JJTL

JJTL

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5w30 is what i run. its a sbc. it will be fine with whatever ha. if you are track driving, different story! and if u are cold starting in -30c, different story!

I track my Z as many times as i can in the summer, and before that was an 86 4+3, i run 15w40 at the track, and only synthetic, due to its resistance to heat breakdown exceeding 300f.

for street driving, long as its clean, really doesnt matter, in my opinion, based on my experience.

On that 86 high miler i had, it wasn’t maintained very good. Lots of hard crusty sludge. Id read a thread on cf about just running the cheapest oil u could find through it because you were only going to let it stay in the engine for a couple heat cycles and then drop change it. This technique worked quite well on that car. when i removed vc’s again a few months later (about three oil changes) it was substantially “cleaned up”. once that was done i then began to run synthetic 10w40 for the track and always had that in there until i sold it.

my high miler had extremely smelly oil! if you dont have nasty oil, you can pretty mich disregard the part about doing a few cleaning sacrificial oil changes
Thanks for the tips! Oil looks pretty clean on the dipstick at least.

I was leaning towards running Castrol GTX or Castrol GTX High Mileage, 5W30.
 
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JJ, one thing to share, is that most c4’s, have at least a couple issues when they change hands. you mentioned you plan on doing some wrenching. I also do mine, as a hobby, because its fun.

you may very well discover a leak requiring you to drain oil or coolant to fix. might be wise to just drive it a couple times to “discover”.

not sure what ur experience level on sbc is but with a bit of googling and some forum questions you can fix most things real quick.

mentioning the hidden bolt under the ac compressror right now! DO NOT strip that bolt by using one size to small torx bit!
 
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JJ, one thing to share, is that most c4’s, have at least a couple issues when they change hands. you mentioned you plan on doing some wrenching. I also do mine, as a hobby, because its fun.

you may very well discover a leak requiring you to drain oil or coolant to fix. might be wise to just drive it a couple times to “discover”.

not sure what ur experience level on sbc is but with a bit of googling and some forum questions you can fix most things real quick.

mentioning the hidden bolt under the ac compressror right now! DO NOT strip that bolt by using one size to small torx bit!
Great points. First SBC, but typically pretty mechanically inclined, so looking forward to the challenge. For sure once the warmer weather arrives, I plan to drive it a bit and also do a full inspection to determine what it actually needs.

Dually noted on the hidden AC compressor bolt! ;). AC is actually one of the things on my list already. Does everyone convert to R134?
 
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for ac, on all my old cars, ive bought a vacuum pump set on ebay, quite affordable and has worked great on about 10 vehicles. lots of easy vids to follow on youtube.

need a high side adapter. and low. also on ebay/amazon. the low side adapter sometimes comes with the r134a or r12a kits from autovalue or walmart etc.

work awesome. !
 
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for ac, on all my old cars, ive bought a vacuum pump set on ebay, quite affordable and has worked great on about 10 vehicles. lots of easy vids to follow on youtube.

need a high side adapter. and low. also on ebay/amazon. the low side adapter sometimes comes with the r134a or r12a kits from autovalue or walmart etc.

work awesome. !
Awesome, YouTube University here I come! Watched a few vids, doesn't seem too bad, but certainly the first time I've done it.

First I need to check if I have any leaks. Previous owner had disconnected the wire harness to the AC compressor, and told me the AC doesn't work. So I assume at the very least the refrigerant has leaked out.
 
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right. like 100% of the c4’s ive purchased ranging in price from a $1000 roach to a $15000k ZR1, every one has had empty refrigerant!!

after that connector is back on, put the car to defrost and see what happens.

if it squeals like a pig there may be issuues with the compressor itself. pretty rare. sometimes its just the magnetic clutch not the whole compressor.

but if my experience is any indication, more than likely you will plug it in and nothing will happen. the ac compressor will not engage the clutch.

next thing to do while the car is running would be to find the low side pressure switch on the ac plumbing. its on the passenger side. i cant remember exactly which switch it is but i think its the switch on the larger diameter ac pipe coming out of the evaportator enclosure.

remove the low pressure switch, i *think* its a squeeze and pull type deal.

take a paperclip and jump the pigtail on the harness. not the switch itself in the pipe. (thats no longer connected to the harness!). jump the harness.

if u r calling for ac on the hvac unit (put on defrost) then that ac clutch should engage and now spin. remove the jumper and it should stop. you just simulated as if the system had refrigerant in it.

thats what i did on all my c4’s. hope yours is that easy!

obviously, it is possible there is a leak. (for certain jobs bubba will dc the ac lines and not bother to refill) i always put one bottle of ac stop leak in as i am refilling.

i am *not* a mechanic or ac guy and i am filly aware that what i did deviates from factory refill but.....i have icecold ac. in all my cars. cheers.
 
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right. like 100% of the c4’s ive purchased ranging in price from a $1000 roach to a $15000k ZR1, every one has had empty refrigerant!!

after that connector is back on, put the car to defrost and see what happens.

if it squeals like a pig there may be issuues with the compressor itself. pretty rare. sometimes its just the magnetic clutch not the whole compressor.

but if my experience is any indication, more than likely you will plug it in and nothing will happen. the ac compressor will not engage the clutch.

next thing to do while the car is running would be to find the low side pressure switch on the ac plumbing. its on the passenger side. i cant remember exactly which switch it is but i think its the switch on the larger diameter ac pipe coming out of the evaportator enclosure.

remove the low pressure switch, i *think* its a squeeze and pull type deal.

take a paperclip and jump the pigtail on the harness. not the switch itself in the pipe. (thats no longer connected to the harness!). jump the harness.

if u r calling for ac on the hvac unit (put on defrost) then that ac clutch should engage and now spin. remove the jumper and it should stop. you just simulated as if the system had refrigerant in it.

thats what i did on all my c4’s. hope yours is that easy!

obviously, it is possible there is a leak. (for certain jobs bubba will dc the ac lines and not bother to refill) i always put one bottle of ac stop leak in as i am refilling.

i am *not* a mechanic or ac guy and i am filly aware that what i did deviates from factory refill but.....i have icecold ac. in all my cars. cheers.
also, i may be able to help you with a 1987 shop manual if you have need
 
JJTL

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right. like 100% of the c4’s ive purchased ranging in price from a $1000 roach to a $15000k ZR1, every one has had empty refrigerant!!

after that connector is back on, put the car to defrost and see what happens.

if it squeals like a pig there may be issuues with the compressor itself. pretty rare. sometimes its just the magnetic clutch not the whole compressor.

but if my experience is any indication, more than likely you will plug it in and nothing will happen. the ac compressor will not engage the clutch.

next thing to do while the car is running would be to find the low side pressure switch on the ac plumbing. its on the passenger side. i cant remember exactly which switch it is but i think its the switch on the larger diameter ac pipe coming out of the evaportator enclosure.

remove the low pressure switch, i *think* its a squeeze and pull type deal.

take a paperclip and jump the pigtail on the harness. not the switch itself in the pipe. (thats no longer connected to the harness!). jump the harness.

if u r calling for ac on the hvac unit (put on defrost) then that ac clutch should engage and now spin. remove the jumper and it should stop. you just simulated as if the system had refrigerant in it.

thats what i did on all my c4’s. hope yours is that easy!

obviously, it is possible there is a leak. (for certain jobs bubba will dc the ac lines and not bother to refill) i always put one bottle of ac stop leak in as i am refilling.

i am *not* a mechanic or ac guy and i am filly aware that what i did deviates from factory refill but.....i have icecold ac. in all my cars. cheers.

also, i may be able to help you with a 1987 shop manual if you have need
Well this is awesome. Just printed off your instructions for my notes. Thanks!

If converting from R12a to R134a, do you need to flush the system first?

I did pick up a new 1987 Service Manual, but thanks for the offer! Spring cannot come soon enough!
 
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i feel the same. been a long cold winter here too. sometimes i go out and sit in my c4 just to be in it. lol. lame i know.

i have never flushed it and ive had no problems.

there is all sorts of differing opinions on the stuff. my work truck is an 06 tacoma. my ac compressor seized and when i replaced it, i refilled with this same emzone stuff. working great.

what i really like about it is the fact that im self sufficient with it now.
 
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i feel the same. been a long cold winter here too. sometimes i go out and sit in my c4 just to be in it. lol. lame i know.

i have never flushed it and ive had no problems.

there is all sorts of differing opinions on the stuff. my work truck is an 06 tacoma. my ac compressor seized and when i replaced it, i refilled with this same emzone stuff. working great.

what i really like about it is the fact that im self sufficient with it now.
note that if your compressor has grenaded, system will need to be flished! you should be able to tell if comp has grenaded though from the sound as you jump low pressure switch. 👍

report on how it goes and i can walk u through it.
 
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i feel the same. been a long cold winter here too. sometimes i go out and sit in my c4 just to be in it. lol. lame i know.

i have never flushed it and ive had no problems.

there is all sorts of differing opinions on the stuff. my work truck is an 06 tacoma. my ac compressor seized and when i replaced it, i refilled with this same emzone stuff. working great.

what i really like about it is the fact that im self sufficient with it now.
I hope to be as self sufficient as I can on this one as well.

Ha sit in it, I say good night to it every evening :Biggrin:!
note that if your compressor has grenaded, system will need to be flished! you should be able to tell if comp has grenaded though from the sound as you jump low pressure switch. 👍

report on how it goes and i can walk u through it.
Will do. Still a few months out I guess. Got a pretty decent "to do list" though already lol.
 
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Thought I would post an update on the tire situation. After much searching I was able to find a like-new set of used 255/50R16 BFGooderich g-Force Sport Comp2 tires. The tires have really low miles, have DOT date codes of 2019 (so about 3 years old) and the tread is in great, near new condition. I should be able to run these for a few years, to buy some more time to figure out the next move; or perhaps even a manufacturer will once again make a run of 255/50R16 tires.

Thanks again for all the input here. Come on Spring!
Josh
 
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Howdy!

Well I finally had a dedicated weekend of working on the Vette, getting it ready for the road. After picking it up in January, the plan has always been to do a full service on it, since I have very little information on when fluids and other routine maintenance were completed. Was able to get the engine oil & filter changed, the 4 speed gear oil changed, the overdrive oil & filter changed, and the rear end oil changed. All went very good!.....until I noticed fresh gear oil from the transmission leaking. I had noticed that when I drained the trans, the oil was definitely low. This explains that. I think I'll create a separate thread here about the issue, and see if any Doug Nash 4+3 experts can shed some light on the issue.

If its useful to anyone, here are the fluids used:

Engine Oil: Castrol GTX (traditional oil) 5W-30
Doug Nash 4+3 - 4 Speed: Castrol 80W-90 Gear Oil GL-5 (traditional oil)
Doug Nash 4+3 - Overdrive: Motormaster ATF Dexron III (traditional oil)
Rear Differential: Royal Purple MaxGear 75W-90 Gear Oil with Friction Additive (synthetic oil)

Here are a few pics from the weekend. I at least got to drive it around the block a few times. It sure wants to go! Unfortunately, the trans leak is too bad to be driving it around just yet. Nice to see it outside though!!!
 

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Vette1993

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You did not specify where the leak is from, tailshaft (seal), side cover (gasket) possible housing crack. Check it out carefully.
 
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You did not specify where the leak is from, tailshaft (seal), side cover (gasket) possible housing crack. Check it out carefully.
Fair enough. As I mentioned above, I thought creating a separate thread for the issue would be helpful to get more eyes on it. Here is the description I gave in the dedicated thread about the leak, and what I know so far. I'm in the process still of trying to track down exactly where it is coming from.
  • Leak is clearly fresh 4 speed gear oil (gold in colour, not red like the ATF in the overdrive).
  • In changing both the oils in the trans and the overdrive, so far I have no evidence of the oils mixing. Clear gold colour.
  • Oil is leaking somewhere in the area between the 4 speed trans and the overdrive.
  • Oil is leaking down onto the top of the oil pan for the overdrive, and then rolls over it.
  • Don't see obvious leaks from the seal/gasket between the trans and overdrive, but hard to see.
  • Test drive didn't reveal any concerning noises, grinding or difficulty shifting. In fact it was all quite smooth.
Thanks for your input!
Josh
 
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I hope not...but you might have a hairline crack in the casing. May have to pull transmission to check it out.
Well the good news is there are about half a dozen other things it could be before we have to start thinking that way haha :thumbs:.

Jokes aside, thanks for the input. We'll get it figured out.
 
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Hi there everyone!

A new 1987 C4 owner from Kitchener-Waterloo, joining you here. Just picked up our Nassau Blue (Medium Blue) C4 last week, we trailered it home since it's so cold here! -15C is not ideal weather to be loading a car, but you do what you have too.

The car is blue on blue with about 117,000 kms on the odometer. 4+3 Doug Nash manual, which I believe was required in '87 for the Z51 packaged. Overall, optioned pretty highly. The last owner only put about 3,000 kms on it in the last 3 years, so needs full servicing and tune up to bring it up to our standards. In good shape otherwise, though.

One thing I'm already learning from reading some of the last threads here, is the availability (or lack there of!) of 255/50R16 tires. The DOT dates on the current Dunlops is 2003, so they are just too old to try and eek any further life out of them. I've been searching everywhere for BFGooderich g-Force Sport Comp-2 tires, but there are just none available. Don't want to give up on them, but seems it's also true they may no longer be produced. Hope they change their mind! Anyone heard any further updates? My sources here say they have no production date set in the system.

I'm aware of some of the Toyo Proxes options (RA1 and R888R), however, my plan is to regularly drive the car from May - Oct. Not sure how well these tires would be on the street, especially in the Spring and Fall temps. The final option is looking at 245/50R16 tires. These are not that common either, but I do have a source for some Cooper Zeon RS3-G1 tires in stock and available. The car has the 9.5" wide tires, so I understand the 245 might be right at the minimum.

If anyone has an other tire ideas, or comments on running either the RA1s, or running 245s, I am all ears!

Look forward to learning as much as I can from all of you, and thanks in advance for your help.
Josh
Congrats. Better pics eh. Go with Michelins - put on all the vets I've owned - on my fifth. Good luck. My home town in London.
 

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