3.4L L28 stroker

[t-tom]

i know this is an old post, but happened any more info on the set-up

[Speedtripper]

...and what happened???

 

Not sure if this topic is no longer the flavor of the decade, but I am in the process of a very similar build with a LD28 block. Block has been bored to 89mm. Min wall thickness of 3mm. Interesting to see the wall thicknesses are in the 3mm - 5mm range. So there is some shift in the core.

I have decided not to use the LD28 crank as it would also require welding, so have opted to use a L28 which is being welded and stroked. Currently set at 90mm. Using the forged 4g63 rod (149.86mm) with the 48mm big end. Small end has been rebushed to 21mm. Piston is a standard 89mm KA24E. Piston requires a 1.4mm skim to remove the slight dish. This gets it to a 0.01 positive deck height for use with a 1mm gasket.

Interesting to note that despite the increased displacement - 2.8 to 3.35 there is a weight saving of 257g per cylinder over the standard L28 piston and rod. Standard is 1355.6g. New rod/piston combo is 1098.6g

If anyone is interested in this build, let me know, and I will post as things happen.

[Tony D]

Les Collins Racing in Australia is producing L34's for some time. Think it's 90x90...

Make an order and wait for delivery!

 

In fact, search for videos of "The Green Monster"

Edited February 14, 2016 by Tony D

[Speedtripper]

Thanks Tony.

 

I am aware of that. They use a modified RB30 crank which involves the widening of all journals, and machining to snout and flywheel flange. Honda rods are used and special pistons with a low comp height to make the rod ratio acceptable. I don't live in Australia so having someone build one for me is not an option and besides that, where is the fun?

 

This is a slightly different approach, being based on the LD28 block. I have read plenty of thumb suck info regarding this block, probably because of the 'small' pistons it houses. There is a lot of presumption regarding wall thickness etc. I have also read suggestions about using liners. It is not necessary. I have the block sitting in the garage, machined to 89mm. The wall thickness is not less than 3mm at any point based on 12 measurements in each bore. I thought about going 89.5mm but decided that another rebore in my pocket was a safer bet.

 

My approach is to use as many "off the shelf" parts as possible. The only specialized work is the welding and offset grinding to the crank. I agree with a previous post of yours where you stated that a lot welded cranks if done correctly see years of service. The point is to find someone who specializes in crankshaft repairs, and not a run of the mill shop - pardon the pun.

 

Finding LD28 blocks in South Africa is not an issue. A contact has a fleet of Patrols which have been converted from petrol to diesel, and as they run out of rebores they become scrap.

 

There may be people in other countries which also had the diesel motor, so this build might be of interest to them.

 

I appreciate that this is a very old thread, but if anyone is interested, as I said, I will update the information.

[Nelsonian]

Please do keep updating with progress.

[Lurcher]

Thanks Tony.

 

I am aware of that. They use a modified RB30 crank which involves the widening of all journals, and machining to snout and flywheel flange. Honda rods are used and special pistons with a low comp height to make the rod ratio acceptable. 

 

I'm sorry but that is incorrect. Who has fed you this incorrect information?

The crankshaft in the Green Hornet L34 is a an 90mm stroke EN26 billet item made by a company in Australia.

The rods are not Honda - they are a custom ordered Carrillo's, and the pistons are custom raised crown forged units for 11:1 CR.

 

I'm curious: how are you able to weld & then offset grind a standard L28 crankshaft to get it to 90mm of stroke? 

[Gareth. J.]

Very interesting info about the LD block wall thickness! I threw my block out without even checking it after reading about the small bores being unable to bored to 89mm

 

Would be keen to see a build thread on your particular engine combo speedtripper.

[Tony D]

That was my information as well, the 90X90 was a custom crank unit, not a modified unit from another engine.

[Speedtripper]

My apologies to all.

 

Having checked a pm which I received some years back, the convo I had was with Peter at PMC: "we off set grind the crank (RB30) to 89mm stroke thats why we run the 48mm pin , and there fine , have run them in 700hp turbo rbs for the last 5 years " and not LCR. I'm getting old and all Aussies look the same to me. ; ) Lurcher you are correct - that is an entirely different set up. And a price tag in a different time zone I might suggest.

 

My build is for those who can't afford that spec and/or like to do as much of the prep themselves.

 

I would like to put a question out there regarding a camshaft. As this is going to be as street car, and where I live is pretty hilly I require something which will give good performance but not require riding the clutch all the time. Any suggestions?

 

I'm hoping for something in the 300hp range. But street-able. My thinking is that with the extra cc I can tone the cam down. Possibly around the 290 degree mark? I will build my head around that - valves sizes and CR. Anyone with similar specs, that can report back? I do have a set of 45mm ITBs on my car so that should be sufficient. Pictures of which are in my gallery. You will see the LD28 on the stand too. I will update with some more pictures soon.

 

My car is about is about to undergo a complete tear down, so this engine will not be running for a while. I will however post as stuff happens. If anyone would like any specific info on the build, just let me know and I will be happy to reply.

 

Please remember that this is a low-budget build, using as many off the shelf parts as possible.

 

Thanks for any input, in advance.

[Xnke]

Not all LD28 blocks can be bored that big. I have two here that are into the water jacket at 86mm.

 

I'd love to get my hands on 8 or 10 88mm bore-able LD28 blocks.

[Speedtripper]

Wow! I wonder if there are different versions - based on year? The engine number on mine is: LD28 180644 how does that compare to yours?

[Xnke]

They're in storage right  now, I'd have to drive an hour to go get them. After cutting two into the jacket I quit, but I have seen them set up with dry liners in diesel shops here.

[Speedtripper]

Ok, no worries. I have no other block to compare it to, so can only call it as it is. As we never got the Maxima diesel, is it possible that it comes from an older model of something else? Info on the LD28 is not conclusive. I was led to believe that we got the diesel in some older model Patrols. Either way.... I will forge on.

[WhitleyTune]

I've always wondered this too. LD28 stock bore is 84.5mm. No way you are into water at 86mm, that would make the bore wall thickness under 1mm? Diesels need to be strong and the LD is known stout. 

 

Could be a case of location as well as what car they came out of. A Patrol in S.A. is going to get more of a hard life than a Maxima in the states. 

[inline6]

Not sure if this topic is no longer the flavor of the decade, but I am in the process of a very similar build with a LD28 block. Block has been bored to 89mm. Min wall thickness of 3mm. Interesting to see the wall thicknesses are in the 3mm - 5mm range. So there is some shift in the core.

If anyone is interested in this build, let me know, and I will post as things happen.

 

So, you've sonic tested after boring and have 3 to 5 mm?  

 

Yes, very interested in seeing more about this engine.  I am exploring using an LD28 block for a new engine.  My engine builder started examining the one I just sent him.  It came from a US spec Maxima.  He knocked out the front and rear freeze plugs and estimated the bore thickness at around .220". However, he notes that there are spaces between the as cast bores, meaning none of the bores are siamesed. He's going to sonic test a few of them to see what we're faced with.  IF the bores are around .220" thick, we MIGHT be able to bore to 89 mm and have .120" (3 mm wall left).  He is very doubtful...

 

Maybe those Patrol engines are different?

Edited February 20, 2016 by inline6

[Xnke]

I'm thinking there are at least two versions of the LD28 block, as I've seen dry-linered blocks in diesel shops before. The bores were cut a lot bigger than 84.5mm, then dry-sleeved back to 84.5mm with thick sleeves.

 

I tried to buy a few of those blocks but was unable to get the diesel shop to sell them. I then got two from maximas and they were bored to 86ish mm and hit water at the bottom of the bore. They may have simply been corroded badly too.

 

I had a plan using the LD28 block, an offset-ground LD28 crankshaft, and 4G63 rods hung on a custom piston (may have been a stock piston for a different application, I'd have to look again) that gave a 3.3L block with what I considered at the time to be desirable properties. If I could get an LD block to go 89mm, I could probably work in even more stroke...maybe even 88 or 89x90.

[inline6]

My Maxima block will be machined this week and we'll see what is possible with it.  The plan is to go to wet liners.  It would be amazing if the block will take an 89 mm bore.  I don't think it will.  If we break through, we'll keep going to 88 or so mm and examine the height of the deck and the height of the floor of the block.  Should know more soon.  I wish I could get my hands on a block that would take a bore of 89 mm.  I tried looking for a Nissan Patrol diesel block on a couple of auction sites in South Africa.  Nothing on either of those.

Edited March 15, 2016 by inline6

[Mack]

I am very interested in this build.  I still have the block I took a crank out of and sold many moons ago, as well as a COMPLETE LD28 that I am holding on to for now.  

[inline6]

Any updates, Speedtripper?

[Speedtripper]

Howzit guys.

I know this has been a while... but I warn you that this is not a mad panic, so progress will be slow as I start to tear down my car for a full rebuild. (Another story for another day).

I am going to attempt to upload some pictures to show where I am so far on this build. Block has been bored to 89mm. I could have gone to 89.5 safely, but decided some insurance was a better idea. The crank was in the process of being machined, when the machinist was hit with bad health and nothing happened for a while. While this was happening I decided to push the envelope a little further and explore a 92mm stroke over the planned 90mm stroke. As this was going to put me in "unknown" territory and as I have already been shot down for asking "sensitive" questions, I decided against it and throw a simple pattern together to test possible/probable interference issues in the block. (LD28 block for those who have forgotten).

The results were better than expected. Not only was the pattern extremely accurate (luck more than anything) but there is zero clearance issues. It gets close in places. I would guess in the region of 1mm, but that is easily sorted out.

The piston (KA24) will be trimmed to the required height depending on the head gasket. Probably in the region of 1mm which will remove the .7mm dish.  I measured at TDC and got a positive reading of 1.89mm. The reading at BDC was 90.21. This gives a final stroke of 92.1mm. (I was stoked with the accuracy... all things considered).

Now to get the crank completed..... I will keep posting updates.

I must add that the point of this build is to see what is possible with a "modest" budget. It is not a substitute for a purpose built race motor (in a crate) from one of the big names.