350 4bbl Timing???

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Can anyone tell me where the timing should be set on a 1970 350 4bbl automatic?<P>Thanks!<BR>Steve Audish<BR>

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Steve - <P>For your timing question, check out this website: <A HREF="http://www.atlantabuick.com/Tune-Up-2.htm" TARGET=_blank>http://www.atlantabuick.com/Tune-Up-2.htm</A> <P>Year One sells a book called GS Facts and Figures by Steven L Dove. I would suggest you get it. Also get the Year One catalog for your car - <A HREF="http://www.yearone.com/" TARGET=_blank>http://www.yearone.com/</A> They both contain a wealth of knowledge about GSs. I would also suggest joining the GSCA if you are not already a member ( <A HREF="http://www.buickgsca.com/" TARGET=_blank>http://www.buickgsca.com/</A> ). It's the best $35 you can spend on your Buick.<P>Marc Conigliari<p>[This message has been edited by Marc Conigliari (edited 10-02-2000).]

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Thanks for all the great info Marc!<P>Steve Audish<BR>1970 GS 350 <A HREF="http://www.lspbc.org" TARGET=_blank>http://www.lspbc.org</A>

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Although the factory spec call for 0 degrees, for decent performance I think you will find 10-12 degrees a huge improvement. Most experts also suggest re-curving the distributor to get 34-36 degrees of mechanical advance in by 2500 RPM.<P>There is a great post somewhere in the archives that describes how to add a 34 degree mark to your balancer.<P>I have a '69 Skylark 350-4 that I run at 10 degrees with HEI and I am very happy with how it runs. If I back the timing down between 0-8 degrees, the car will bog if I stomp on it.<P>Hope that helps!<P>Ron*<P>------------------<BR>'69 Skylark Convertible 350-4

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I set the timing to 6 degrees as the data sheet stated, but I am still getting some pinging on heavier acceleration.<P>I am going to install the Pertonix Ignitor and coil this weekend. Maybe this will solve the problem.<P>P.S. I just bought the car and I have not even cracked open the distributor to see what kind of condition it is in. The car seems to run great in every other way. Starts easy, and runs smooooth.<P>Thanks,<BR>Steve Audish<BR>1970 GS 350 <A HREF="http://www.lspbc.org" TARGET=_blank>http://www.lspbc.org</A>

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I have a 69 GS 350 with a turbo timing cover.<BR>Is there a timing mark available that I can put on the cover so I can ajust timing? I can't seem to find the right timing.<P>------------------<BR>Gatomon

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Yes, there is a plastic timing mark "tab" that bolts onto the cover with two small bolts. You can find one at a salvage yard on just about any Buick V-6 from the 80's. Or send me an email with your address and I'll mail one to you. I've got an extra one in a parts box.<P>Ron*<P>------------------<BR>'69 Skylark Convertible 350-4

[Guest]

Steve,<P>Are you running at least 93 Octane gas? I believe that the '70 350 had 10.25:1 advertised compression ratio. Lower octane gas would definately contribute to your pinging problem.<P>Ron*<P>------------------<BR>'69 Skylark Convertible 350-4

[Guest]

Steve,<P>Are you running at least 93 Octane gas? I believe that the '70 350 had 10.25:1 advertised compression ratio. Lower octane gas would definately contribute to your pinging problem.<P>Ron*<P>------------------<BR>'69 Skylark Convertible 350-4

[Guest]

Uhhh...93 Octane...that would be a no.<P>I didn't realize that this was a requirement with these cars. I have been running 89 and it is still costing me $23 to fill up!!! Not to mention the fact that I must get about 12 miles per gallon. This is my daily driver until February.<P>I can't imagine that this is the 350 with the higher horsepower that they put out in 1970. If it is, it sure doesn't feel like 300+ horsepower. I'm sure my 87 GN was not pushing 300 horses and it felt like it would walk all over this GS. I'm sure there are factors that I am not considering. The 350 was rebuilt to stock specs with the exception of being bored thirty over.<P>I did install the PerTronix Ignitor kit and the Flame Thrower coil last night. It does seem to run smoother now, but I still need to play with the timing a bit. I had to run the power line back to the fuse block because it wasn't starting properly. This made a huge difference.<P>Guess my next tank full should be 93 octane just to see if it makes a difference.<P>Steve

[Guest]

Steve,<P>With new pistons, all bets are off on the compression ratio. Buick changed compression ratio on all the 350's through a use of different pistons only.<P>If you can, try to find out what compression ratio the new pistons provide from the builder.<P>As I understand it, you're supposed to take your compression ratio, move the decimal one digit to the right and that is the approximate octane rating your supposed to run.<P>9.5:1 = 95 octane<BR>10:25:1 = 102.5 octane<P>FYI - I did some more checking, and in 1970 there were two 350-4's. One rated at 9:1 and the other at 10.25:1.<P>I hope the Pertronix setup works out good for you. I went with an HEI distributor I picked up at the salvage yard and it works great.<P>Ron*<P>------------------<BR>'69 Skylark Convertible 350-4

[Guest]

I guess my biggest problem is that I have no idea what the guy did to the engine when he rebuilt it. <P>I bought the car off of the second owner and it was the original owner who did the rebuild/restoration.<P>All the info I got was "bored thirty over" which isn't much help since that is normal procedure for a rebuild.<P>What cracks me up the most is that the guy rebuilt the engine to stock specs and he installed a shift kit and 3:90 gears. It shifts like a fast car, has the RPMs of a fast car, but step on the pedal and the truth comes out.<P>Like I said though, maybe the Grand National spoiled me.<P>Any other way of finding out the comperssion ratio?<P>Steve

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Steve,<BR>Do a compression check. 150 is about 9.5<BR>175 is 10.25 up<BR>Using a big cam can change everything with lift and durration. My 70 Pontiac race car should have 11 to 1 but the cam gives me readings with compression gauge of 150 lbs.<P>------------------<BR>Gatomon

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If 150 is 9.5, and the books say that '71s have 8.5, then how would mine give an overall average of 160? Highest 170, Lowest 153.<P>Currious about this..<P>Scott<BR>

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As Blackcat says, valve timing can have a major effect on compression; the only way the cylinder can build pressure is when the valves are closed.<P>Pressure that high in an 8.5:1 motor would lead me to suspect some carbon build-up that is accounting for the higher numbers on the compression gauge. Overall though it sounds as if your motor is pretty even...<P>As far as stock timing specs are concerned for the 1970 350 motors equipped with auto or 4 speed, 6 degrees BTDC is the same across the board for all the engines, even the hi-comp version.<P>Matthew

[Guest]

Steve,<BR>Have you run the car on 93 gas? Does it still ping? My 69 350 does the sane thing.<BR>I just kept retarding the timing till it stopped. That was the reason I was looking for a timing tab. I also used aftermarket gas boosters. My 350 has forged trw's and a compcams 260H cam. It sounds nice and has get up and go along with get up and gone gas milage.<P>------------------<BR>Gatomon

[Guest]

I have yet to run a tank of 93 octane. I've had the car for two weeks.<P>Unfortunately, I just filled up with a tank of 89 so I'll make sure I put the good stuff in next time. I'll also make sure to keep my foot out of it until it's all gone.<P>Steve

[Guest]

FYI:<P>My 1970 'Lark is a 9.0:1 350-2 and probably has some carbon built up in the combustion chambers. Compression hasn't been checked yet but I am running at 8 degrees BTDC and using 87 octane fuel. No matter what I do I can't get the engine to ping... it just won't. The car has TONS of power since replacing the ignition - almost hard to believe it is a 2 bbl. My understanding is that the ignition curve on the 2 bbl distributor is even more aggressive than the 4 bbl motors, putting more of both centrifugal and vacuum advance in at lower rpm.<P>It must be the higher compression in your engine (with some possible carbon?) that is giving you the trouble. My '67 340-4 (10.25:1) didn't ping under load but I always ran 92 octane in that car.<P>Matthew

[Guest]

I have a 1970 350 4b high compression.<P>I have added the protronix unit and I have recurved the distributor it is all in by 2500 and removed the vacuum advance. I have the initial timing set to 10 degrees and the total is at 30 . I have had it higher but with 120,000 on the original unit I don't want to push it. I run sunoco 94 and it runs great. I need to save my pennies so I can get some decent gears.and that should change the response from the start. otherwise if I step on it from 40mph it just screams top end is very good. The recurve kit was 8 bucks and it made a major difference.