Re: 73 Chevelle, getting close

by 73ss Mon Nov 18, 2019 7:31 pm

Flywheel wrote:Thanks 73SS. I'll be surprised if I didnt screw someting up... Lol. Trans and headers installed. Now its lookin really cool. As I'm fiddling with the detent cable I notice that now my throttle cable is stuck..the stock detent is not adjustable so I may just go ahead and replace both of them.. I went with a 2000-2300 stall converter, I'm hoping that was a good choice.

The detent cable should go directly to the gas pedal and not the carb on a '73. Hopefully your trans will work fine. Don't be alarmed if the car doesn't move at first. It can sometimes take a good 10 min or so for the converter to fill all the way up with fluid.

by Flywheel Mon Nov 18, 2019 8:42 pm

I think I'm gonna go with a later model detent, I like being able to adjust it. Disconnect detent, adjust modulator and dial in shift points, then reconnect and dial in passing gear. I was able to get about a quart into the converter before installing. I'll dump in 4 quarts before initial start up, then add 2 more during cam break in. Afyer cam break in I'll adjust fluid level then check for engagement while its on the stands.
But heres a question. I dont wanna screw a heater control valve into an edelbrock intake, it just looks wierd. So is the stock control valve normally closed until vacuum is applied? If so I found a nice compact inline valve I can install close to the bulkhead

by 73ss Mon Nov 18, 2019 9:07 pm

That I don't know. You do need the valve if it's an A\c car, otherwise heat will blow all the time, even when it's on cold.

by Flywheel Mon Nov 18, 2019 11:18 pm

I have confirmed that the heater control valve is normally open and it closes, stopping flow to the heater core when vacuum is applied. Using an AC vacuum pump I have also confirmed that when applying vacuum to the climate control switch, that in any position hot or cold, heater or AC, I have no vacuum in the heater control valve hose. Through firewall vacuum hose integrity was also verified using a vacuum pump. Looks like a manual valve will be installed until I feel the need to locate and purchase a vacuum switch. #itwantsmoremoney

by Flywheel Wed Nov 27, 2019 1:07 am

Heres the latest photo. The plan is to start it Thanksgiving morning. Open headers for cam break in, should be fun!

73 Chevelle, getting close - Page 2 20191114

by bracketchev1221 Wed Nov 27, 2019 8:20 am

Flywheel wrote:I have confirmed that the heater control valve is normally open and it closes, stopping flow to the heater core when vacuum is applied. Using an AC vacuum pump I have also confirmed that when applying vacuum to the climate control switch, that in any position hot or cold, heater or AC, I have no vacuum in the heater control valve hose. Through firewall vacuum hose integrity was also verified using a vacuum pump. Looks like a manual valve will be installed until I feel the need to locate and purchase a vacuum switch. #itwantsmoremoney

As far as I know, the heater control valve only cycles when the AC is on max a/c setting. This makes sure there is no coolant going through the heater core. Otherwise it will not move on any other setting from what I have seen.

by Flywheel Wed Nov 27, 2019 9:53 am

Thanks bracket. I'll retest.

by Flywheel Thu Nov 28, 2019 12:38 pm

Started her up this morning. Cam broke in, no leaks, good oil pressure, I have drive and reverse.. I am thankful! Happy thanksgiving everyone!!

by g3chevy / Mr Pontiac Sun Dec 01, 2019 2:09 am

Considering all the work you've done to the motor and tranny it's amazing everything functions without issue. You must have the golden touch!

by Flywheel Sun Dec 01, 2019 11:24 am

Thank you sir, I do have a green thumb, maybe there's some connection. Right now I'm trying to figure out why I only have high speed blower with the AC set to Max. I have all blower speeds in every other mode. Is that normal operation?
I ordered the exhaust kit from Jegs on black friday, still gotta build the PS pump, torque the A arms, grease the chassis and set the toe before I can test drive. Also gotta locate the wire for the temp light and figure out what the previous owner wired the electric choke to (some existing wire). Still need to replace the Vent duct hoses I removed a year ago.. It was nice to turn the blower on and not smell rat filth.

by g3chevy / Mr Pontiac Sun Dec 01, 2019 2:21 pm

Maybe I should acquire a green thumb too. Then I might have better luck with projects on my Laguna. I believe on 73-75 models that when A/C is set on Max you have only the high speed blower option. On 76 & 77 models I think it works on all settings. At least it did on my 77 El Camino I just sold. Love to hear your 73 running when you get the exhaust put on. Maybe you can post a video to YouTube? Oh, and to keep rats and mice out of my vehicles that I store for any length of time I use dryer sheets. I place them under the seats and in the A/C ducts and that usually does the trick.

by Flywheel Sun Dec 01, 2019 2:37 pm

Thanks! That does appear to be the case according to the wiring diagram. And you gotta love the blower always on low speed when the ignition is on feature, I'll be addding a switch to remedy that. (Not a problem really, it just annoys me)
I'll definately post a youtube video once the exhaust is on. I had a heck of a time getting WOT with the edelbrock carb, ended up tweaking the go fast pedal a bit to get more throw.
I had the typical no power to (some electrial load) until you wiggle a fuse concern. Cleaned the terminals and fuses, and treated with Stabilant 22. I've never had a repeated poor connection after using Stabilant.

by Flywheel Sat Dec 07, 2019 7:12 pm

Exhaust is on.. Here's the Vid.

by g3chevy / Mr Pontiac Sat Dec 07, 2019 9:39 pm

Nice! Now that's how a muscle car should look and sound!

by Flywheel Sat Dec 07, 2019 11:24 pm

Thank you sir, that is the perfect compliment!! Yeah, you don't wanna see THAT front bumper coming at ya! You're lookin' at whiplash, or tetnus, or both! I squared the left side, set the toe a 1/16th out.. No power steering (about to order the can and seals), but I took it for a spin around the neighborhood.. I have carb issues, not enough or possibly very little pump shot and it's running very rich. It also randomly misfires now and then, several cylinders in succession, under hard throttle, under load. I want to blame the carb but I'm not so sure that's a carb issue, although it has been sitting for a year. Not sure how old the control module is, but it looks old. who knows how long it ran on resistance wire in the past..
I can highly recommend the jegs exhaust kits, it was a breeze to install and looks great. 2/12 inch exhaust is a tight fit over the rear axle, and the kit works perfectly. The right side header (flowtech) turns up a bit at the collector, enough that I had to clearance the pipe at the cross member slightly, but I only had to clearance one tube at the lower control arm bracket on the right bank, again, slightly. I've never built a car for the street before (for myself).. The best way I can describe driving it... I feel like I stole something!! Laughing

Now here's the question. Do I start on the body in spring, or, do I straighten, align, and paint the front bumper satin black, throw in a premiered filler panel and enjoy the summer? I need to restore the door panels, but I don't wanna do those until I bolt the mirrors on for the last time, which I need to replace because they are broken. I have the mirrors, I guess I could satin black them too for a few months. Think I like plan B.

by Joe73 Sun Dec 08, 2019 5:16 pm

Car looks and sounds great!!! Which jegs kit did you use? Were the mufflers offset/offset or offset/center ? Any pics of the system under the floor?

by Flywheel Sun Dec 08, 2019 6:00 pm

Thanks Joe! I used - Header-Back Dual 2-1/2 in. Exhaust Kit 1973-1977 Chevelle, Malibu, El Camino, Monte Carlo, Cutlass, Century, Regal, Grand Prix Part Number : 555-30542. Mufflers are offset inlet, centered outlet. I don't have an under floor photo but the pipes hug the line of the floor pan perfectly. a couple of pipes require cutting the length to fit.
Ordred the power steering can, seal kit, carb kit and a delco control module today. I'll probably spring for the replacement plastic inner fenders after christmas, I have one plastic and one metal right now, and they're rough.

by Joe73 Sun Dec 08, 2019 6:06 pm

Awesome !!! I have and like the Jegs kit as well. But I purchased the 68-72 stainless kit just because they use the offset/offset mufflers. Im using the Pypes Race Pros. No issues going over the axle or clearing everything. Everything lines up real nicely in mine as well. I cut a bit off the length of the tailpipes because I want to use factory turn down tips. My exhaust isnt installed yet because I'd like to tweak the front pipe just a pinch for a better fit. I wont be using the supplied brackets and such. I'll be welding on a simple walker rod hanger. Great job!! Keep posting pics.

by Flywheel Sun Dec 08, 2019 6:28 pm

I got some straight chrome tips with ends cut at about 45 degrees that were already on the car and were clean enough to keep. I too gotta do some tweaking before I tack the tips in place.

by 73ss Wed Dec 11, 2019 8:01 pm

[quote="Flywheel"]Thank you sir, that is the perfect compliment!! Yeah, you don't wanna see THAT front bumper coming at ya! You're lookin' at whiplash, or tetnus, or both! I squared the left side, set the toe a 1/16th out.. No power steering (about to order the can and seals), but I took it for a spin around the neighborhood.. I have carb issues, not enough or possibly very little pump shot and it's running very rich. It also randomly misfires now and then, several cylinders in succession, under hard throttle, under load. I want to blame the carb but I'm not so sure that's a carb issue, although it has been sitting for a year. Not sure how old the control module is, but it looks old. who knows how long it ran on resistance wire in the past..
[/quote

Kind of sounds like a total timing issue. Is that a factory HEI or aftermarket? You may have too much advance. Have you played with total timing? The factory HEI's had LOTS of centrifical advance, upwards of 40~50 degrees that didn't all come in well past 4000rpm's, On top of what the vacuum advance added. If you replaced the springs with lighter ones it makes that much timing come in even quicker. Most all of these distributors were installed in lean, low compression slugs. They are also tuned to be used with a EGR valve which everyone ditched. You can braze or mig-weld the advance slots shut a small amount to limit total advance.
The old small cap points distributors had small bushings you could add or remove from the limit pin to adjust the centrifical advance. Much easier to tune. MSD and most all of the aftermarket use this design in their small cap distributors. they stole it from GM and call it their own.

by Flywheel Wed Dec 11, 2019 10:05 pm

73SS, I had the vacuum advance disconnected for the first drive. I just made sure it didn't exceed 36 on throttle snap. I've since connected it, and if my hand pump gauge is correct it's full advance at 15 in. I'm now at 8 deg BTDC base timing. I can't remember what it was with the vacuum line connected but again not exceeding 36 on throttle snap. It's a stock HEI and probably stock springs. Gonna work on it more once I get the PS back on, and see if it's resolved. It's a bear getting in and out of the shop otherwise. I got the PS Pump can today and should get the seal kit tomorrow. I don't think I've exceeded 4k RPMS though, it's pretty Rowdy and I've not left the neighborhood yet. lol
I fiddled with the carb the other night and I got the pump shot straightened out, just needed more stroke, no more bogging on throttle snap. It idles at 750 RPM in gear, and I have no more adjustment. If I press on the linkage I can get it to idle lower.. I have two springs on it, it's plenty of tension. No vacuum leaks that I can tell, quickly idles down when placing my hand on the choke horn and will die.
Thanks for the tip about mig welding the advance slots. Wish I could make a data recording on a test drive, but what fun would that be?

by bracketchev1221 Fri Dec 13, 2019 8:20 am

What does the engine idle at in neutral? I'm not a big fan of idling the engines too low especially with a flat tappet cam. The cam relies on oil splash off the crank and trying to idle it low takes that away. If it is idling at 850-900 in neutral, I wouldn't try to make it go lower. As far as timing, that is a whole other issue. You could spend hours screwing with that trying to get a better curve. For me, I like to put as much initial timing in it as I can. That allows you to close down the carb as much as possible and clean up the idle. I ran my Nova at 18 initial and 36 total. My race car idled around 30 and advanced to 36. I tried locked out timing once on the race car and broke 2 flexplates and 1 starter. Check on the total timing because you want to see where it stops advancing. It may still be advancing at 4500 rpm, like my Nova was. That one I had originally filled in the advance slots with epoxy to limit the travel so that it only had 18 degrees mechanical advance. Later on I went to an MSD ready to run, 8360 or 8361 I forget the number now but it had the built in rev limiter and you could change the stop bushings for travel limiting.

by Joe73 Fri Dec 13, 2019 11:45 am

I agree with ray. Go after that timing. Id check the dizzy first. A stock dizzy and even a stock MSD (I have the 8361 and out of the box the springs didnt stop advancing til over 4500 rpm) will advance over 4k. Thats not good.

That 8 degrees btdc is way too low. I have mine at 18 degree / no advance at 850 idle which gives me 34 degrees at 2000 rpm. BOTH WITH NO ADVANCE.

WITH ADVANCE I have 35 degrees at 920 rpm and 52 degree at 2000 rpm.

Your vacuum advance should be hooked up to MANIFOLD vacuum which would be the base plate of the carb and lower.

If your mixture screws on the carb dont make a noticeable change when you mess with them, your butterflies are open too much exposing your transfer slots.

by Flywheel Fri Dec 13, 2019 1:39 pm

I'm getting about 950 to 1000 RPM at idle in neutral. Vacuum adv is connected correctly, to manifold vac. Is 8 to 12 not factory specs with the vac advance disconnected? Being it's an iron head motor with flat tops and 63CC chambers, I'm thinking a little less timing is appropriate. 50 degrees is about right for cruising, but at WOT when the vacuum advance drops out, we should see anywhere from 32 to 42 depending on the tune. Again, I can't remember what it was with the adv connected at idle, but I wanna say 20. My understanding is that the reason you will see a ton of mech adv on some distributors is because its calibrated for port vacuum advance on smog motors that were closer to 0 BTDC. At throttle snap I saw no more than 38 degrees, that doesn't mimic 4500 RPM WOT, but my misfire didn't occur under those conditions, it was more like quarter throttle at 2800. My burnout was flawless Very Happy

I really think it was trash in the carb or a bad control module.

Mixture screws make a noticeable change when adjusted. I can't make it idle any lower but we all agree it doesn't need to so no problem, I guess.

Ray, I ran a locked out distributor on a stock car. Set to 38 degrees for racing, 42 for qualifying. Always pushed the start button to get it spinning before flipping the ignition switch on.

I'll definitely be looking at the timing @ 4500+, vacuum adv disconnected, to see just how much mechanical adv it has, then do the math. I will be swapping out the control module though, either way, because it's already ordered, it's old and cruddy, and I don't like walking.

Thanks for all the input, timing is a great topic!!

by bracketchev1221 Sat Dec 14, 2019 8:38 am

I tried the switch flipping while cranking, it’s actually how I always started it. Mine was a 14:1 548 and it just never worked right. HOWEVER, I will admit it MAY have been my fault. I had a 10/25 degree start retard I the car and figured it may start better on 25 retard. So I clipped the wire and went. I never tried the 10 degree setting and after having all my issues and giving up on locked timing I started to see others claiming 10 worked better than 25. So maybe that was the cause. I just didn’t want to risk it anymore. I missed my clean starting engine but man did it idle great at 40 degrees timing. It would start and run almost dead cold, where before I had to hold the gas until it reached about 140 degrees. On the dyno I don’t know that locked out timing helps peak power but I know it helps low end torque because you have the timing in right away. This helps a tight converter automatic car get moving better.

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