LT1 vs. 350 SB

[Guest krescent]

hey everyone

 

Ok, well i'm 17, new to Zs (and chevy's for that matter) as this whole time i was looking at..lets say.."newer" imports haha...i hope i dont get flamed, But anyway,

 

My father has a 71 240z with a STRAIGHT body (minus a knick on the hood) and running engine (original)...he's planning on giving it to me...and after last night i dont think it's such a bad idea anymore (for those of you living in the SoCal area, i went to Irwindale speedway and saw some baaaaaaaadaass 240's racing)

 

anyway, just like that other post, i'm considering a V8 swap...but am on a budget (i feel it'll take time anyway, but i think its worth the wait)

 

now, i could get an idea on the cost from the "How much did everyone spend on their V8 Conversion? " post, but i only found one person that did a 350 swap (from the search)

 

I was just wondering if anyone could tell me the ups and downs of each engine (LT1 and 350 SB) and if one costs more to convert than the other.

 

Oh, and also, if its not too much to ask could anyone BALLPARK me the cost of the absolute MINIMUM requirements to have a Z converted to either engine, just driveable without any un-necessary engine/suspension modifications.

 

because those probably wont come until later anyway(my pockets arent THAT deep hehe)

 

thanks!!

 

-sean

[Guest krescent]

oh, last question...coming from someone who hasn't done a conversion before(but has swapped other engines)..about how many hours will it take? is it more practical to have a shop do it? thanks

[Here comes trouble]

This is not a brush-off to your questions..... but obtain for your self a JTR Manual to convert a Z to a SBC... which will answer most of your questions.. with a fundemental knowledge of this book will enable you to follow these posts where you can confine your questions to problematic issues. There is a majority of members well past converting their Z's and their concerns are with highly technical problems and solutions..and own their own personal wave length communication with like members in the evolution to their Z cars. Many websites of members are available to study.... I find cruizing these web sights quite insightful for my continuing education. The archives are quite extensive

[Guest tony78_280z]

...but i only found one person that did a 350 swap (from the search)...

[Michael]

As seen above, the general reply to such questions: Get the JTR manual, do a search, study the posts, and only then start asking targeted questions.

 

But I would like to add this: while there are many excellent reasons for doing a V8 swap in the Z, please keep in mind that it's a major undertaking, even with what on first blush appears to be a "bare bones" swap program. Unless your dad has the desire and the skills to guide you step-by-step through the program, or unless you're a mechanic-in-training yourself, the cost/benefit ratio of a swap in your circumstances probably isn't favorable. Yes, there are exceptions; but they're just that - exceptions.

 

So perhaps under the circumstances the best approach is to wait, and postpone the swap until some years down the road, when you have a reliable daily driver, a garage of your own, and so forth.

[wheelman]

I agree in part with Michael, postpone your swap for awhile, but not necessarily until you are totally established in life. In the mean time get some wrenching experience with the stock Z. It'll provide many opportunities to gain experience and still have more than enough horse power to get you into trouble. If you insist on doing the swap, plan on the car being down for a long time and do your research first. In other words learn all you can about what your in for (see previous replies, plan the swap), get another car to use as a daily driver and plan on having very little money to do anything but work on the car (that is if you want to do it right).

 

Wheelman

[Pop N Wood]

A 240 is a nice running engine. The cars are an absolute blast to drive. I orginally bought my 240 with a V8 in mind, but the inline 6 proved so much fun to drive and easy to work on.

 

Swap now or later. Either way you can't go wrong.

[Guest Battle Pope]

Am I an idiot, or is the LT1 a 350?

 

shebby = not teh know.

[Turbo Meister]

i went to Irwindale speedway and saw some baaaaaaaadaass 240's racing. sean

Sean,

Did you talk to the drivers of the 3 Z's that were racing last night? We would have provided much info. Did you see my red Z run 6.30 at 112 in the 1/8 th mile?

Hanns

[A. G. Olphart]

Sean- The guys are right about buying the JTR manual... you can get it here:

http://www.jagsthatrun.com/

 

Frankly, I don't know the difference between an engine swap and a conversion. If you have done or been involved in a swap, you know the score: Motor/transmission mounts, cooling system, drive shaft and exhaust. Big hammer where required. (Little things like building mounts to retain proper driveshaft alignment are where it gets interesting). A few wires here and there.

 

If I remember correctly, the LT1 is a 350 with reverse flow cooling, and there is also a later aluminum LS1 350. All will work, but the JTR book is/was based on the old cast iron 350. buy the book, and see.

The JTR book suggests buying a running donor car, so you can grab whatever you need (and you will know for sure your new V8 Z will run, as you drove the donor long enough to feel comfortable with the drivetrain). The later fuel injected engines are nice, but if a person doesn't buy a running donor car, it would be easy to miss some of the bits needed to make the engine run.

 

The 240 is a neat car. If your dad is willing to give you his (WOW!) you will have a fun ride while you find the right donor car.

 

If you have tools and a place to work, it will take time and a firm commitment. If you don't have long term shop space, I'd suggest putting it off a while. (I wouldn't hire a conversion by a shop on an open ended deal... that sort of thing could put a strain on the shop owner's honesty).

 

Hope this is kind of what you were looking for.

[Corzette]

Hanns, 6.30 at 112? OMG...I wish I could have seen it.....one of these days...Im gonna start saving money from the 24th of June 2005 until sometime in 2010....lol When I get back from japan I will have many questions on how to do it up!

 

Terry

[Guest krescent]

OK! thanks everyone, it looks like i'll be buying this manual..

 

and yeah i have been thinking about it..i think i want to get the body/interior/suspension straight before i do any swapping..i mean, id rather have a good looking Z with the original motor instead of blowing my money on an engine that i dont know about installing

 

 

but eventually i'll make that leap..and when i do i'll let all of you know how it goes!

[jt1]

Krescent, I think that is an excellent idea. It's really great that your father is going to give you a straight 71 Z. This is a very cool car, but also a 30+ year old one. You need to check it over closely and make sure it's ready to be driven on a regular basis. Check the brake system over closely, replace the rubber lines with braided stainless, check the pads, shoes, and calipers, and completely flush the system and put in fresh fluid. Check all the wheel bearings and U joints and replace if necessary. Check the oil in the trans and diff, change it if it looks bad, and check the seals. Then move on to the suspension, there's a good posibility there's worn rubber bushings that need replaced. If the struts haven't been replaced in the past, it may need struts and possibily springs. Check out the cooling system and electrical system. It's a good idea to replace all the rubber lines on the car. Detail and clean up the interior and exterior of the car and get it looking good, maybe with some sharp new wheels. Learn to adjust the valves, timing, and carbs, and clean up and detail the underhood area. Buy the JTR book, a factory service manual, and hang out and read and learn here at HybridZ. This is the premier resource on the internet for good tech on Z cars.

 

All this is going to give you a much better idea of what's involved in a V8 swap. I think $2500 is an absolute minimum to budget, and you're going to need garage space and access to tools like a cherry picker, floor jack and jackstands, and there's a pretty steep learning curve involved. I think two months is a lightning fast time period for a swap, and you're not going to be able to drive the car in this period, which is going to interfer with a job, hanging out with your friends, and escorting the occasional young lady around. Building a V8 Z is a substantial commitment of time and money, and the last thing you want to do is wind up with a disassembled car, no time and money to finish it, and your parents mad at you.

 

A V8 Z is a wicked fast car, but a nice looking, nice running 6 cyl is no slouch, and will get a lot attention and provide you with a lot of enjoyment working on it and driving it, and you will learn TONS of stuff that will help with a V8 swap when the time's right.

 

I'm not trying to beat you up at all; this is just friendly advice from an old guy who used to be a really stupid young guy!!!!!!!

 

John

[pparaska]

You're on the right track, and jt1 has some very good points too.

 

I'd do the following, before getting into the V8 swap:

 

 

• Make sure it's structurally sound for your application.
  
  • If it has visible and hidden rust in the structural areas of the frame rails, inner and outer rocker panels, etc., don't do the V8. The Z body is a bit of a flexi-flyer, and when these areas rust (or other areas in the load path from the suspension to the other end of the car), you don't want to make it a higher performance vehicle. Ditch it and get a rust free body from the Southwest USA or something.
    
  • Consider weld-in subframe connectors. They can make a rusty-floored Z a bit stiffer, and if there's any rocker panel rust, can help replace some of that missing stiffness to the chassis.
    
  • Consider a well designed roll bar/cage. This depends on what you want to do with the car. Do a lot of searching in the chassis forum before you do anything.
    

 

• Get it reliable:
  
  • Make SURE the fuel system is ready for daily driving.
    
    • That means probably removing the tank, having it cleaned, if it's been sitting a lot.
      
    • Some people have done away with the stock hoses and expansion tank in the right sail panel area, and just use the top rear fitting on the tank as the vent line to the filler tube. Plug off the other vent fittings to the tank (top front, and one near the muffler area). Getting all those hoses out of the interior will pay dividends and not hurt how the car runs.
      
    • Replace the rubber hoses in the lines from the tank to the engine, if they are old. Maybe the electric fuel pump too, if there's one at the tank (probably not on a stock 71)
      
    • Replace all rubber fuel hoses in the engine compartment if they are original or in bad shape.
      

(An old car can cause you a ton of trouble in the fuel system if it's been sitting. Take care of this first.)

 

 

• Get any
  Electrical System Issues
  worked out.
  
  

 

• Get the Brake System in good working order, and consider upgrades now if you're going to be doing track days, etc.
  
  • This can mean rebuilding the stock brake system if it needs maintenance, new rotors, rebuilt calipers, high performance brake pads, shoes; rebuilt or new wheel cylinders. Rebuilt or new Master cylinder. Hopefully the brake booster still works. Inspect the operation of the distribution block below the master cylinder.
    
  • Or get a 280ZX master cylinder and talk to RossC or others that have brake kits. This is not cheap, but if you plan on having a bunch of power in the V8 and drive it hard, do it now if the brakes are in rough shape.
    

 

• Suspension:
  
  • Replace all the bushings with Urethane, replace the steering coupler with urethane or nylon part, REPLACE THE STEERING RACK BUSHINGS WITH AFTERMARKET ONES THAT HOLD THE RACK TIGHT.
    
  • If you intend to do track days, or need inboard clearance for wide wheels you plan on using, look into a coilover setup. You can do this fairly cheaply these days. Do a lot of searching here on the suspension forum for how to do the coilover swap and consider how to lower the car and keep bump travel - either section the struts or use a shorter strut top mount.
    
  • Match any aftermarket strut cartridge replacements to your uses and whether you section the struts, and to the spring rates you choose.
    

After all of that, you'll have a reliable car with a chassis, suspension, and brakes ready for daily driving and hopefully ready for the level of power you intend to add with a V8 (this can vary from 200hp to the-sky-is-the-limit) and the use you intend for the car.

 

The V8 swap should be done only after you've done all of the above, IMO.

[wpnmkr]

Positively powerful post pete! You should call it the "Z primer".Chris