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Old 05-16-2018, 12:40 PM   #1
Josh Randall
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Default New guy with questions.

I bought a 30 CCPU a few weeks ago.

It runs good but i'm chasing a knock.

I found the timing gear to be loose so i replaced it.
That didn't cure the problem.

It doesn't knock if the spark lever is left all the way up but then it has poor power.... Also it stops knocking when i shift into third gear loading the engine. (first and second gear still has the knock).

I did a search and found read lots of old threads.. But non addressed this condition.

Thanks for any suggestions.

Randall
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Old 05-16-2018, 04:14 PM   #2
aermotor
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Default Re: New guy with questions.

I would start with checking the timing. Welcome to a great group.

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Old 05-16-2018, 05:37 PM   #3
Josh Randall
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Default Re: New guy with questions.

Thanks for the reply
I set the timing per the Les Andrews book..

Timing does affect the knock.. At idle with the spark lever all the way up it doesn't knock.. but pull it down 4 or 5 notches and it starts knocking... The noise is steady but without rhythm. I've been driving it with only 3 or 4 notches down and that seems to help.

Randall
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Old 05-16-2018, 06:28 PM   #4
FRANK PKNY
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Default Re: New guy with questions.

While you have the knock going strong. Short out one spark plug at a time, you may find one cylinder that when shorted the knock stops, if so mostlikely a rod knock. It's not real hard to pull the pan and check all the rods and mains are a bit harder to do, however it's doable. While you have it knocking press in the clutch, if it stops you may have a bad main thrust bearing problem. The knock getting better when you retard the spark indicates a rod bearing or a main bearing. If you plan on doing the checks , let us know what you find. Good luck, PS there's lots of real good guys on this site, a few skirts also.
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Old 05-17-2018, 12:02 AM   #5
Benson
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Default Re: New guy with questions.

A very lean mixture will make for "advanced" timing and will knock under partial throttle conditions. I would open GAV an additional 1/4 turn and see if knock is reduced. then try additional 1/4 turn.

If so try a known good carb.

Carbs from factory were setup to run with 1/4 turn on GAV with an additional 1/4 turn for a total of 1/2 when under load in mud sand or going up a steep hill.

See operator manual. I do not have a scanned copy of instruction manual.

Besides manual is copyrighted and Ford has been known to threaten with lawyers in some cases when they find out.


Normal spark setting should be about 50% of quadrant after it starts.

Last edited by Benson; 05-17-2018 at 07:24 AM.
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Old 05-17-2018, 07:27 AM   #6
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Default Re: New guy with questions.

Another thought ...

Might want to put in fresh gas ... Old gasoline will act funny.

I find that fresh winter gas will work just fine in in my "modern" Fuel Injection cars when mixed with gas in the tank. Note: (never old stinky unknown gas)

A couple of times I found that if I put a match to some year old gas from a Model A tank that it would not even light off. That is crappy gas! All of the volatile stuff had evaporated off.

I would use fresh gas from a high volume BRAND NAME station.

Why I buy from brand named stations this time of year.

Government says:

1. That all distributors/dealers have to purge all Winter gas from their lines by May first.

2. Then retailers have until June 1st to purge their tanks.

One guess here ... who do you think buys the leftover Winter gas this time of year?

It is the discount stations that sell the leftover Winter gas!

Winter gas works "OK" in FI ed cars with oxygen sensors and such; as mixture is constantly adjusted unlike carbureted cars where mixture is fixed.

You do not want to get stuck with WINTER gas this time of year with all of its vapor lock problems with hot days coming soon.

Details are found here:

https://www.eia.gov/todayinenergy/detail.php?id=11031

Last edited by Benson; 05-17-2018 at 08:55 AM.
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Old 05-17-2018, 07:35 AM   #7
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Default Re: New guy with questions.

Here is a copy of the Instruction Manual from the internet.
http://motormayhem.net/wp-uploads/20...ion-Manual.pdf
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Old 05-17-2018, 07:44 AM   #8
Josh Randall
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Default Re: New guy with questions.

Thanks for all the replies....

I'll try those things and report back..

Randall
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Old 05-17-2018, 07:47 AM   #9
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Default Re: New guy with questions.

Bite the Bullet! Take the oil pan off and check the rods. While you've got it apart, clean the sludge out of it and clean the oil pump screen. Adjust your bearings and reassemble in reverse order. I bought an unknown engine once and was told to check the mains. I did and the center main was shot but there was loads of sludge in the pan, AND the oil screen was about 75% clogged. You will hear someone say "Use 30 weight, non detergent oil"! Do what you want, but whenever I hear that, I think of the clogged up oil screen and what it did to the mains. My suggestion is to use 15/40 Rotella and change at 1000 miles. Remember, The worst oils of today are better than the best oils of 1930.
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Old 05-17-2018, 08:19 AM   #10
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Default Re: New guy with questions.

Quote:
Originally Posted by Benson View Post
Another thought ...

Might want to put in fresh gas ... Old gasoline will act funny.

I would use fresh gas from a high volume station. You do not want to get stuck with WINTER gas this time of year with all of its vapor lock problems with hot days coming soon.
^^^^^^^ This
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Old 05-17-2018, 08:29 AM   #11
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Default Re: New guy with questions.

Welcome Josh:
Follow the advice above and you'll knock the knock right out of that knocker.
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Old 05-18-2018, 09:01 AM   #12
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Default Re: New guy with questions.

Drained the tank and refilled with fresh gas, turned the GAV out enough to make it run rich, also grounded the plugs one at a time .. all great suggestions..but

Knock is still there ...
Ordered gaskets... time to pull the pan..

Randall
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Old 05-18-2018, 01:46 PM   #13
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Default Re: New guy with questions.

Mine has a knock coming from the oil pump drive gear where it meshes with the cam. Take a long screwdriver and place it under the dizzy on the block and you may just hear it knocking back and forth. It will need a new plunger spring in the timing cover if that is the problem.

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Old 05-18-2018, 04:06 PM   #14
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Default Re: New guy with questions.

Check that the crankshaft pulley is tight on the crankshaft. Two piece pulley? I bought an engine once that everyone said had a wrist pin knock, tightened the crank pulley, and it went away. I had first pulled the pan to check the rod bearings and noticed the loose pulley in the process.
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Old 05-18-2018, 07:29 PM   #15
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Default Re: New guy with questions.

I'll check the cam button and pulley before dropping the pan.
Thanks for all the advice fellas!

Randall

Last edited by Josh Randall; 05-23-2018 at 03:03 PM.
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Old 05-18-2018, 07:50 PM   #16
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Default Re: New guy with questions.

Quote:
Originally Posted by Josh Randall View Post
Drained the tank and refilled with fresh gas, turned the GAV out enough to make it run rich, also grounded the plugs one at a time .. all great suggestions..but

Knock is still there ...
Ordered gaskets... time to pull the pan..

Randall
Was there any different knock sound on any one of the plugs? If so, may tell you if it is one rod or another.

Also, it could be a value that needs adjusting (if you have adjustables)
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Old 05-19-2018, 09:43 AM   #17
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Default Re: New guy with questions.

Knock never changed with grounding plugs, not sure if i have adjustable tappets... I'll try the new suggestions next week.
Thanks

Randall
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Old 05-19-2018, 11:04 AM   #18
Jim Brierley
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Default Re: New guy with questions.

Sounds to me that you have piston slap??? If so, and you can stand the noise, just drive it and don't worry about it. If the noise bothers you, remove the pistons and replace them or have them knurled to increase their size a little. When removed, you may find the cylinders have worn and then you are looking at a major rebuild.
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Old 05-19-2018, 02:03 PM   #19
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Default Re: New guy with questions.

Quote:
Originally Posted by Josh Randall View Post
Knock never changed with grounding plugs, not sure if i have adjustable tappets... I'll try the new suggestions next week.
Thanks

Randall
I had a "knock" that sonded more like a click. I adjusted values and it seems to help. But remember I am no expert on A's.
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Last edited by Fred K-OR; 05-19-2018 at 03:30 PM.
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Old 05-20-2018, 08:05 PM   #20
Josh Randall
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Default Re: New guy with questions.

I found the problem. Too much timing advance.

I installed a Nu-Rex timing tab so I could check the timing with a timing light.

Turns out I had 5 degrees BTDC initial with the spark lever all the way up.
When the lever was pulled all the way down it went to over 35 degrees BTDC.

Adjusted the points cam around, to top the timing out at 20 degrees..
Much better!


I don't know why the dist plate is able to move so far? (35 degrees).

Thanks to all that responded.

Randall
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