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Another DOHC L6 head [pic heavy]


josh817

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In school we learn that building a database and knowledge base is the first step to design work. Gathering relative information and lessons learned is the key to not reinventing the wheel and repeating mistakes. Let this be your database. You will have to read his blog to build your knowledge base (lessons leaerned).

 

I stumbled over this. I beleive it's RB26 based but I don't think related to the PMC member on here (Peter?).

 

Take a gander, maybe it will stimulate your engineering senses.

 

Work your way up from page 6. I will post some highlights of the head and cam timing. The man does spectacular work, making the head, intake, and headers. Send him some love by visiting his blog.

http://spark88.blog.fc2.com/category60-5.html

 

 

He started out with a prototype which is why you see the timing gears switched to the other side. Limited Japanese translation translation...

 

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Edited by josh817
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I forgot to mention he did the same thing (RB26 head) without the gear drive.

 

I think PMC Peter made a comment about the gear drive just being a hassle but I can't be certain. I thought I remember him saying he had a customer that was actually removing the gear drive in place of a timing chain. I won't go there though... :P

 

http://spark88.blog.fc2.com/category50-6.html

 

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Edited by josh817
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So now what's the advantage of this vs. a fully functioning ITB rb25/26? It's not like the L bottom end is so superior, nor are rb20 bellhousings hard to find, neither are motor mounts expensive to fab?

 

My first thought would also start with the fact that rb heads have to be ported, there's tons of expense to upgrading them for higher lift cams, high rpm etc.... this is why rb's are moneypits, they nitpick you to death on the smallest changes, because there's just so many.

 

By contrast, Derek can make a pre-ported head designed for any high power application, either large port throats for high lift cams, or narrower high velocity ports for long duration low-lift de-strokers, that only need a little basic cleanup to be plug-n-play.

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By contrast, Derek can make a pre-ported head designed for any high power application, either large port throats for high lift cams, or narrower high velocity ports for long duration low-lift de-strokers, that only need a little basic cleanup to be plug-n-play.

 

When that's a proven, commercially viable and commercially available "plug-n-play" product, give us a call back....

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Of course none of this makes sense financially when you can plop in other conversions. I doubt Derek is doing his work to make a great deal of money. A lot of us find this odd joy in designing/building stuff.

 

 

When I was younger, my father would go through cars like candy. He would buy a heap, spend 2 years restoring it, a month driving it, and then sell. He has no interest in driving them!

 

The cool factor is the main driver too.

 

 

Right now I'm trying to understand this:

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In the other pics he had cut a cross section off the front (to even it out with the block) which broke into two oil plugs and a water freeze plug (it appeared). I'm guessing this front plate was RTV'd on to block off the water jacket with those 5 holes remaining open for oil drainage?

Edited by josh817
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Not understanding your question, rephrase?

I believe what he is saying is that it is very easy to get an L28 block bored to 3.0L or 3.1L with crank whereas doing so with an RB block is not as straight forward, thus justifying the convenience of taking an RB head and putting it onto an L series block.

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I believe what he is saying

 

Yea dealing with Tony for the last 2 years had me saying that to myself more than once:) Talk bout cryptic.

 

I stumbled across this guys blog when I was doing the initial research on the head. I was amazed the stuff he was accomplishing working out of what looks to be a portable canvas garage and an old enclosed trailer. I looked at his approach like something artisanal where is my approach is more production. 

 

And it looks like he got his done before me:)

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Josh has it correct. The questions being posed have to be viewed as purely rhetorical to keep oneself sane.

Anybody who has done any research whatsoever on the RB knows taking and RB 26 to RB 28 is NOT a simple proposition.

 

And short of sourcing an RB30 SOHC Block from Oz to make an RB30+.... Going any bigger is indeed a costly, huge undertaking.

 

It literally is easier and cheaper to make it from an L-Series bottom end.

 

I posed the question just as it was stated. Your lack of response shows you haven't done your homework to ask what you did, otherwise it would not have been phrased that way.

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Yea dealing with Tony for the last 2 years had me saying that to myself more than once:) Talk bout cryptic

Charles has a broken elbow.

Lovers meet at midnight.

The parakeet wears a yellow rain slicker.

Yes, we have no bananas.

My hovercraft is full of eels.

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Thanks for the insult, I'll read it when I'm dead...

 

I wonder what your problem is with an rb30 + rb26 head? It can be done in an hour, except for the numerous little upgrades you'll no doubt want to do while it's open.

 

It's not like the rb30 blocks aren't plentiful down under, and sea freight is pretty cheap... it would likely be a non-turbo higher compression block, but apples to apples, you'd want new pistons anyway.

 

So tell me again how ordering an rb30 is more expensive than modifying the rb head and l28 block to interlock?

 

Now aside from that, you can just as easily order a stroker crank for the rb as you can the l-series, neither is cheap, but it's the "easy" way.

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Well the 26 head is a bit more difficult than the 25, neither has been done in an hour from what I can tell.  Most guys probably won't do their first one in a day.  Last I checked it was $1500 to ship a pallet from OZ to ATL which is less than that horny guy would make on the way better head.  I think some folks are looking at this wrong any way... It is not that the rb head is an upgrade to the L28, more like an L28 bottom is an upgrade for the RB.  Here's to a 25 year legal R32 with a 3.3L, Merica!

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That's what I'm asking, what's the advantage of the L bottom end vs an rb30 with forged rods/pistons? And then what's the advantage if both got a brian crower stroker crank for example?

 

The comparison ignored any of the common changes you'd have to do to both setups, so don't jump all over me for missing facts; mod for mod the costs seem fairly similar to me. And we can ignore any janky rtv sealed timing housings...

 

The rb25de (ie. non-vvl head) would take the least effort, but I assumed you'd want the ITBs for apples to apples...

 

The NEO head would require the most work, for the most gain too perhaps?

 

PS. I looked into importing an rb30 (or a few) a while back, and with my accounts and I got around $900 estimated shipping.

Edited by G-E
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You didn't state that in your original post.

 

The RB 30 is easier than trying to make an RB26 even a 2.8... Much less 3.0. The Neo25 head is cheap, plentiful, and works just as well on an RB30 block though...so there goes the Mystic RB26 head optimised for forced induction.

 

There is just one problem for everyone in America, and Japan: Neither place has RB30's and BOTH places HAVE thousands of 3 Liter L-Series bottom ends running around CHEAP.

 

Hence, putting the head on the cheapest item you have available, and can get ready replacements for.

 

This is a semantic argument by sticking to the RB30 (again, not mentioned originally) which continues the problem of parts availability, fittment in chassis, etc...

 

The L28 fits the chassis available, is cheap, and parts are readily available to 3.2 or 3.3 L 

 

Anything on an RB30 will be custom, custom, custom and cost cubic dollars.

 

It really is easily seen if you look at it and don't have an agenda.

 

And I know people who imported RB30's and did the head conversion in SoCal. For me it's not an internet exercise. Shipping via CFR Rinkens on non-priority contanerised shipment is five engines packed/stacked in crate $500 (basically put the engines in a motorcycle shipping crate.) If you demand point to point service and insist on immediate departure instead of sharing space with other people's load, the price can indeed easily double. I'm never in a hurry when it comes to shipping.

Edited by Tony D
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In canada we don't have an abundance of L blocks, so we'd need to get something from a hoarder, or shipped from somewhere else, and shipping via truck is easily as expensive as sea+train, so there's not much plus side.

 

Add to that, rb26's are the most commonly blown up, it's just a side effect of the target market, so while we have plenty of skylines running around, rb25's are more often sold as complete units, rb26 heads are regularly available on their own.

 

I don't have an agenda, I have a point of view, I seem to see a different picture than you, that doesn't make it wrong.

 

As for everything being custom on rb30? Dunno where you got that, most parts interchange with other rb's just fine, or in many cases use the same parts as the common vg30, like bearings... unless you're worried about a "custom" oil pan you can find from a 200zr in aus/nz with the engine, get RIPS to make you one, get in steel from enjuku, sheet aluminum from mckinney, or get a cast aluminum one from whitehead up here?

 

Mechanically there's really nothing special about the rb30, but I don't see the L blocks being special either, both are strong, both are heavy...

 

If the modification cost of the head as per the original post is greater than importing the necessary parts, the clear advantage is to the rb block.

 

And then we're left with the rotating mass increase on the hybrid from the timing parts, whereas the rb30+dohc can get the longer gates racing timing belt from enjuku or rawbrokerage, I'd say this could be an advantage to the rb again.

Edited by G-E
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