the stock 350 in my 1970 buick skylark has a horrible vaccum. i cant figure out where it is coming from. i just replaced the water pump, and previous to that installation, the vaccum was either nonexistant or not nearly as bad. it sounds like it is coming from the top end of the engine, but i cant seem to find it. are there any typical gaskets or other problems that could be causing this? also, is there a simple diagnostic technique to find out where it is coming from? ~charlie~
sounds like you have a broken or cracked vacum line. go through all the lines and see if any are loose, or have cracks in them. check and see if you didnt lose a cap on one of the unused carb ports. brad.
When you say bad vac, can I assume it's running like crap? Not enough vac for the power brakes? or just a "sucking" sound from the top of the engine? A little more clarification would help. over 30 years, it's a good bet that all your soft rubber lines are shot. replacing them all is a $20 affair, and usually under an hour. To find a spacific leak, buy a can of spray starting fluid, and spray quick little puffs of it around the top of the engine. when it's sucked into the leak, the idle will smooth out for a second or two
If you think you have a leak grab a can of carb cleaner and spray the vac . lines. When you come to a cracked one the engine will pick up speed . Then you may as well replace all of them and be done with it . Good luck !:laugh: :TU:
thanks guys Darryl- yeah...the car is running like crap. the power brakes seem to be working fine, and yes, the vaccum i spoke of is a really loud and consistent hissing from the top end. does that help? any more info would be greatly appreciated.
Refer to my post in your other thread: http://www.v8buick.com/showthread.php?s=&threadid=31512&highlight=horrible+vaccum
when my 71 lark had bad vac. it turned out it was the advanced timeing in the dist. cap the thing was rusted to bad and wasnt opening/closing.. i put another one on there.. wow did that givee that 350 alot more power.
