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Building a V8Z cheaply and safely


Guest John Adkins

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Guest John Adkins

Over in Suspension and Chassis forum we were

discussing putting a leaf spring rear suspension in as a way to save money. SpencZ then voiced his opinion about building a V8 Z which was (Im going to paraphrase here) "If don't want to spend the money to do everything first class then don't build at all." His philosophy is that if you build it cheaply you'll build a shoddy car and have a death trap.

 

I respect his opinion and admire his work(wow what a chassis he's built into his Z!)

 

I do agree with him in that you should try to build the safest car you can, but just because you are trying to build a car as cheaply as possible it doesn't mean it'll be a piece of crap that'll kill you.

I think you have to have a good well-thought out plan and don't rush the work.

 

A lot of people on this board are going all out with full tube frames, coil over suspensions, aluminum engines, six speed transmissions,etc., but some of us have families to support and car projects are just hobbies that we can't invest $50,000 into.

 

What I plan to do is to upgrade my z in stages:

 

The first stage would be:

mildly built V8 with automatic transmission

minimum chassis reinforcements to handle a V8 (front strut bar? )

full suspension rebuild

stiffer springs

upgraded brakes (toyota calipers in front)

 

Then as finances allow, upgrade the engine's horsepower and update the rest of the car to match (rearend, suspension, more chassis reinforcements,bigger brakes,etc).

 

I figure a mild 350 would be at least 300 hp,

double what a stock Z has. I think that's a good starting point!

 

I feel this can be done cheaply but with good workmanship.

 

What do you all think?

 

[This message has been edited by John Adkins (edited May 01, 2000).]

 

[This message has been edited by John Adkins (edited May 01, 2000).]

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This type of question has been asked alot before.

It would be real cool if we could get some of the talent together here to make up some "recommended car build sheets" for various stages and price ranges of V8 Z cars.

Maybe broken down by approx price range like:

$3500 to $5000

Engine = Used 305/350

Exauhst = single 2.50" / SuperTurbo muffler

Trans = Th350 or T5

Springs = Stock or Enbach Sport

Subframe = none

 

Well you guys get the idea, we could start these as a single thread per build and have everyone add to it and hash them out.

Then ill take the final info and create a tech post for each and post it in the Tech area.

Just an idea guys, might work if we all add somthing to it .

 

 

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Dan "I need bigger tires" Porter, 78 280Z, 383, 475hp, Comming soon T56, Move outa my WAY!!!

http://24.4.88.44/members/dporter/DanZ.html

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Guest RON JONES

I,ve been looking for another Z to do as a real street car.I would do pretty much the samething you just described John.

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OK, here is where I come from on this issue... Remember Ron Stoy from Zcar.com? Everyone knows how much I simply love him, right? Well three years ago I was him...I had his same views about the whole conversion thing.... You know why? I drove one of those shoddy, poorly done death traps that someone with no engineering, little skills, and less cash threw together....It scared me to death.

 

Now, I don't want to lend to the negative opinions about doing a well converted Zcar, and certainly all the billet and aeroquip fittings, braided lines, T56, race suspension, brake upgrades, and other mods are not necessary. However, somewhere else I posted the thought that I personally would not do a V8 conversion for less than 300HP, and my thoughts are that 300HP deserve more attention to brakes and suspension mods, including upgrades to the chassis in the form of serious stiffening. Reason I touch on that is I have seen several Zcars suffer from tears in the shock towers and frame rails from moderately modified Zcars that were not properly stiffened in the chassis. Now think about this... The Zcar is known to suffer from rotting frame rails and floor boards... So if you have to replace those before doing a serious upgrade (And most do...), you can easily pay a shop up top $1000 for matterials and installation. Much cheaper if you do it yourself, although not everyone owns a welder and has the skills to use one. Now, say the car you use is of the "Stock" nature. Now you probably have rotting bushings, ball joints, tie rods and blown struts... and leaking wheel cyclinders, a stuck booster, and a shot master cylinder.... all the sudden the factory replacement parts to get the car back to factory spec are upwards of $1000... you are $2000 in the hole and you haven't spent a dime on the V8 conversion. OK, now you buy the JTR book and kit...$350. Buy a junkyard motor and say you rebuild it...just bearings, rings and have the valve seats check and the head gone over... If you do all the basics yourself... You will probably have $800-1000 in the motor... Now coupled with the cheapest trans you can go with and making the driveshaft... You probably have another $800 in everything including the shifter...

 

Most likely you will need accesories and other doodads like a radiator and fuel pump...You will have another $1000 in extras guaranteed... it always snowballs (Right Pete?) and then you are looking at a basically stock suspension and stock braking Z with about 200HP for about $6000.....plus the cost of the car... For that money, and a little bit more, you could make the mods people recommend here on this board... get 300+HP with the wonders of modern brakes and suspension and better trans options... I personaly think that a clean Z and $10000 is a good starting point for a well done V8 Conversion and I'd bet that most Mild v8 conversions are in that ball park.

 

Mine is crazy expensive and my CC bill reminds me every month, but it doesn't have to be crazy like mine to get well into the many thousands of dollars.....

 

Just my .02!

 

Mike

 

------------------

 

"I will not be a spectator in the sport of life!"

mjk

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SuperDan: I love the idea of the thread per dollar/power range, and the tech articles that could result. I'd say that like any committee written guideline, it will take a long time to wring out - but it will be worth it.

 

Mikelly: Thanks for the new nic-name for my car: "The Snowball" smile.gif. I love it. Yes, my car started out as a simple V8 conversion with some rust replacement, sturctural improvement. The rust was everywhere once I was done with the structural mods, and it became a body restoration (don't ask how much that cost me). And now everything is being re-engineered (well not as much as SpencZ's car, but all systems are being changed to improve performance and update them.

 

I really agree with Mike on the structural and brakes/suspension issues. These cars are not the stiffest/strongest (there is a difference) things out there without rust, and with rust they are quite fragile with 300 lbft of torque or more added by the V8. Then you go drive it hard with the V8 and you are asking more of the suspension and brakes (and unibody). This sets up a disaster waiting to happen if the car is rusted bad enough. And the rust can hide from you in structural areas you may not realize (ends of rocker boxes that you can't see, hidden rust in the frame rails under the hood, etc.)

 

The upshot is that we ought to say what level of body stiffening/strengthening is needed for the level of power being added.

 

Mike has a good point about power added. If you're just putting a stock 350 in, it is still a significant increase in the stresses the car will see, and some form of structual and brake/suspension work is still going to be needed. The thing is you quickly get on the slippery slope when doing these things and you see that for a little more money and effort in the structural/brakes/suspension areas, you can really upgrade them and have an acceptable margin of saftey for adding more power than just a stock 300 hp V8 would add.

 

------------------

Pete Paraska - 73 540Z - Marathon Z Project - pparaska@tidalwave.net">pparaska@tidalwave.net -

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Guest John Adkins

Thanks for the replies. You guys have brought

up good points about chassis structural integrity and rust. Seems to me one of the keys to building a budget but quality and safe V8 is to start with a rust free body...

 

Fixing a rusty chassis and rebuilding the suspension is really needed, even for stock Zs. My Z is still L24 powered and I am currently buying parts (bushings, etc) to rebuild the front suspension. Luckily, I don't have much floorpan rust!

 

[This message has been edited by John Adkins (edited May 01, 2000).]

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quote:

Originally posted by John Adkins:

Thanks for the replies. You guys have brought

up good points about chassis structural integrity and rust. Seems to me one of the keys to building a budget but quality and safe V8 is to start with a rust free body...

 

Yep. Mike Knell (JTR manual author) says this several times through out the manual.

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Guest Frank280z

I definitely agree with you guys. A non-rusty Z is the way to start. As far as finances go. Do what your budget allows. This

is my first conversion. And it is not cheap at all. But one of my major concerns is chassis stiffening. Rebuilt floors and subframe connectors so far.

 

A well thoughout plan and a non-rusty Z will get you there the right way.

Frank280z

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Guest John Adkins

What HP level would subframe connectors be absolutely necessary? That is assuming that the chassis is sound.

 

I was thinking a strut tower bar would be a good place to start with chassis reinforcements with a mild V8 and subframe connectors later?

 

Thanks,

 

John

 

 

quote:

Originally posted by Frank280z:

But one of my major concerns is chassis stiffening. Rebuilt floors and subframe connectors so far.

 

Frank280z

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Guest Frank280z

John,

Your guess is as good as mine. Like I said this is my first conversion. I'm following some ideas these guys throw around and whatever else I could pick up just talking to local hobbiests. My engine is rated at 425hp. Mated to a manual transmission. I wanted to stiffen the thin floors up as much as I could before I go tooling around with it. Modified 79-93 mustang bolt on sf connectors run the length of the floors $79.00. This is what I used. There might be more cons than pros for this mod. But it worked for me. I also added flat stock to the floorpan for more stiffness.

 

Frank280z

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I personally saw a 250HP L6 car twist hard enough at an autoX that the passenger side door came open going around a corner. We checked the latch mechanism and it was fine. This car had stiff springs, shocks and sway bars in it.... Once he added subframes and stronger floor pans the doors never moved again. This same car had wrinkled the sheetmetal in the roof and rear quarters slightly....Before he added the subframes and floorpans. He was running slicks for autoX and the car was pushing some serious Gs in the corners and he drove it hard on the street. Keep in Mind that this car was rust free, meaning no holes in the pans or frame rails. there was minor surface rust, but that was it. This car didn't have the gobbs of torque that the V8s put out either...

 

Mike

 

------------------

 

"I will not be a spectator in the sport of life!"

mjk

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Guest mattrp

From the sounds of it, I have spent the least of any of you guys. I estimate $6500-7000 in my car, including the price of the car. I spent $2300 on the car, a little over $3000 on the V8 conversion, $1000 on the suspension, plus some odds and ends which always pop up. I kept the engine conversion so cheap by gutting a 84 camaro z28 I bought for $700. So that has left me with:

 

305, only rebuilt the heads, will do bottom

High lift cam

T-5 tranny, didnt rebuild

ground control coilovers

R200 rear end

Custom rear sway bar

stock tires - getting autox slicks

 

In other words, one fast car.

 

My best words of advice, you WILL spend way more money than you expected. Go for it.

 

Matt

72 500Z

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Believe me, there's plenty of us out there that are survivng in our Z cars without much more than engine/transmission transplants. For those of you fortunate enough to have the money/ time/ and passion for the project, and I mean this sincerely, more power to you. If you are going to push it to the limit, top end racing or whatever, then yeah you need to be concerned with every detail and safty issue. Ditto if you need 450 hp. If you want a fast street car that can give you a lot of bang for a buck, then you can do that too, with out the high dollars. Some will shun a high powered Z with a original chassis, but come on, if you are running some decent hp in a light car, then living without risk isn't in your future. My .02 says build a car the best your wallet will let you. BTW I wouldn't trust a rusted out Z with a Yugo motor in it. A sound chassis can give plenty of good support for a street machine. Personally I don't think anyone can come up with a magic hp number that turns the Z unsafe. I think a large part of that will be who gets behind the wheel. Who did the wrenching? Who did the welding?. Did you remember to tighten your mounts? How about your lug nuts? If I had $100K to spend anywhere, it would go straight into my Z. I don't, but I've been enjoying the hell out of it for many years now with few complaints. Do your best with what you have, learn from it, improve it when you can and most of all, enjoy it!

JS

 

[This message has been edited by John Scott (edited May 04, 2000).]

 

[This message has been edited by John Scott (edited May 04, 2000).]

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