Hooking up vacuum lines after timing - Team Camaro Tech
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post #1 of 9 (permalink) Old Jan 23rd, 17, 10:43 AM Thread Starter
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Pat
 
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Hooking up vacuum lines after timing

Hey guys, new member here... just got done posting a thread in that section as well. I've got '67 camaro with a 327 and a 2 speed powerglide. I've finally got the thing running and timed again after replacing the carb and harmonic balancer (it was a 2 piece one that kept moving the timing mark) and I'm really excited to get this thing on the road. I'm having a few problems though that are probably pretty simple. With all the vacuum ports plugged besides the rear one on the carb going to the pcv the engine finally runs and sounds great! The problem is when I hook up the vacuum advance and trans modulator the car sounds pretty bad but still runs. Before I start changing things I figured I would ask for a little help. The car has run well with this distributor before and nothing has been changed as far as the vacuum advance. I've replaced all the vacuum lines except the portion for the trans that is hardline. I've got the vac advance hooked up to ported vac and the trans hooked up to manifold. For starters, is this right? Ive got an msd 8362 distributor if that makes a difference. I'm thinking my problem might be as simple as just needing to adjust the timing with the vacuum lines hooked up to dial it in again, but I wanted to double check before I start changing things. My last question is about the brake booster, I've read that I can tee it off of a manifold vacuum source but I'm a little confused because the only port near that size is the one I'm using for pcv on the rear of the carb and I've read you aren't supposed to tee the brakes off of the pcv.
Any and all help would be greatly appreciated so thanks in advance.
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post #2 of 9 (permalink) Old Jan 23rd, 17, 10:54 AM
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Don
 
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Re: Hooking up vacuum lines after timing

Modulator leaking? Booster vac should be directly off intake. If you don't have enough ports, get a manifold fitting to make it right. Autozone has these on the help section. Mine has an inverted male fitting to fit a metal tube for booster on one side and 3 smaller nipples for other needs. .

Be sure the booster check valve, "plastic fitting" is not leaking as well as the booster.
Carb should feed your pcv.

Don
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post #3 of 9 (permalink) Old Jan 23rd, 17, 10:58 AM Thread Starter
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Re: Hooking up vacuum lines after timing

I replaced the modulator with a new one thinking the same thing. I suppose I should have double checked the new one to make sure it doesnt leak but I'm positive its fully seated against the transmission. I will be able to hook up a hand vacuum pump in a few hours to test it for sure though

I don't have enough ports so I guess I'll grab a manifold fitting on my way home. Where on the manifold should this go?
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post #4 of 9 (permalink) Old Jan 23rd, 17, 11:05 AM
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Re: Hooking up vacuum lines after timing

Quote:
Originally Posted by p12nash View Post
I replaced the modulator with a new one thinking the same thing. I suppose I should have double checked the new one to make sure it doesnt leak but I'm positive its fully seated against the transmission. I will be able to hook up a hand vacuum pump in a few hours to test it for sure though

I don't have enough ports so I guess I'll grab a manifold fitting on my way home. Where on the manifold should this go?
1967 - 1969 Camaro Intake Manifold Vacuum Fitting, Threaded Booster Tube and Three Vacuum Ports

Don
TC # 349
Zdld17:69 Z/RS,306, NOR141111, 9N554XXX, 12A, X3G, 59/59,723, AFR 195,CCC282/290HR, TKO 600, BU1122B1E Owner since Dec 1968

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post #5 of 9 (permalink) Old Jan 23rd, 17, 02:30 PM
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Mike
 
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Re: Hooking up vacuum lines after timing

What are your timing settings without vacuum advance? Did you verify TDC with the new balancer? There is some differences in where the timing mark is located on new SBC balancers. Is it in the same location as your old one relative to the keyway slot? Once you are sure you're timed correctly, you may want to try manifold vacuum for your VA.

1967 RS 327/275hp

Last edited by trland; Jan 23rd, 17 at 02:47 PM.
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post #6 of 9 (permalink) Old Jan 23rd, 17, 05:00 PM
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Al
 
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Re: Hooking up vacuum lines after timing

There were a couple of options as to how the PCV
system was set up in 67. This may or may not be
contributing to your issue. Here is a good thread from
CRG explaining the system. You may have to join
CRG to view the pics. Joining is free.
I need a bit of help... (Vacuum and PCV)

Al

my 67' build thread:
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post #7 of 9 (permalink) Old Jan 24th, 17, 10:33 AM Thread Starter
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Re: Hooking up vacuum lines after timing

I verified TDC when changing the balancer using a piston stop. It's just timed by ear right now, however it's running the best it ever has (without vac lines hooked up). I'm sure it's timed correctly right now, but I'll put a light on it and find out exactly what I've got it set to. I ordered that part for the brake booster line, thanks for the link. I also hooked up my hand vacuum pump to the hard line in the engine bay that goes to the trans modulator and I couldn't get it to hold any vac. I think the piece of vacuum hose between the hardline and the modulator must be leaking. I remember it being very loose and I just didn't have any extra on hand when I replaced the modulator. I'll replace that today and get back to you guys about whether or not that solved the problem, it seems to be the likely culprit to me. Thanks again for help so far, I really appreciate it
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post #8 of 9 (permalink) Old Jan 24th, 17, 07:18 PM
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Re: Hooking up vacuum lines after timing

This will sound stupid simple but have you inspected the hose for cracks and splits? I've been bitten before thinking its something major only to find a spot of dry rot or mouse nibble.


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post #9 of 9 (permalink) Old Jan 27th, 17, 08:30 PM Thread Starter
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Re: Hooking up vacuum lines after timing

Sorry about the delay, I got swamped at work and didn't end up having any time to play with the car. This afternoon I hooked up a hand vacuum pump to every vac line and found the transmission modulator line wouldn't hold much vacuum at all. I replaced every vac line on the car and tested them, the only one with any sort of leak is still the transmission modulator line. I think it might be the modulator itself, however it's basically brand new. If I hook the hand pump up directly to the modulator should it leak any vacuum whatsoever? Right now it leaks very slowly (If I continue to pump at any sort of pace the leak is basically not noticable but when I stop pumping it takes about 30 seconds to lose 10 in hg) Would this leak be indicative of a larger problem in the transmission or is it likely just the modulator or even the gasket between the modulator and transmission? Thanks for the help
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