Engine issues

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Feb 23, 2024 | 02:54 PM

#16

Max Capacity

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Joined: Jun 2013

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From: Tolland, CT

I'll vouch for the Chemtrol Berryman, I use their B12 in all my vehicles in Oct, before the cold weather sets in. Walmart has it for $4.00, used to be $1.99 a few years back.

How many miles on the engine, timing chain ? Oh, I see, rebuilt engine.

I'm leaning towards, pull the spark plugs and see what they look like.

Feb 23, 2024 | 08:05 PM

#17

robbyfowler6

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Just took it for a test drive, disconnecting the vacuum hose from distributor definitely seemed to help the metallic noise, although it still seems to stutter a small amount when accelerating, but it was driveable for a 15 min drive. Didn’t try any longer. Could the stutter be a misfire? I set the timing with the distributor vaccum disconnected at about 5-6 degrees advanced.

Feb 23, 2024 | 08:52 PM

#18

Franklin2

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From: Virginia

Quote:

Originally Posted by robbyfowler6

The problem getting better when disconnecting the vacuum advance proves the noise is pre-ignition. But 5-6 degrees BTDC is very conservative and should not give you this problem. Two possibilities may be the cause; The harmonic balancer has slipped and you cannot use the timing marks, or did you just rebuild this engine? Was it put together with different parts or replacement parts like the timing cover or the balancer? Sometimes parts are not compatible, the pointer for the timing may be the wrong one for the balancer or the other way around.

How does it run otherwise. With the timing set at 5-6 BTDC, the engine should be very doggy and low on power.

Feb 23, 2024 | 10:16 PM

#19

robbyfowler6

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Quote:

Originally Posted by Franklin2

the balancer had a key notch that aligned with the crank and only went on one way. The engine seemed like it ran good enough otherwise for the 15 min drive, besides the small stutters at acceleration

Feb 24, 2024 | 05:30 AM

#20

FuzzFace2

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From: Angier, NC

Quote:

Originally Posted by robbyfowler6

The balancer had a key notch that aligned with the crank and only went on one way. The engine seemed like it ran good enough otherwise for the 15 min drive, besides the small stutters at acceleration

Yes the balencer can only go on one way so that it keeps the balance.

If you look at it, it is made in 3 parts. A inner that has the key way, a thin rubber in the center and the outer part with the timing numbers.
The outer part can slip on the rubber and that can throw off the timing.
The only way to know for sure it has not slipped is to check with a piston stop.
You install the stop and then turn the motor over by hand till it hits the stop and mark the balencer.
Then turn by hand in the other direction till it stops and mark the balencer.
Half way between the 2 marks is true TDC and you go by that when timing the motor.
Dave ----

Feb 24, 2024 | 07:09 AM

#21

Franklin2

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From: Virginia

Quote:

Originally Posted by robbyfowler6

the balancer had a key notch that aligned with the crank and only went on one way. The engine seemed like it ran good enough otherwise for the 15 min drive, besides the small stutters at acceleration

So you have stuttering on acceleration now, but no noise with the vacuum line plugged? There are several experiments you can do if you want to play with it. You can advance the timing to 10 BTDC and then see what that does. Does it run better and the noise is still not there (vacuum line still disconnected).

In my experience when you de-smog these engines and modify them, you can't use the stock vacuum advance. I would try and get it running it's best with the vacuum advance disconnected, and then address the vacuum advance last, possibly getting a aftermarket adjustable one. But I would not put this on the top priority list. Make sure everything else with the engine is doing ok.

Feb 24, 2024 | 09:05 AM

#22

kr98664

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Quote:

Originally Posted by FuzzFace2

The outer part can slip on the rubber and that can throw off the timing.
The only way to know for sure it has not slipped is to check with a piston stop...

It's important to check the accuracy of the timing marks, but it's possible to get an adequate approximation if you don't have a piston stop. It would not be precise enough if degreeing a cam, for example, but should be good enough to check for slippage of the timing marks.

Use something semi-rigid, such as a soda straw or piece of wire. Insert it through the spark plug hole and turn the crankshaft with a breaker bar and socket to move the piston up and down. You should be able to get a reasonable approximation of TDC for checking the timing marks.

Don't use a rigid item that could break off inside the cylinder, such as a screwdriver or dowel. I do not care to discuss how I learned this...