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nolant178

My 350 (probably) powered 260z!

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Hello all! 

 

I just purchased a '74 260z with what I believe to be a GM 350 powering it.

 

I say I believe it to be that motor because the previous owner had said separately that it was a 327, then a 350. Upon inspecting the motor, I found the cast code: GM 3970010. My research tells me that its either from a '69 z28 Camaro, or any Chevy V8 from the 70's, most likely a truck motor. I'll be doing more research, but if anyone happens to know more, let me know!

 

I picked her up from a gentleman in Iowa for $8k. The body has a little bit of rust here an there, but nothing terrifying that I've found yet. The motor runs like a monster, which is great! The gauges are mostly not working, which is my 2nd project, after I replace the brakes. The car currently has a "pantera" style hatch, and came with the OEM hatch as well. I will probably swap to the OEM, however the pantera is growing on me....

 

I plan on adding an air dam, fender flares (I know, you either love them or hate them...), and a ducktail spoiler. I haven't decided if I'm doing coils yet, however it's very likely. For wheels, i'm leaning heavy towards Watanabe replicas, but that's a way's off still.

 

To Do List

  • Brakes - Completely Replace front: Waiting on Parts
  • Gauges - Almost all are wrong/not working
  • Paint Correction - rust removal and paint run repair
  • Suspension Bushings - Probably PU, except for TC rods
  • Interior - Dashboard replacement & cable management (likely at same time as gauge repair)
  • Tires - Existing tires are very old, tread is great but there are some cracks forming, replacing with mediocre tires since they will be replaced w/ new wheels
  • Suspension - Probably Coils, will need to do research
  • Body Accents/Aero: Air Dam, Fender Flares, and Ducktail. All painted black.
  • Wheels: Probably Rota RKR or other Watanabe reps, not until flares/suspension are sorted out, need wider tires to match.
  • Color: The paint job the previous owner gave it is of decent quality, however I'm not a fan of the pull-me-over red. Will switch to color code 302: Leave Green Metallic.
  • Engine: Bigger/better carb, long pipes, and replace wimpy exhaust.

 

 

In the GarageOffloading

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Edited by nolant178
Completed task on to-do list.

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Whew! All my parts for the bearings and brakes came in. I went with OEM parts for this job. My buddy and I worked on this for a while last night, and finally got the job done! After cleaning up the garage and putting the car back on the ground I was finally sitting in the driver seat, ready to take my first ride since I've owned it.

 

I turn the key and hear *Crank...Crank...tickticktickticktick". Turns out I drained the battery while testing the lights and electronics earlier. I looked around for a bit, but I couldn't find my jumper cables. I'll be buying a few sets of cables for my various cars, and probably a portable jumper on my way home from work today... I'll get to drive her soon!

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Alrighty. So I got the car running for a little on Friday after I got home from work! My mistake was... I ran it too low and sucked up junk from the bottom of the fuel tank.

 

Saturday I spend the day troubleshooting my fuel delivery issue, and got my new tires (cheapo tires).

 

I replaced the in-line filter on sunday and got it running, and nice and clean. It looks like my electronic choke assembly has a vacuum leak. The kickdown cable is frayed and currently disconnected from my Henderson Quadrajet Carb. I may look into a rebuild or new carb at some point.

 

I did get her cleaned up and running pretty well, so I went for some cruises. I did hit a large bump though... and UH OH! I think I popped a mount somewhere. When i'm on the gas, everything is fine, but when I take my foot off and coast at speeds greater than about 10-15mph, I hear this rhythmic THUD and feel it in the floorboard. I'm thinking I busted a trans or diff mount. I'm gonna lift the car up when I get home from work to see what I've done.

 

It was nice driving it around for a few hours. I had a guy jokingly want to buy it, and lots of looks and questions throughout the day. Too bad I broke a mount, however I'm glad it happened during a leisurely cruise and not during a drive to/from work! Wish me luck in the diagnosis!

 

While i'm under the car looking at the mounts, I'm assuming my suspension bushings are all gonna be shot - I plan on doing PU bushings soon - I've heard that PU TC rod bushings tend to cause failure, has anyone else heard this? I may get some OEM rubber bushings for that application unless someone else has a different suggestion?

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Quick update: I found a video that demonstrates my sound. I found that I had one lug on the passenger rear that was slightly looser than the FSM 65lbs of torque, but I doubt that was really it. I guess i'll go for a spin to find out.

 

Heres the video: 

 

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The issue is not related to lug nuts. The sound is definitely coming from the rear. At this point I'm guessing maybe a broken U Joint or something with my half shafts...

 

I wanted to take a break from troubleshooting that tonight, so I picked up some aluminum polish and a Mothers Powerball and polished my slot mags. I'm blown away with what 5 mins can do. I'm 100% gonna buy the cone version to get into the tighter spots to finish this job!

 

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So over the past few days I've taken the mustache bar out. I've decided that while I have any parts out of the car, I'm gonna clean them up, hit them with a wire brush, and get some fresh paint on them. I'm hoping this will clean up the look of the car as I go!

 

The uninstall wasn't bad, the only problem (aside from 44 yr old seized hardware) was that the previous owner routed the exhaust directly over some bolts I needed to remove. As a result I had to detach part of the exhaust, just enough to move it to the side to make room for my impact wrench. In detaching the exhaust, I snapped the end of an exhaust hanger, so that will have to be replaced before I cinch it all back up. The underside of this car is so dirty... it's just caked in dried mud! The paint is already in pretty poor shape... I'm wondering if I might just run it through an automatic wash with an undercarriage cleaner just to get it a bit nicer under there...

 

My PU bushing set should come in today! The reinstall should be much easier, as I wont be fighting 44 years of rust and Iowa mud. After I get these bushings in, the next step will be to use the rest of the set!

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Welcome to HybridZ and congrats on your find.  If the car truly has minimal rust, $8K is a pretty good price....especially in the midwest.

 

If your block is from a truck engine, that's actually a good thing....many of those '70's-era SBC truck engines were fitted with 4-bolt mains.  Pretty indestructible for most applications.

 

The Pantera hatch is pretty rare these days, and quite desirable in some circles.  If you decide you don't want to keep it, you could certainly sell it for a pretty penny.

 

The PU bushings will help immensely.  In addition to the mustache bar bushings going bad, the bushings on the inner mounts of your rear lower control arms are often disintegrated, which gives similar symptoms to what you're experiencing.  If you ordered an entire bushing kit, please take note that it is recommended you NOT use PU bushings on the front tension control rods.  The OEM rubber bushings are intended to flex in the frame mount, and PU bushings can overstress the mount and cause fractures/breaks in the metal and/or welds.

 

Don't waste a single opportunity to clean your electrical connections and grounds.  The S30's had some sketchy engineering on their electrical systems, and 45 years of sitting around hasn't improved the situation.  There are kits available to integrate modern relays into your parking lights and headlights, or you can design your own mod....either way, it's a big improvement on the factory design.

 

Good luck with it and don't hesitate to ask questions.  This is probably the best forum on the website for high-performance Z cars.  :-)

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5 minutes ago, jhm said:

Welcome to HybridZ and congrats on your find.  If the car truly has minimal rust, $8K is a pretty good price....especially in the midwest.

 

If your block is from a truck engine, that's actually a good thing....many of those '70's-era SBC truck engines were fitted with 4-bolt mains.  Pretty indestructible for most applications.

 

The Pantera hatch is pretty rare these days, and quite desirable in some circles.  If you decide you don't want to keep it, you could certainly sell it for a pretty penny.

 

The PU bushings will help immensely.  In addition to the mustache bar bushings going bad, the bushings on the inner mounts of your rear lower control arms are often disintegrated, which gives similar symptoms to what you're experiencing.  If you ordered an entire bushing kit, please take note that it is recommended you NOT use PU bushings on the front tension control rods.  The OEM rubber bushings are intended to flex in the frame mount, and PU bushings can overstress the mount and cause fractures/breaks in the metal and/or welds.

 

Don't waste a single opportunity to clean your electrical connections and grounds.  The S30's had some sketchy engineering on their electrical systems, and 45 years of sitting around hasn't improved the situation.  There are kits available to integrate modern relays into your parking lights and headlights, or you can design your own mod....either way, it's a big improvement on the factory design.

 

Good luck with it and don't hesitate to ask questions.  This is probably the best forum on the website for high-performance Z cars.  :-)

Hey there! 

 

That's exciting to hear about the block and the hatch. The hatch has been growing on me, but I haven't put the stock hatch on it yet to compare!

 

I had actually heard that about the TC rods, and was going to get the OEM rubber bushings for that! Scary stuff... And it totally looks like all the wiring in the car will have to be addressed at some point. Its functional for now, but not elegant by any stretch of the imagination. I'm not great w/ electrical stuff, so I'll likely be enlisting the help of others with that! 

 

I look forward to continuing this build! Thanks again for the info!

 

 

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Gahhh!

 

So I replaced the mustache bar bushings, but my noise is still present. I neglected to service the control arm bushing that was mentioned by jhm and am regretting it... I'll probably have to pull things apart again to get there. 

 

So my problem still exists, but its not like those bushings didn't need to be replaced, so it wasn't a total waste of time/effort. I'm going to try to record a video with the noise tonight to post and see if someone is able to help diagnose. At this point it could be the control arm bushings as previously mentioned, or maybe a u-joint.... or could be my diff is bad... idk.

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From your video and written description of the noise, it's rhythmic, and only on the backside of the throttle....is that correct?  Loose or worn half-shafts or driveshaft could cause noise like that.  Check all your u-joints and nuts/bolts for looseness.  Also check your differential mounting points.  If you can feel it in the floorboards, that would seem to indicate driveshaft vs half-shafts, but not definitively.

 

Possibly wheel bearings also, but usually not during straight-line driving, and I don't think one would normally feel the movement in the floorboards.

 

Good luck with it.

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1 minute ago, jhm said:

From your video and written description of the noise, it's rhythmic, and only on the backside of the throttle....is that correct?  Loose or worn half-shafts or driveshaft could cause noise like that.  Check all your u-joints and nuts/bolts for looseness.  Also check your differential mounting points.  If you can feel it in the floorboards, that would seem to indicate driveshaft vs half-shafts, but not definitively.

 

Possibly wheel bearings also, but usually not during straight-line driving, and I don't think one would normally feel the movement in the floorboards.

 

Good luck with it.

Yeah, the noise is rhythmic, only when I'm NOT (coasting or braking only) on the throttle, at speeds above 25MPH. The speed of the noise as well as the volume of the noise increase and decrease relative to speed. 

 

I did toy around with the u-joints previously. There is some minor play in the driveshaft joint at the diff, as well as the driver's side halfshaft on both sides. The play is very small, so small that you can only really feel it, not so much see it. I think my  next step is to replace all my u-joints and see if that helps.

 

Thanks for the ideas! I was pretty disappointed after replacing those bushings last night, only to have the noise still occur :(

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I've started the process of replacing the U Joints in my car. I currently have the driver's side half shaft out and have the u joints removed from the shaft.\

 

The issue became more apparent when my buddy Tim came over. We cautiously put the rear on jack stands and nervously turned it on and gave it some gas. There was a definite vibration coming from the rear, probably one of the half shafts.

 

Unfortunately I wasn't quite sure on how to remove the half shaft and wound up breaking my driver's side differential side retainer. I was lucky enough to find a replacement which is currently on it's way, thanks to @z240!

 

I'm gonna be working with my buddy Anthony to replace the u joints in the half shafts. Once the retainer arrives, I'll get it all reassembled and hopefully my noise will be fixed! 

 

If the noise still persists... I'll do the u-joints on the drive shaft as well... beyond that I'm worried that its my diff.

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I've been slowly replacing the U joints in my car. Some of them were quite tricky to press out... especially the ones on the wheel side housing of the half-shafts. The flange is not flat, so it's difficult to press them without the whole unit popping out of the press, quite dangerously.

 

Oh well... nothing a little grinder cant fix! ock8yaIkiXRapIHRDLRWGPEDJ2ii-JGUPixX2iFWtDjrMI9AM7anPWd6ZeRyOxSHO0-btAwYrfDW5tCzJS5XPZqgsFZCowlRFL32g6dHfDLToswvCdz1L1zANGqSwud7f79DcN1J2HwtcbqqJVD1haHxQTtpOWMjU0d49QqpehukQJLcoS92uKwb1vbJTvx9U73jW9puJmXEnBbTe6dNmZFRKavBqBH6LemEislsb5xxCzoD0DmR9_qti1q5fPrjyMQW8V4wvvmxUKpmRn3h9hDWAxxmhOnjxGFn4M2KYXi4yezWaqFRzL7r1mxVib4y6jjgFg6tugY1vXzqkk1ra4zfBSS-t_PRAKe06ReiMm1AitTPiKSyKbtVz7qbgU2OLqLRoAMz-6cOPV6QbUEa5YV18DE5n1l9HPjNMs2l9wMXRfdw2o2xCSSbg0NEtzAGq932QANlkUa6hO3uJSFHIxZfmkMZQ6R-IgACwoKTq24wDQ2eXHj5awthLgkR1-FsXWfqOw2BRSfVudttANhRdzPxAgYjSstZslK-DLAMtePar19JZxNXrnfy1Rq4eG30E_ee1OXxN3JV3witUlbZeZ7XyXZrLCTy1c_Sk5E=w730-h972-no

 

That'll get that pesky old u-joint out! I'm not mostly waiting for the carrier to come in, and I'll just zip her back up! Hoping to be on the road soon!

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On 4/3/2018 at 12:14 PM, nolant178 said:

Unfortunately I wasn't quite sure on how to remove the half shaft and wound up breaking my driver's side differential side retainer. I was lucky enough to find a replacement which is currently on it's way, thanks to @z240!

 

I'm gonna be working with my buddy Anthony to replace the u joints in the half shafts. Once the retainer arrives, I'll get it all reassembled and hopefully my noise will be fixed! 

 

If the noise still persists... I'll do the u-joints on the drive shaft as well... beyond that I'm worried that its my diff.

 

I've seen your other posts about the broken side plate and just realized that you're planning to install a V8.  Might be more cost effective to swap to an R200 instead of fixing the R180.  

 

The way to evaluate a u-joint is to stick a long screwdriver or other thin metal bar into the yoke and reef it around while shining a bright light on the cap seal area.  If it's worn you'll see it move.  If it's worn and dry, red powder will be apparent at the seal edge.  The seal might even be cracked and broken.  Heat on the yoke helps a lot for changing u-joints.  A lot.

 

You can evaluate the diff by removing the cover and examining the pinion shaft hole for slop and wear.

 

The R180 is not a good choice for a V8 though.  Too much torque.  You'll either stress the diff itself or do lots of one wheel burnouts, which are bad for it too.

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15 minutes ago, NewZed said:

 

I've seen your other posts about the broken side plate and just realized that you're planning to install a V8.  Might be more cost effective to swap to an R200 instead of fixing the R180.  

 

The way to evaluate a u-joint is to stick a long screwdriver or other thin metal bar into the yoke and reef it around while shining a bright light on the cap seal area.  If it's worn you'll see it move.  If it's worn and dry, red powder will be apparent at the seal edge.  The seal might even be cracked and broken.  Heat on the yoke helps a lot for changing u-joints.  A lot.

 

You can evaluate the diff by removing the cover and examining the pinion shaft hole for slop and wear.

 

The R180 is not a good choice for a V8 though.  Too much torque.  You'll either stress the diff itself or do lots of one wheel burnouts, which are bad for it too.

Hi NewZed! It actually already has a V8! I was thinking with the Auto trans the r180 might hold up ok. I've been looking into the R200. I got the broken side plate for about $35, shipped, so fairly cost effective to replace!

 

I want to do the R200 swap, i'm a total rookie when it comes to working on cars so as easy as it may seem to others, it has me intimidated a bit!

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I didn't read the whole thread.  I just saw the "probably" and assumed it meant future 350, not 350 vs 327.

 

I watched your video.  One way to differentiate between the two halfshafts and a wheel or bearing problem, and the propeller shaft and diff, might be to find a big parking lot and do tight circles, both left and right, at the same speed.  If it's a half shaft or wheel bearing or wheel the noise will be faster when that shaft is outside, because it's spinning faster.  If it's the propeller shaft and/or diff it won't change as long as speed is the same.  So, basically, if the speed of the noise changes depending on which way you're turning then it's somewhere after the output of the diff.  If it doesn't it's inside the diff or before it.  The basis of why they call it a "differential".

 

A diff swap is all big bolts and heavy objects.  Nothing to be nervous about.

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21 minutes ago, NewZed said:

I didn't read the whole thread.  I just saw the "probably" and assumed it meant future 350, not 350 vs 327.

 

I watched your video.  One way to differentiate between the two halfshafts and a wheel or bearing problem, and the propeller shaft and diff, might be to find a big parking lot and do tight circles, both left and right, at the same speed.  If it's a half shaft or wheel bearing or wheel the noise will be faster when that shaft is outside, because it's spinning faster.  If it's the propeller shaft and/or diff it won't change as long as speed is the same.  So, basically, if the speed of the noise changes depending on which way you're turning then it's somewhere after the output of the diff.  If it doesn't it's inside the diff or before it.  The basis of why they call it a "differential".

 

A diff swap is all big bolts and heavy objects.  Nothing to be nervous about.

That's a very nice way to diagnose that, thank you!  I'll have the u-joints on the half-shafts replaced by wednesday, hopefully. If the noise still happens at that point, I'll have to use that to determine the cause. If its the differential itself, I'll 100% be upgrading the R200. From my understanding i'll need the diff itself, a mustache bar from a 280z or zx that had an r200, the rear diff cover from a 280z or zx, and the stub axles, which would then attach to my existing half shafts. does that sound correct?

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.....no.....

 

280ZX's don't use a mustache bar.  You need a 280Z bar.  But you can use a 280ZX dif.  You need the piece that connects the two drop down supports, that the back ends of the control arms, with bushings, are attached to.  It is s curved for the R200, your R180 piece is straight.  People call it the dogbone.  And a 280Z R200 front differential mount.  Or an RTz design mount, which he designed for V8 applications.  People have finagled the R180 parts to make them work but getting 280Z parts is easier.  Here is a link to a guy who sells the RTz style front diff mount.  https://www.technoversions.com/

 

Since you're under there you should really just check all of the rubber bushings in the area.  There is a lot of rubber that is now dried out and aged.

 

Post up some good well-lit shots of the the rear suspension mounting points and the diff and we'll pick it apart.

 

 

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1 hour ago, NewZed said:

.....no.....

 

280ZX's don't use a mustache bar.  You need a 280Z bar.  But you can use a 280ZX dif.  You need the piece that connects the two drop down supports, that the back ends of the control arms, with bushings, are attached to.  It is s curved for the R200, your R180 piece is straight.  People call it the dogbone.  And a 280Z R200 front differential mount.  Or an RTz design mount, which he designed for V8 applications.  People have finagled the R180 parts to make them work but getting 280Z parts is easier.  Here is a link to a guy who sells the RTz style front diff mount.  https://www.technoversions.com/

 

Since you're under there you should really just check all of the rubber bushings in the area.  There is a lot of rubber that is now dried out and aged.

 

Post up some good well-lit shots of the the rear suspension mounting points and the diff and we'll pick it apart.

 

 

Yeah, I definitely need to replace bushings all over the place. I bought a polyurethane master set, and have already replaced the mustache bar bushings (I thought that might be the source of my sound...) I'll get some pictures of the rear set up. I currently have the half-shafts out for u-joint replacement, so I have lots of room for pictures

 

Thanks for all the good info. I'll have to start sourcing these parts!

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I've been slowly replacing the U Joints in my car to remove this rhythmic clunking noise. I started with the half-shafts thinking they were the most likely culprit. I finished those last night and took it for a test drive fully expecting to hear the noise still... and I did.

 

At the recommendation of @NewZed I took it to an open parking lot and did some testing. First I held the brakes and gave it some gas (not enough to burn rubber), and found that I could hear the noise even when the car isn't moving.

 

Next I drove in tight circles in both directions at the same speed - the noise was consistent in both directions. 

 

I think this means its something to do w/ my Drive Shaft - so I'm gonna try replacing those U Joints next to see! The lack of difference in tempo/volume when going in different directions tells me its probably not the diff, which is encouraging! If anyone reads this and has any other ideas as to what it could be let me know!

 

To diagnose this noise I've: 

  • Checked under the car for any loose bits/exhaust hangers etc
  • Replaced worn mustache bar bushings
  • Replaced half-shaft U joints

Hoping its the drive shaft U joints that resolve it at this point, otherwise I'm worried I've exhausted my current troubleshooting ideas.

 

Thanks for reading!

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5 hours ago, nolant178 said:

First I held the brakes and gave it some gas (not enough to burn rubber), and found that I could hear the noise even when the car isn't moving.

 

I looked through the thread and can't tell exactly, if the car has an automatic transmission.  But, if by "not moving" you mean zero MPH, then the problem is probably in your torque converter or transmission.

 

The wheels, differential and various drive and propeller shafts are all solidly locked together.  The only part that can move with the engine crankshaft is the torque converter and transmission input shaft, if the car is not moving.

 

When I watched your video "torque converter" popped in to my head as a cause.  It might be as simple as loose torque converter flex plate bolts.  I would check them soon, the beating will be damaging.

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1 hour ago, NewZed said:

 

I looked through the thread and can't tell exactly, if the car has an automatic transmission.  But, if by "not moving" you mean zero MPH, then the problem is probably in your torque converter or transmission.

 

The wheels, differential and various drive and propeller shafts are all solidly locked together.  The only part that can move with the engine crankshaft is the torque converter and transmission input shaft, if the car is not moving.

 

When I watched your video "torque converter" popped in to my head as a cause.  It might be as simple as loose torque converter flex plate bolts.  I would check them soon, the beating will be damaging.

This makes an unfortunate amount of sense. I did notice that after having the rear of the car lifted for a week and a half I found a puddle of ATF under the car. 

 

Looks like I'll be checking this out! Thanks again, you're extremely helpful!

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The sound is distinctly coming from the rear, not the Torque Converter or trans. The video I posted is close, but the location is wrong. I think what's going on is I've broken a tooth (at least) on my ring or pinion gear in my diff. I'm gonna crack it open over the weekend and see what I can find out.

 

If that's the case, I'm going to look at doing the R180 lsd swap from an STI. I'll post pictures of the diff when I crack it open to show you what I find!

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The driveshaft could easily transmit motion to the diff, making the pinion gear bounce off of the ring gear.  The noise might be from the diff but the problem is probably in the trans or converter.  There's no way the car would move like it does if you had a tooth missing.  And at zero MPH the pinion gear would have to be slipping over the ring gear.  That would make a terrible grinding noise.

 

Put your camera under the car while you do the zero speed load test.  You'll probably see the propeller shaft bouncing back and forth a degree or two.

 

On the other hand, taking things apart is always a good learning experience.  You'll want to know your diff condition anyway.  The R180 really is small for a 350.

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