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New cylinder head project


Xnke

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Getting started on the P90 head I picked up a while back. This is the beginning of what I would consider a full effort street port, since working the chambers much harder than this results in limited life. I have not started on the ports yet, just worked on the chambers and the water jackets. I'm getting this going now, since i pulled my N42 off to change a suspected blown headgasket, but turned out the head was cracked between cylinders 2 and 3, right on the deck surface. This is for the M62 supercharged engine; I saw 68kpa of boost before I noticed the temps just kept climbing...

 

Valve unshrouding:

 

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Water jacket modifications...AKA "Why the hell are you drilling holes in that cylinder head?!?"

 

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Because down inside here, the exhaust port and intake port are connected with a web of casting flash. It shouldn't be there...I got in with a small drill bit and drilled and chipped out all the casting flash between the ports.

 

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Marking out for the port sizing.

 

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Intake valves will remain 44mm diameter, and exhaust valves will be cut down from LS1 exhaust valves, to 36mm diameter. The LS1 valves need to have the diameter reduced, margin thinned, 25* back-cut applied, the stems cut down by 8.3mm, and the keeper groove re-cut lower on the stem. Even with all that work, it's cheaper to buy a set of Manley LS1 exhaust valves, cut them down and re-groove, than it is for a set of Ferrea standard alloy +1mm L28 valves.

 

The circled bolt holes will get drilled and helicoiled, as they often pull out in normal service and the threads gall up occasionally too. I use 2D series helicoils for this as they are twice as long as the normal ones.

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Hate to break it to you Peter...we've been doing this for nigh on 10 years now that I know of...

 

This, combined with external water lines over #5 and #6, are how we on this side of the pond run 680HP turbo motors on the street, daily drivers. It's REALLY effective!

 

My air hammer broke, so I am dropping the head off at my machinist's to have the guides knocked back, this 'un will be getting a TK style port job. (Last one of his datto heads I read on saw him make 204CFM intake at 400 thou lift!) It doesn't look like a US port when he's done, but I can't argue with the results. Valve guide boss removed, guide tapered, ports worked to 40MM...I'll be stopping at 38mm.

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Interesting. I have two heads that this was done on, plus I do it on all my "more than street work" heads. Granted, I don't do much for many, yet. I learned about the casting flash from Rebello Racing, back when I first started in Z cars.

 

having a hard time deciding if a 36mm exhaust valve is the way to go. The seat inserts will barely hold the bigger valve, but the ID of the seat insert is smaller than the port by more than I am comfortable with. Stock valves will have the best curtain area and be the least shrouded, +1mm exhaust will be acceptable in the chamber, but only just. the larger valve will allow me to open the seat up more and remove most of the raised lip under the insert, though.

 

Any pointers there?

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That's great Alan have you got any pics ,

i have two mates that were works engine men , and they said they did not do this mod , but i shore it must have been done . there work was top stuff if any one were to do it the works Nissan team would have , 

 

i collect heads for a hobby and have some rebello heads and there full race spec and they not drilled , and i have some from japan as well none have this mod ,  Les has been around Nissan racing engines since 1977 and has not seen it , but then again we don't have 680 hp L motors , its funny how you guy got that hp from the L the works nissan rb26 did not have that when it raced hear , and our V8 race cars still dont have that at the engine , also funny how my zed is the fastest L on the time cards on hybrid z and it did it with 350kw

 

i am shore nissan did do this mod  , but id love to see a pic alan can you please try find some 

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The 680HP street-driven 280ZX is featured with dyno sheets in a few import performance mags over here, It's JeffP's over on HybridZ. It makes much more HP at higher boost levels...but most of the time, it's set up for about that. I don't even want to THINK about the money in that build...

 

Kinetic-Sunbelt engines in GA has a turn-key 600HP+ L28ET for sale, was 12K USD last I checked. It's advertised to make 600HP minimum, and they can turn the wick up for you if you need it...with an accompanying shortening of engine life. This engine is very real as I've actually layed eyes on it and seen the dyno sheet.

 

Electramotive raced a 750HP+ engine in the mid 80's over here...after the car was no longer competing, it was revealed that the engine made just north of 1100HP, Electramotive just chose to publish the HP at 7200RPM at that specific boost level, as that is what the car was raced at most of the time. For qualifying, they would turn the wick up...the engine was run up on the dyno to 8200-8500RPM, according to the dyno operator that worked on it. (this last bit was from TonyD, and I did a little follow up on it later...Seems to be correct, but I have no proof.)

 

I guess the AU-US engine building hate isn't going to come down any. Was hoping to get some insight from a different perspective, but I can get along fine regardless.

 

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Come on let's not get our knickers in a knot.

 

He didn't even come here spruiking that he made up some fabulous new technique all on his own, he was just stating what he was doing.

 

This "dumb US builder" vs "aussie backyard mechanic ingenuity" complex we have is making every interesting build thread go to sh!t. Peter stopped posting on hybrid and this guy is going to stop posting here and I am not going to have anything interesting to read while I'm at work ;)

 

Let's get over our insecurities and just stand by the work. No need for the 'we do better than you' attitude.

 

Peter the work you post says enough about your engines. The threads you post are elevating your builds into almost mythical status, you don't need to be worried about who is using/stealing your ideas or if they are even your ideas to start with. Just keep doing what your doing and I'm sure people will still want engines built by you.

 

Rant over, please let Xnke continue posting about his build...

 

 

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i have two mates that were works engine men , and they said they did not do this mod , but i shore it must have been done . there work was top stuff if any one were to do it the works Nissan team would have ,

 

I think that your idea of a "Works" engine builder, and my definition of a "Works" engine builder, are very likely to be different in this particular case. I'm talking about Japanese staff, working at Omori and Oppama ( and Murayama ) in the late 1960s and early to mid 1970s. I'm not talking about satellite operation staff, working elsewhere, and I'm purely talking about Works ( and subsequently Works-connected ) L6s from the early 1970s.

 

I collect heads for a hobby and have some rebello heads and there full race spec and they not drilled ' date=' and i have some from japan as well none have this mod ,  Les has been around Nissan racing engines since 1977 and has not seen it , but then again...........[/quote']

 

Just because you and Les haven't seen it, doesn't mean it didn't happen.

 

This is a big company we are talking about here. Even in the mid to late Sixties they were casting special heads and blocks, 'selecting' better castings and forgings, and homologating special parts to support their racing and rallying efforts. There was all sorts going on that most people have no clue about. 

 

i am shore nissan did do this mod  , but id love to see a pic alan can you please try find some

 

In short order, the problems of remaining flash and sprue in stock production heads was negated with race-dedicated castings ( some of them sand cast instead of pressure die-cast ) which didn't need the drilling / fettling / re-plugging. It's all in hand-written notes from the Works engine building staff that I have been allowed to look at and photograph. I'm not going to post any photos here. You'll just have to believe for now.

 

I'm not interested in any "our engines are better / more powerful than yours" pissing contests. I'm interested in matters historical, and the subject is far deeper than most realise. I just want Nissan's racing and rallying efforts and the work of the relevant staff to be understood and appreciated, that's all. 

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I have no problem with your answer Alan , works engine men would not have taken pics , and i know they would not have drilled a stock head lol ,  i have been building a LZ and can see how good there work was .

 

Did they ever run a N42 head or a P90  , in Japan  on a works car .

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N42, yes ( although not a 'normal' N42 casting... ) but in 'semi-Works' guise in Grand Champion series circuit racing.

 

P90, not as far as I know. Privateers used them in Japanese circuit racing though. P90 head was a bit 'late' for my focus of interest really....

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Alan, have you done, or maybe consider doing, a book, with detailed explanation and pictures, on ALL the photos, documents, notes, drawings and history on what you have in your pissession, while you are able?

 

My engine builder, of my historic Datsun Sports 2000. ( history back to 1968) has recently suffered a spate of ill heath, and is now not able to supply to me all the important details on my U20 engine. The internals of which are quite non standard. Frustrating to say the least.

Sure i can pull it down, measure it all up, but there is far more info than that, ie source of specialist parts, original vs current worn specs.

 

Anyway, maybe something to consider, i'm sure many would be prepared to purchase a definative comprehensive tome from a renowned historian.

 

Back on topic, one thing to consider, way back in the day, remember, the engines and cars were just not pushed as hard as today, they just didn't need to be, as their fellow competitors and cars were likewise at a level.

 

One thing, racing at circuits was conducted on tall bias ply tyres with far less grip!

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Geez Sinisha. You print that pic out on a dot matrix printer?  :P

 

On a side note. I'm actually quite famous in my primary school for inventing the "head lock".

True story

Point being. Just because I'd never seen it before, doesn't mean it had never been done!

 

Everyone keep posting. You're all beautiful, ladies.  :D

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Hello one and all,

 

Here is a pic of my old L28T engine from 1995, notice water manifold (black with blue lines feeding it).

This mod was done by a gentelman by the name of John Bennet.

 

cheers,

Sinisha

 

I can definitely confirm this, I know that engine went to a guy by the name of Jack Kuzior who I haven't seen or heard from in years now. I recall him talking about the custom head re-drilling and cooling mods due to cylinder #5 (my memory here) getting hot under the collar. The head was N42 casting.

 

This is the car the engine was in last I knew of.

http://www.autospeed.com/cms/A_108383/article.html

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Been having a rough time applying some of the suggestions PMC made a while back, but I have four of the exhaust ports roughed in, just the two center ports to go. Pictures later this evening, there is a very pretty girl coming out to spend a little time this evening so little to no work tonight.

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Not that kind of visit; I'm not that lucky...yet. Not for lack of effort, that's for sure!

 

She did help me go through the stash of bent files and cartridge rolls trying to find something to reach the last little bit of the short turn in the exhaust ports...there is a spot that I just can't get at yet and it's the last spot to do. After that, it's a little here, a little there, to get them all as close to identical as I can get them. (they're close, but they can get closer.) Port #1 was finished out completely, and match-up templates were made to make this job easier.

 

The intake ports, being round, are much easier for me; templates are simpler and there is less port re-shaping involved overall.

 

Exhaust ports will end up 30mm wide x 40mm tall, to match up with the header. Intakes are 38mm round; and I have 38mm templates made up from a past port job already, although they were for an E88 head...port is slightly different. P90 port is a slightly larger STR, and the valve guide bump is smaller.

 

The lower compression ratio from the larger volume will be most welcome; as going from a 42cc chamber to a 52cc chamber will drop me from 9.72:1 to 8.1:1...much more blower-friendly!

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