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ScramblerX

Just aquired - 73 240Z with SBF 306

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Hey all,

 

I’m a Datsun newbie! Always wanted a 240z/510 project and finally made it happen over the weekend. I picked up the 73 Datsun 250 miles away from home with the “guaranteed to make the drive” from the owner – which it did not but we’ll get to that later.

 

1973 Datsun with a SBF 306 engine with GT40p heads, single plane intake, 750 Holley HP carb, speedway headers, 3” exhaust, manual valve-body c-4 transmission with SFI bell housing and 9” stall converter, TCI shifter, R200 posi rear end, Meziere water pump. I realize the 750 carb is probably too big, I think its what the PO had around and tuned it work. Motor seems to run strong, starts up pretty easily from a cold start and sounds like a beast. I however am a complete V8 newbie.

 

Here are some pics of the car/engine.

 

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I ended up having to tow the car after 40 miles of driving as smoke started to fill the cab, when I pulled over it seemed like transmission fluid was dripping onto the exhaust. Upon examination we found the speedometer (speedometer and tach not hooked up) cable opening was closed with a rubber bushing and a wingnut. I tightened up the wingnut and have taken it for some very short trips and it has not leaked yet. So that either fixed the problem, or when the fluid gets hot it begins to leak (I think I read something about a overflow on the top of the C4.)

 

So I am working that out. Problem is – I am not a huge auto guy and would prefer a 5-speed. I don’t even know where to start with wrapping my head around what that would entail.

 

I have 2 large questions at the moment. The first is the transmission which has no transmission cooler – and it not hooked up to the radiator for cooling – is this a problem?

 

The second is the flywheel – it looks like casing was trimmed back for some reason and the flywheel is exposed – is this a problem?

 

post-54286-0-62402900-1487707766_thumb.jpg

 

Thanks for any help.

Edited by ScramblerX

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That carburetor is way too big for that engine.  A 600 cfm would work much better.

 

How is the engine mounted in the car?  Is it mounted solidly using a mid plate sandwiched between the bell-housing and block?  If the engine is not mounted solid, then that alternator mounting could cause problems when the engine moves around during acceleration.

 

The exposed flex plate for the transmission shouldn't be a problem, but I would make some kind of cover. 

 

You do need a transmission cooler of some sort, or you will burn up that transmission on the street.  This was obviously someone's drag race car, so they didn't worry about transmission heat.

 

I have a T5 in my SBF (331 stroker) powered car.  I use a Tilton hydraulic throw out bearing and 7/8 clutch master cylinder.  If you look back at some of my older posts, I provide details of the installation.

Edited by 74_5.0L_Z

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That carburetor is way too big for that engine.  A 600 cfm would work much better.

 

How is the engine mounted in the car?  Is it mounted solidly using a mid plate sandwiched between the bell-housing and block?  If the engine is not mounted solid, then that alternator mounting could cause problems when the engine moves around during acceleration.

 

The exposed flex plate for the transmission shouldn't be a problem, but I would make some kind of cover. 

 

You do need a transmission cooler of some sort, or you will burn up that transmission on the street.  This was obviously someone's drag race car, so they didn't worry about transmission heat.

 

I have a T5 in my SBF (331 stroker) powered car.  I use a Tilton hydraulic throw out bearing and 7/8 clutch master cylinder.  If you look back at some of my older posts, I provide details of the installation.

 

Everything i read about the carb agrees with you that it is oversized, I'll have to deal with that at some point.

 

regarding the transmission cooler, I'm really only driving it about 20 miles or less right now - is that something i need to look at immediately? Should I go with an external mounted or hook it up to the radiator?

It seems like there is a ton of money in the auto - I just don't want to add more if i can get the T5 in.

 

The engine is solidly mounted, I'll have to take some pictures of it at some point.

 

thanks so much for the help!!

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Use an external cooler, its cheap and easy. You can't just 'hook it up' to the radiator; it would have to have a separate cooler built into it to accommodate such a thing. IMO its a stupid design that OEMs use and its a potential for disaster if it leaks. 

 

T5 swap would be nice! You'd need to take care of clutch hydraulics, modify the mounts, and get a new driveshaft. Not a plug-n-play job but not too hard either. 

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Use an external cooler, its cheap and easy. You can't just 'hook it up' to the radiator; it would have to have a separate cooler built into it to accommodate such a thing. IMO its a stupid design that OEMs use and its a potential for disaster if it leaks. 

 

T5 swap would be nice! You'd need to take care of clutch hydraulics, modify the mounts, and get a new driveshaft. Not a plug-n-play job but not too hard either. 

 

Thanks for the info!

I agree, I think a T5 is in my future at some point but for now I'll have to deal with the auto.

I guess i'll have to do some research on an external cooler.  

 

thanks.

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Pretty sure that you can edit the title of a thread.  Change "small block chevy" to "small block ford", maybe?  Only if you want to catch the eyes of the Ford people though, instead of the chevy people.

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Pretty sure that you can edit the title of a thread.  Change "small block chevy" to "small block ford", maybe?  Only if you want to catch the eyes of the Ford people though, instead of the chevy people.

WHOA! Epic fail on my part.

 

Thanks for the heads up, I just updated the title.

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Posted (edited)

One other item to consider, you mentioned the engine is 'solid mounted', well that in itself should be changed if you're street driving it...but the other item I was concerned with is the alternator mount on the frame rail.  As the engine rocks around (on rubber mounts) you'll either tear up the belt, the alternator bearings, etc.  That tensioner arm should be connected to the engine block/heads etc, so they can all move as one unit.  

 

Oh...and verify that it actually has a 'posi' unit.  Very few people have put them in as it's generally expensive or not straightforward to do so in an R200.  It's easy for a seller to claim to have a posi when they sell a car as who's going to open it up to check when they buy it? 

Edited by yellowoctupus

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Hey.  Great car.  Have fun and enjoy your project.  It seems that without the transmission cooler, the cooling system is sort of minimal.  Like: purpose built for run long enough to complete a quarter-miler pass.

Is that remote water pump adequate for road driving?

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Thanks for the help guys.

 

One other item to consider, you mentioned the engine is 'solid mounted', well that in itself should be changed if you're street driving it...but the other item I was concerned with is the alternator mount on the frame rail.  As the engine rocks around (on rubber mounts) you'll either tear up the belt, the alternator bearings, etc.  That tensioner arm should be connected to the engine block/heads etc, so they can all move as one unit.  

 

Oh...and verify that it actually has a 'posi' unit.  Very few people have put them in as it's generally expensive or not straightforward to do so in an R200.  It's easy for a seller to claim to have a posi when they sell a car as who's going to open it up to check when they buy it? 

Is there an semi-easy way to check? I did notice I don't have a R200 finned cover.

 

Hey.  Great car.  Have fun and enjoy your project.  It seems that without the transmission cooler, the cooling system is sort of minimal.  Like: purpose built for run long enough to complete a quarter-miler pass.

Is that remote water pump adequate for road driving?

Thanks,

I definitely need to do some transmission cooler research. Autos are a foreign language to me, lol. Should i try a Ford forum for help in that subject?

 

About the water pump, I am not sure, I've only run it about 15 mins or less sense I got it home but the temperature gauge looks alright.

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Posted (edited)
Is there an semi-easy way to check?

 

 

 

Jack the car up by the differential so both rear tires are hanging.  Then spin one of the tires, if they spin opposite directions, it's an open differential, if they won't spin or spin the same direction, then you have some sort of posi or locker.

 

Per the automatic trans cooler topic, OEMS generally run your transmission cooler line into a side tank of your radiator which somewhat defeats the point of trying to cool your trans fluid (if your engine coolant / radiator is 200°F+ already.....).  It will help keep your temps from going beserk, but you're much better off plumbing in a generic or junkyard cooler, which is like a little radiator that mounts in front of your engine radiator.  

 

Basically, when trans fluid goes over 250°, the viscosity drops dramatically, which changes the fluid's friction (and changes the way it interacts with clutch discs, bands etc inside your trans).  It's a downhill spiral; your fluid gets hot, the discs start slipping, all that extra wear puts bits and pieces floating around in your fluid, which then pumps around places you don't want little bits of metal and what not.  And then your transmission dies..  Ack.

 

I installed an aftermarket cooler and a temp gauge on my Cherokee, and was able to pull a large trailer (4500#) through mountain passes in the summer heat (105°F), no problem.   Towing, you have to keep the torque converter locked if you want to keep heat down.  Whenever the TC unlocks, you get a bit more torque (it feels like it's downshifting) but it's cranking out a TON of heat.  The temp gauge needle will go from 180°F to 250°F incredibly fast if you don't manually downshift it.  I know you're probably not planning on doing a lot of towing with your Z, but it was a learning experience for me too.

Edited by yellowoctupus

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Jack the car up by the differential so both rear tires are hanging.  Then spin one of the tires, if they spin opposite directions, it's an open differential, if they won't spin or spin the same direction, then you have some sort of posi or locker.

 

Oh man, I knew that - I just wasn't thinking I guess.

 

Thanks for the info about the cooler, i'll have to get on it. I'd like a transmission temp gauge as well so i can keep an eye on it.

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Posted (edited)

Jack the car up by the differential so both rear tires are hanging.  Then spin one of the tires, if they spin opposite directions, it's an open differential, if they won't spin or spin the same direction, then you have some sort of posi or locker.

 

Jacked the car up over the weekend to start working on a suspension refresh. The rear wheels do spin in the same direction so there is some kind of locker - however it does not have the standard finned cover i have seen online. here is a picture of it.

 

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post-54286-0-37541200-1491853418_thumb.jpg

Edited by ScramblerX

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Lol, that's probably not the definition of a Posi in anyone else's book.  You may want to keep your eye open for another diff then.  Driving around with street tires on a welded diff is not much fun, besides the fact it puts huge amounts of stress on your universal joints etc. 

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Lol, that's probably not the definition of a Posi in anyone else's book.  You may want to keep your eye open for another diff then.  Driving around with street tires on a welded diff is not much fun, besides the fact it puts huge amounts of stress on your universal joints etc. 

Agreed - just another thing to add to the list.  :D

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Family life and motorcycle priorities kept me away from the Z but I'm hoping to finally get the wheels back on this weekend.

I decided to watch my budget and try to keep the mods in control which is really against my nature. Meaning I'm still pouring money into it but decided not to go to coilovers or aftermarket control arms, rods, ect.

I Rebuilt the rear suspension a couple months ago. New poly bushings all around, blasted and painted the everything, Vogtland lowering springs w/ stagg shocks. The new wheels and tires were rubbing on the old suspension and are still rubbing so picked up a fender roller and am hoping to fix that. (picture is before lowering springs).

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The front gets the same new shock/springs, bushings, blasting & paint, TC rods got the radial bearings, new wheels bearings, stoptech rotors, SW-8 calipers, Silver Mine pads, steel lines, ball joints and tie-rods.

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IMG_20171011_121713_530.thumb.jpg.fc004deaf670d0e693bd7170c4480798.jpg

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