NSW Corvettes

Technical Tips => Pre 84 => Topic started by: Speedvette on February 28, 2016, 11:20:40 PM

Title: General help with my 72 Corvette Stingray
Post by: Speedvette on February 28, 2016, 11:20:40 PM
Hi all,

I bought my first Corvette Stingray about 1 week ago. All original matching numbers 72 Corvette Stingray which is a pleasure to drive.

(http://i317.photobucket.com/albums/mm394/wayno845/126e713c-0e9e-494e-9531-914585d97321_zpsmql7tu1m.jpg) (http://s317.photobucket.com/user/wayno845/media/126e713c-0e9e-494e-9531-914585d97321_zpsmql7tu1m.jpg.html)

(http://i317.photobucket.com/albums/mm394/wayno845/05493e57-8a03-43c4-8afc-96db277db8c7_zpsxnzvb0dd.jpg) (http://s317.photobucket.com/user/wayno845/media/05493e57-8a03-43c4-8afc-96db277db8c7_zpsxnzvb0dd.jpg.html)

I have a few little things I want to fix but need some advice on these issues. It seems like the heater is always on around my feet. I have noticed the vent box above my feet drivers side which is beside the steering column has a hole in it, the hole being about the size of a 10 cent piece, looks like it's meant to be there. Has had some tape over it at some stage. Is this hole supposed to be there? If it is I guess I just may have to plug it somehow.

Also there is a tap handle on the heater line in the engine bay. As I understand it, its supposed to have some sort of electric valve but instead has the manual valve. I checked it tonight and it was in the closed position, so I dont think this is the reason for the hot air coming out of the vent.

Lastly I have a PCV valve that has 2 outlets on the top of it. I need to get a new one as sometimes this one get a little noisy. Where could I get one like this?

Cheers
Title: Re: General help with my 72 Corvette Stingray
Post by: metalhead on February 29, 2016, 08:51:24 AM
Welcome! I'm no expert, but I'm sure if I get something wrong I'll be corrected! Firstly, these cars are known for bad heat soak into the footwells. If it didn't have aircon then the heater core did not originally have any way of turning it off to my knowledge, so the tap is a useful addition. Check for unplugged holes in the firewall (dark garage and someone shining a torch from the engine bay is a good way to start). I believe there are some holes that were originally for carpet plugs that are often open. I have my heater core bypassed at the moment (leaking) and it still feels like the heater is cranked in the footwell, so this is on my list too!

Not sure about the pcv or the hole in the vent you're referring to, sorry, but I'm sure someone else will be able to help out.

Great looking car!
Title: Re: General help with my 72 Corvette Stingray
Post by: sirfixalot on February 29, 2016, 08:54:40 AM
Is hole on R/hand side of column above the accelerator pedal? Car being LHD the heater box is on R/hand side of car.The main reason for hot air coming into cabin is holes in firewall.Park the car in a dark garage & put a bright light in engine bay then look in car under dash for light bleeding thru.Don't know why the PCV would be making a noise
Title: Re: General help with my 72 Corvette Stingray
Post by: Scott on February 29, 2016, 09:02:21 AM
As said, lots of heat comes through the holes in the firewall.  The tap on the heater line will be an add-on by someone trying to cool the interior down.  On mine, the water runs through the heater core all the time and the flaps in the heater box keep the heat out, in theory.  In realty most the seals in the heater are had it and let in lots of heat.  Half way down the page there are some pics of my heater box.  It's an air-con one so may be a little different.

http://nswcorvettes.com.au/forum/index.php/topic,6964.72.html (http://nswcorvettes.com.au/forum/index.php/topic,6964.72.html)
Title: Re: General help with my 72 Corvette Stingray
Post by: Speedvette on February 29, 2016, 10:19:22 AM
Thanks guys. I'll check for any firewall leaks and fill those in as best I can. The car has recently had a new heater core installed also but as I said the valve was in the closed position.

The hole in the heater box is to the right of the column ( LHD Car), I'll try and get a pic up for you guys. It definitely feels like most of the heat is coming from this hole. Not sure whether I should just seal it over with a decent tape or drill 2 small holes and screw a bit of flat plastic over it for a permanent fix. The plastic will probably look like a more meant to be there fix.

As for the PCV I'll just see if I can get something similar from the local auto parts shop.

I'll add more little issues as time goes on.

Cheers.
Title: Re: General help with my 72 Corvette Stingray
Post by: Vettech on February 29, 2016, 12:06:27 PM
I would definitely check for holes in the fire wall. Mines RHD and had a total of 32 holes, even an 1/8th" hole lets in a virtual thermal lance of heat. Once the car has forward motion, a partial vacumm is created in the cabin which sucks in the red hot air which is straight off the manifold/exhaust. People used to say Corvettes are just hot, get used to it,  "COS". In my experience, holes and the fact that the internal heat shield and other liners have been removed and not replaced are the cause. Good luck.
 Oh! Remember that the air for the heater comes in via the plenum chamber at the top of the firewall. On 78's there is a rubber seal, which seals the hood to the top of the fire wall, if this is missing or is as hard as rock, then hot air will flow thru and up the windscreen, some will enter the plenum, thru heater matrix and your back to oven basting conditions. Also the internal, heat barrier, underfelt, carpet etc extend right up the inside of the fire wall, not just to the pedals. Great looking car !..
Title: Re: General help with my 72 Corvette Stingray
Post by: Scott on February 29, 2016, 12:17:45 PM
Not sure whether I should just seal it over with a decent tape or drill 2 small holes and screw a bit of flat plastic over it for a permanent fix. The plastic will probably look like a more meant to be there fix.

Best option is to buy rubber grommets from the local rubber place that fit the existing holes.  Like below, but the blanked off ones.  Masters will stock them as well, but at much more $$$. 

(http://www.customgasketmfg.com/Images/Rubber-Grommets-Bushings.jpg)
Title: Re: General help with my 72 Corvette Stingray
Post by: bfit on February 29, 2016, 01:04:51 PM
mate there are a few hole in the fire wall that should have rubber plugs  in them.
these are a tapered plug, you can find them on most of the suppliers in the US .

check the car to see if the trans tunnel insulation is still in place.
on a trip a good amount of heat will come from the transmission  tunnel.
also make sure the heat shields are in place on the foot well  engine side  of both floor sections .
if they are  there take them of and insulate behind them and refit.

Use something like Dynamat extreme on the inside of the car.
I found that a thermal heat shield on the fire wall engine side and under the floor between the floor and the exhaust cuts down a lot of the hear transfer into the cab.
 
when you are a little more familiar with the car pull the carpets and insulator the interior floor and firewall.
 
Title: Re: General help with my 72 Corvette Stingray
Post by: 77CVT on February 29, 2016, 05:30:11 PM
Heat shield on engine side is far more effective than shielding the cabin side.   My 71 has metal "false floor" shields behind the exhaust which help.

These cars are great in winter - don't even need a heater!  ;-)  Plugging every little hole in the firewall helps.

Just get used to driving with the window down.  :bolt:

On my old 77 I attached foam with foil backing and lined from the bottom of the firewall, under the floor to the back of the seat (attached with washers/rivets).  Couldn't really see it and boy did it make an enormous difference. 
Title: Re: General help with my 72 Corvette Stingray
Post by: bfit on February 29, 2016, 06:00:19 PM
Heat shield on engine side is far more effective than shielding the cabin side.   My 71 has metal "false floor" shields behind the exhaust which help. 

Exactly
As I said re move the  heat shield on the engine side  of fire wall . Insulate behind them on the fire wall and refit shields .
I run a BB  in a 70 modle headers and large exhaust . Every thing that's generates heat.
My car. Does not get hot even on a 40 deg day
Bfit
Title: Re: General help with my 72 Corvette Stingray
Post by: Speedvette on March 01, 2016, 12:24:37 AM
Cheers guys. I've got some time this weekend so i'll fix these firewall holes then.

I need to get my front seats recovered. My interior code is 412. Looked at what EcklersCorvette sells in the U.S and it seems they only have Medium Blue original seat covers for a 72. Also looked at Corvette America's website and they only have a Royal blue for a 72. Which one would I be after? If anyone has the blue interior in a 72 I'd appreciate some help in making the right choice the first time. :thumb:

PCV is fixed too. Turned out to be a Ford PCV  :lol:

Here's a photo of the hole in the drivers side vent box just to the right of the steering column. It almost looks like to me that the box has come apart, what do you guys think?

(http://i317.photobucket.com/albums/mm394/wayno845/20160229_142846_zpskeroukdh.jpg) (http://s317.photobucket.com/user/wayno845/media/20160229_142846_zpskeroukdh.jpg.html)
Title: Re: General help with my 72 Corvette Stingray
Post by: Vettech on March 01, 2016, 11:02:37 AM
Experience with early ford/comadore tells me that is a join, and the hole looks to be moulded, some just have a hole like that to give air to the feet. The long join would have a spongy tape on one side, when pushed together forms a seal, or they use duct tape to seal and support.
Title: Re: General help with my 72 Corvette Stingray
Post by: bfit on March 01, 2016, 11:56:38 AM
you can see rite through the  duct
    a guess from me is that there should or could be a butterfly  to open or close the duct.
Title: Re: General help with my 72 Corvette Stingray
Post by: wabco40 on March 01, 2016, 12:10:34 PM
Looks like the duct has come apart. Can you push the two together?
Title: Re: General help with my 72 Corvette Stingray
Post by: bfit on March 01, 2016, 12:30:56 PM
Looks like the duct has come apart. Can you push the two together?
now that's a good possibility
Title: Re: General help with my 72 Corvette Stingray
Post by: Speedvette on March 01, 2016, 12:40:53 PM
I checked the duct and it definitely looks like its come apart. Tried to compress it together but could only get about 5mm out of it. Are they easy to remove and repair because there aint much room under there?

Checked the firewall while I was under there and there were no holes in the firewall, looks like all rubber grommets are still in place.
Title: Re: General help with my 72 Corvette Stingray
Post by: 73RAT on March 01, 2016, 08:43:42 PM
The duct definitely comes apart and yours is just about there.  The scalloping or 'hole' you see should be pushed inside, mine had done the same and it was previously PVC duct taped - don't waste your time as the tape quickly gets hot and hard and you'll be trying to clean it off next! It looks like GM use double sided tape - if you can slide it together, you may be able to do the same, or else use an adhesive that cures so it will hold, but can be removed by a sharp blade down the joint without damaging the plastic at a later date.  Sikaflex type, but it could stink a little as it cures and heats so there may be better water based products.

The heat restricting flap is mounted inside the duct above the one you show in the pic.  it has a control cable connected to it, pretty sure the ducts pictured are just to direct air downstream of the flap.   

My ducts are out of the car, they were easily removed, but I stripped the whole interior inc dash so not sure what contortions you might need to limber up for...  If you want I can take some pics of duct pieces on the w/e so you can see the metal tabs that screw up, but I find sites like Corvette America etc. have pretty good assembly manual diagrams and most often photos of the parts - just search the part description.

Like the other guys, I have spent a lot of time putting good quality sound / heat insulation under the carpet, under the trans tunnel and there are also foam seals between the chasis and body at the firewall and between the tunnel & trans (mines auto & I am not sure if this is factory)  - but i didn't do external to the fire wall, good idea!  But with the block hugging extractors and side pipes the exhaust gets out just behind the wheels so I'll get a sore ear instead of hot legs.

Good to see the PCV was a common part, great looking car and have fun with it!
Title: Re: General help with my 72 Corvette Stingray
Post by: Speedvette on March 02, 2016, 12:56:51 AM
Guess I've got 2 options to fix the duct. I can either find 2 grommets for the scalloped holes and just plug them up, or find a way to squeeze the duct together and fix it properly with double sided tape. I might try and squeeze the duct together with a G clamp but have to be mindful I dont squeeze it too much and crack it. I'll give it a go over the weekend.

Can anyone give me some advice on the reproductions seat covers from Ecklers, Corvette America and Mid America Motorworks? Whats their quality like and why Ecklers lists only Medium Blue for a 72 and Corvette America list only Royal Blue for a 72? Just trying to nut out exactly what reproduction seat covers I need to buy.

Thanks all.  :bouncesmile:
Title: Re: General help with my 72 Corvette Stingray
Post by: rosco on March 02, 2016, 08:15:30 AM
Have a look at Wilcox for seat they are very good and will give you the advise you need.
1972 was royal blue by the way not medium blue but they will give you a sample color via the net if you ask.
https://willcoxcorvette.com
Ross
Title: Re: General help with my 72 Corvette Stingray
Post by: Speedvette on March 02, 2016, 11:32:37 AM
Thanks Rosco. I sent through an email.

I need to replace the clock but then everybody probably already knew that. Think I know where to get a 2nd hand one. Are they easy to remove and replace and what needs to be removed to change it?
Title: Re: General help with my 72 Corvette Stingray
Post by: craigh on March 03, 2016, 05:23:22 AM
The hole is normal part of the duct tube that goes to the drivers side ball vent in lower dash.

You can see the remnants from the stick on seal tape that goes around that duct where it pushes together that is meant to seal it together where it joins.

It is not pushed in fully, that's why it's showing up like that.....however after 40+ years the parts don't always go together as well as they should.  (To be honest they probably did not go together perfectly when new :)

The tube is held in place at both ends by pressure and there is a bracket with a screw that mounts near the bottom edge of drivers dash, next to under dash light and odometer reset knob.

Remove the screw and you can move the duct around a bit more.  then bend bracket to fit again once happy with position.

See if that helps.
Title: Re: General help with my 72 Corvette Stingray
Post by: Speedvette on March 03, 2016, 02:28:51 PM
Cheers Craig.

I tried to super glue it together yesterday while holding it together by hand but the glue just wouldn't hold. I'll be going down the street tomorrow so I'll try and get some double sided tape and seal it up that way.

In regards to the seats. I sent an email to Willcox Corvette and all they can send is a picture of what the seats look like, not really too helpful in my opinion as the colour might still not match the interior. I'm hoping their supplier might be able to send me a sample through the mail but thats probably a long shot.

Got a problem with the alarm too, not working at all. Do these alarms have a fuse somewhere?

Thanks all for your help so far. More questions will come no doubt.

Cheers.
Title: Re: General help with my 72 Corvette Stingray
Post by: bfit on March 03, 2016, 03:21:41 PM
clean the duct  in the area  to be joined  with acetone. its very potent crap so lots of ventilation when your using it .
use plumbers silastic ( as it is air harding )
sikaflex   make some good products as well,

you will need to keep the joint together over night to make sure it will stay there.
Bfit

 
Title: Re: General help with my 72 Corvette Stingray
Post by: craigh on March 03, 2016, 05:16:51 PM
I would not try and glue or silicone the duct parts together, feel free to put some tape over the hole but consider ...... You may have to remove the cross over tube at another time when you want to get to wiring, drop the steering column, update the duct balls etc etc.

As for your seats my 71 is Bridgehampton Blue and I purchased new seat covers and foams from Wilcox corvette (made by Corvette America) Perfect match and I think it was royal blue, check my build thread for details.

Check this site

http://corvettec3.ca/interior.htm (http://corvettec3.ca/interior.htm)

Looks like the blue code is the same for 71 and 72 even though in 71 it's called dark blue.

Do you have any pictures of the current blue seats.
Title: Re: General help with my 72 Corvette Stingray
Post by: Speedvette on March 04, 2016, 01:30:47 AM
I would not try and glue or silicone the duct parts together, feel free to put some tape over the hole but consider ...... You may have to remove the cross over tube at another time when you want to get to wiring, drop the steering column, update the duct balls etc etc.

As for your seats my 71 is Bridgehampton Blue and I purchased new seat covers and foams from Wilcox corvette (made by Corvette America) Perfect match and I think it was royal blue, check my build thread for details.

Check this site

http://corvettec3.ca/interior.htm (http://corvettec3.ca/interior.htm)

Looks like the blue code is the same for 71 and 72 even though in 71 it's called dark blue.

Do you have any pictures of the current blue seats.

Yes my interior code is 412, presuming yours is the same. Looked at your build thread and it is an impressive one at that. Your original seats look identical to mine, in fact your whole interior looks the same. I would like to buy the seat covers this weekend as Willcox Corvette has a sale on which could save up to 20%.

Here's the link if anyone's interested.

http://www.corvetteforum.com/forums/c3-general/3788489-willcox-weekend-sale-carpet-dash-pads-door-panels-and-seat-cover-specials.html (http://www.corvetteforum.com/forums/c3-general/3788489-willcox-weekend-sale-carpet-dash-pads-door-panels-and-seat-cover-specials.html)

Lastly I have noticed the external blue for 70 and 71 is called BridgeHampton blue. The blue for a 72 is called Targa Blue. And the blue for 73 is called Dark Blue. My question being, are these colours essentially the same colours? I ask because I ordered some touch up paint however the maker of the paint didnt have a listing for Targa Blue, so he made it up from his listing of Dark Blue being the 73 colour.
Title: Re: General help with my 72 Corvette Stingray
Post by: craigh on March 04, 2016, 03:20:35 AM
The blue body colours were different between those years.

However your Vette has likely been painted in the last 40 years so it probably won't be 100% the original colour.

What I mean by that is paints have changed a lot in 40 years with the removal of chemical and pigments that were deemed harmful.  As such modern mixes are not exactly like the originals.

Also depends how close the match was when they did your last paint.

I have a set of colour cards from 1971 that were used in dealers to show customers and while they have aged with time it is clear my blue is not exactly like the card. 

Have also seem many bridgehamton blue vettes here and in the US and have seen lots of variation.
Title: Re: General help with my 72 Corvette Stingray
Post by: 73RAT on March 04, 2016, 09:39:39 AM
It took me literally years to get the correct mix formula for my Mulsanne Blue - my Brother-in-law is a rep for PPG and in the end he had to got through the tech guys in the states.  In saying that, it is 2K paint so will look very different to the original finish in terms of depth and reflectance (I did flip flop between factory acrylic finish or the 2K).  So even if the formula was correct, as said in the post above the pigments are different and also it will change depending on the application and flake settlement (wet film thickness of the spray) and what sort of light it is under.  Non-metallics have a much better chance at matching, but fading is an issue and as said above, who knows what actual colour it could have been resprayed. 

There is a pretty good site paintref.com that lists cars, OEM codes and shows some pictures of the cars with the similar paint option in the OEM colour, this site will also filter into 'Blue Corvettes' which will list and picture every blue Corvette with OEM codes so you can seee what colours had the same codes but different names.

I have attached as an example the Mulsanne Blue list that shows how the same GM code was called different colours.  Also pictures of the 1972 GM colour charts as mentioned above - don't use these to match paint!  Surprisingly my Mulsanne Blue is very similar to current? Mazda Astron Blue...go figure...but the Duplicolor touch-up pen and touch-up spray was acceptably close to do some out of the way touch-ups.
Title: Re: General help with my 72 Corvette Stingray
Post by: Speedvette on March 04, 2016, 10:44:38 AM
Looks like 72 Targa Blue is the exact same colour as the 73 Blue according to that website paintref.com. They have the same manufacturing, Chrysler, Diztler and Dupont code.

http://paintref.com/cgi-bin/colorcodedisplay.cgi?type=sample&ditzler=2432&syear=1972&smanuf=GM&smodel=Corvette&sname=Targa%20Blue&name=corvette1972WA4282&scomm= (http://paintref.com/cgi-bin/colorcodedisplay.cgi?type=sample&ditzler=2432&syear=1972&smanuf=GM&smodel=Corvette&sname=Targa%20Blue&name=corvette1972WA4282&scomm=)

http://paintref.com/cgi-bin/colorcodedisplay.cgi?type=sample&ditzler=2432&syear=1973&smanuf=GM&smodel=Corvette&sname=Targa%20Blue&name=corvette1973WA4282&scomm= (http://paintref.com/cgi-bin/colorcodedisplay.cgi?type=sample&ditzler=2432&syear=1973&smanuf=GM&smodel=Corvette&sname=Targa%20Blue&name=corvette1973WA4282&scomm=)
Title: Re: General help with my 72 Corvette Stingray
Post by: 73RAT on March 04, 2016, 11:21:05 AM
OEM listing is the same on the colour charts, so probably.  I found paint shops here in Australia struggled to convert the GM OEM codes into a mix formula (hence sourcing from PPG in the US) but maybe that was just my colour, as there seemed to be some conflicting OEM codes. 

See if you can find someone locally that has recently resprayed a car the same color and has kept the formula, even better if they can put some spare paint on a flat sample coupon to compare with your car and/or park the cars together or put a painted piece of one car against the other.  The base colour on a coupon will not be shiny or have the same flake lay when dry so will still look a little different...

There maybe a paint repair place / supplier that has a photospectrometer type gadget for paint matching and you can remove & use something like the gas filler cap to get a sample pot made. The local paint supplier was able to eye match a non-metallic paint for my EJ Holden and when I sprayed the bonnet and front nose panels I couldn't see any difference between bonnet and guards.
Title: Re: General help with my 72 Corvette Stingray
Post by: Speedvette on March 04, 2016, 12:02:56 PM
I got the touch up paint about 15 minutes ago. I applied to sme small chips that I have and the colour is extremely close if not a match. Obviously will need to dry properly but I'm pretty happy with the colour.
Title: Re: General help with my 72 Corvette Stingray
Post by: bfit on March 04, 2016, 12:53:40 PM
OEM listing is the same on the colour charts, so probably.  I found paint shops here in Australia struggled to convert the GM OEM codes into a mix formula (hence sourcing from PPG in the US) but maybe that was just my colour, as there seemed to be some conflicting OEM codes. 

See if you can find someone locally that has recently resprayed a car the same color and has kept the formula, even better if they can put some spare paint on a flat sample coupon to compare with your car and/or park the cars together or put a painted piece of one car against the other.  The base colour on a coupon will not be shiny or have the same flake lay when dry so will still look a little different...

There maybe a paint repair place / supplier that has a photospectrometer type gadget for paint matching and you can remove & use something like the gas filler cap to get a sample pot made. The local paint supplier was able to eye match a non-metallic paint for my EJ Holden and when I sprayed the bonnet and front nose panels I couldn't see any difference between bonnet and guards.
the problem is not that the local paint suppliers can not convert the formula's  for the  colours
its that the paints now days are completely different products.

Back in the 60`s /70`s the paint  were  nitrocellulose lacquer ( duco )  I don't remember what the base of the metallic paints was at that time.
bfit
Title: Re: General help with my 72 Corvette Stingray
Post by: craigh on March 04, 2016, 04:14:07 PM
It took me literally years to get the correct mix formula for my Mulsanne Blue - my Brother-in-law is a rep for PPG and in the end he had to got through the tech guys in the states.  In saying that, it is 2K paint so will look very different to the original finish in terms of depth and reflectance (I did flip flop between factory acrylic finish or the 2K).  So even if the formula was correct, as said in the post above the pigments are different and also it will change depending on the application and flake settlement (wet film thickness of the spray) and what sort of light it is under.  Non-metallics have a much better chance at matching, but fading is an issue and as said above, who knows what actual colour it could have been resprayed. 

There is a pretty good site paintref.com that lists cars, OEM codes and shows some pictures of the cars with the similar paint option in the OEM colour, this site will also filter into 'Blue Corvettes' which will list and picture every blue Corvette with OEM codes so you can seee what colours had the same codes but different names.

I have attached as an example the Mulsanne Blue list that shows how the same GM code was called different colours.  Also pictures of the 1972 GM colour charts as mentioned above - don't use these to match paint!  Surprisingly my Mulsanne Blue is very similar to current? Mazda Astron Blue...go figure...but the Duplicolor touch-up pen and touch-up spray was acceptably close to do some out of the way touch-ups.

Any chance you have  the same pages PPG above form. 71 ?
Title: Re: General help with my 72 Corvette Stingray
Post by: 73RAT on March 05, 2016, 09:30:09 AM
Hi craigh - not really sure but is this what you were after?
Title: Re: General help with my 72 Corvette Stingray
Post by: craigh on March 05, 2016, 09:38:00 AM
Perfect thanks