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Truth or heresay? OS Giken to finally reproduce the TC24-B1 head


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You pay what you pay for new Nissan Parts. Brake Drums came from the Nissan Supply Train at some point. That is their "source" there today. NIB, maybe NOS, but they are in the new format grey Nissan boxes. Same for complete brake booster assemblies. If Nissan has it, they can get it there, they don't obsolete parts inventory like in the USA.

 

You pay the BIG ¥ for TRULY NLA items that can't be found on a parts shelf in some dealers parts shelf in the mountains someplace! Then likely you get something totally handmade, with all costs attached as discussed in this thread.

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Back on topic though, why would OSG be hesitant to run a turbo on that head? From that old youtube clip Tony D posted they were running twin turbo setups back in the eighties so i am sure its not something they haven't worked with before.

 

The ( single, then twin, then single ) turbocharged OSG TC24-B1 was nothing to do with OSG directly. It was Auto Select's project. They simply bought the TC24-B1 parts from OSG, and built their own engines using it.

 

OSG didn't make or build a turbocharged TC24-B1.

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The amount of knowledge you guys have is humbling. Where most of us can usually tell where a part goes after it falls off of our cars and on to the driveway, you guys (the hybridz.org forum) could tell us its exact specifications, where it was made, the engineer who designed it, and whether or not Albrecht Goertz had a hand in it. Great thread. Well i hope to see the TC24 back and out on the track soon.

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Categorically, Goertz didn't have anything to say/do with the S30 and especially not the OSGTC24B1!!!

 

Haha i knew that the old Goertz myth would touch a nerve with someone. I know his involvement (or lack there of) has been well discussed and has been pretty much proved that he wasnt involved in the s30 project. Just saying that if there is something we need to know about Z's this is the place to get it. Well i know a TC24B1 head is pretty much a long shot but i am hoping to save enough to at least get one of OSG superb LSD.

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Hmmmm....I wonder if OSG produces the timing gear set for the stock-style valvetrain?

 

That would be really bitchin' cool, in my opinion. And it doesn't look like a major modification to what they are using on the TC24B1Z setup.

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There are 6x gear to gear interfaces in the cam drive. How in the hell do they expect to keep that from getting sloppy FAST.

 

I wondered the same thing at first, but knew I'd seen similar in motorcycle engines so I looked around and sure enough it seems that MOST high hp motorcycle engines using timing gear arrangements that are quite similar. Granted those engines go 20-40k between overhauls... I'd imagine that as long as they kept the gears well lubricated they shouldn't wear any worse than transmission gears, but I am quite curious how well they're getting oiled and what start up wear is going to be like on them.

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There are 6x gear to gear interfaces in the cam drive. How in the hell do they expect to keep that from getting sloppy FAST.

 

You're reminding me of some of the silly comments passed when Kameari's 'Twin Idler' cam chain tensioner first started coming to the attention of the web-footed amongst us.

 

Apparently the cam chain was going to "...twang like a geetar string...", and it would all turn to sh*t in short order. Perhaps ol' web-foot would have been more used to hearing banjos than "geetars"? In any case, I don't hear any "geetars" or banjos several years later. Perhaps it's too early to tell, huh?

 

 

 

Here's another theory: Perhaps OSG ( like KEW ) know what they are doing.....

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Dealing with timing gear interfaces which have high-loadings on them for rotor timing, we normally run 0.00015" backlash on them, and 50,000 hours later they still maintain that number.

Given that the standard dyno test at full load for most OEM's consists of 200 hours which they consider equivalent to 100,000 miles I would say "How in the hell do they expect to keep that from getting sloppy FAST. " is a non-starter for a question.

If you read my comments in the other post on how tight they are at room temperature, I would say they depend on thermal growth of the engine to IMPART some 'slop' to get adequate running clearances in the valve train.

 

That, and the fact that any 'slop' in the timing gear setup even under the worst wear will still give significantly BETTER timing control compared to the BEST chain-drive setup... "Slop" is a matter of degrees. Far to much overhype of wear inducing "Slop"---best to ask the question "Compared to the stock chain-drive setup how much better will this control cam timing than even a new timing chain." Which I would say is probably somewhere on the order of being 4 to 600X more precise ESPECIALLY under deceleration.

 

Let's make no mistake about it, timing chains are a cost-driven option. They are cheap. Gears don't wear, and don't induce tolerance loss anywhere near what chains do. Chains are also quieter, a consideration in most commercially produced engines.

 

What is the wear-rate and 'slop inducement' into all those Gear Drive Conversions on Small Block Chevy Lumps sitting by the tens of thousands around the US of A. Why were they introduced? And how often to they run out of tolerance to a point where they need replacement?

 

Red Herring of a Theoretical Question, IMO.

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The Peugeot V8 has only 4 interfaces, and those Chevy V8 setups only have 2.

6 interfaces is excessive and represents a workaround at best.

 

I don't know what you're counting as "interfaces" in the Peugeot V8 aero engine. If we take "interfaces" to mean gear-to-gear meshing, then the Peugeot V8 aero engine of 1915 certainly had no less than sixteen. Eighteen if you count what was going on at the other end ( with the propellor reduction gears ).

 

And "workaround"? The OSG TC24 was/is designed around a production cylinder block which was originally designed to use a flappy chain to drive one camshaft. You could say that by definition any such conversion is a "workaround", but that's so obvious it's hardly worth pointing it out...

 

I'm struggling to understand what you think is so *bad* about multiple straight-cut gear drives in auto engines? They've been extremely successful over the last ninety years or so. Here's one example that you might have heard of: It's called the Ford Cosworth DFV ( 'Double Four Valve' ). How many "interfaces" do you see here?

 

http://www.historicengines.com/dfv/specs.html

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5 from crank to cam on an antique design. I am describing the number of interfaces that have clearances that add to inaccuracies and can also cause harmonics.

 

If the gear-to-gear tolerances are 4x as accurate as a chain then the design is worse; considering there are 6x as many gear-to-gear interfaces.

 

This could be argued in several ways but I set upon this 4x/6x example to show the uselessness of your assertions without real data or even accurate descriptions of differences between systems.

 

I would assert that a belt is a better way for a lot of reasons.

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