All:

New to the forum, made a few posts. I am 20+ years out of the Z game, but recently purchased a 1972 240Z, numbers matching. The previous owner kept it mostly original, but did add a 5-speed and a 4.11 R180.

The car needs a rebuild, it doesn't have spunk to it. I considered doing a resto on it, but given the tranny and rear-end, perhaps a "resto-mod" or stealth Z is in order.

I considered the idea of the Rebello 2.7L, but searching this board indicates this is a $4,000- $5,000 expense :eek: So I started thinking I could do this on my own if I were to obtain a 260 crank and rods, add higher compression pistons, and maybe have Rebello do an Improved Touring job on the head.

Yes, this is only a 2.6L, but for maybe $2,000 plus my time, I am thinking I could come close to the 200 or so HP Rebello advertises.

Any thoughts? Am I a nut? I don't want to pull the block and rebore if I can avoid it, my funds are low.

Thanks in advance!

If it's worn bad enough to require a rebuild, it probably NEEDS to be bored anyway.

If you're not going to be stuck on numbers matching, find a decent 2.8 from a 280ZX and use it as your starting point. You should be able to get an '82 or '83 with flat-top pistons for a few hundred bucks. Then put your IT head on that instead.

While the following site may not have perfect info, it can be used as a good starting point.

http://www.geocities.com/zgarage2001/engine.html

Arne,

Thanks for the feedback, I know Bryan Little's site well! Unfortunately, I want to keep numbers matching. Otherwise, his site was what kept me motivated to someday get back into the Z game!

I know these motors fairly well, I only have 148K miles on it, so I don't think it needs to be re-bored. When I tear it down that should indicate whether or not I should.

Assuming I don't need a rebore, and I want to keep my numbers matching, am I still crazy or does this sound like a reasonable plan to getting some more oomph out of my 240?

I should add that I'd be looking for 180 - 190 rwhp if possible

I just got home and read your post. I know it is important to some restorers to keep the numbers correct. I know the value of these cars will be greater if you have the original engine in the car. Here is what I would do. Take you engine out and buy yourself a 260 engine long block. If you install the 260 crank and rods and bore the 240 block .060 over with a new set of standard pistons, you will have 2658 cc's with about 10:1 compression. (Or, install the stock 260 pistons with new rings. CR will be 9.6 and you will still have 2565 cc's) It will essentially be a 260 engine in your 240 block. Do a head rebuild, take .010 off and bolt on your 240 head. 280 valves are another option) It will have a lot of torque and be fun to drive. Your stock SU's and exhaust manifold will work fine with a mild cam. It will perform and look stock for the "purists". Just an idea from the old racer!

Nice suggestion! But how about just dropping in a L28 crank in the original motor?

That gives me the extra torque, but numbers would still match. I'd also be around 9.5:1 compression, so I think I could make some decent power like that.

Visually, it would still be numbers matching with no modifications to the block (I'd store the 240 crank).

You'd need the L28 crank and rods both. The result is the same as the 260 crank and rods, as they are the same.

Yep, that's what I meant!

Still debating whether it's worth it. The added displacement may only be worth 10HP at crank, so it's not much. I think with a cylinder head job from a good supplier, I could squeeze decent HP while being streetable and getting more ponies.

If you want HP, you will need to spend money. By placing a 260/280 crank with rods in your 240 block, you will have a bit more then 10 hp. You will also be increasing you CR by nearly 1 point. With a bigger cam and some head mods you could be looking at 20-25 hp. When you say you want 175-180 hp w/o spending any money and using the 240 engine, we have a problem. I don't think you can have it both ways. I would just rebuild your 240 engine and put it in as a new stocker. IMHO, You cannot get any better then that.

Well, I am not saying I won't spend money, I don't want to drop $5K into a full blown Rebello/Sunbelt motor.

About 20 years ago I had a 280 that I modified a bit and it responded well for little dollars (sort of the Bryan Little/Z Car Garage thing).

I am budgeting about $2K or so on engine work. The car has good compression, and doesn't burn oil, but seems a bit sluggish off the line. The previous owner told me that the guy he purchased it from put in a new cam. If he did, I can't tell, or he just dumped in a cam without other mods (porting, etc.).

For $2K, I think I could get a first rate head re-work. Maybe specify some mods, but I think that's reasonable. If I do that + the 280 crank and rods (which I already have in my possession), I think I could get to the 180 mark.

Did you really say you wanted 190 hp to the "Rear Wheels"? Wow, I have dyno'd a couple of cars and you will be looking at crank HP rating of 220-225 hp. Doubt if you can get that out of a "stock" 240 no matter how many mods you make. You are stymied be the exhaust manifold, the SU's and port size. How about just putting a rebuilt 240 engine in your car and being satisfied. Think how smooth that baby will run!

Did you say you cannot get your 'Z' off the line with a 4.11 diff? That thing should be a tire smoker!