Club Cobra

Club Cobra (http://www.clubcobra.com/forums/)
-   Small Block Talk (http://www.clubcobra.com/forums/small-block-talk/)
-   -   Power brake vacuum problem,help... (http://www.clubcobra.com/forums/small-block-talk/66017-power-brake-vacuum-problem-help.html)

V-8 07-07-2005 09:49 AM
Power brake vacuum problem,help...
 
Hi Guys;
My power brakes doesn't work properly at low rpms. Because of that i can't drive my car in the city traffic. First i had bought a vacuum can but it couldn't solve the problem. Now while i was looking http://store.summitracing.com/defaul...h.asp&x=30&y=7 to this unit , i remember that i'm using http://store.summitracing.com/defaul...h.asp&x=50&y=8 so if i do an inlet to the vacuum side of the vacuum pump to the booster and close the intake manifold vacuum side.It will be ok?it will be enough for my power brakes? I wish i can explane what i want to do... THANKS

nevermind65 07-08-2005 04:04 PM
You must have a pretty horrendous cam to supply such little vacuum? Are you sure there isn't another problem somewhere?

Is the check valve working correctly? Have you pulled a vacuum on the booster independently to see if it holds? Is the cam degreed properly and/or initial timing set correctly?

Personally, I would look at another booster if you are determined to have power brakes instead of hooking up a vacuum pump. I had a truck with 5" of vacuum at idle and the power brakes worked fine with 4 wheel disks. I used a small diameter booster out of a 1 ton truck. Hit the pedal too hard and you would either lock them up or go through the windshield.

nevermind65 07-09-2005 04:51 PM
Here's a better bet. Buy a hydroboost unit from a newer Mustang Cobra and remove the vacuum booster altogether.

V-8 07-10-2005 12:37 PM
I haven't got P/S :(

V-8 07-10-2005 12:44 PM
Quote:
Originally posted by nevermind65


You must have a pretty horrendous cam to supply such little vacuum? Are you sure there isn't another problem somewhere?

Is the check valve working correctly? Have you pulled a vacuum on the booster independently to see if it holds? Is the cam degreed properly and/or initial timing set correctly?

Personally, I would look at another booster if you are determined to have power brakes instead of hooking up a vacuum pump. I had a truck with 5" of vacuum at idle and the power brakes worked fine with 4 wheel disks. I used a small diameter booster out of a 1 ton truck. Hit the pedal too hard and you would either lock them up or go through the windshield.
Yes the cam shaft is too big mech roller comp cams 240-246 and 608-614 lift. We checked every think and valve also. The problem is there is no vacuum in the idle. At the high rpms it is ok...

nevermind65 07-11-2005 02:43 PM
You don't necessarily need p/s. The Cobra set-up had a separate pump used exclusively for the hydroboost. If you were looking at hooking up a vacuum pump, this should be about the same and you'll never have to worry about vacuum again.

Why not just change the cam if it's too big? Sounds like it is causing more headaches than what's it's worth.

Excaliber 07-11-2005 03:31 PM
Why not just change the cam? Eh eh,,, well THATS what I was going to do when my old cam failed. But nooooooo, I couldn't stop there. Next thing you know I've stareing at a bare block and a complete rebuild.

...just got carried away I guess. :LOL:

nevermind65 07-11-2005 04:02 PM
I know exactly what you mean. I just traded a Lil Red Express truck I've had for 12 years for a Cobra Kit car. The Lil Red started out as needing "just a paint job". $15k later, and I was done.

I can see after 1 week I'm already headed down that path with the Cobra.

Considering he has such a huge cam, my assumption is somebody must have already torn the engine down and rebuilt it. You can't get that much lift out of factory heads with no modifications, and to run that big of a cam without about 10-11:1 compression, the car would be a slug. But hey...you never know!

V-8 07-11-2005 04:42 PM
Quote:
Originally posted by nevermind65


I know exactly what you mean. I just traded a Lil Red Express truck I've had for 12 years for a Cobra Kit car. The Lil Red started out as needing "just a paint job". $15k later, and I was done.

I can see after 1 week I'm already headed down that path with the Cobra.

Considering he has such a huge cam, my assumption is somebody must have already torn the engine down and rebuilt it. You can't get that much lift out of factory heads with no modifications, and to run that big of a cam without about 10-11:1 compression, the car would be a slug. But hey...you never know!
spects:
*408w full 4340 forged steel, 6.250 rods, JE forged- alm. pistons
*TFS twisted wedge alm. heads full ported & polished and reshaped comb. chambers
*full ported & polished EDELBROCK Victor jr. intake
*12.5:1 comp ratio
*MSD pro-billet dist-MSD 6a-MSD 50000 volt coil (blue)
*23 total advance , 98 octan pump gas
*...

V-8 07-11-2005 04:54 PM
Quote:
Originally posted by nevermind65


You don't necessarily need p/s. The Cobra set-up had a separate pump used exclusively for the hydroboost. If you were looking at hooking up a vacuum pump, this should be about the same and you'll never have to worry about vacuum again.

Why not just change the cam if it's too big? Sounds like it is causing more headaches than what's it's worth.
Hehe may be when we rebuilt my engine again, we will run with a hydraulic cam. But now, no.
Ok, if my project won't work i will buy an electric vacuum pump. But first of all i want to try my project. What is your ideas about my project?


All times are GMT -7. The time now is 12:06 PM.

Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
The representations expressed are the representations and opinions of the clubcobra.com forum members and do not necessarily reflect the opinions and viewpoints of the site owners, moderators, Shelby American, any other replica manufacturer, Ford Motor Company. This website has been planned and developed by clubcobra.com and its forum members and should not be construed as being endorsed by Ford Motor Company, or Shelby American or any other manufacturer unless expressly noted by that entity. "Cobra" and the Cobra logo are registered trademarks for Ford Motor Co., Inc. clubcobra.com forum members agree not to post any copyrighted material unless the copyrighted material is owned by you. Although we do not and cannot review the messages posted and are not responsible for the content of any of these messages, we reserve the right to delete any message for any reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold us harmless with respect to any claim based upon transmission of your message(s). Thank you for visiting clubcobra.com. For full policy documentation refer to the following link: