The Three Litre Thread

[SLY33]

please continue 3 litre discussions here

..i believe it was johns OS motor that went to AED.

..i dont think the price for the OS 3 litre is by any means expensive if you plan on using its potential!

cheers

[Gav]

I'll transfer my queries from the other thread:

How suitable is the OS 3 litre block to being used in a road car application?

Are there under bonnet (or other ) clearance issues when fitting to an otherwise standard engine bay?

[R31Nismoid]

this is almost a merger with the RB30 one isnt it?

see how it goes... if it becomes to similar it gets merged. Keep it to OS 3ltr only

[bfi.inc]

I'll transfer my queries from the other thread:

How suitable is the OS 3 litre block to being used in a road car application?

Are there under bonnet (or other ) clearance issues when fitting to an otherwise standard engine bay?

<{POST_SNAPBACK}>

sits about an inch higher in engine bay.Not a drama.As for a road car application?Keirs with the TD05s was frightening.Keirs words were after first drive along the lines of "it is like comparing a big block to a mini".(ie original bore motor.) Even with the tdo5s,his initial burnout at the drags consisted of sitting stationary,selecting fourth,and sliding the clutch.

[R31Nismoid]

GTR here pumping 500-550rwkw as a circuit car.

Its not been pulled down since it was done approx 3 years ago (from the other thread) i'd hardly say the Aus RB30 bottom end is weak or not upto the task

Depends possibly what the application of 3ltr is maybe? I dont know if anyone has done a big power drag GTR with the Aus 3ltr.

Certainly no shortage of VL's _

[Sydneykid]

The OS 3 Litre has some advantages and some disadvantages, the most obvious advantage is it uses the N1 RB26 4wd block, arguable the best RB block casting to use in a high boost, high rpm environment.

Other than its exorbitant cost, the big disadvantage of the OS 3 litre is it poor stroke / rod length ratio (1.65 to 1). This is because OS used the RB26 (121.5mm) rod with the 86 mm stroker crank. That's why the block is only 18 mm taller than an RB26 and an RB30 is 38 mm taller. The RB30 rod length (152.5 mm) gives a much more favourable rod / stroke ratio of 1.79 to 1.

Personally, if I was building a high boost, high rpm, 3 litre, drag engine I would use an N1 block with a 38 mm spacer and 152.5 mm rods. That way I would get the advantages both without the disadvantages. It would make more torque and rev just as hard with a forged crank, rods etc. Plus I reckon it would cost around half what an OS 3 litre costs.

cheers

[Sydneykid]

The other thread was getting interesting and I wanted to continue the flow, so I have copied the last couple across.........

If you put an RB30 in a GTR with any big sort of power, see how long it takes to crack the block. An RB30 block wasn't desgned to have the load of a front diff hanging of the bottom of it. I know of a few people that have tried to run decent power with them and they don't last.

A bread and butter BNR32 05U block will handle 700-800PS any day.

I reckon they are a good option in a rear drive skyline or maybe in a reasonable mild GTR...but not for any serious power.

And what you say about the Giken engine not having spot on clearances...what is spot on? Were they too big or too small? Bearing clearances or piston to bore? I reckon they would be set up with about 2 thou on the bore and 1.8-2 thou on the bearings.

And you think that 20k is expensive for a decent engine? Try to buy the parts for it...a decent crank is 5 grand plus. Another 4 grand for a run of the mill nissan block, a couple of grand to get it sleeved. Add another 2.5g for decent yankee rods. Pistons and rings of any sort are $1500. Then you've got all the fastners and spacer plate.

Then you've got the machining costs and the labour to assemble it. And have you ever seen some of the Japanese assembly rooms? Climate controlled to 273K and 1 atm pressure. Absolutely spotless with assemblers in white coats. And then you say the clearances weren't spot on?

My 20 cents, questions and suggestions;

1. What's "serious power"? 700 BHP, 800 BHP, 1000 BHP, 1200 BHP, More ?????

2. It's not a question of WHAT clearances, but CONSISTENT clearances, if OS decide 2/1000 is OK on the mains, then I have no problem with that. What I do have a problem with is is measuring #1 at 1.93, #2 at 2.04, #3 at 1.97 #4 at 1.96 #5 at 2.03 and #6 at 1.96. That's unacceptable.

3. What's a "reasonable mild GTR" ? Is it one with 250 rwkw, or 300 rwkw or 400 rwkw? A stock standard RB30 block will hold 750 bhp all day.

4. Have you seen the combo 4wd sump adaptor and main bearing support for an RB30? I have no doubt that it would easily hold up the 30 kgs that a 4wd sump and driveshafts weigh.

5. Have you actually cut up an RB30 block and compared it with an RB26 block? There is not as much difference as some people would have you believe.

6. Prices change every day, as more and more Skylines/RB's find their way to the US and the exclusive supply agreements with the Jap brand names run out. I can get an 86 mm forged crank for ~$US2,000, a 200 bhp capable conrod is ~$US110, forged pistons with rings are ~$120 each. It has gotten so a 1200 bhp RB30 botom end shouldn't cost more than ~$10K.

7. (As posted elsewhere) The OS 3 Litre has some advantages and some disadvantages, the most obvious advantage is it uses the N1 RB26 4wd block, arguably the best RB block casting to use in a high boost, high rpm environment.

Other than its exorbitant cost, the big disadvantage of the OS 3 litre is it poor stroke / rod length ratio (1.65 to 1). This is because OS used the RB26 (121.5mm) rod with the 86 mm stroker crank. That's why the block (with spacer) is only 18 mm taller than an RB26 and an RB30 is 38 mm taller. The RB30 rod length (152.5 mm) gives a much more favourable rod / stroke ratio of 1.79 to 1.

Personally, if I was building a high boost, high rpm, 3 litre, drag engine I would use an N1 block with a 38 mm spacer and 152.5 mm rods. That way I would get the advantages of both without the disadvantages. It would make more torque and rev just as hard with a forged crank, rods etc. Plus I reckon it would cost around half what an OS 3 litre costs.

8. The other RB's with 2.7 and 2.8 litre capacity suffer from similar issues. If they had better rod/stroke ratios they would produce more torque at lower rod, crank and block loadings. Or more torque at the same loadings.

There are many factors involved and it can't be simplified down to one block is better than another.

Yep...that's very true. One problem though. The tolerences you are talking about are tiny.

One hundredth of a thousandth of an inch (0.000001") is 0.000254mm which is a quater of a 10 thousandth of a mm.

No one can measure to that tolerance with mechanical instruments.

Every race engine builder I have ever spoken too (including one that builds top fuel engines) would be more than happy with +/- 0.05 thou on a 2 thou clearance.

cheers 

OK, so I will change my example to...........

2. It's not a question of WHAT clearances, but CONSISTENT clearances, if OS decide 2/1000 is OK on the mains, then I have no problem with that. What I do have a problem with is is measuring #1 at 1.3, #2 at 2.4, #3 at 1.7 #4 at 1.6 #5 at 2.3 and #6 at 1.6. That's unacceptable.

What about the rest of the post, I would be interested in some feedback on the logic?

cheers

Edited December 8, 2005 by Sydneykid

[R31Nismoid]

Thanks SK.

I will move/merge from the original posters etc later tonight myself and i'll edit your post "if" i can get it working, not sure yet.

I sure you wont mind. This thread gonnd get real good

[djhatton]

Thankyou.In my comments,i restrained from openly criticising a workshop or actually naming them in regard to reworking an OS motor.I felt it important though to correct the "WILLALL " reworked the OS motor issue.A good example of why threads such as EG: "is this workshop any good" should be deleted immediately.Comments such as "i heard willalls had to rebuild OS motor" which are ill informed can have repurcussions on the named workshop.For instance,should i read that comment in ignorance,i may conclude that Peter Hall believes he knows more than OS GIKEN.Fortunately,i know that not to be true of Peterand Keir.In fact,when Keir levered open the crate,Peter ,keir and I were stunned at the metallurgy and workmanship of the OS motor.Peter Hall is a fastidious and talented engine builder who openly acknowledges the Japanese craftsman.

<{POST_SNAPBACK}>

20k really isn't that much when you talk about big power. Ask someone who's built an 800hp 350 Chev how much it owes them.

Also, there are no right and wrong clearances...it all comes down to a comprimise and a judgment call.

<{POST_SNAPBACK}>

ok i'll straighten my post out a little

bfi.inc, i am absolutely not criticising the willall workshop. i've heard nothing bad about their work. nor did i state that the engine had to be "rebuilt" - i.e. it broke. i read that one user of the os 3l (and i can confirm that it was munro to stand corrected on that) had his os engine disassembled and was reassembled differently because the tolerances were less than desirable. may have been an unlucky engine to come out of the crate... who knows. i have no doubt the quality of each individual part is awesome, but the assembly was not up to the standard of the goodies lurking within (according to AED). i still stand by my belief, regardless of who makes it, if it aint perfect, i wouldn't be happy.

and mik, relatively, 20g may be awesome value for money in the breakdown of parts. i'm not disputing that. sure, $20,000 isn't a lot in comparison to what many people spend on their engines (i know one rb26 here in canberra that was built on stock capacity/crank/block that cost the owner in the vacinity of $15large) but its still $20k and i'd want perfection for that.

either way the os is a phenomenal thing and on my dream list. one day maybe...

my 2 yen

d

Edited December 8, 2005 by djhatton

[NXTIME]

ok i'll straighten my post out a little

bfi.inc, i am absolutely not criticising the willall workshop. i've heard nothing bad about their work. nor did i state that the engine had to be "rebuilt" - i.e. it broke. i read that one user of the os 3l (and i can confirm that it was munro) had his os engine disassembled and was reassembled differently because the tolerances were less than desirable. may have been an unlucky engine to come out of the crate... who knows. i have no doubt the quality of each individual part is awesome, but the assembly was not up to the standard of the goodies lurking within (according to AED). i still stand by my belief, regardless of who makes it, if it aint perfect, i wouldn't be happy.

and mik, relatively, 20g may be awesome value for money in the breakdown of parts. i'm not disputing that. sure, $20,000 isn't a lot in comparison to what many people spend on their engines (i know one rb26 here in canberra that was built on stock capacity/crank/block that cost the owner in the vacinity of $15large) but its still $20k and i'd want perfection for that.

either way the os is a phenomenal thing and on my dream list. one day maybe...

my 2 yen

d

<{POST_SNAPBACK}>

Exactly how did they come to disassemble a brand new 25K engine? And why?

[djhatton]

??? who knows. perhaps they just decided it would be a good learning experience, only to discover it was out of whack. perhaps they were just curious??? i'm not too sure i thought it was a bit premature too, opening an engine that'd never been turned over let alone fitted to a car... but they did!

d

[Mik]

The other thread was getting interesting and I wanted to continue the flow, so I have copied the last couple across.........

OK, so I will change my example to...........

2. It's not a question of WHAT clearances, but CONSISTENT clearances, if OS decide 2/1000 is OK on the mains, then I have no problem with that. What I do have a problem with is is measuring #1 at 1.3, #2 at 2.4, #3 at 1.7 #4 at 1.6 #5 at 2.3 and #6 at 1.6. That's unacceptable.

What about the rest of the post, I would be interested in some feedback on the logic?

cheers

<{POST_SNAPBACK}>

Sorry mate...was at work and didn't have time to reply fully...will do later.

Yep...that much variation would be adsolutely shocking. But I'm not sure how you could get it that bad even if you tried. Nissan work to 3 one thousandths of a mm tolerance which is about a 10 thousandth of an inch. I assume Giken use a new block, so the tunnel would be fine. Don't know what bearings they use, but even the aussie ACLs I used measured up pretty good (less than 0.005mm variation in shell thickness).

I'm guessing if someone truely did strip a Giken short engine and rebuilt due to bad clearances, I think they would have been of the opinion that 2 thou (assuming that's even what they use) is too small. Most people form the old school laugh at you when you tell them you will be running 8000rpm and 700hp with 1.8 thou clearances.

Just another interesting point. The guy we use to do cranks checked my new jap crank fro starightness befiore I used it. He said it is the straightest new crank he has ever seen out of the box. He said that most yankee cranks ( mostly v8s) usuallly have a couple of thou runout.

Edited December 8, 2005 by Mik

[Mik]

The other thread was getting interesting and I wanted to continue the flow, so I have copied the last couple across.........

OK, so I will change my example to...........

2. It's not a question of WHAT clearances, but CONSISTENT clearances, if OS decide 2/1000 is OK on the mains, then I have no problem with that. What I do have a problem with is is measuring #1 at 1.3, #2 at 2.4, #3 at 1.7 #4 at 1.6 #5 at 2.3 and #6 at 1.6. That's unacceptable.

What about the rest of the post, I would be interested in some feedback on the logic?

cheers

<{POST_SNAPBACK}>

okay...

1. By serious power, I meant 700-800ps. I have never tried it, but from what I have heard from a couple of people who have, the blocks crack around the ribs at the bottom. They seem to now like the stress off the from diff bolted to the bottom of the block. Not sure if all RB30 blocks afre the same???

I reckon an RB30 would be good in a street driven 500-600hp GTR with 2430s / 2860s / groups A turbos to make the same power as it would with a 2.6 with a lot less revs. Whether or not it is worth the hassle of fitting, I don't know.

2. See above post

3. See 1.

4. A hyundai Excel engine would hold the weight of the sump/diff, but what about the torsional load?

5. Never cut one up, but have had a good look. They are quite different. Also, the RB26 blocks have a different metalurgy...higher Mg content.

6. Your prices are interesting. A US$2000 forged crank is a bargain. Had I known that, I may have taken a different route with my engine build.

The cheaoest US made pistons / rings I could find were about US$160 a pop.

$110 a pop for rods is dirt cheap...they must be Chinese for that?? What brand? Carillo / Pauter / Crower / Arrow are far more than that.

Your comment about the Jap agreements is an intersting one. I too used to believ that the Jap gear came from the states, but I have seeen severl Jap branded cranks that are stamped with made in Japan.

It's a common concensus that HKS/Trust rods are Carillos, but they are not. They use ARP fasteners and speak to Mr Carillo himslelf...he will not touch ARP...only SPS.

Similarly, Tomei pistons are very different to anything form the states. Nice long skirts, made for 2 thou clearances. The bloke that bored my block was so impressed with the pistons that he wanted to know if they made anything to suit a 350 Chev for his sprint car engines.

7. Agreed, but the GT block is supposedly even better.

I agree with you fully about the rod ratio, which is why I was thinking about using custom rods and pistons to get a bigger rod ratio for my engine. But, when it somes down to it...the Jap stroker kits happily rev to 11krpm plus and don't smash piston skirts. Again a 350 chev builder would laugh at you if you told them you can do that with a 1.6 rod ratio.

The big problem with the 38mm spacer is how do you fit it in the car? I know there is no chance in a BCNR33 or BNR34, never really had a close enough look on a BNR32 though. I'm not real keen on droping the sub frame.

[R31Nismoid]

RB26/30 using RB30 is a fit into a GTR i believe

Its only an issue in a 33-t when using a stocker plenum

[bfi.inc]

ok i'll straighten my post out a little

bfi.inc, i am absolutely not criticising the willall workshop. i've heard nothing bad about their work. nor did i state that the engine had to be "rebuilt" - i.e. it broke. i read that one user of the os 3l (and i can confirm that it was munro to stand corrected on that) had his os engine disassembled and was reassembled differently because the tolerances were less than desirable. may have been an unlucky engine to come out of the crate... who knows. i have no doubt the quality of each individual part is awesome, but the assembly was not up to the standard of the goodies lurking within (according to AED). i still stand by my belief, regardless of who makes it, if it aint perfect, i wouldn't be happy.

and mik, relatively, 20g may be awesome value for money in the breakdown of parts. i'm not disputing that. sure, $20,000 isn't a lot in comparison to what many people spend on their engines (i know one rb26 here in canberra that was built on stock capacity/crank/block that cost the owner in the vacinity of $15large) but its still $20k and i'd want perfection for that.

either way the os is a phenomenal thing and on my dream list. one day maybe...

ok.now it is all out in the  open.AED charged john $7000 to rebuild the motor.(much to mark Tilbrooks surprise). Since then john has AED rebuild another couple of RB"S and neither got past the running in stage.

my 2 yen

d

<{POST_SNAPBACK}>

[bfi.inc]

??? who knows. perhaps they just decided it would be a good learning experience, only to discover it was out of whack. perhaps they were just curious??? i'm not too sure i thought it was a bit premature too, opening an engine that'd never been turned over let alone fitted to a car... but they did!

d

<{POST_SNAPBACK}>

you dont know so why speculate. I do but cant be bothered.Its easier to let the crap,regular slander,uninformed and uneducated opinions blather away(some notable exceptions).

[chops]

bfi, is it Munro's current engine that was "disassembled"?

If so, I can think of a pretty good reason too, but it may not be free for public info yet.

Edited December 8, 2005 by chops

[9krpm]

Anyone on here vouch for AED?

I and some local pple certainly DO NOT

Interesting read regarding hte OS3L....thanks.

Did someone say that the T517z 8cm is too small for the 3L? Why is this and how does a T517z 10cm be better *scratch head*?

[R31Nismoid]

because they are too small. thats why people said it

more commonly used on 2.6 and they arent the best turbos if your afer anything resembling response

[rev210]

Someone mentioned different metalurgy on the RB26 to the RB30.

Call me skeptical but, I would have thought that the Nickel casting process used by all nissan 'B' blocks (from the B in RB) would be fine for all of them. The differences in the regular and N1 blocks is ribbing and no mention of metalurgy?

If there is more Mg then tell us what the concentration is in each block and where the source of information is?