Power Timing your Buick V8

The only way to figure out the specs of the cam without any documentation is to degree the cam in the engine. That entails using a cam degree wheel and kit. There is a sticky in the BB engine forum on cam degreeing, have a look at it.

Bare minimum for power brakes is 10" of vacuum. Put a vacuum gauge on the engine and see what it pulls. Initial timing can affect vacuum at idle.

As far as you heater troubles, you'll have to trouble shoot it with a meter. Get the Buick Chassis manual for your year Buick.

 

Possibly, but I wouldn't bother. It would be a lot of bother for questionable gain, but if you have time on your hands, go for it. I'm sure a jetting change would be of benefit also. If you had 2 carburetors, you could jet one for winter and summer.

 

The only time you need to make a second mark is when you DON'T have a dial back advance timing light. The mark you make is on the balancer, and has NOTHING to do with what your current initial timing is. There is a factory groove/mark on the balancer. The second 30* mark would be 1 3/4" clockwise along the balancer, from that factory mark. You would then use that 30* mark to set your total timing. Rev the engine until that 30* mark stops moving up. You MUST have light springs to do this, don't even bother if you have the factory springs as they will not allow full advance until at least 4000 RPM in most cases. Once the mark stops moving up, hold the engine at that RPM ,and turn the distributor until the 30* mark aligns with the 0 on the tab for 30*, with the 2 for 32*, etc.

Make sure to plug your vacuum advance, and be as PRECISE as you can with that 1 3/4" mark. Being off a very small amount can make a significant difference and error. A dial back light is much easier to deal with.

 

No, you really can't. Excessive RPM drop can be from too little initial timing, but you can easily test if that is the case. Just advance the initial timing up to 20* or so, and back the idle speed down, and put it in gear. See if it helps. Just don't drive the car like that. Excessive RPM drop can also result from very light springs in the distributor, because the mechanical advance is partially in at idle. When you put it in gear, you lose advance and RPM. A lot depends on the cam you are running. Bigger cams are going to want more initial timing. They will also want more idle air, and you may need to modify the carburetor you are using.

 

I'm saying you can advance the timing at idle, to see if it improves your RPM drop when going from Park to Drive, but don't drive the car like that because it may over advance if you nail it. I'm thinking you have no idea where your total timing is, so you really shouldn't be beating on the car at all.

You can't get close without the light springs. When the balancer mark moves up, what you are seeing is the weights extending out, and when the mark stops, that is the point where the weights are fully extended, and there is no more mechanical advance left in the distributor. That is the point where you can adjust the total timing by turning the distributor. How can you possibly get close, if the stock springs won't allow that until 4000 RPM or more. You don't want to have to rev the engine in neutral that high. It's not good for the engine, and your neighbors will want to lynch you:grin: Do you know the part number for the distributor in the engine now? That may help approximate how much initial timing you can run.

 

OK,
That is a great distributor to have. Have a look at the specs for that distributor. The maximum mechanical advance in that distributor is 12-16*@ 3000 RPM. That means if you want 32* total timing, you should be able to run up to 16* of initial timing (16 + 16 = 32*) The reason they list the advance as 12-16* is because due to the manufacturing tolerances of the day, it could be any where in that range. Could be 12, 13, 14, 15, or 16*. Try power timing the engine at 3000 RPM to 32* with the stock springs, and see where your initial ends up.

 

Plenty of guys use a stiffer relief spring or shim a stock spring to increase the relief pressure. Nothing wrong with that. The clearances inside the oil pump have a lot to do with maintaining proper oil pressure as the engine and oil warm to operating temperatures. Back in the day, when new timing covers were no longer available, the fix for a worn cover was the high volume/high pressure oil pump kit. The kit included a set of gears that were 1/4" longer, along with a spacer plate. The longer gears dramatically increased the load on the front of the cam, the timing gears, and chain, especially with cold thick oil. This lead to wiped out front cam bearings, timing chain stretch, worn cam and distributor gears, and snapped roll pins. Today, with the new covers available from TA Performance, the only need for the HV/HP pump kit is for racing engines running bigger racing clearances. A stock oil pump with proper internal clearances will provide all the oil pressure you need for any Buick engine. Hope that answers your question.

 

Locking the distributor out to run straight timing.

Recently got this idea from a posting by TheSilverBuick. I made a lock out plate for my small body distributor so that I could run a straight 34* timing. My engine has a more stable idle in and out of gear, and it cranks just fine with the 20* MSD crank retard at 14*. completely reversible too. I run my vacuum advance limited to 10*, so it cruises at 44*, and 34* at WOT.

 

Yes, you can experiment by advancing ignition timing at altitude. Lower atmospheric pressure and air density results in less cylinder fill, and can require more time to burn, thus more advance is necessary. I've read a range of 1-2*/1000 ft, but I'd start slow, and experiment.