Hi Gents Drove the 70 Skylark Custom today for the first time since installing new motor(11:1-455),new 400 trans(3500 stall),new 12 bolt rear(3.73's) What a rush!!:TU: Anyways my brake pedal is fairly hard which I think means I don't have hardly any vacuum assist because of that cam,am I right? I should mention the car has 4-drum power assist & it worked fine with the 350.The rear brakes were bled until no bubbles appeared. What is the cheapest,easiest, route to regain the vacuum it needs? Thanks-Harry
I'm not sure about easiest, but on some of the more radical 'road' engines I've built over here (I'm in the UK!), and where they wanted vacuum brakes rather than a race setup, I simply installed an external vacuum pump from a small diesel car. Regardless of cam or cam timing, perfect servo brakes every time -Gavin
A hydroboost brake set-up from an 80's Oldsmobile diesel car works like a charm :TU: ! Car Craft article about insalling hydroboost in a model year 1971 A Body GS: Click here :Comp: Gavin: Why don't you introduce yourself in the Wet behind the ears?? section of the board ? :TU:
A vacuum can can help. I'm running TA's 290-08hl which is pushing the limits for power assist. I installed a comp cams vac can and it helped.
This is what it says in the article: At the end of the article: Power Brake Service Inc. Longbeach CA Click here :Comp:
I'm going to try the vacuum cannister first & if that doesn't work I'll have to investigate a vacuum pump.I may also go to standard brakes but I'm not sure if that would be sufficent stopping power? I haven't read a lot of posts about others losing a lot of vacuum with the 510 cam,perhaps I should do another bleed,I'm also going to get a vac gauge to see what it is doing. Harry
Well the vacuum at idle is only 3hg so I installed a comp cam vacuum reservoir & it helps.At least now it will lock up all 4 wheels on a panic stop but that's it,the pedal feel still isn't right. I'm not comfortable with that so it's back to spending more cash.
Hi Harry, how & where is the distributor set-up? Yes you will need a vac pump or manual brakes. Good to see your up and running. Chris
Thanks Chris it's been a long old road installing everything by myself but the worst is over.I had an idea this was going to happen The distributor is a MSD Pro Billet set at 10* initial,32* total,idle is set low. Jamie,I'm curious how did you like the manual brakes? What is your brake set-up? That's a damn stout ET your running there.
Jamie Shoot me a contact number or link for Marcel as you know shipping items from the US is getting out of hand & would prefer to save a bit .I'm still not sure what I'm going to do for this brake issue,I was going to go all manual but these parts guys around here tell me that standard brake booster was not available for 1970 Skylark,Blah,Blah,Blah. That sucks losing a good motor but it will come back stronger with them wicked heads.I say you gain a lot more ET
Harry call Marcel @ 1 888 474 5343. He's got all kinds of cool options from rear disc conversions to powder coated calipers.I can't keep it all straight and you will like to talk with him he's a great friend and a true Buick guy. Good luck on your mission to slow that beast down.Do you plan to run it down the track?I'm trying to remember if you had your build on hold for awhile and finally finished it. Jamie
Harry, here is a link to the vaccun pump kit. part# 28146 http://www.autoanything.com/brakes/61A3151A0A0.aspx
summit has one that is slightly cheaper and i think the footprint is smaller too http://www.summitracing.com/parts/RSD-EVP01/#
I like the pump from Autoanything,cost will be $ 232.16 plus about $50.00 shipping,also got a line on rotors & spindles for $150.00,probably will go this way. Thanks for the links,avatar:Brow: Next thing I'll be confused about is the master cylinder/booster/distribution block set-up. Jamie Thanks for the number.My build has been agonizingly slow trying to save for parts but It's finally running now.You bet it's going to see track time,got a couple of BBC preachers who like to talk smack.I've got a 383 75 Vega that runs 11:70's and the Buick feels a LOT stronger. Harry
Has anyone out there ever tried runing a vacuum line off their mechanical fuel pump suction port to your power booster, or reserve tank. Needless to say you must already be suppling fuel VIA electric pump. I'm planning on giving it a shot. Larry
Harry, Glad to see your project is coming along. On big cams you need a lot more initial timing. You should set up the distributor for no more than 12 degrees mechanical advance. Then you can go to 20 degrees initial timing and have 32 at full advance. This will give you more vacuum, better idle and quicker throttle response.
