Thanks I will try that tomorrow. I did that today and it idled a little smoother. Will I have to replace the intake gasket again?
Not to hijack the thread but, do y'all recommend using the rubber intake gaskets or as I've found with chevy's is it better to just use a thick line of RTV?
The rubber gaskets at the front and rear of the intake are for oil control only. They will have nothing to do with an intake leak. Any intake leak will be around the intake ports on the heads..
The rear part of the Buick 350 intake is the most likely place to leak. This is neoprene and I shave off the grooves with a razor blade and then add THIN RTV layers lightly on both sides. I let the intake sit for 2 hours after the initial 15 foot pounds torque on the intake bolts, then I torque to spec in the designated order. If the RTV is too fresh and you do not trim the neoprene gasket then it will all spit out the back side when you torque to spec.
Here is a question for you. If your engine is pissing oil onto the transmission from a leaking oil seal between the intake manifold and the block then would you have lower vacuum readings? Or would your engine LOVE the fact that the wedge between the crank and the main bearings was being leaked all underneath the car?
Hey funny man I believe you know what I was saying. I adjusted the timing to several spots and couldn't get it anywhere near what the book says to set it at.
Well yes the engine will like 12-15 degrees timing at idle, the key to making this work is limiting the mechanical timing to 18-20 degrees, all in by 2200 rpms and equate to 30-35 degrees of timing. If you advance the initial timing setting and do not make modifications to the mechanical advance and vacuum advance then you are going to overtime the engine and destroy it. The safe way is to tune for total timing of 28 degrees for low comrpession engines and 32-36 for high compression engine.
How exactly do you modify vacuum advance and mechanical advance? I had my motor tuned perfectly and it ran flawlessly except for the burnt trans, and all me my buddies and my dad have ever done to any of our cars is set the initial timing, and look and the total timing, dads 396 gets set at 36 and I had mine at around 32 if I remember right and about 13 initial. I'd like to be enlightened myself about this whole timing thing, the way some of you small block buick guys describe tuning these motors to a beginner looks like trigg, algebra, and calculus put together, tuning carbuerated v8's is not that complicated, not to hijack the thread but, I believe his problem isn't timing, nor a vacuum leak, vacuum leaks make the motor run rough at idle and low rpm, when you flatten the go pedal the vacuum leak doesn't affect anything anymore, especially power, I should know my motor was diseased with multiple large vacuum leaks at different times. I agree with doing a compression test, but that I dont think is the problem, as he has added performance parts recently and this lull in power didn't occur over time. I strongly suggest you look into the health of your transmission, I suggested that because I kept adding performance upgrades to my 350 and the car got slower with everything I did to it, the more power I pushed on the 350 the quicker the trans burnt out, thus acceleration especially right from a stop suffered. I would think your carb could be a problem area too, what carb is it? The knowledge among buick guys seems to be that the bigger the better when it comes to carbs, apparently stock rebuilt 455 q jets work really well, I noticed a decrease in torque going from my boggy old 750 holley to a brand new 670.
You have made the most sense to me. I am not nearly as experienced as most people on here. I can understand Trig, algebra and calculus better than this. I have been able to get it to run a little better though. I just got finished tinkering with it and it's running a little smoother and performing a little better. I didn't get to break the cam in properly because my carb was leaking like a sieve. The carb I bought was from a board member that said it ran fine when he pulled the motor 7 yrs. ago. I don't expect it to perform like a rebuilt carb but was hoping after letting it run a little it might loosen up. It is a 750 quadrajet.
Some weld the slots in the dist. for the mechanical advance then file out the slot till you get the amount of total advance. This is particularly important to do if you have a HEI style dist. since many of them have HUGE amounts of advance compared to the most of the points dist. this requires a lower initial timing setting to keep the total timing happy and not over-timed. I just modified a HEI dist to give 14 degrees mechanical advance, with the initial timing set at 20 degrees 34 total timing all in by 2400 rpms. There are so many variables in this each combination of parts so it takes trial and error to extract the BEST power combination for any given engine. Things like engine health, vehicle weight, gearing ect all come into play when it comes to timing settings. An engine dyno is where you can quickly and easily extract the best combination and save tons of tuning. Buick 350s need some timing early in the rpms, all 350s I have heard gain about 20 ft of tq and when initial timing is moved about 6-10 degrees higher than the factory spec. The problem is you need to reduce the mechanical advance. The next step is to find the right combination of springs to control the mechanical advance and how quickly it comes in. I use an adjustable crane vacuum advance kit that comes with various weight springs for the mechanical advance. Then there is the vacuum canister, the crane adjustable unit has the advantage that you can use an allen key to adjust the rate at which it comes in. If you hear any ping that only happens when you have the vacuum advance plugged in then you know you need to either limit the amount of vacuum advance (a nut and bolt work or welding the slot), or use the allen key to slow it down. So I end up with a very smooth idle (TA212 cam), 700 rpm idle, stock NOS 73 Q jet and idle mixture screws are happy at 2 and screws out however a half turn either way and the idle quality goes to the garbage.
If I'm not mistaken, you'd have to use way too much RTV on the ends.. the gap can be quite large unless you have machined a fair bit off your heads. I know mine was slightly inbetween since the heads are milled 20 thou. Had to trim down the rubber gasket.
I can get it down to 8* with a fairly smooth idle. I exchanged my points for a pertronix ignition that worked great before the parts were added. How do you set the mechanical advance with this ignition?
You set it the same way as with points. The pertronix replaces the points in a regular distributor. So the initial, vacuum, and mechanical are set the same way. And this was covered earlier in the thread. Not to be a jerk but it sounds to me like there's some confusion going on here. A lot of this stuff is fairly basic if you know the fundamentals: ignition tuning, carb adjustment, etc. I don't know if there is some sort of a tutorial on this stuff, maybe somebody else can get a helpful link? You'll figure it out, just don't get discouraged with the setbacks.
Here's the timing thread, works for small blocks too: http://www.v8buick.com/showthread.php?t=63475 Devon
