Building a L28

[Glen]

I have a L28 sitting on my shed floor, the previous owner ran the oil almost right out as the cam journals are cracked but the bottom end is fine. Bore looks spot on. Must have got very hot!

 

Im looking at head work, cam, flattops and everything balanced.

I want to know if it is possible to get 180-200 rwhp with 240 carbs? I'm allowing 4-5 k to do the engine re-build but i thought some of that would go on a ceramic clutch. Triples look and sound great but thats a lot extra to buy and setup professionally.

 

If i cant get 180-200rwhp what can i expect from the 240 carbs with the motor rebuilt.

 

 

any input would be greatly appreciated

[Zedman240®]

Problem with the 240 carbs is they are limited to the amount of air the engine needs to get the hp you are after. One thing worth a try is a triple 240 carb setup. I think Daniel (dazzed) once made a manifold to suit 3 240 carbs and that made a big difference! A lot easier to setup than dual throat carbs but you have to make a manifold. Daniel did sell that setup and I know who has it but he may be reluctant to part with it. Looks weird but goes damn well!

[reverendzed]

I have just done what you are wanting to do, Pm me if you want the details of what I did.  What I did find was that power  and performance with the 240 carbs compared to my triple Mikunis was like chalk and cheese.  What I have learned is that you can do all sorts to the motor but without the correct carbs or injection most of its performance is made redundant and never used.

Rev.

[Glen]

My main issue is i have a budget of 5k. I wouldnt have thought i could build a motor and then add tripples to it aswell within that budget. Unless i build it in my shed and get len brennan to dial it in but I like the idea of getting a professional to build the motor. Rev, I remember you got your mikinus imported can you recall for how much landed at your doorstep.

[Glen]

well nowinstead of putting 5K into the motor i think i should put it into the whole car and get it ready for sprintdays. So i thought about keeping the 2.6 and shaving the head to bring compression up, nice cam and putting the 2.8 head on once it is ported. Whats everyones thoughts on that.

[gav240z]

well nowinstead of putting 5K into the motor i think i should put it into the whole car and get it ready for sprintdays. So i thought about keeping the 2.6 and shaving the head to bring compression up, nice cam and putting the 2.8 head on once it is ported. Whats everyones thoughts on that.

 

Sensible, before I went away overseas I was going to stick triple mikuni's on my existing L28 and considered sticking a lumpier cam in it 74 deg or something.

 

Even though I have an LD28 crank and L14 rods and huge camshaft waiting to be put into a motor. I figure the build will be at least 10k for the kind of L31 I want and I'd rather spend the money on other areas first.

 

This way I could obtain another L28 block, and build it up slowly over a couple of years sinking cash into it every so often, while still enjoying doing other stuff to the car and enjoying the L28 with triples and cam.

 

At least that was my plan and it sounded good to me, but then I realised how much I was spending on the Z and figured I should travel while I'm young still and mortgage free.

 

So that's where I am now .

 

I think your plan to do some mild work to the L26 sounds good though. A rebuild is serious work and if you don't have the cash now you will probably have to skip a few areas so may as well do it over a longer period of time and do exactly what you want.

 

You can get some good power out of a L-series without major work and huge expense.

[260Coupe]

well nowinstead of putting 5K into the motor i think i should put it into the whole car and get it ready for sprintdays. So i thought about keeping the 2.6 and shaving the head to bring compression up, nice cam and putting the 2.8 head on once it is ported. Whats everyones thoughts on that.

 

No need to shave the head to up comp on an L26, this will only create problems as you need to shave a hell of a lot to go from 8.3:1 to 10:1. To shave that much off your head creat issues with your valve train as you will have to shim the cam towers to maintain timing chain tension and then go fat on the lash pads etc......this creates many headaches (in IMHO)

 

Read my L26 refresh thread, find some L24 flat top pistons and you can up the comp to 10:1 easily and produce a nice tractable smooth engine that will equal the power of an L28 that revs freely to 6500

 

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

 

 

[Glen]

thanks, i thought flattops would be hard to source for the L26. Dont get me wrong id rather use flattops than shave a head. I had read your thread a few times before. some good info in there and thats what made me think about doing the 26 instead. Im going to pull apart the L28 bottom end and have a look whether its up for a rebuild or not, if it is i will just use the L28 head onto the L26. First up i will be after some Cam journals for the L28 head. What cam should i look at using? The cars primary use will be sprintdays and i will still use it every now and then on the road aswell but mostly club sprint days. Also some 2 inch Su's i thought might work well instead of triples as that should hopefully keep my insurance down.

[Glen]

well been searching on the net for a while now and cant find any L24 flattops

[Mr240z]

Whats triples got to do with insurance

i dont pay anymore and they know

[reverendzed]

You could try this link http://cgi.ebay.com/ebaymotors/Datsun-Z-240Z-280Z-510-620-New-86-5mm-Flat-Top-Pistons_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1421Q7c39Q3a1Q7c66Q3a2Q7c65Q3a12Q7c240Q3a1318QQ_trksidZp3286Q2ec0Q2em14QQhashZitem160289740321QQitemZ160289740321

Or if that doesn't work type the item number into ebay U.S : 160289740321

don't know why your insurance would change between SU's and triples, I'm with Shannons and when I let them know Of my changes my premium only increased to cover the extra value (unless that's what you mean.... )

Rev.

[Glen]

Whats triples got to do with insurance

i dont pay anymore and they know

 

I thought they up it each time you put a performance part to it. Looks as though im wrong

thanks for the link rev, looking for L24's though. i have sourced L28's in aus already for $279 iirc

[gav240z]

No need to shave the head to up comp on an L26, this will only create problems as you need to shave a hell of a lot to go from 8.3:1 to 10:1. To shave that much off your head creat issues with your valve train as you will have to shim the cam towers to maintain timing chain tension and then go fat on the lash pads etc......this creates many headaches (in IMHO)

 

Read my L26 refresh thread, find some L24 flat top pistons and you can up the comp to 10:1 easily and produce a nice tractable smooth engine that will equal the power of an L28 that revs freely to 6500

 

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

 

Very good points made by Alan. You honestly don't need a bucket of cash to get good results. Just sensible mods.

 

I should have picked up on the head shaving business. Alan is right its not worth the headache. I'm not sure when it comes to using an L28 head on an L26 block (same block as 240z), I know many have done it the other way around. Like my L28 has an early E88 head (same as E31) on it. These heads are excellent for high comp motors as they have a high quench chamber design.

 

Another words you might want to find a closed chamber E88 head to replace your 260z (open chamber E88) there are two version of the E88 so it can be confusing.

 

My E88 had larger valves fitted and a very mild cam wacked into it. Hence the reason I wanted to put Triple and a bigger cam on it, just for a bit of fun .

 

One of the most important things to do is re-graph your electronic distributor. I can say for certain it makes an amazing difference to the way your L-series will rev. Give it plenty of advance .

[Glen]

Went around to Len Brennans house today, spoke about all sorts of stuff, mainly his rally car . After deciding what we would do to my 2.8 he started his up and man did it sound awesome. I cant believe he is 72 he is still so full of life. After he told me what he had done to his motor i asked for a duplicate All i have to do is find some tripple 45's at a reasonable price. 

[gav240z]

Went around to Len Brennans house today, spoke about all sorts of stuff, mainly his rally car . After deciding what we would do to my 2.8 he started his up and man did it sound awesome. I cant believe he is 72 he is still so full of life. After he told me what he had done to his motor i asked for a duplicate All i have to do is find some tripple 45's at a reasonable price. 

 

Haha, yeah Len is a cool bloke. I love the roll cage in his Z its a work of art. I didn't realise Len was working on Zeds.

[Hunter]

How much is this duplicate going to cost?

 

[Toecutter]

My E88 had larger valves fitted and a very mild cam wacked into it. Hence the reason I wanted to put Triple and a bigger cam on it, just for a bit of fun .

 

I just bought another L28 from Lurch. It's an F54 block with an L24 E88 head thats had larger L28 valves fitted. Not sure if compression would be too high with flat tops on this combo but looking forward to learning a bit more as my build progress's. Will be keeping an eye out on this area of the forums on the coming months.

 

Sulio

 

Any progress Glen?

[Mr240z]

Hey Sulio, I,m building the same l28 with flat tops .I,ve tried to work out the ozdats

Engine design Utility but only getting static compression ratio 8.245 not sure if i did it right

 

http://www.ozdat.com/ozdatonline/enginedesign/

 

[XRQTR]

On my calculator if you keep it all standard with a standard head gasket and bore size your static comp should be around 9.8:1

 

with a 60' overbore 10.1:1

add a 1mm gasket 10.38:1

with a 120' overbore 10.65:1

120' overbore and standard gasket gives 10.38:1

 

In fact the e88 and n42 heads give almost the same comp ratios

[Glen]

Progress has been a little slow but good things take time. Len is fairly busy at the moment but a few things have been done. Crank has been cleaned up and hot bathed, the block has been hot bathed and shot peaned (spelling) and checked to be true, the head has been cleaned with the injector notches welded. Cam has been reground 72 degrees, i dropped the clutch off to him Exedy ceramic button clutch. Fly wheel has been balanced and lightened aswell. He told me he really likes to put in time and get things perfect but sadly the real jobs that make real money are taking precedence which is fair enough considering. Im expecting it back and all together by the end of Jan as he said he should be quite after christmas.

 

shall keep you posted.

[Glen]

Just some pics of my Crank