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#3383852 - 05/29/14 10:36 AM Re: Pinging goes away after vacuum adv disc - why? [Re: sasilverbullet]
Vikas Offline


Registered: 07/22/05
Posts: 7838
Loc: NorthEast
If the dyno shop tested it under certain conditions, don't you then need to run the vehicle under similar set up?

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#3383898 - 05/29/14 11:44 AM Re: Pinging goes away after vacuum adv disc - why? [Re: sasilverbullet]
threeputtpar Offline


Registered: 08/04/11
Posts: 1451
Loc: Appleton, WI
I'd agree with 440Magnum, that they set it up wrong in your particular instance.

You'll probably need to start off by checking base timing with the vacuum line to the dist disconnected and plugged. I'm guessing that it will be advanced compared to what your FSM states it should be. You may even have to pull the dist and set it to a different tooth to be able to get it to base spec.

Once set, run it like that with vacuum hooked back up and see what shakes out. Fine tune the base timing from there to get the full advance right up until you just start to get the slightest pinging on acceleration, and then back it off 1 degree.

This is how I had to set the timing on a 1974 Pontiac 400 that I installed in a 1979 Grand Prix in place of the 301. I eventually ditched the original 1974 dist and put a GM HEI in its place.


Edited by threeputtpar (05/29/14 11:46 AM)
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#3383902 - 05/29/14 11:50 AM Re: Pinging goes away after vacuum adv disc - why? [Re: sasilverbullet]
Smoky14 Offline


Registered: 04/23/03
Posts: 955
Loc: Nowhere NM
They make an adjustable vacuum advance. An allen head screw sits inside the vac port. You may luck out and have one.

Smoky
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#3383921 - 05/29/14 12:34 PM Re: Pinging goes away after vacuum adv disc - why? [Re: sasilverbullet]
Volvohead Offline


Registered: 05/25/05
Posts: 3331
Loc: SE Pa
Originally Posted By: sasilverbullet
This one's stumping me - on my newly overhauled 460 in my 70 Lincoln MK III, it pings on acceleration. If I disconnect the vacuum advance it doesn't ping.

Why?

??? ??? ???


As I mentioned in your other post, your pinging issue might be in part caused by the mechanical advance springs. They weaken over time, and then run the advance up too quickly with RPMs. The additional vacuum advance is driving the advance above specs. Sometimes the springs flat out break. It's very common with the Autolites of that period after so many years.

You don't want to disable vacuum advance as it is better related to actual engine loads. Some of the vacuum sections also had dual advance-retard features for early emissions control.

But putting tighter/newer springs in the mechanical advance can eliminate the pinging overall. It's under the breaker plate, and takes all of ten minutes. When we tracked them, there were performance calibrated advance springs available. We could very precisely tune the advance on these. But after 45 years, I don't know what calibrations exist for these old buggers.

Between tighter advance springs and water injection, you can often get those engines running ping free with today's fuels. The only other thing I might add is a little MMO to the fuel to compensate for the unleaded that they were not designed for.

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#3383958 - 05/29/14 01:19 PM Re: Pinging goes away after vacuum adv disc - why? [Re: sasilverbullet]
SteveSRT8 Offline


Registered: 10/10/08
Posts: 14249
Loc: Sunny Florida
Where is the distributor machine? Find a speed shop that has one and tailor the timing as you want it.

It's fully adjustable...
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#3384010 - 05/29/14 02:40 PM Re: Pinging goes away after vacuum adv disc - why? [Re: sasilverbullet]
Chris142 Online   content


Registered: 06/05/03
Posts: 11056
Loc: apple valley, ca
How much advance is the vacuum advance giving it? Is the carb jetted lean?
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#3384159 - 05/29/14 05:32 PM Re: Pinging goes away after vacuum adv disc - why? [Re: sasilverbullet]
Merkava_4 Online   content


Registered: 01/30/07
Posts: 8855
Loc: Clovis, CA
NOW HEAR THIS -- NOW HEAR THIS:

Your 1970 Lincoln being that it's PRE-smog era probably has right around 11:1 compression. What you need for that is stiffer advance springs on your distributor. How do I know this? Because I put stiffer advance springs on my 1970 Cougar and it did the trick. That basically recurves the timing so that the timing doesn't advance too quickly. Those cars back then were supposed to be fed 108 octane gasoline. 93 was considered a low octane back then.

http://image.highperformancepontiac.com/...nce-springs.jpg

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#3384161 - 05/29/14 05:33 PM Re: Pinging goes away after vacuum adv disc - why? [Re: SteveSRT8]
440Magnum Offline


Registered: 02/01/09
Posts: 6099
Loc: Texas
Originally Posted By: SteveSRT8
Where is the distributor machine? Find a speed shop that has one and tailor the timing as you want it.

It's fully adjustable...



Find a speed shop with someone who still knows how to operate the distributor machine.

:-P
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#3384219 - 05/29/14 06:44 PM Re: Pinging goes away after vacuum adv disc - why? [Re: 440Magnum]
Volvohead Offline


Registered: 05/25/05
Posts: 3331
Loc: SE Pa
Originally Posted By: 440Magnum
Originally Posted By: SteveSRT8
Where is the distributor machine? Find a speed shop that has one and tailor the timing as you want it.

It's fully adjustable...



Find a speed shop with someone who still knows how to operate the distributor machine.

:-P



No need for any of that. All you need is a timing light, some marker tape, and a portable tach. And new springs.

Unless you need a shaft and gear rebuild, all you do is risk chewing up the oil seal by pulling the distributor.

You can rebuild and recalibrate the top end of these Autolite distributors with it in the engine. Done dozens of them. Piece of cake.

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#3384232 - 05/29/14 06:53 PM Re: Pinging goes away after vacuum adv disc - why? [Re: punisher]
wag123 Offline


Registered: 06/14/11
Posts: 490
Loc: Texas
It sounds to me like the dyno shop got almost everything right... except maybe the vacuum advance diaphragm, and/or perhaps the power valve in the carburetor, neither of which come into play during a full throttle maximum power output pull.
From what I have read, with the HP that your engine is producing, my guess is that you have a pretty healthy cam in the engine and that it doesn't have all of the 1970 pollution control devices on it anymore. For what you are running, 36 degrees of total mechanical advance should be about right.
As far as the vacuum supply to the distributor, they have that right as well. Lacking an air pump, you should be running manifold vacuum to the distributor, not port vacuum. But, that is NOT the way that it came from the factory. Prior to the use of exhaust air pumps (which started appearing in 1967-1968), distributor advance vacuum was always taken from the manifold. After air pumps were used, distributor advance vacuum was almost always taken from the carburetor throttle vacuum port. The difference is that, with the vacuum advance taken from the manifold, you got about 1/2 of the full vacuum advance at idle. With the vacuum advance taken from the carburetor throttle port, you got ZERO vacuum advance at idle. This is strictly an emissions control thing!
With the HP your are running, total combined advance should be about 46 to 48 degrees (with premium fuel), which means that the distributor vacuum advance diaphragm should only be contributing between 10 to 12 degrees. Also, check your engine vacuum at idle, with the cam you have it is likely around 11-12 inches. At steady-state cruising speed the vacuum is likely about 15-16 inches. If this is the case, the vacuum advance needs to be set up such that it drops out completely below 9-10 inches of vacuum, gives you about 5-6 degrees of advance at 11-12 inches (idle vacuum), and a maximum of 10-12 degrees advance at maximum vacuum (15-16 inches). Adjust these numbers to the actual vacuum readings you are getting from your engine.
Next, the carburetor power valve. The power valve richens up the A-F mixture ratio during acceleration. If the power valve is too lean for your engine, you will get pinging during acceleration because the engine is running too lean. For this you also go by vacuum. For this problem you would need to install a power valve that opens sooner, at a higher vacuum. If the power valve is opening at 5 inches of vacuum, you would need to go with something that opens at 9-10 inches of vacuum.
You might be wondering why the dyno shop didn't check/adjust these things. Because their concern is tuning the engine for a maximum power full throttle pull, not tuning for street drivability at partial throttle settings. None of the above factors affect full throttle pull maximum power output.
To do these adjustments you will need 2 tools, an accurate vacuum gauge, and an adjustable timing light.


Edited by wag123 (05/29/14 07:03 PM)

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#3384240 - 05/29/14 06:58 PM Re: Pinging goes away after vacuum adv disc - why? [Re: sasilverbullet]
Errtt Offline


Registered: 11/14/10
Posts: 2111
Loc: California
When I was a kid and didn't have a timing light, I'd set #1 cylinder on compression stroke, then align the damper timing mark to spec. Then, with loose distributor, slide a piece of the clear wrapper from my smokes between the points, with the distributor retarded and a slight pulling on the clear wrapper, slowly advance the distributor and as soon as the clear wrapper starts to slip, lock down the distributor. Thought - with the timing marks aligned, when the points break contact, the coil field collapse inducing the voltage into the secondary coil windings sending the juice down the plug wire to the spark plug, close to where it should fire, without vacuum advance.
Then test run and tweak the distributor as needed until I can get a hold of someone later with a dwell meter and timing light. Oh, and would spruce up the points if needed with matchbook. If the points lasted long and stayed in good condition, I would keep the same capacitor in it and throw the new/unused in the glovebox.
Must have correct vacuum - clean in the springs and weights etc. Pull vacuum on the hose to the vacuum advance and you should see the plate move.


Edited by Errtt (05/29/14 07:00 PM)
Edit Reason: add

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#3384253 - 05/29/14 07:19 PM Re: Pinging goes away after vacuum adv disc - why? [Re: Merkava_4]
dnastrau Offline


Registered: 12/13/06
Posts: 280
Loc: PA
Originally Posted By: Merkava_4
NOW HEAR THIS -- NOW HEAR THIS:

Your 1970 Lincoln being that it's PRE-smog era probably has right around 11:1 compression. What you need for that is stiffer advance springs on your distributor. How do I know this? Because I put stiffer advance springs on my 1970 Cougar and it did the trick. That basically recurves the timing so that the timing doesn't advance too quickly. Those cars back then were supposed to be fed 108 octane gasoline. 93 was considered a low octane back then.

http://image.highperformancepontiac.com/...nce-springs.jpg


In 1970, Ford required a minimum Research octane of 98 (not 108) in its' premium fuel engines, 94 Research octane for regular fuel engines. This information came from a 1970 Ford owner's manual.

However, fuels in the US and Canada were listed with the Research octane number before about 1975 or so (the same method still used in countries other than the US and Canada today) and then switched to the R+M/2 method that we see on US/Canadian pumps today. That number is 4 - 5 numbers lower than the Research number from 1970. Therefore, the current 93 octane (R+M/2 method) premium should get you about 97 - 98 Research octane - close to the minimum octane required in 1970.

Hopefully the ignition timing tips that Merkava listed above and others have mentioned in this thread will solve your problem without having to resort to additional octane boosters or spiking the tank with racing fuel, etc.

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#3384268 - 05/29/14 07:31 PM Re: Pinging goes away after vacuum adv disc - why? [Re: sasilverbullet]
Volvohead Offline


Registered: 05/25/05
Posts: 3331
Loc: SE Pa
This is from '68 for the 429, but the '70 460 was basically the same. This should get you where you need to be.

http://www.oldcarmanualproject.com/manua...lement_0060.htm

http://www.oldcarmanualproject.com/manuals/Ford/1967/TBird%20Shop/Group%209/pages/Ignition_0020.htm

http://www.oldcarmanualproject.com/manua...lement_0149.htm

Nice that this stuff is now on the internet. All my older books are packed away somewhere, along with my older timing guns and dwell gauges.

This is easy peasy work.

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#3384335 - 05/29/14 08:21 PM Re: Pinging goes away after vacuum adv disc - why? [Re: sasilverbullet]
Trav Offline


Registered: 11/20/06
Posts: 9123
Loc: MA, Mittelfranken.de
A lot of the old engines just run without.

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#3384423 - 05/29/14 09:45 PM Re: Pinging goes away after vacuum adv disc - why? [Re: sasilverbullet]
Chris142 Online   content


Registered: 06/05/03
Posts: 11056
Loc: apple valley, ca
The rebuilder lowered the compression to around 8.5-1
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