Corvette C4 ZR-1 resto project - Jonny Smith Barn Find Car

Corvette C4 ZR-1 resto project - Jonny Smith Barn Find Car

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Llew

Original Poster:

260 posts

209 months

Wednesday 15th May
quotequote all
Hi guys

As some of you will have seen on Youtube I am the lunatic who is restoring the recent Late Brake Show "barn find" (well more of a driveway find) Corvette ZR-1...

I thought I'd start a post here in case anyone was interested in the car! I'll probaly use this thread to post updates and insights...

Situation so far in a nutshell:

Starts and runs, not well (yet)

Overhaul of fuel system (pumps, filter, injectors) complete
Ignition coils and plugs replaced (NGK leads were rubbish so we've reverted back to the standard ones)
All hoses and vac lines inspected and *seem* okay although I wouldn't be surprised if they start bursting once the car is driveable and goes through heat cycles etc.

It now appears that the alternator is not working properly so there is one on it's way to us anytime now courtesy of Rock Auto... I am hoping that once the alternator is fitted the car will run better (battery only delivering circa 11 volts)... I also need to replace the belt tensioner pulley which has play in the bearing so I'm in the process of sorting that...

The next video will show us installing new injectors.

Next step will be to go over the cooling system and flush the old coolant out, replace the thermostat etc.




motomk

2,155 posts

246 months

Thursday 16th May
quotequote all
Mentioned this car to my friend who has a 1990 C4 but not a ZR1. He said they should replace the injectors as they are prone to leaking.
His car also has the FX3 suspension which I think is similar to your car.
His car had fuel pressure problems which he eventually traced back to the fuel pump unit and the pulse dampener which we removed and replaced with some fuel proof hose. Don't think I saw one on your car when you had the fuel pump out the car. You have 2 fuel pumps where he only has one.

Tyres were another issue, as they are a rare size down here. He has Mickey Thompsons on it now. I thought they only made drag and 4WD tyres.
https://www.mickeythompsontires.com/street-tires/s...
These are way better than the old rock hard tyres it had on it.

I have mentioned it on here before, they are pretty easy to work on even for the novices like me and my friend. It does spend a lot of time in the motomk garage getting bits swapped over though. He also heavily sponsors Rockauto for parts! He always tries and gets OEM, Although we did go local for the brakes as we could raid a few of the Ford/Holden parts bins for them.




Om

1,818 posts

80 months

Thursday 16th May
quotequote all
Nice to see a thread on this car here. I recall the reviews of these in the early 90s (and driving one in Test Drive II...)!

I watched the Late Brake video and have seen some of your follow ups. I was amazed how well the interior came up with even a partial clean (at least from 6ft...). Fingers crossed for progress!


MrSmith901

274 posts

131 months

Thursday 16th May
quotequote all
Very interested in a thread on this. I own a 1992 C4, not a ZR1, but it is a manual 6 speed. Good luck with the restoration!

Llew

Original Poster:

260 posts

209 months

Thursday 16th May
quotequote all
Om said:
Nice to see a thread on this car here. I recall the reviews of these in the early 90s (and driving one in Test Drive II...)!

I watched the Late Brake video and have seen some of your follow ups. I was amazed how well the interior came up with even a partial clean (at least from 6ft...). Fingers crossed for progress!
Thanks, I thought it was worth creating a thread smile

I can remember these on Test Drive II - Good old Amigas eh! The interior has responded well to a first pass. In reality it is a bit grimy and will need the seats etc stripping out to do it properly which is pointless at this stage. I'm very much looking forward to doing a nerd level detail on it though!

Llew

Original Poster:

260 posts

209 months

Thursday 16th May
quotequote all
MrSmith901 said:
Very interested in a thread on this. I own a 1992 C4, not a ZR1, but it is a manual 6 speed. Good luck with the restoration!
Very nice! smile I bet it's got the same ZF box in it as my ZR1...?

Llew

Original Poster:

260 posts

209 months

Thursday 16th May
quotequote all
motomk said:
He said they should replace the injectors as they are prone to leaking.
His car also has the FX3 suspension which I think is similar to your car.
His car had fuel pressure problems which he eventually traced back to the fuel pump unit and the pulse dampener which we removed and replaced with some fuel proof hose. Don't think I saw one on your car when you had the fuel pump out the car. You have 2 fuel pumps where he only has one.

Tyres were another issue, as they are a rare size down here. He has Mickey Thompsons on it now. I thought they only made drag and 4WD tyres.
https://www.mickeythompsontires.com/street-tires/s...
These are way better than the old rock hard tyres it had on it.
In the video I'm releasing on Sunday I replace the injectors - It was always the plan but I wanted to slowly make changes and see what the effect of each change was, just out of interest really and to help me learn about the car... !

I replaced the pumps (you're right, ZR1 has x2) but not the socks. I have a set on order but they haven't arrived yet - Same with the pump assembly gasket which is a bit crusty on my car!

Tyres wise the choice is either a £2000 set of Michelins or a £1200 set of Nitto NT-555's which seem to be the go-to for most American ZR1 owners (they are a Toyo tyre actually, so similar compound I'd imagine to something like a Proxes TR1 I'd imagine). OE tyre on a Hellcat apparently...

I could also go Mickey Thompson but I've heard mixed reviews about them, it would be interesting to get some feedback from your friend....

MrSmith901

274 posts

131 months

Friday 17th May
quotequote all
Llew said:
Very nice! smile I bet it's got the same ZF box in it as my ZR1...?
I think it might have! From my understanding there are early ZFs (89-93.5), with an input torque rating of 450 lb/ft, and late ZFs (93.5-96), with a 400 lb/ft. rating. This is a significant difference as the helix angle on the gears is different. This was done to make the transmission quieter.

Here is my car:


LarJammer

2,244 posts

212 months

Friday 17th May
quotequote all
Been watching your videos with interest, the ZR1 is one of the few desirable US cars. What's the ultimate plan with it? Keep it / sell it / auction it off?

Llew

Original Poster:

260 posts

209 months

Friday 17th May
quotequote all
MrSmith901 said:
I think it might have! From my understanding there are early ZFs (89-93.5), with an input torque rating of 450 lb/ft, and late ZFs (93.5-96), with a 400 lb/ft. rating. This is a significant difference as the helix angle on the gears is different. This was done to make the transmission quieter.
Your car looks a peach! smile I wish mine was that clean! Ha!

I think the box is the same but the input shaft is a different length (and obviously the bell housing is a different shape)... How do you find yours to drive? I've had a couple of manual C5's but never driven a C4...

Llew

Original Poster:

260 posts

209 months

Friday 17th May
quotequote all
LarJammer said:
Been watching your videos with interest, the ZR1 is one of the few desirable US cars. What's the ultimate plan with it? Keep it / sell it / auction it off?
Thanks for watching! It is definitely an interesting car - In my opninion the true C4 halo car - Obviously you've got the Callaways but because they're not a GM in house project I think people see them as more of a curio. Then of course the Grand Sport with the LT4 which is no doubt a cool car but somehow isn't as enigmatic as the ZR-1.

Plan is to keep it once it's finished, one of us might buy the other out (we're not sure yet) but it won't be sold, at least not for the foreseeable future. Saving this car isn't about the money for us.

MrSmith901

274 posts

131 months

Friday 17th May
quotequote all
Llew said:
Your car looks a peach! smile I wish mine was that clean! Ha!

I think the box is the same but the input shaft is a different length (and obviously the bell housing is a different shape)... How do you find yours to drive? I've had a couple of manual C5's but never driven a C4...
Thanks! The paint is in very good condition for it's age, none of the usual cracking etc.

The car itself is great to drive. I wasn't sure what to expect when I first test drove one, but they actually drive more like a modern car than I thought they would, it was a big leap from the C3. Very stable at high speed, good feedback in the corners, I think the manual box makes quite a difference. I drove an auto first and it's quite a lazy box, the manual 6 speed allows you to be in full control of what the engine is doing. The box is great, no crunches, not particularly heavy.

In non ZR1 form I think the C4 is a bit of a bargain, but then I am biased. My 1992 is 300bhp as standard, with a manual 6 speed, 0-60 time was quoted at 5.3 seconds. Not super numbers by today's standards but it feels so much faster as you are basically sat on the floor. It's a real event to drive and never had so much attention in a car before. Would absolutely love a a ZR1 though!


James_N

2,975 posts

236 months

Friday 17th May
quotequote all
Nice to see a thead on the car on here. I've been greatly enjoying the youtube content so far smile

Llew

Original Poster:

260 posts

209 months

Friday 17th May
quotequote all
MrSmith901 said:
Thanks! The paint is in very good condition for it's age, none of the usual cracking etc.

The car itself is great to drive. I wasn't sure what to expect when I first test drove one, but they actually drive more like a modern car than I thought they would, it was a big leap from the C3. Very stable at high speed, good feedback in the corners, I think the manual box makes quite a difference. I drove an auto first and it's quite a lazy box, the manual 6 speed allows you to be in full control of what the engine is doing. The box is great, no crunches, not particularly heavy.

In non ZR1 form I think the C4 is a bit of a bargain, but then I am biased. My 1992 is 300bhp as standard, with a manual 6 speed, 0-60 time was quoted at 5.3 seconds. Not super numbers by today's standards but it feels so much faster as you are basically sat on the floor. It's a real event to drive and never had so much attention in a car before. Would absolutely love a a ZR1 though!
Agreed - Excellent value and the LHD is a non issue for me personally.

It's funny, they have a reputation in Europe for being terrible cars but from what I've seen they age very well and wear their miles well too... Agreed re the auto vs manual thing. I drove a C6 auto and it was really unpredicatable and generally vague feeling compared to the C5 I had at the time. I'm lucky with the views on my channel and the ZR-1 isn't a social media vanity project but I am hoping it gives a bit of exposure to Corvette in the UK and maybe influences people to take more interest in them smile

Llew

Original Poster:

260 posts

209 months

Friday 17th May
quotequote all
James_N said:
Nice to see a thead on the car on here. I've been greatly enjoying the youtube content so far smile
Thanks James! Next episode lands on Sunday... ! smile

MrSmith901

274 posts

131 months

Saturday 18th May
quotequote all
Llew said:
Agreed - Excellent value and the LHD is a non issue for me personally.

It's funny, they have a reputation in Europe for being terrible cars but from what I've seen they age very well and wear their miles well too... Agreed re the auto vs manual thing. I drove a C6 auto and it was really unpredicatable and generally vague feeling compared to the C5 I had at the time. I'm lucky with the views on my channel and the ZR-1 isn't a social media vanity project but I am hoping it gives a bit of exposure to Corvette in the UK and maybe influences people to take more interest in them smile
Well you have one more subscriber in me haha. I am on video 2 and will work my way through for sure.

mdk1

459 posts

211 months

Sunday 19th May
quotequote all
Glad to see a thread on here about your journey with the car, subscribed after Johnnys LBS vid, and enjoying your updates, nice to see what happens to a car after a driveway/ Barn find.

jrb43

811 posts

257 months

Monday 20th May
quotequote all
Llew said:
Om said:
Nice to see a thread on this car here. I recall the reviews of these in the early 90s (and driving one in Test Drive II...)!

I watched the Late Brake video and have seen some of your follow ups. I was amazed how well the interior came up with even a partial clean (at least from 6ft...). Fingers crossed for progress!
Thanks, I thought it was worth creating a thread smile

I can remember these on Test Drive II - Good old Amigas eh! The interior has responded well to a first pass. In reality it is a bit grimy and will need the seats etc stripping out to do it properly which is pointless at this stage. I'm very much looking forward to doing a nerd level detail on it though!
This has been troubling me because I distinctly remember Test Drive II - The Dual. It's the only game I ever played on our PC and I racked up hundreds of hours. Driving one of only two cars: Porsche 959 and Ferrari F40. Gear change was via the num pad: the 959 required 718293 while the F40 had a dogleg 5-speed so 18293 (I think...)

I've done some digging and it turns out there was a supplemental data disk that contained extra cars: a Lotus Turbo Esprit, Ferrari Testarossa, Ruf Twin Turbo, Lamborghini Countach and a Corvette ZR1. Apparently there was also a muscle car disk too.

Having now discovered that my childhood was incomplete, I'm now going to have to work out how to build an emulator or something so that a) I can fill in the missing parts of my development and b) my son doesn't suffer the same deprivation I did... biggrin

Om

1,818 posts

80 months

Monday 20th May
quotequote all
jrb43 said:
Llew said:
Om said:
Nice to see a thread on this car here. I recall the reviews of these in the early 90s (and driving one in Test Drive II...)!

I watched the Late Brake video and have seen some of your follow ups. I was amazed how well the interior came up with even a partial clean (at least from 6ft...). Fingers crossed for progress!
Thanks, I thought it was worth creating a thread smile

I can remember these on Test Drive II - Good old Amigas eh! The interior has responded well to a first pass. In reality it is a bit grimy and will need the seats etc stripping out to do it properly which is pointless at this stage. I'm very much looking forward to doing a nerd level detail on it though!
This has been troubling me because I distinctly remember Test Drive II - The Dual. It's the only game I ever played on our PC and I racked up hundreds of hours. Driving one of only two cars: Porsche 959 and Ferrari F40. Gear change was via the num pad: the 959 required 718293 while the F40 had a dogleg 5-speed so 18293 (I think...)

I've done some digging and it turns out there was a supplemental data disk that contained extra cars: a Lotus Turbo Esprit, Ferrari Testarossa, Ruf Twin Turbo, Lamborghini Countach and a Corvette ZR1. Apparently there was also a muscle car disk too.

Having now discovered that my childhood was incomplete, I'm now going to have to work out how to build an emulator or something so that a) I can fill in the missing parts of my development and b) my son doesn't suffer the same deprivation I did... biggrin
Indeed, the ZR1 was part of an add-on pack. You snooze, you lose!

Llew

Original Poster:

260 posts

209 months

Monday 20th May
quotequote all


There's a blast from the past!