build after 24 years

[munters]

Im starting to rebuild my 72 240

 

Im from Switzerland and its difficult to change/up power here.

I need to have matching parts (visible). I know after reading and searching a lot here and at classic zcar.

Nobody suggests to upgrade the l24. But that's exactly what I HAVE to do.

My idea is to stroke and overbore (1.5mm) it to 2.7 with a mild cam and mild porting.

Im starting this tread to ask some questions and show the progress.

[240zip]

Rebello (here in the US) makes a 2.4L motor that's stroked and bored to a 2.7 I believe. It's called the "Purist" 2.7.

 

This setup uses your existing 240Z engine so your numbers match. The motor has a big bore, long-rod combination and the E-31 or E-88 cylinder touring style head from your stock 240Z engine. On pump gas this motor produces 240 HP with SU carbs or 270 HP with tripple carbs (as shown).

 

http://www.rebelloracing.com/enginebuild.htm

 

While you'll need to check with him on prices, I'm going to guess that unless you can do this on your own, with the current exchange rate, it might be cheaper to simply import the motor from the US.

 

a 240HP motor would be incredible and you have access to better gas in Suisse than we do here. The motor is just one aspect of a proper build. suspension, brakes, transmission, differential, the exhaust. It's a complete package.

[munters]

The Rebello engine looks tempting... but for shure not cheap.

I do have two engines and don't want to buy another one.

First I have to check for the price incl. shipping to the states and back.

Compare this to our machine work prices in Switzerland which are much higher and then decide

if I go with rebello or do it myself.

 

Yes Im going to upgrade the suspension and a rear disc Brake conversion.

I hope the 5 gear box is strong enough, because again I can just upgrade the internals.

The exhaust is the next problem I will need to build it without headers but best flow possible.

 

My goal is like with my other restorations i have done. Not a single screw not touched.

Edited October 14, 2011 by munters

[240zip]

When we did the suspension, we removed all the bolts, cleaned them, bead blasted if necessary, then had them re-plated (cadnium.

 

 

We also powder coated the suspension pieces after media blasting them.

 

 

I used the BetaMax conversion hubs to add a Subaru R180 3.7 ratio LSD. I did not do a rear disc brake conversion.

[munters]

This looks exactly the way im going to do it. good job.

I didn't research for a differential conversion yet.

[240zip]

I think I got the greatest joy from the engine build. We took a 280ZX 2.8L block, bored it out .5mm, then added an E31 head with a mild cam with a 270 duration and a .45 lift. We added headers, a nice custom fabricated exhaust and 42DCOE's which were rebuilt in Rex Chalmers in the US. We had a custom radiator that has the exact dimensions and fittings for the 240Z. Many hang too low when placed into the 240Z. Most of the pieces under the hood were plated. It's by no means perfect, but it's nice for a car that actually gets drive and see some time at the track. We did go with the 5 speed. It's an early one with the closer ratio gears. We rebuilt it, added a lightened flywheel and a stage 2 clutch. Right now it has the Pertronix Ignitor, MSD 6AL, and the stock distributor. The crank damper was rebuilt. Nothing very aggressive, but it's fun as heck to drive.

 

 

Right now I'm dealing with some low RPM issues which seem to be tied to the issue of vacuum advance not working with the Webers. Hopefully that will be sorted out soon.

 

 

We've done a few photo shoots with the car.

 

 

In terms of future upgrades, we're going to focus on getting the interior this Winter. There are a few bits and pieces that need to get plated and then re-installed. Once I have a load of parts to bring to the place that does my plating, I'll likely swap out those pieces.

[luseboy]

This looks exactly the way im going to do it. good job.

I didn't research for a differential conversion yet.

 

You can get a limited slip diff out of a 300zx and if you change the rear cover and the mount for the driveshaft, it pretty much bolts right in. There's many posts about it on here and other places. Also another thing you might consider for your build is a lighter flywheel. There'd be no way for them to know it was there without taking off the tranny, and it makes your power more efficent. Personally I plan to use an arizona Z car 12 lb flywheel with an aftermarket 2+2 clutch kit. You could do an aluminum driveshaft too come to think of it, MSA sells one. I'd think if you painted it black they wouldn't be able to tell.

 

Also you haven't talked about carbs yet. I assume you need to use your SU's. Check out Ztherapy, apparently they do a great job of modifying SU carbs.

[240zip]

on the 300ZX differential. Yes ... you can get one, but it's a R200 ... not a R180. The R180 LSD units from the Subaru STi's are often easier to source. I have an LSD unit from a 300ZX Turbo. I had to get the mustache bar from a 280Z and the cover from a R200 (also from a 280Z). I was lucky in that I found the R200 unit in a junk yard and it came from a low mileage wreck. I'm saving my R200 for the turbo build we're working on.

[beermanpete]

The Subaru STi R180 LSD is a true bolt-in upgrade. You buy the Subaru diff. and the necessary output shafts from Beta Motorsports. That is all you need. The original propeller shaft, drive axles, and mustache bar are re-used. It looks identical to the OE diff as well.

 

We put one in our car. I works great.

Edited October 14, 2011 by beermanpete

[munters]

240zip

Your engine would be nice but I hope a stroked overbored l24 will be nearly as fun to drive.

The engine bay looks nice as well.

The more I see and read the more im excited about the endresult.

 

The Flywheel is one mod for shure.

The differential would be the STI one but I have to check, if they look equal.

 

I'm thinking of rebuilding both my tripple Weber (I bought them 20 years ago but never used them) and the SUs.

I'm going to try to build a stock looking Airfilter housing and hope they don't know what was stock.

otherwise use the SUs.

 

Thanks for helping in the deciding process.

[munters]

I'm a bit further with my research on how to...

There is still a problem. I can not install any headers. Is there a way to "open" the stock manifold to flow better?

I could not find to much informations on that.

 

There is a long way of research and calculations before I can even Start to buy parts

 

The summary till now:

Rebello = 6k + shippement 1k or 2k

 

Bore and hone here 2K

Head here (no porting involved) 2k

Pistons Crank Rods here 2k

Parts for Head incl. Cam here 500

Build the engine here without porting 6500$

 

Compared to a rebello between 6k and 8k incl. ported head and tuned carbs.

Looks like the engine will be shipped to the US and back.

 

Sort of crazy but makes sense.

Any thoughts?

[1 tuff z]

I had Scott make me a custom rad for my LS1 z, he's in Buffalo, just 90 miles from where I live. Been in my Z for 20,000 miles now and zero issues. Great looking engine bay by the way!

 

We had a custom radiator that has the exact dimensions and fittings for the 240Z. Many hang too low when placed into the 240Z.

 

[rossman]

I'm a bit further with my research on how to...

There is still a problem. I can not install any headers. Is there a way to "open" the stock manifold to flow better?

I could not find to much informations on that.

 

There is a long way of research and calculations before I can even Start to buy parts

 

The summary till now:

Rebello = 6k + shippement 1k or 2k

 

Bore and hone here 2K

Head here (no porting involved) 2k

Pistons Crank Rods here 2k

Parts for Head incl. Cam here 500

Build the engine here without porting 6500$

 

Compared to a rebello between 6k and 8k incl. ported head and tuned carbs.

Looks like the engine will be shipped to the US and back.

 

Sort of crazy but makes sense.

Any thought

 

Also considered that Rebello has been building race proven L6s for many years. He will build a complete package with portred head and a matching custom ground cam based on your requirements. Will your Swiss builder do the same thing?

[Xnke]

Munters, can you list out EVERY limitation that is placed on you by the state? I.E., matching number block, exhaust, intake, must be carbed or fuel injected, available gasoline grades, ect?

 

Once you know all the rules, you can look at how to evade them without breaking them.

[munters]

Munters, can you list out EVERY limitation that is placed on you by the state? I.E., matching number block, exhaust, intake, must be carbed or fuel injected, available gasoline grades, ect?

 

Once you know all the rules, you can look at how to evade them without breaking them.

 

 

Matching Block (not serial number) and according head. Intake and exhaust are not checked (just noise), but headers are not allowed. Carbed, because EFI didn't exist.

Max HC is 1500 and max Co is 2.5.

Gasoline grade is 98 Ron = 93 or 94 AKI (US)

They have a tec doc with where to find numbers, and how it looks like all the sizes/lenght and diameters.

For example I will try to show up with tripple Webers and hope there is nothing written in it.

[munters]

Also considered that Rebello has been building race proven L6s for many years. He will build a complete package with portred head and a matching custom ground cam based on your requirements. Will your Swiss builder do the same thing?

 

No, not at all this speaks as well for rebello.

[Xnke]

Alright. The bottom in is a fairly simple deal, in your case I would do the following for a non-exotic mashup, IF I was going to do anything but a stock dimensions rebuild with forged slugs

 

L28 crank, stroke 79mm

L24 rods, at 133.3mm

ARP Rod bolts

Z20S piston-this can be hard to find, but forged units would be 85mm diameter, 35.5mm pin height, and have zero dish, with a standard Nissan ring pack

P30 block, wall-thickness checked and bored to 85mm

I'd go with the 280ZX turbo/auto oil pump. Don't know if you got the KA24e engine over there in the pickups, but that pump is the same.

 

Now, since you're saying you will be required to run an E31 or E88 head; then things are going to get interesting.

 

You have the advantage of a little bit better gas, but not much. I'm running 87 octane here, at 9.7:1 compression; so you should have little trouble with what I propose.

 

Take the E88 to the welding shop, and have them weld the chambers up, till you end up with something that looks similar to the Maxima N47 small chamber head. It'll take time with sanding wraps and carbide bits to get it cut back out to the smooth heart-shaped chambers that you're looking for, but it's worth it for the properties of such a chamber design. Cut the valves out to full L28 size, and run a Nissan L28e headgasket, instead of the L24. Arrive at 39CC combustion chambers, for a 10.9:1 compression ratio. The ported intake and should be done carefully, making certain to keep some taper between the carb throat all the way down the the valve neck. Just having a honkin' big tube isn't as desirable.

 

Cam selection will be important...look for a cam with about 220 to 230 degrees of duration at 1mm valve lift. Lift, with the stock retainers and Rebello Outer Spring set (which I find to be an excellent cost/performance ratio for a street build) should be kept under 12mm, and you will need to use the smaller Ford valve stem seals mentioned elsewhere on this site. You will have significant cam lope at idle. This helps to keep detonation under control by lowering the effective compression in the lower RPM band, and essentially raising the compression as RPM's climb, so by the time you're up to full static compression or better you're above the RPM band that detonation normally occurs in. A stock cam grind will leave you stuck running very weak ignition timing, or costly race-only fuel.

 

Personally, I would go with a programmable ignition, but the factory distributor can be recurved to provide about 24* of idle timing lead, ramping up to about 30 degrees of lead by 2400RPM, 34 degrees at 3000RPM, 36 degrees at 3500RPM to top out. This is only a starting point on timing lead; your engine builder will be able to help considerably with this.

 

As for the exhaust, well, Good luck. I dropped the cast steel manifold and went with a well-respected header design, but since you can't run headers you'll need to figure out how to get around the limitations of the stock manifold. It's not a terrible piece...but it is cast steel and can be welded.I'd get a cutoff wheel, pop that sucker open in two halves, and "port" the interior of it as much as I felt I could go before welding it back together.

[Challenger]

Throw whatever cylinder head you want on there... grind down the marking (p90, n47, etc) and somehow put one on that looks like the original. haha

 

Sure glad I live in the US, sure sounds like its hard to build an old fast car.

 

Good luck.

[Pharaohabq]

One comment here... If they're not concerned with the actual engine serial # (Which isn't usually a concern in any S30) then it would likely be cheaper for Rebello to source you an engine locally and ship it to you. That would likely be cheaper than shipping yours from Switz to the US. I'm sure Rebello does things like swapping out the dist to the ZX dist to elim points and such. Aside from that the internals aren't obvious, but too loud a cam might tip the state off that there's something changed.

You mentioned a 5 sp. the original 240's didn't have 5 speeds availible. that may be an issue, if anything swap a 4 speed shifter ball to it. The ZX 5 speeds were stronger. You likely won't have any issue breaking things, even at 2.7L.

[HS30-H]

You mentioned a 5 sp. the original 240's didn't have 5 speeds availible.

 

If the car in question is an original European market car, then it would have had a 5-speed fitted as original equipment.

 

 

munters,

If you need any help with original documentation to help your cause, then let me know. We have helped several European and Scandinavian owners beat and/or circumvent their local restrictions in the past, and you're not the only one building such a car in Switzerland I believe.