Need to drill intake for power brake booster?

[Pman1961]

Okay, last issue (I hope) I need to take care of prior to driving my car with the new motor. I have a KCR 445 sbf and it is a hoss! Car with previous motor never had a pcv. I've driven the car around 5 miles and I've experienced my dipstick popping up slightly and misting oil on the headers, etc. It seems the breather on the valve covers drip a little oil also. My plan is to run the pcv from the valve cover to the 3/8" vacuum port at the rear of the carburetor base. There is not enough hood clearance to use a 1" spacer with a 3/8" barb on it and I currently run a 1/4" carb spacer and that is about the max for my engine combo and hood. I will be drilling and tapping on the assembled motor. It looks as though I could use a right angle drill and tap a hole at the rear of the intake just below the base. The other option would be to tap into the drivers side rear runner I believe number 8. I can protect particles from falling down the runners more easily and with confidence tapping into the rear below the base. I've begun making a diaper out of duct tape (many redundant layers). My question is.....with the vacuum ports for the pcv (constant vacuum) and power brake booster (intermitting vacuum) being above one another approximately 3/4" to an 1" apart would there be any issues with the two components not working properly? Thanks in advance.

[Barnsnake]

I've seen OEM Ford setups using a vacuum "tree" with 4 outlets mounted into a single intake runner. Two in the plenum shouldn't be an issue.

[Pman1961]

I agree....just wanted to have some reassurance. The motor is one heck-of-a-pump. I would think it is okay too.

[CHANMADD]

Mine is set up like that, its worked perfectly, I originally had the same symptoms. I have a hose from the base to the vacuum booster with a Tee close to the carb for the pcv. The vacuum advance I took off the side port on the Holley, I did have it off the base , but that is too much vacuum .
John

[menace1]

This is from my notes.



Proper way to run vacuum hoses.

Select a location in the intake plenum to plumb your vacuum source to. Since the PCV is basically a controlled, perpetual vacuum leak, you must allow it to pull vacuum evenly from all cylinders. If the location bleeds vacuum from only one cylinder (typical of plumbing it into a single port runner) or from one bank of cylinders (typical of plumbing from one side of a dual plane intake), those affected cylinders will lean out compared to the others and potentially cause severe engine damage.

You do not want to "T" into the source going to your power brakes. The perpetual vacuum leak associated with the PCV system will diminish supply and intensity to the brake diaphragm, thus reducing your power brake performance. Since power brakes generally do not rob vacuum under power, it is relatively safe to plumb the brakes from a single port on the intake, unlike the PCV demands.

If you have a dual plane intake, you must make sure the PCV supply pulls from all cylinders evenly, such as from the nipple found at the back of most carburetors, or from a nipple in a carb spacer, which you can drill into it it's 1" or thicker. If you have a single plane intake, selecting a location in the open plenum just under the carb is ideal. Select a location (either front, back or sides) that will allow linkages to clear as well as allow the fitting itself to be screwed into the intake without interference. Mark this location with a center punch.

Now, remove the carb from the intake manifold. Then tear off single pieces of VIVA® brand paper toweling (it is the "clothiest"), and ball them up individually and place one into each port runner of the intake. Then take a flat sheet and lay it down on the plenum floor like a carpet. Now place another couple balls of toweling in the plenum, but with a heavy grease coating the top of these balls. Finally, take duct tape and tape the backside of where you are about to drill your hole leaving an "air pocket" in the center for the drill to enter into and not damage the tape. Redundancy is the key to confidently knowing that there is NO way ANY debris will ever pass by all these your lines of cautionary defense in this procedure.

Using the appropriate drill in accordance to the NPT pipe thread tap you will be using, coat the drill bit with grease to catch most of the chips. After drilling, tap the hole with more grease coating the tap as well. Pipe taps control the depth of the fitting by it's tapping depth. Trial and error will achieve perfect results by occasionally test installing the fitting while you are tapping. Do not tap too deep right off.

You can use a vacuum cleaner or light air pressure to remove any surface chips or debris. By first removing the grease coated paper towels, you should get most of it. As you remove more and more layers, if anything slips past, the next layer will surely get it. Once you get to the balls of toweling in each individual port, you can blow out the plenum area with light compressed air then remove the individual balls. Do not forget any paper towing in the intake.

Reinstall the carb and you done! That's it. And as you can surmise just by reading this simple but very effective procedure, you will not have to worry even the least about the fear of drilling your intake while still on the engine. Average time for this procedure is less than 1/2 hour.

Hope this helps,

Glenn

[Pman1961]

Thanks Glenn and to all who replied. I have a single plane Ford Motorsport Victor Jr. style intake and the best location will be at the top of the plenum in the rear to clear linkages of the carb. I can use a right angle drill and have clearance to drill and tap. Possibly may have to cut the drill bit down in length. I'll complete the procedure tomorrow and follow up.

[menace1]

Originally Posted by Pman1961

Thanks Glenn and to all who replied. I have a single plane Ford Motorsport Victor Jr. style intake and the best location will be at the top of the plenum in the rear to clear linkages of the carb. I can use a right angle drill and have clearance to drill and tap. Possibly may have to cut the drill bit down in length. I'll complete the procedure tomorrow and follow up.

Don't cut the drill bit, just mark the depth with a sharpie. Goto my public profile/albums/winter bling add-ons 2nd pic and you'll see what I did on my victor jr manifold...

[Pman1961]

Menace1....I've never mastered this site. Every time I start a new thread it takes 10 minutes to figure out how to do it. So obviously I'm having a difficult time located the winter bling add-on photo you mentioned. Can you please help me out. Thanks.

[akfish]

Club Cobra - menace1's Album: Winter bling add-ons

[bobcowan]

Originally Posted by Pman1961

Okay, last issue (I hope) I will be drilling and tapping on the assembled motor.

You're not really going to do that, are you?

[CHANMADD]

Contrary to your own advice it looks like the brake booster comes off a single intake runner??????

[vector1]

i would pull off the common plenum area if possible.

something to think about--on a vw jetta tdi i routed the crankcase to atmosphere rather than back through the turbo, which is a hose that is routed down the side to the bottom of the car. there is no residue that i noticed after 150k+ miles although it has been through rain occasionally. something to consider.

[Pman1961]

Thanks for the link akfish. Bobcowan. If the intake was off I would do it similar to the pic in the link as my fellow Cobra friend's is plumbed this way. Since the intake is on the car I am going to drill just below the base at the rear using a right angle drill. I've already made a diaper (many times over) in the plenum to catch any particles that may fall into the plenum and down the runners. I would not take the chance of trying to seal the plenum that far down the runner and drill and tap as in the pic. I had to tap for my water temperature sensor while on the assembled motor and it worked just fine. I dipped the drill bit in grease, drilled a little, cleaned bit, dipped in grease, drilled a little more and so on. Use the same technic using the tap and there was minimal shavings in grease that fell to the floor of the water jacket and just dabbed it up with a q-tip. I assure everyone...it is taped up to the hilt and only shavings that will get by will fall into the sealed open plenum only. Thanks for your concern. Metal particles and combustion chambers would be a bad mix!

[mreid]

You can also stick your shop vac in the plenum while you are drilling.

As for the power brake connection to a single runner. It is not an issue for the brakes as once the vacuum signal to the booster is established, it doesn't bleed off until you use the brakes. The pcv is a continual vacuum leak that will lean out the cylinder over time and must be conected to the plenum or carb base.