350 Going Boom, Won't Start

I read thru this and I have a couple of things for you to try.

If you have different bushings for the distributor put in the biggest one, this way the distributor will not advance as far and you will be able to have more initial advance. Keep your total down to at least 28 or 26 if you have to. You should be able to get to 30 but maybe not, the gas could be crap out there how much ethanol is in it? If 20 % you may need some more jet in.

Try using spark plug NGK YR5 I use this one for the nitrous and this is basically the colder plug for the 1970 350 engine. This may help you creep back up on timing.

I had seen in one posts that you were down 2 qts on the oil. You could be burning some oil and If this is so, this will reduce the octane in your gas and you will ping.

When you put in your heavy springs in your distributor it did not ping because you had to hit a higher rpm before it would ping, this may have been as high as 4500 rpm with the heavy springs. You should be able to run the medium springs and get it all in at 2500 rpm. Also with the heavy springs in you bog off the line unless you are using the vac advance then it will not bog.

If all else fails run 5 gal of race gas with your 15 gal of 93 and this will help out the ping problem This may help you get back up to 30 to 34 on the timing and it may just get better gas mileage as compared to running 26 on the timing.

 

Thanks for the advice! The MSD spring kit also came with bushings, so I will put in the biggest one. Will try those plugs as well.

Race gas would be funny. Not sure of the composition of th gas out here in CA . . .

 

You should have 3 different size bushings to put in the HEI to stop the advance.

 

I had read in on of the posts that he bought a new HEI and I thought they had a way to change the advance stop bushing. He did say that he had springs and bushings so I hope he did not take it that was the part to change. I am sure he is talking about the bushings that come with the MSD spring and weight kit which is not what I was talking about, hope he read that right. He seems to have the timing down low you would think it would not ping but if it is burning some oil this might be causing the problem.

 

My distributor is a stock points unit that was converted to HEI by Dave's Small Body HEIs. When I said bushings, yes I was talking about the little advance stop bushings that came with my MSD mechanical advance kit. So these will not work with my distributor?

Going by my idle being about 2 degrees BTDC and total being about 28, my distributor has 26 or so degrees of built in timing correct? So I need to reduce the built in timing by limiting the movement of the mechanical advance via a bushing so I can still have a reasonable idle timing while reducing my total?

 

Hmm ok yeah I will give him a ring and ask. My balancer was rebuilt before I installed the distirbutor and I verified my TDC mark with a piston stop.

 

Mr Gasket makes a bushing kit to limit your dist. Mechacinal advance... You have too much mechanical advance resulting in too low of timing down low and too much timing up top.

 

Sean - is this the kit you are referring too?

https://www.summitracing.com/int/parts/mrg-927g/overview/year/1970/make/buick/model/skylark

My only concern is that it only comes with one size bushing, don't I need an assortment to dial in my total mechanical advance? How come the MSD bushings only work with MSD distributors, are the pins that the bushings go on a different size than my points distributor?

Thanks for your help as always! Hope everyone is having a good holiday season.

 

Hi Larry,

Do you have a part number for a Mr. Gasket kit that will work with my distributor?

The only others I can find on Summit is this one which has 2 sets of bushings:

https://www.summitracing.com/int/parts/mrg-929g/overview/

But it says it's for an HEI. This won't fit will it?

And this one:

https://www.summitracing.com/int/parts/mrg-928g/overview/

It says it comes with bushings but doesn't say how many. But it says it's for a points unit.

If I can't find the right kit I'm temped to try and turn my own set of bushings on the lathe at work . . .

 

Just found the Mr. Gasket 928G kit on Amazon and it looks like it only comes with 1 bushing. I wonder if it's the same size bushing as the 927G kit? And is it the right size bushing to limit my total enough?

https://www.amazon.com/Mr-Gasket-928G-Advance-Curve/dp/B000CMF26I

 

None of those kits will stop the advance any earlier. The bushing is to put in on the pins on the top where the weights go since most are worn out. The springs are just for rates of advance, (how fast the timing advances). The advance stop bushing stops the advance before the weights pull out all the way. The bushing on the MSD is underneath the weight set up. You may not be able to change this at all but I know it can be done. There is an article around here somewhere to tell you how to do it.

I just looked at that 928g kit and that one might work for you but there is only 1 stop bushing. Not much info on how it works I would call Summit on that one and ask them about it.

Actually that kit sucks because the spring loop is not in the center of the spring and I have found that they do not work as good as the ones that have the spring loop in the middle of the spring. I bet there is a better kit out there you just have to find it.

 

If memory serves I'm at 2-4 degrees initial and 26-28 degrees total so I have about 22 - 26 degrees total built-in mechanical advance. I know that's not very helpful because it's a big range but unfortunately I can't go out to the car and double check right now because I'm in Europe for the holidays and don't get back until Jan 5th!

I'm pretty sure I'm more in the 26 degrees total built-in range though . . .

I want to take it down to like 24 total with 6 or so of initial and see if it still pings. I feel like if it still pings with that little of advance curve/that little of total advance number it must be a lean issue . . .

 

Which carb again?

 

Stock Quadrajet rebuilt at Everyday Performance, electric choke conversion.

 

Bump.

Anybody got more info on what I need to do to my distributor to adjust the total mechanical advance?

 

My thoughts are get a different distributer. Sounds like you might have a 69 and earlier unit. An electronic conversion would be good too.