Bitsa engine

[bullzed]

So I'm at a point where I'm ready to begin building another engine. I've been having a look around and I'm pretty sure the way I want to go is as such:

 

Block: L28 F54 (possible 1.5/2mm overbore depending on sonic test)

Head: L26 E88

Crank: L24

Rods: L24 H beam forged

Pistons: L28 flat tops forged (oversize to whatever bore is safe)

Cam: Something geared away from everyday driveability towards mid range and top end.

Lightened flywheel

Suitable valvetrain components

 

From what little information I've been able to find about this combo, the static compression falls around 9.5 to 10.1 depending on headgasket thickness. It becomes destroked to just less than 2.7L but with the shorter stroke can be pushed to rev harder.

 

Basically what I'm looking to pull from this engine in the end is a hard (and high) revving destroker which I can aim for 220hp at the wheels with.

 

Would anyone have any info or helpful advice when it comes to mating this combo together?

 

Cheers

Zac

[Riceburner]

Any head work planned?

[bullzed]

Yeah port and polish, deshrounding of the valves, may shave it a few thou. Haven't decided to what degree I want to take the rebuild, but we've got a few heads which we're going to play around with and flow bench.

[d3c0y]

Hey Zac,

 

 

My mates and I have often talked about building this setup, but from talking to people in the know it doesn't perform very well and would be a prick to drive with a big cam. The old adage of "There is no replacement for displacement" always ends up proving true, especially when it comes to N/A builds which are expensive for HP per $ as it is (so you want to get all the help you can get). What is your peak rev target? To put it in perspective, my 3.4L will rev to 8000rpm every day of the week and due to the way it's built, the tacho flicks around there much faster than a normal L. 

 

 

220rwhp is a very tough L-series in any guise and as Gareth suggested will require a lot of money to be spent on the head. Specifically with porting and getting bigger valves into it, you could easily run up a bill of $5k without even trying. There are also better rods to use than the L24 rods when you are building a custom motor too. If you get your pistons custom made, you can raise the pin height and used a longer rod (like an FJ20 140mm long rod) which will give it a better rod:stroke ratio which will intern make it rev even harder. E88 is a bad choice of head, you will want a P90 or at least an N42. I'm guessing you put it in there to up the compression but you can change that with piston design and really you want at least 10:1 if you are sticking a race cam in the top.

 

 

When doing big overbore, you actually want an N42 block as there is more meat in them, but even then PMC went through 4 blocks to find mine which then only went out to 89mm. You will need to spend money on getting the crank race prep'd and checked too.

 

 

You will want to budget at least $15k to build the long motor by itself (no carbs or headers etc) and you will need a pro engine builder to strap it together. I have re-built a few L's in my time but when you are chasing this kind of power it's a different level.

 

 

A much more common (well it used to be back in the day with racers) was to just get an L28, and run the FJ20 rods with custom 3mm over pistons to give you a short stroke 3.0L (2.945L or something close to that). It will make more power than your 2.7L will every day of the week. I'm looking at building one shortly with 44014, using Kameari SPL pistons, forged rods, triple 45s and 310/520 cam we scored off gumtree. It's all going to be balanced and have some mild head work and we aim for a bit over 200hp at the crank with that to put things in perspective.

 

 

At the end of the day i would love to see you build this engine, but it would suck for you to drop a ton of money on something that could be a lot better.

[luvemfast]

As Jake said. My PMC is pretty much the last example he gave.

N42 oversize to 89mm bore.

Ported P90

FJ20 forged spool rods.

Custom forged domed JE pistons.

75 deg high lift cam.

Prepped crank.

ATI harmonic balancer.

Recurved dizzy

Lightened flywheel.

Triple 44PHH Mikuni's.

Custom headers, designed by the late Peter Hall.

And more.

 

This will spin to 7,500rpm all day, but I don't do it.

It's made 146kW at the wheels. But that's only at 6,000rpm as the exhaust needs to go up to 3" and change the cam to a 76deg. Then it'll go 160-170kW's.

What you're proposing Zac, will be a fun cheap motor.

What Jake and I have are not cheap, but very good. (Jakes is a bit mental)

 

Pick 2 of these. Good. Fast. Cheap.

Good and cheap. Not fast.

Fast and cheap. Not good.

Good and fast. Not cheap!

[PZG302]

If you need another block Zac I have a N42/N42 combo taking up room that I will never use, so for $400 it's all yours. I also have a set of  rods suitable for what you want that came out of my race motor, replaced with a set I bought off Jason when I did my rebuild and a piston sample to get the same made that was in my race motor that Zedevan bought.

 

I also have a bare N42 head that hasn't been touched so can be added to the bank you have, make a fair offer and it's yours.

 

I also have a few other odds and ends lying around like lash pads and rockers from the race kit that are now just taking up room now I will be using a SR tractor motor to go racing.

 

I would go with what Jake said, use the "stroker" rods to give you a better rod/stroke ratio so it revs harder and be prepared to spend. My last rebuild was around $8k to put together with new pistons, block checked. cleaned and honed as it was already mm overbore, the head just needed new springs, valves were good, new rockers and lash pads were used as insurance. The head was already done so just needed to be cleaned, checked and a touch taken off the face to ensure it was true. This motor produced 195rwhp and 212ftlb of torque on the dyno it was tuned on. It was set up as truck motor with a very flat torque curve and pulled better than a 14 year old school boy.

 

To get a good motor built, I would allow $1k per pot. This will give you a great street motor that if maintained properly will last for quite a few years and provide a heap of fun.

[bullzed]

Thanks for all the responses, so many ideas to choose from! But I guess that's how it goes with every new build

 

Matt I'll send you a PM regarding your long motor and assort spare bits!

 

From what I've gathered I'm intrigued by the longer rod idea.

 

I'm also in discussions with Jason regarding some of the builds he has done, and even though it may not yield the highest hp I could obtain per dollar, I'd love to build a destroker to rev to 9k.

 

I'm considering N42 block now due to the larger bore walls, FJ20 forged rods, pin height adjusted custom pistons, knife-edged and lightened L24 crank, Kameari valve train (don't worry, I have the catalogue and understand that there are 82 yen to a dollar, not 820  ), 75 or 76 degree cam, Kameari headers, 2.5" stainless or 1.75" twin stainless exhaust.

 

Now obviously there are all of the little things too, I understand that, but just trying to get a handle on the main aspects of the motor build.

 

Also I understand the price tag on all of this, I've set aside 20k over the next 12 months to do so 

[gav240z]

Ok, what do you want to get out of this motor? How do you want it to drive? Do you want low down toque or do you want to rev it's nuts off to make power?

 

20K is a lot to throw at an engine, I won't stop you but I think you can achieve a lot without going to extreme's I'm currently evaluating my options also. I have an F54 block with E31 head on it, not sure if it's had larger valves fitted or not. Will know once I've removed it from block. I also have a spare N42 head as another option.

 

It becomes a slippery slope once you start modifying, so sticking with a budget and working to it is the best way to go I think. At least it's what I'm trying to do.

 

I like the approach laid out here:

 

http://datsunspirit.com/?page_id=333

http://datsunspirit.com/?page_id=511

 

Also worth re-reading this post by Alan if you're looking for a respectable budget build / bang for buck.

 

http://www.viczcar.com/forum/index.php/topic,2415.0.html

 

If you want to make power in a 280zx I'd recommend going turbo. So easy to get power from forced induction.

 

 

[Zedman240®]

What induction are you planning on using? To rev to 9k, you'll need something with a rather large throat...

[bullzed]

I've been advised 44PHH's or 45 DCOE's. I can imagine 48's would be a little large for a 2.6ish litre destroker.

 

I am wanting it to rev it's tits off, I already have a decently torquey L26 2.7L in my Z at the moment with DHLA40s, it's a good setup for a street car and it'll most likely end up in an HR30 or something when this new motor goes in the Z.

 

I know 20k is a lot of money, but this build is for the sake of building this type of engine, a high redline L6 engine. I realise 20k could get me 600HP with an RB25 or similar, but this NA screamer is a route I would love to take.

[Riceburner]

Is this a street or track car? I imagine if it's able to rev to 9k there's going to be big driveability issues below 4-5k.

 

Will the gearbox and clutch handle 9k shifts?

[bullzed]

That's factoring in an RB20DET box conversion and cushioned full face organic Kameari clutch. Should be fine for 9k shifts, given the right person is driving it!

 

It's going to be street registered but it won't be a city car, at most it'll travel along highways to get to tracks.

[Enzo]

Hi,

    As Gav suggested check out the Datsun Spirit web site. I have ordered parts from Eiji and the pistons are being made now. I am using an N42 block with N42 head. 88mm forged short skirt pistons with 29mm pin height. 139.5 mm long rods. Pistons and rods are half the weight of the originals.  45mm inlet and 36.5mm exhaust valves which can be used with the original seats and are longer in the stem for a high lift cam to keep the rocker geometry respectable. I went this way because the pistons and rods complement each other. He also has pistons with a shorter height if you want to run with a Diesel crank. The head work will be done by James at MIA Engines in Sydney. I intend using the motor for street and occasional hill climbs and sprints when I move back east at the end of the year.

    Good luck with your build.

David

[d3c0y]

 

In case you havent thought of this, if you do the maths on your combination you maybe a few mm short on your deck height. You cant run the same rod and piston combo as a motor with an L28 crank for the obvious reason the L24 has shorter stroke.

 

RB20 box has crap ratios for this kind of motor and will make it drive worse. You really want a close ratio gear set to get the most from it. Also factor in a nice short diff like a 4.3. Don't forget to refresh all your unis in the axles and driveshaft while you are doing this so you don't break them first time out.

 

 

44 Mikunis can do up to about 300hp so they should be fine. Don't forget you will need to get the big 40mm chokes for them. On the subject of ancilleries i would talk to Stewart Wilkins about headers and dont foret to factor in another $650 for an ATi under drive balancer. I got mine from Summit racing as it was the cheapest.

 

 

I would talk to your head guy before being set on a Kameri valve train as their valve spring rates can be quite high. Realistically if you want to make power you are going to need to go a minimum of a 76 cam probably bigger to get the revs you want.

 

 

Btw it's called a short stroke not a de-stroker lol.

 

 

If you get a small diameter twin plate clutch over a normal size single plate, that will help with the revs too.

 

 

I also highly suggest reading "How to modify your Nissan & Datsun OHC engine" book. It will give you an idea of what's involved in making an engine like this. I read it a couple of times and then got PMC to do it all lol.

 

 

 

Enzo why are you going so big on the exhaust valve? The flow bench work i've had done suggests that you don't get a worth while gain from going too big.

[bullzed]

Yeah I've realised the pistons won't come up to level with the block, but I'm sure messing around with FJ20 rods and a custom pin-height in the pistons I can make a combo that's going to give me the height I need.

 

Close ratio will be hard to obtain, I'm sure I can work something out but in the mean time I'm going to focus on the engine. Header wise I'm going to go Kameari, once I've worked out flow rates etc in the head I'll be able to narrow my decision down to sizing.

 

Also a colloquial term for short stroking a motor is de-stroker, you'll find it's used quite commonly 

 

In terms of balancers I'm up to date with them, as you say it'll definitely need to be underdriven.

 

Obviously this thread is all speculation at the moment and things will only become definite as the build progresses, but I'm just trying to get my head around what is needed for the build in a general sense.

 

I do in fact have a copy of 'How to modify your Nissan & Datsun OHC Engine', and I'm currently reading it 

 

Thanks for all your help guys, it's much appreciated!

[d3c0y]

Kameari and OS Giken make close ratio gearsets for 71B boxes.