OK - so I got this diesel motor....

[rayaapp2]

LD28 rods = Forged same as other L series....

 

For anyone saying they cant find L20A E etc... 6 cylinder L series 2L, I cant seam to sell my bottom end for $150, but if it is so rare and hard to find maybe I should be charging more... I have seen several of them in the greater Sacramento Ca area in the past 2 years on CL.

 

LD28 block and crank combo make a good gas stroker combo together with large bore... Its just not any easier to build than a regular F54 casting... when you compare the cost vs strength game. So its whatever floats your boat.

 

 

DAW contact 1fastz for his sonic testing info...

 

 

TonyD If you go with the 5spd I could use the 4spd auto... My Datsun Maxima is a 3psd Auto. It would be nice to have the spare anyway.

Edited June 8, 2010 by rayaapp2

[Tony D]

For one I don't KNOW that the rods are cast, I just thought I read that they were cast, hence the If I Recall Correctly. Also IIRC, Nissan forged the rods because it was more expensive at the time to cast for some reason. I could be way off base, but that's how it goes when I think I think I read something somewhere

 

Please stop that...

[e_racer1999]

Please stop that...

OK!

[DAW]

The LD28 rod is basically an FJ20 rod except with a larger wrist pin. This is why I question other anecdotal info about the LD28 that I read...that an engine with 21:1 c.r. or so, would have weak internals or thin cylinder walls. I'd sure like to see some sonic testing data.

DAW

[Tony D]

as referenced Bryan Blake (1fastz) claims to have done some sonic testing on the LD, but I don't know if the numbers are published anywhere. I know he has the equipment to do it at the shop, and it's how he found shifted cores and corrosion in the water jackets on the other blocks he was boring.

Edited June 9, 2010 by Tony D

[DAW]

Thanks, Tony D, I PM'd him and asked about the sonic testing.

DAW

[rayaapp2]

Just try to get the L20ET turbo, same internals as the L28ET, but with a .48 A/R housing, meaning full boost is available at well under 1700 rpms on a diesel.

 

Yes, I have a penchant for JDM stuff that wasn't available here. But that appears to be the correct A/R for the LD28 (at least I'm betting on it, I got three of them in a milk crate two months ago for my LD28T conversion of a 77 280Z Coupe in my back yard!)

 

My quandary is wether to keep that tasty diesel four speed autobox on there for my daily commuter duties, or go with the spare ZX Box I have laying around... Decisions, decisions...

 

If this is totally side tracking the conversation I apologize and any further replies will be done via PM or email.

Tony, You have mentioned this turbo setup to me before. Im curious because you go onto mention where you think full boost will be available to you with this setup on an LD. Is it because you have a good idea based on other engines youve seen and you generally have a good idea how certain sized turbos work with engines in general or is it much more in depth? I ask because I know how to figure out VE(volumetric Efficiency) for a gas motor, but its been a total guessing game to try and figure out the LD... Any ideas where I might find VE for the LD?

 

Thanks

[Tony D]

? on the VE.

 

The European LD Turbos use a .48 A/R exhaust housing. Some on the forums have poo poohed their existence, but they do exist. Just kind of rare now...

[kiwi303]

Some on the forums have poo poohed their existence, but they do exist.

 

LD28T's are in NZ in some of the older diesel cars and patrols as well, seen at least one LD28T patrol on Trademe in the past and I believe a TD maxima was available.

[Tony D]

To say I would kill for one of the properly calibrated turbo pumps, the manifolds and turbo would not be an overstatement of the facts in this case...

[kiwi303]

Would you buy a boat just to get your hands on a LD28T? http://www.trademe.co.nz/Trade-Me-Motors/Boats-marine/Motorboats/auction-253871719.htm

[DAW]

No response from 1fastz; does anyone else have sonic testing data comparing the L28 cylinder thickness to that of the LD28 block?

DAW

[ezzzzzzz]

No response from 1fastz; does anyone else have sonic testing data comparing the L28 cylinder thickness to that of the LD28 block?

DAW

 

I've built a petrol 2.8 using the LD block and crank, L20B rods, JE pistons and a P90A (mechanical) head. It is nearly square, has a great rod/stroke ratio of about 1.73 and compression at 8.3:1. It was no easy task to figure everything out. There are coolant holes to tap and fill, head bolts to resolve (of which I have worked it out for those that might follow this path), etc. Prior to the machine work I did some measuring of bore separation at the head gasket surface and the gap between the cylinders (through a freeze plug hole). Somewhere in here is a post of that info in some detail. The bottom line is there is enough material to punch out a cylinder about .040. After that it starts getting thin. I only went .020 over so I could do another rebuild if it ever came to past. The stock bore of the LD is 84.5mm. I went to 85mm. There is no possible way to get out to 89mm (or even 87mm comfortably). There just isn't enough wall to work with. I suppose you could sleeve it but the cost would be crazy for the results gained. My 'stroker' 2.8 is going to be SC'd when I get back to finishing the intake, bracketry and pulley system.

[fhptom]

With all the success of Audi & Puegot in the 24hrs of LeMans I would love to take a complete Maxima diesel setup and put it in a z car and then give it to Gene Banks as a challenge to turn it into a screamer like he has done with so many other diesel motors/cars. His Banks Performance team has resources to solve a lot of the issues that seem to arise from this discussion and he always seems to take these challenges personal and does not like failure.

 

Tom

[Tony D]

There is no possible way to get out to 89mm (or even 87mm comfortably). There just isn't enough wall to work with. I suppose you could sleeve it but the cost would be crazy for the results gained.

 

Then you shouldn't say it can't be done.

 

Your logic for not sleeving an LD Block for displacement INCREASE is the EXACT same logic I was arguing above for using a STANDARD L-Block with an L20A crank on a displacement DECREASE for 'rod/stroke maximization'....

 

So now I can play a particularly pernicious devil's advocate and say the logic works for BOTH arguments: if you disalow sleeves for displacement increase, then using an LD Block to convert to gas for a set 2.5 or 2.6 displacement has no advantages over simply using a standard L28 Block as you get the same R/S ratio with the L20A crank!

 

This took a long time coming, but I'm glad you guys finally saw my point: For R/S Ratio, the cheapest way is to use the L28 / L20A combination---you get the R/S Ratio advantages and absolutely no conversion headaches: drop in and spin!

 

NOW, if you are willing to commit $$$$$$$ to a project, then a WET LINERED LD28 for CAPACITY INCREASE is the route to go.

 

The argument for a 'destroked' LD28 was economically foolish, you get the same results much cheaper using standard parts with the L28/L20A combination.

 

The logical way to go with the LD is displacement INCREASE not DECREASE!

 

[DAW]

Then you shouldn't say it can't be done.

 

Your logic for not sleeving an LD Block for displacement INCREASE is the EXACT same logic I was arguing above for using a STANDARD L-Block with an L20A crank on a displacement DECREASE for 'rod/stroke maximization'....

 

So now I can play a particularly pernicious devil's advocate and say the logic works for BOTH arguments: if you disalow sleeves for displacement increase, then using an LD Block to convert to gas for a set 2.5 or 2.6 displacement has no advantages over simply using a standard L28 Block as you get the same R/S ratio with the L20A crank!

 

This took a long time coming, but I'm glad you guys finally saw my point: For R/S Ratio, the cheapest way is to use the L28 / L20A combination---you get the R/S Ratio advantages and absolutely no conversion headaches: drop in and spin!

 

NOW, if you are willing to commit $$$$$$$ to a project, then a WET LINERED LD28 for CAPACITY INCREASE is the route to go.

 

The argument for a 'destroked' LD28 was economically foolish, you get the same results much cheaper using standard parts with the L28/L20A combination.

 

The logical way to go with the LD is displacement INCREASE not DECREASE!

 

[DAW]

Destroking the LD28 makes no sense, it would make more sense to try to stroke it...like offset grinding the rod journals and using a long rod with a smaller (but still strong enough) big end. I think I got an estimate for offset grinding and it wasn't exorbitant. (e.g., for another engine, I was considering using Toyota 3S-GTE rods, IIRC, which were 138mm with the correct b.e. width to be used with an offset ground crank of an L18, but the idea is the same as an L28).

 

Economically, bang-for-buck, simply taking an LD28 shortblock, adapting a P90/turbo topend (head/intake-exhaust, engine mgmt, etc), and going with high boost makes some sense for a low cost approach to a street/solo engine. I'm kicking myself for building a na and using the N42 head/topend. I may do another one and do turbo route (when I find the time). BMW has used pistons in their L4 and L6 engines which had 45mm or so of compression ht., and the 1" wristpins are nice...as are the 140mm rods. The objective isn't a high rpm engine anyway; it's low rpm torque and detonation resistance not available with an L28ET (the other good pwr/$ solution). I've never heard my gas LD28/N42 ping but my F54 [flat-tops]/N42 pings like crazy, requiring timing retard.

DAW

Edited June 16, 2010 by DAW

[Tony D]

The objective isn't a high rpm engine anyway; it's low rpm torque and detonation resistance not available with an L28ET (the other good pwr/$ solution). I've never heard my gas LD28/N42 ping but my F54 [flat-tops]/N42 pings like crazy, requiring timing retard.

DAW

 

Reference the original post, this was a R/S ratio for RPMS originally with a capacity of around 2.5L using an L28.

 

That formula is more effectively accomplished with the L28/L20A destroke. (which also happens to have the same detonation resistance as the dwell and R/S is similar if not identical.)

 

DAW, I AGREE, 'destroking' the LD block is ludicrous when L20A cranks are still plentiful. Some would say finding an L20A would be EASIER than finding the LD28 block to begin with!!!

 

But improved R/S is available... There are pistons out there that will let you run L20B rods (check the length) in the conventional L28 Block. I know, I have a set...

[ezzzzzzz]

Me - "There is no possible way to get out to 89mm (or even 87mm comfortably)."

 

Tony - "Then you shouldn't say it can't be done."

 

I kinda expected someone to make that response. I did clarify that sleeving was an alternative but, as you also pointed out, it means a lot of $$$$$. After many dollars and hours invested it is still an archaic engine by any measure. It would be cheaper to drop in an LSx but you lose the wonderful sound of a L6 winding up. The destroked 2.5 would be a great engine with the better r/s ratio. Giving up .3 liters to gain an engine that would spin at 9000 would suit some. I opted for the r/s ratio while keeping the displacement and creating a square engine. For the street, torque is king. That's my opinion and I'm sticking to it.

[roger280zx]

With all the success of Audi & Puegot in the 24hrs of LeMans I would love to take a complete Maxima diesel setup and put it in a z car and then give it to Gene Banks as a challenge to turn it into a screamer like he has done with so many other diesel motors/cars. His Banks Performance team has resources to solve a lot of the issues that seem to arise from this discussion and he always seems to take these challenges personal and does not like failure.

 

Tom

 

Instead of giving it to Gene Banks..?.. Why not just apply the theories and practices of Gale Banks to an LD. He is not secretive about the overall theory of building high power diesels. He says they build race enginges the same way every one else does; by moving the power band higher. He showed some examples where they where removing pounds from a piston and pin assembly! When peak torque is at 3800 or 4800 instead of 1800 you don't need a piston pin that looks like it should be rifled and used in anti-aircraft artillery. It is still a recipricating air pump that burns a fuel. Make it move more air and spin higher and you will get the results you are looking for. I would say the only hard part to acheiving massive LD power would be the injection pump and maybe the cam. Both can be figured out with a little tuning though.