Valve cover differences

[GregP]

What years had which covers? For example; what should an original 72 cover look like? Was there a difference for auto vs 4speed transmissions? I really like the polished look but am I correct in assuming that this is not an original look?

Thanks,

Greg

[260Zed]

Is the coil mounted in that position normally on the L20A six?

[HS30-H]

Not on the S30-series Z.

Bear in mind that the L20 I posted a pic of was the first Nissan L-series engine, and was fitted to the 1965 Cedric Special Six. There are lots of detail differences between that engine and the L20A that was first used in the 1969 S30-series Z.

[g72s20]

I'm sure I saw a cam cover with the script "HYPER 6" in raised letters from the rear to the front on an old Nissan 6 motor (it was old then) I was offered with a Prince...~ 20 (too many) years ago. At that time I thought it was the second one I had seen. Am I kidding myself? or has anybody else in their travels seen one of these? ...or any clues??

Jim.

[texasz]

What years had which covers? For example; what should an original 72 cover look like? Was there a difference for auto vs 4speed transmissions? I really like the polished look but am I correct in assuming that this is not an original look?

Thanks,

Greg

Kinda of a trick question as the lines are quite blurry at times when you are talking about what part came stock on what car with the Z. In short here's what I know:

"NISSAN 2400 OHC" came on '69-very early '71

"NISSAN OHC" from '71 to '83 (non-turbo cars)

"TURBO" on the '81 - '83 turbo 280ZX

"NISSAN" is a JDM item and I do not know the years

"BOB SHARP" is a custom item for the Bob Sharp race team

"" I have no idea about these

[Carl Beck]

Hi Texasz (everyone)

As far as we have been able to determine to date, the switch from the NISSAN 2400 OHC valve cover to the NISSAN OHC valve cover, at least here in North America, took place with the beginning of production of the 240-Z equipped with an A/T. That would make it around 09/70 at about HLS30 089xx. For a brief time cars past that VIN arrived with either one, but we have found none with production dates later than 10/70 to have been equipped with the "2400" type. All of the A/T cars seem to have had the NISSAN OHC valve covers.

FWIW,

Carl B.

Clearwater, FL USA

http://ZHome.com

[Victor Laury]

I saw a JDM (aftermarket I think) cover with the Large block lettered NISSAN. But this cover was plastic. Les Cannaday had it in his shop and was very excited over it. As to why he was so jazzed, I didn't catch the story.

[TomoHawk]

If you removed the letters "ISSAN" from the top (later models, I think), it would just say

"Z"

[montoya_fan01]

only if you looked at it ****-eyed :paranoid:

[Carl Beck]

Thanks Alan,

Looks like an awful lot like a longer version of a Sr311 cover...perhapse the L series evolved from the changes in its engine?(not to hijack the thread...)

Will

Hi Will (everyone):

Interesting point and based on everything I can find, it would seem to hold some truth.

Lets continue the discussion a bit farther... and see if we can find out where the valve covers in question came from.....

With the merger of Prince into Nissan starting in 1965 and being completed in early 66, the development of Nissan's racing program and engine development efforts were halted, and the Prince R-380 was advanced. Prince had far more experience in both competition and the design of OHC engines... so why not put it to use. Actually the Prince G7 of 1961 looks amazingly like the Nissan L20 of 1966. (picture below as used in the Skyline 2000 GT A & B from 64 thru 67) Both in turn reflect the M/B engine of the early 50's... with intake/exhaust and spark plugs swapping sides of the engine.

One of the first design jobs the engineers from Prince (in addition to the Competition Development efforts), were assigned at Nissan, was the development of the overhead cam & associated head for the 2000 Roadster. The result was a new head with overhead cam, mounted on the older Austin derived block - aka the U20. With twin S.U's a 150HP 2.0L introduced in 67.

While all this was happening in 65/66, our friend Mr. K was lobbying Nissan Motors Ltd. for a 1600cc engine in the upcoming 510. As originally spec.'s the 510 was to be a 1300cc, but Mr. K felt that was too small an engine for his US Market. Not getting the support from the management chain in either the Design Department or the Export Department, he felt was critical to the success of the 510 in the Export market, he called on an older friend, whom he had known from MITI and who was then a high ranking Nissan Official... a Memo ordering the 1600cc engine for the 510 was drafted, signed by Mr. Matsumura and sent down the management chain in April 66. (there is a chapter about this in Halberstan's "The Reckoning". - and this is part of Mr. K's troubles with H.Q. over the years)

The L16 was thus born in 67 and introduced in the 1968 510. This is the beginning of the "L Series" engines we all know and love today. It was in fact a complete new engine design. new block, new head, new "Valve Cover". One might call it the next generation of Nissan L Series engines at Nissan; where one Parent was Nissan and the other Prince, but it was not otherwise related to their previous "L" Type engines.

In 67 when Mr, K ask for an L24 for the Datsun Z, the L16 In-line four, became an L24 In-line six. 1595cc/4=398.75cc x 6 = 2392.5 aka 2393cc. Same bore/stroke, valve train components etc. In effect the L16 with larger valves and two additional cylinders. (this kept parts inventory and mechanical training common to the two engines used in the export market). In this case the L24 might be viewed as simply the Grown Up version of the younger L16.

In 68 the Cedric G130 received an L23, which would appear to be a shorter stroke version of the L24. (bore 83/ stroke 69.7). It would be interesting to see what the block casting numbers are on these engines. In 69 the Cedric G130-U received the L24.

The L20A that by the end of 1969 was standard in the JDM Fairlady Z's. must have come into being some time after the L24 was specified and design started. Why would I think that???

Mr. Matsuo tells us in his book "Fairlady Z Story", that he had concerns that the L24 specified for the Z (around Aug. of 1967) would meet with very high taxes in Japan, thus resulting in a model too expensive to sell in the domestic market. When he expressed these concerns to Nissan Management, he was told to use the Prince S20 for the JDM market version (this eventually became the famous Z432 model incidentally). So at least we know that in Aug. of 1967 the L24 with both Standard and Automatic transmissions were planned for the Z and that the S20 was specified for the JDM by Nissan Management. The L20A must not have been around at that time - otherwise Mr. Matsuo's concerns about engine size for the JDM market, would not have existed at that point.

It would appear that by Oct. 69 the L20A had been conceived, and was already starting production, as it showed up in the spec. sheets, press packages etc. Of course in Oct. of 69 the spec. sheets/ sales brochure outlined an L24 with triple solex side drafts, 10:1 compression and 175HP for the Export Market at that time too. (sad we didn't get it as planned;-(

So our L24 Valve Covers are simply streatched versions of the L13/16 valve covers. I think there was an L16 valve cover that said "DATSUN OHC" on it. Maybe I'll try to get one, and have to modified to fit an L24. That would be a conversation piece!

FWIW,

Carl B.

Carl Beck

Clearwater, FL USA

http://ZHome.com

[HS30-H]

Wow Carl, it seems just like old times. You are spouting backward, revisionist - almost 'Creationist' - untruths and plain lies about Nissan history again.

With the merger of Prince into Nissan starting in 1965 and being completed in early 66, the development of Nissan's racing program and engine development efforts were halted, and the Prince R-380 was advanced. Prince had far more experience in both competition and the design of OHC engines... so why not put it to use. Actually the Prince G7 of 1961 looks amazingly like the Nissan L20 of 1966. (picture below as used in the Skyline 2000 GT A & B from 64 thru 67) Both in turn reflect the M/B engine of the early 50's...

You're too late. The Nissan 'L-gata' engine had already been designed, tested, productionised and fitted in cars before Prince was merged with Nissan in 65/66.

I'll just repeat a quote from you for emphasis:

Actually the Prince G7 of 1961 looks amazingly like the Nissan L20 of 1966.

Why did you choose 1966 Carl? Does that year's L20 have any special significance over and above the L20 of 1964 or 1965? Surely you are not saying that the L20 didn't exist before 1966?.......

......As originally spec.'s the 510 was to be a 1300cc, but Mr. K felt that was too small an engine for his US Market. ........

You're still looking down the wrong end of that telescope, Carl.......

..... a memo ordering the 1600cc engine for the 510 was drafted, signed by Mr. Matsumura and sent down the management chain in April 66. (there is a chapter about this in Halberstan's "The Reckoning". - and this is part of Mr. K's troubles with H.Q. over the years)

Oh dear, I can see where that is leading you:

The L16 was thus born in 67 and introduced in the 1968 510. This is the beginning of the "L Series" engines we all know and love today.

There it is. Total nonsense backed up with unrelated and irrelevant data. I find it distressing to think that people will read what you have written and treat it as historical fact, just because it comes from the keyboard of a known and trusted 'scholar' on the subject of the Z. They are being misled.

Carl, the beginning of the Nissan 'L-Gata' engine came more than three years before that. Why are you perpetuating the myth that the L16 'begat' the L24 - when BOTH of them are simply evolutions of the L20 six that was already on the test bed in 1964, and in a production vehicle by 1965?

It was in fact a complete new engine design. new block, new head, new "Valve Cover". One might call it the next generation of Nissan L Series engines at Nissan; where one Parent was Nissan and the other Prince, but it was not otherwise related to their previous "L" Type engines.

Complete bullsh*t. This is the distortion of historical facts simply to suit the 'truth' as offered by Nissan Motor Co. USA's advertising copy - which you seem to have fallen hook, line and sinker for more than 35 years ago. How can you say that they were "unrelated"??!! This is complete nonsense. Its just laughable.

Just how you seem to think you can draw an arbitrary line of demarcation across a clear timeline of evolutionary development - for the sole purpose of supporting a lie - is shocking and shameful. I thought you had learned some fresh history about the true evolution of the Nissan 'L-Gata' engine on this forum over the last few years, but it seems not. Now you are simply distorting the truth to make it fit other lies.

And it goes on:

The L20A that by the end of 1969 was standard in the JDM Fairlady Z's. must have come into being some time after the L24 was specified and design started. Why would I think that???

Yes - indeed why?

Would it perhaps be related to the fact that you obviously know next to nothing about the origin, design and production history of the Nissan 'L-Gata' engine? Would it possibly be related to the fact that your version of 'Z history' on zhome.com for some inexplicable reason completely ignores the Japanese home-market L20-engined cars? Is that a clue? Only you know the answer.

I remember you telling me that you thought the Japanese L20-engined cars were "irrelevant" to the history of the '240Z'. A clear demonstration of the way you approach the history of the S30-series Z. Quite bizarre.

Mr. Matsuo tells us in his book "Fairlady Z Story", that he had concerns that the L24 specified for the Z (around Aug. of 1967) would meet with very high taxes in Japan, thus resulting in a model too expensive to sell in the domestic market. When he expressed these concerns to Nissan Management, he was told to use the Prince S20 for the JDM market version (this eventually became the famous Z432 model incidentally). So at least we know that in Aug. of 1967 the L24 with both Standard and Automatic transmissions were planned for the Z and that the S20 was specified for the JDM by Nissan Management. The L20A must not have been around at that time - otherwise Mr. Matsuo's concerns about engine size for the JDM market, would not have existed at that point.

You obviously misunderstand the situation here too. Matsuo was indeed worried about going above the 2 litre taxation class in the Japanese market ( and it wasn't just Matsuo of course....). However, what you don't seem to have grasped is that the S30-series Z was slated to have both the L20 and the L24 for the Japanese market at that point - with the L24 also being used for 'Export' versions and a Japanese home market 'peformance' model ( in fact, the decision to use the L20 engine in the Z predated the existence of the L24 engine ). This was quashed by higher management who wanted to make the 'performance' home market model use the S20 twin cam - which would give them a prestige high performance model that stayed within the 2 litre taxation class.

How you can imagine that the L20-engined Z didn't come into being until after the L24-engine had been specified for the Z just demonstrates that you always have the cart before the horse. I can't help thinking that this is further evidence of your desire to 'prove' that the HLS30U was some kind of Z genesis, and that you are prepared to distort the facts in order to 'prove' it.

It would appear that by Oct. 69 the L20A had been conceived, and was already starting production, as it showed up in the spec. sheets, press packages etc.

Duh.......

If you took the time to research it properly ( and that means from Japanese sources, you would see that the L20A was already powering many of the cars that were sitting in the car park at Nissan's Japanese press-preview event for the S30-series Z in October 1969! At that point, it had been around for the best part of five years..........

Some recommended reading for people who are interested in the true history of the Nissan 'L-Gata' engine. Unfortunately, it is written in Japanese - but that should not be a surprise, surely?:

*'Ten Years Of Japanese Engine History' - by Eizo Ikeda. Published in the February 1972 issue of 'Motor Fan' magazine ( Japan ).

*'Secrets Of The Nissan 'L-Gata' Engine' - Published by Sankaido Motor Books ( Japan ) 2005.

*'Interview With Mr Hiroshi Iida - Designer Of The L20-type engine' - written by Manabu Kumano. Published in issue no.102 of 'Nostalgic Hero' magazine ( Japan ) - April 2004.

I'll just finish off by posting this picture, which depicts the L20 six as fitted to the 1965 H130 'Cedric Special Six'. THIS engine was the true evolutionary ancestor of 'our' Nissan L-series engines:

Alan T.

[texasz]

Just came across this link which shows a new valve cover which I have never seen before, the "NISSAN 2000 OHC" http://www1.odn.ne.jp/yooopage/myskyline-engin_cover.html