chamber rebuilt, and replace my w58 with the A87 on my stock L20b. I didnt think it would be a problem, until today. i talked with a local datsun guy here in salem, he said he has been into datsuns for 16 years. when i told him of my plan to put a close chamber a87 on my L20b, he said unless i got dished pistons, i would be blowing head gaskets constantly if i ran it on pump gas because the close chamber head would give it really high compression. stretch was telling me how he has an a87 on whatever he has and he runs plus and he said its just fine. but im not sure what engine he has that one. so, would it be bad to put a close chamber a87 head on my stock L20b?

 

Thanks.

Jon

[john510]

Im running an A87 peanut head on my L20 with L18 pistons .040 over and havent had problems so far.I am using 91 octane fuel and timing about 12' btdc.It will ping with timing advanced any more and when the weather is hot it wants to diesel.Headgasket is not an issue yet.

[datzenmike]

I would say he's full of shit but he is either mistaken or believes what he's saying. A closed chamber head raises a stock L20B's compression from 8.4 to (only) 8.9. A stock head gasket will hold this easily, no worries. Also the stock L20B pistons already have an 11.36cc dish in them.

 

Last, you should be aware that the W58 exhaust ports are round and the A-78 ports are square. You can run round ports into a square exhaust manifold but not the other way round. Best to get an L16/18 square port exhaust manifold.

 

 

Im running an A87 peanut head on my L20 with L18 pistons .040 over and havent had problems so far.I am using 91 octane fuel and timing about 12' btdc.It will ping with timing advanced any more and when the weather is hot it wants to diesel.Headgasket is not an issue yet.

 

John if I'm reading you right that's 0.040" over??? Thats a 1mm oversize then?? If so then your compression is 10.08

[banzai510(hainz)]

stock bottom end with closed chamber head is fine.

Flat tops then I would be worried and good gas

[krecs]

So I have heard and read a few different things on closechambers on a stock L20b. My plan is to have my A87 close chamber rebuilt, and replace my w58 with the A87 on my stock L20b. I didnt think it would be a problem, until today. i talked with a local datsun guy here in salem, he said he has been into datsuns for 16 years. when i told him of my plan to put a close chamber a87 on my L20b, he said unless i got dished pistons, i would be blowing head gaskets constantly if i ran it on pump gas because the close chamber head would give it really high compression. stretch was telling me how he has an a87 on whatever he has and he runs plus and he said its just fine. but im not sure what engine he has that one. so, would it be bad to put a close chamber a87 head on my stock L20b?

 

Thanks.

Jon

 

I just put the same head on my stock l20b and run on regular gas it runs great. i will try 91 octane next time and see if it runs better if you don't try you will never know

[crackerjack69]

LOLz, A87 is a stock head... Engineered by the manufacturer specifically for use on an L motor... The person who told you you'll blow your headgasket is smoking crack :D

 

 

[Z chopper]

the 219 head used on the bluebird sss sometime had a87 cast on them aswell as 219, so I figure a regular a87 peanut head would be fine

[crackerjack69]

the 219 head used on the bluebird sss sometime had a87 cast on them aswell as 219, so I figure a regular a87 peanut head would be fine

 

 

SSS had A87 in the usual spot and 219 on the front under the inspection plate.

[datzenmike]

To be clear the 219 head was never used on an L20B but the A-87 was on some early ones. Both had the same combustion chamber size but with different port and valve sizes. There was a fairly rare 210 peanut head that was even smaller used on the L16.

[datsunaholic]

I've never seen an A87 on a stock L20B. Early L20Bs used a U60 head, then the U67. In 1977 (for the '78 model year) they switched to the N56, N58, and W58 heads which used round exhaust ports with liners. The only closed-chamber head used on a factory L20B was the closed-chamber W58 and I have yet to find out what the application was, as every W58 I've pulled off an engine was open (but I have a closed W58 so I know they exist).

 

The PROBLEM with an A87 head is it does have smaller intake ports vs the U60, U67, W58, etc. Valves are usually the same but some (not all) have smaller exhaust valves. That means better low end but strangled top end.

[DatDoug]

I think the W58 peanut came in the 80 720's. I just pulled one from a wrecked 720 & my buddy Benny has 1 he got from an 80 720.

[Z chopper]

but I think the answer to your querie is slap the a87 peanuthead onto your L20b and drive the piss out it

[datzenmike]

I've never seen an A87 on a stock L20B. Early L20Bs used a U60 head, then the U67. In 1977 (for the '78 model year) they switched to the N56, N58, and W58 heads which used round exhaust ports with liners. The only closed-chamber head used on a factory L20B was the closed-chamber W58 and I have yet to find out what the application was, as every W58 I've pulled off an engine was open (but I have a closed W58 so I know they exist).

 

The PROBLEM with an A87 head is it does have smaller intake ports vs the U60, U67, W58, etc. Valves are usually the same but some (not all) have smaller exhaust valves. That means better low end but strangled top end.

 

It's listed in "The 620 Resource" as used on the L20B but I agree I've never seen one. I always thought it was an L18 sort of head.

 

The W58 peanut I found was at a wrecking yard on a shelf with a tag that said '79 200sx. Someone on here also mentioned having one from a '79.I have the head parts numbers for all US and Canadian 200sx and there's nothing special about the '79, in fact the number is the same as the '78 and up 620 and the A10. You would think Nissan would have a part number difference for a closed chamber... unless they are an import motor head that's been passed around from the '80s???

[datsunaholic]

Well, since there's open and closed 210, A87, and W58 heads it's apparently not much they cared about. The casting number was only the first 3 numbers of the last half of the part number anyway.

 

Open-chamber W58 heads were used in the 78-80 model year L20Bs in the US, simultaneously with N56 and N58 heads (which generally only showed up on '78s) I have all 3. The closed-chamber W58 might have been stock on a 200SX but since I've never owned one, let alone taken the head off one I don't know. You could get them at the dealer though. I have a brand-new, never installed (doesn't even have valves in it) W58 peanut, and I've seen used ones. However, the engine in my '74 620 likely came from a 200SX, as I believe the entire drivetrain did. It has an open-chamber W58 on it. I know because I changed the head gasket 3 years ago.

[crackerjack69]

The way I heard it is the laws in Japan were forcing you to retire an engine at rather low mileage. So they were imported and sold here as low mileage motors. Many of them had peanut heads from the factory in the JDM.

[datzenmike]

Doug this is the only photo I have of a 210 closed chamber head...teeny tiny valves. The open chamber 210 was 38.5cc so this has to be much smaller.

 

[Guest 510kamikazifreak]

There was a fairly rare 210 peanut head that was even smaller used on the L16.

 

 

late 68 ,69 even a "few" 70s came with them,(few and far between) .

[datzenmike]

The way I heard it is the laws in Japan were forcing you to retire an engine at rather low mileage. So they were imported and sold here as low mileage motors. Many of them had peanut heads from the factory in the JDM.

 

I think it's around 60K but they run on Km so not sure if the is Km or miles but either way it was cheaper to import a barely broken in 60K motor into N Am that to rebuild one here.The motors were usually just cut out of the cars and loaded in a container and sent. This is how the dual SU on intakes got here. I have a set of the good flattops on an intake from a late L16SSS or more likely an L18SSS motor. The choke cables have been cut just like at a scrap yard and the guy I got them from said they were in the back of a 510 he bought and didn't want them. They are in great shape and probably came over on an import motor. The thing is that these carbs and intakes didn't match anything here and the stock Hitachi would have been put on and theses thrown away. Luckily some were saved.

 

 

 

Another think that makes me think that these have never been run here is the fact that they haven't been 'de-smogged' yet. See the Kleenex stuffed in those three pipes and the big adjustment screw? These are some kind of air bleed and are removed ans sealed up.

.

[Guest kamakazi620]

I gots flat tops and running an A87 peanut gotta run 89 octane and NOT lug it up hills or it will ping,on a l16

[wayno]

I have a W58 peanut head out of a 1980 datsun 720 2wd truck, I beleave it was the original engine.

I have run a W53 closed chamber on a stock L20b for years burning regular pump gas, but I had to mess with the timing because of knocking, as my gas bill is hundreds of dollars a month, I just can't rate premium.

[Skib]

I ran a peanut head on my old L20 with regular. no problems what so ever.

[chester]

I have a W58 peanut head and L20 now. Haven't had a problem with it. I have been thinking of Putting 280zx Flat top pistons in but I dont know if I want to deal with that high of compression, since its like 10.4:1 or something like that.

[datzenmike]

10.68

[jon521]

I would say he's full of shit but he is either mistaken or believes what he's saying

 

 

The person who told you you'll blow your headgasket is smoking crack :D

 

 

haha thanks, but the guy was actually pretty cool, and besides this, he seemed to know what he was talking about. he said he has a 219 sitting around some where he might sell me :)

 

but as far as running the A87 on my L20b, it sounds like im good to go. i need to round up some cash to get it resurfaced and rebuilt by a shop, because my head gasket is leaking now........

 

thank you for your input, cant wait to put the head on ther

[datzenmike]

Do not bother re-surfacing a head unless it needs it. Your old gasket could be leaking from a previous warped head or from overheating or both. Neither ha anything to do with the peanut head. Get a straight edge and check for flatness.