Exciting day - rebuild of 78 coupe

[Paul Benton]

Finally, my car has gone to be sprayed After 3 years of working on it, I can start to think about actually getting to drive it. Paint is going to take at least a month and then I've got to put everything back into the passenger compartment, but at least all the bits are cleaned, repaired, painted, recovered, etc and ready to go in. However, I've discovered a minor problem with my gearbox (a TH350), Once it has warmed up reverse gear is slipping . First gear works fine and had plenty of torque to drive it up onto the trailer, can't really try 2nd or 3rd yet. Hopefully I'll be able to drive it forwards for a while before having to take it off the road again and rebuild the box! Still I always wanted a project and the car hasn't disappointed in that regard.
View attachment 7628

 

[Paul Benton]

Whilst this thread is running; I am going to get my c3 painted at the end of 2024 after finishing a restoration, any experiences for quotes currently being quoted for this would be welcome to give me a ball park number?

 

[johng]

I've heard of people getting quotes from £8k to £10k. I only paid £3k although that was a few years ago now. I think it depends greatly on who you get to do the job and exactly how much you are asking them to do. The guy I used does not have a high end facility (far from it), but I was and still am very pleased with the job he did. The other thing is what you do yourself. I removed everything possible (hence the need to get the car to him on a trailer), seats, carpets, lights, door handles, locks, all trim, fuel filler, etc. He did the rubbing down, what masking up was required and the spraying. Doing these things yourself saves the painter a lot of time and hence saves you money. I would suggest you get the car painted before finishing the restoration for this reason.

 

[johng]

Well had another good day bad day today. The good day was getting the passenger side muffler fitted and it's cover almost fitted. The bad day came when I went to fit the driver's side muffler. I thought this would be easy now I knew what I was doing., it wasn't. The muffler has an attachment to the chassis at the back, then there is a 90 degree bend and finally there is a fitting that connects the bend to the header as shown on the passenger side below.


On the drivers side, even with the 90 degree bend pushed hard against the chassis rail there is a 40mm gap between the fitting and the header!!



I've checked that the bits on both sides are the same length, I did wonder if my engine is not central in the car but there is only a 5mm gap between the headers and the steering box, so the engine can't move over any. The only thing I can think is that the drivers side header has been made incorrectly, or has been badly bent ( although there is no sign of this). Anyone got any other ideas? My current plan is to go to a custom exhaust shop and get a bit of pipe made up to go between the bend and the header fitting.

 

[Chuffer]

I‘ve read before that GM didn’t fit gaskets on the iron heads and manifold. Gaskets were retro fitted if there was a leak.
You'll need a gasket with your headers though.

Very interesting snippet that GM didn`t fit gaskets on iron heads and manifolds . They obviously had high expectations of the quality of the mating faces .

 

[Forrest Gump]

Were the headers “handed” left and right? Headers for rear exiting system are obviously handed but yours for side exit are much more symmetrical.
The engine doesn’t sit centrally in the car BTW, its offset an inch or two towards passenger side.

 

[johng]

Hi Andy, that's interesting if the engine isn't central then that would explain my problem, although you would think Hedman would know that and make the left hand side longer. I did wonder if I'd put the headers on the wrong side, but they are slightly swept back and the 90 degree bends are actually a bit less than 90 degrees. Also if I put them on the opposite sides so they were swept forward the header would foul on the power steering ram and it's bracket.

 

[teamzr1]

Were the headers “handed” left and right? Headers for rear exiting system are obviously handed but yours for side exit are much more symmetrical.
The engine doesn’t sit centrally in the car BTW, its offset an inch or two towards passenger side.

Tough to see in single dimension photo

I think you are correct as it looks like on right side the flange with engine movement left/right on mounts might hit the frame
and left side looks like too far outbound, so if the engine was shifted to the right would fit better ?

Possible the mounting flanges to the heads were not welded to primaries correctly ?
Or those 90 degree bends, not true 90 deg angle bends ?

 

[johng]

I'm guessing that the 90 degree bends are supposed to be different lengths and that I've been sent 2 passenger side bends. I've emailed the vendor to find out.

 

[Forrest Gump]

Thats what got me wondering, if they were symmetrical….and you had been supplied two passenger side ones if you see what I mean. Especially as you’ve already go an issue on drivers side with the clash to steering ram. That’s not the case by the sounds though if theyre slightly swept back.

 

[Forrest Gump]

Hi Andy, that's interesting if the engine isn't central then that would explain my problem, although you would think Hedman would know that and make the left hand side longer. I did wonder if I'd put the headers on the wrong side, but they are slightly swept back and the 90 degree bends are actually a bit less than 90 degrees. Also if I put them on the opposite sides so they were swept forward the header would foul on the power steering ram and it's bracket.

If you measure from the middle of the carb to the fenders you’ll see the offset. I must admit I didn’t notice this for years of having the car! It’s to do with packaging the engine bay and space in the drivers footwell for the pedals.

It could be the headers are somewhat generic, so their projection is intentionally made equal - to suit cars other than Corvettes where the engine is central. Therefore your answer is those 90 deg connecting pipes need to be supplied different lengths for each side.

 

[teamzr1]

For 1978 C3 GM specs
W103 is 69 Inches
So measure outside edge inward 34.5 Inches should be centerline of engine if was mounted that way

 

[Invetterate]

Sorry to hear you are having problems John. It seems pretty poor to me that between a big name manufacturer and a big name supplier they can't supply you with something that actually fits! It is not as if the C3 is that rare......

A trip to Pipecraft would sort it out, I'm sure!

Good luck all round!

 

[johng]

As it happens Mark, I'm making a trip to Basildon tomorrow so I will be calling into Pipecraft if I can't get things sorted with the supplier. Hopefully it was just an error in packing the parts.

 

[Roscobbc]

If Pipecraft can't help Hayward & Scott are just around the corner on the eastern corner of Burnt Mills Ind Est......although most of their work tends to be in stainless........

 

[Oneball]

Looking at this for sale ad the drivers side 90 looks longer like it’s supposed to be longer

 

[johng]

Whilst waiting to hear back from he vendor about the bend, I finished off the fixings for the passenger side cover, which is now ready for paint. I've bought a pair of brackets which go between the chassis rail and the bottom edge of the cover to reinforce it. Weirdly the left hand bracket only fits on the right hand side and vice versa and just to make it even stranger they can only be fitted facing the wrong way around!

 

[johng]

Looking at this for sale ad the drivers side 90 looks longer like it’s supposed to be longer

Yes, I found some photos on the US forum with some measurements that show the drivers side being 35mm longer

 

[CaptainK]

I've bought a pair of brackets which go between the chassis rail and the bottom edge of the cover to reinforce it.

Where did you get the brackets from in the end? And where abouts do they fit? I'd be interested to know about that.

Side covers look good too. What colour are you gonna paint them?

 

[Nassau65]

Covers look great. Aluminium Color as originals will look best in my opinion