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Old 08-12-2012, 10:14 PM   #1
tyler
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Default Knocking

I took a little break from working on my A as I was getting discouraged with all the issues I was having with it. Now I'm back at it and hopefully will be able to drive it to a show this weekend.

What I've had done so far; honed out the cylinders, new rods, rings and pistons. Took up main bearings and complete valve job. Rebuilt distributor, new motor mounts, wiring harness and new Snyder 5.5 head. New "leakless" waterpump.

The car over-heats as I've explained before on here, looks like the old radiator just isn't up to the task of handeling the increased heat of the tighter engine. The radiator did seem to work o.k. with the engine before we rebuilt it but even after having it cleaned out at a shop it still won't cool. I'm waiting on a new radiator.

My problem right now is that the engine knocks with very little advancment of the spark. I think my timing is just a little advanced to start with but I hand crank it and it doesn't kick back on me so it can't be real far off. Driving down the road at 30 or so if I advance more than a third down on the lever I get knocking. The car surges ahead as though it wants to be advanced that much but the knocking starts so I back it off. Seems like I'm not able to take advantage of my 5.5 head. I've tried 93 octane with no improvement.

Is this something that will get better as the engine breaks in or what should I do? I'm thinking about removing the 5.5 head and putting the old standard head back on, at least until the engine is broken in more. I also wonder if it would help with my cooling issue. For some reason, I'm also suspect of my new water pump and wonder if a thermostat would help anything.

Just kind of thinking out loud here, guys. Any and all opinions welcome.

Tyler
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Old 08-12-2012, 10:37 PM   #2
fordfixer
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Default Re: Knocking

The high compression head should not cause overheating. So I would not be worrying about that. You said you honed the cylinders. What is the clearances for the piston and cylinder wall. Maybe piston slap. What clearances did you set the mains and rods? Do you have a two piece crank pulley? They some times can be bad and you will get a knocking sound from it. Did you do anything with the cam shaft? New timing gear? How did the intermediate gear look for the oil pump? Any one of these things can cause a knocking. First though I would retime the engine so that it fires at exactly top dead center. This is the timing pin in the indented position of the timing gear. Make sure that when you time it that the advance lever is in the upward most position. With the HC head you will only need about three to four clicks of the lever on the quadrant. This is when you are going about 45 mph. Otherwise just one or two clicks. I believe it most likely is your timing.
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Old 08-13-2012, 02:25 AM   #3
H. L. Chauvin
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Default Re: Knocking

Hi Tyler,

When one hears a spark knock with advanced timing, connecting rods & main bearings are letting you know they are getting beaten up & flattened at a much faster rate than that of having a properly timed engine -- not a good practice for proper engine maintenance.
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Old 08-13-2012, 06:11 AM   #4
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Default Re: Knocking

Quote:

My problem right now is that the engine knocks with very little advancment of the spark. I think my timing is just a little advanced to start with but I hand crank it and it doesn't kick back on me so it can't be real far off. Driving down the road at 30 or so if I advance more than a third down on the lever I get knocking. The car surges ahead as though it wants to be advanced that much but the knocking starts so I back it off. Seems like I'm not able to take advantage of my 5.5 head. I've tried 93 octane with no improvement.

Unquote:

1. When you say the car surges do you mean that it increases smoothly in speed?

2. Or do you mean that the speed changes by itself with the same throttle plate position, the classic definition of surging?

If the engine is surging that indicates a lean carburetor mixture.

Ford originally set up the Zenith jets to be a slightly lean mixture at sea level with the GAV set to the closed position. The idea was that if the car was run at higher altitude the GAV could be set closer to the closed position and if at sea level you could use 1/4 or a little more to get the correct mixture.

The GAV was never intended to be run at the closed position at sea level.

I have run about 50 carbs on an Exhaust Gas Analyzer and no two have the same air to fuel ratio.

But one thing that seems to prevail is that if the mixture is too lean the engine will knock sooner and more often.

If the engine is surging you might try opening the GAV 1/8th turn more than you normally do.

Carb could be plugged up or you might have a fuel line restriction at the sediment bowl or the carb. Or dirty filter in carb or sediment bowl.

Last edited by Benson; 08-13-2012 at 06:26 AM.
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Old 08-13-2012, 07:14 AM   #5
tyler
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Default Re: Knocking

Thanks for the responces, I'll try to answer as best I can.

I don't know what the clearences are for the cyl. walls and rods and mains. The cyl.'s were standard bore with just a little wear and so we just honed them out and put new standard size pistons and rings back in with new re-babbitted rods. Took the caps off the mains and scraped them to fit with a shim in each side. The old fellow that did all the brain work on this has been doing this work on T's and A's forever, including several of my T's and many other cars in the area and knows what he's doing. Been driving other engines of his for several years with no issues, but nobody's perfect, of course. The pistons seemed to be a good fit in the bores.
Removed and re-installed the camshaft, oil pump was rebuilt, new crank gear and timimg gear. New two piece crank pulley.


i'll try to describe the surging better: I'm driving down the road at, say 30mph. with the spark lever down about 3 clicks. engine doesn't knock but also doesn't seem to have much power. Keeping the throttle in the same position but advancing the spark lever to half way or better, the car runs smoother and with more power but it also starts knocking. In other words, when the spark is advanced to the point where the engine has the most power and runs smoothest, it knocks. If I keep it retarded enough to where it doesn't knock, it seems I'm not able to utilize the power available to me. I don't believe it is a carburation issue.
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Old 08-13-2012, 07:55 AM   #6
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Default Re: Knocking

Timing.......................JMO
Did the dots on the cam shaft gears get aligned correctly when it was re-assembled??
Paul in CT
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Old 08-13-2012, 08:40 AM   #7
Dave in MN
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Default Re: Knocking

Tyler,
Try opening the GAV a bit and place the advance just below where it knocks. With a fresh engine, there is a lot of heat build up with the wearing in of the rings. Excess engine heat will increase the problem. As stated above a richer fuel mixture may lessen the problem. I have the same issue and often run the engine below the max felt power setting to avoid the issue.
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Old 08-13-2012, 10:18 AM   #8
Benson
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Default Re: Knocking

Tyler,

Is there any chance that you have a Model B timing cover? If so the timing on B cover starts at 19 degrees instead of zero. So 19 plus the 40 of stock dist is 59 degrees advance ... WAY too much!

The timing pin on the A cover is close to the timing cover mounting bolt at the 9 o'clock position vs the B cover where timing pin is closer to 10 o'clock mounting bolt.

I never ran a B timing cover with a stock A head so I do not know it the engine knocks at 1/2 advance in that configuration.

But a B cover with a "head with the large B" (5.2 to one) is WAY too far advanced. The HC head needs less spark advance than a stock head or it rattles and knocks.

A note about the spark lever position and HC head. I have run a "Large B" for 45+ years and it likes the lever about 1/3 to 1/2 around town and pulling slow speed hills and a little less than 3/4 MAX (28 degrees) above 50 MPH. (3/4 spark lever position is 30 degrees on stock dist.)

28 degrees is the max I ever run the spark with HC head and less advance at any speed if on a hard pull up a hill. You can hear and feel it pounding if too much.

Last edited by Benson; 08-13-2012 at 10:24 AM.
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Old 08-13-2012, 12:42 PM   #9
tyler
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Default Re: Knocking

I will check to see if it's a B cover by some chance. Maybe I'm just expecting too much but it seems there's a lot more power available to me that I am unable to use without the engine knocking. Does it hurt anything to run the engine with too little advance?

I'm quite sure things were lined up with the cam and crank gears when we reinstalled them. I've also been running the gav a little rich to help with the overheating problem. Spark plugs show it was running rich.

Will things get any better after the engine gets broken in more? If not, I may have a 5.5 head for sale soon.
Thanks again for all the help guys.

Tyler
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Old 08-13-2012, 02:30 PM   #10
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Default Re: Knocking

I had the same problem with my engine . Timed it by the ford service bulletins to get in the ball park and then I would experiment with the dis. cam setting . I would retart it a little ,test drive ,retart some more test drive ,until I found where it ran the best with out rattling ( knocking ) when the spark lever was all the way down. Run high octane gas and GAV at half open . Solve the problem .
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Old 08-13-2012, 07:20 PM   #11
tyler
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Default Re: Knocking

Thanks Duffy. Supposed to rain tomorrow so maybe I"ll get a chance to play around some more. New radiator should be here in a couple days, too.

Tyler
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Old 08-13-2012, 10:49 PM   #12
TerryH
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Default Re: Knocking

I bought my newly restored TS with only about 450 miles on a re-built engine, and immediately had a Snyder 5.5 HC head installed. I have stock ignition and carburetor and set timing by the book. Mine runs great with the spark at about the 9:30 position.... not sure how many clicks that is, but it runs very well in that position, with no pinging, even going up pretty good grades. On the freeway at 55-60 (with o/d) I advance it to about 8:30 and it runs very well. I always run with the gav about 1/4-1/3 open. There was a very noticeable improvement in acceleration and pulling power with the Snyder head, especially nice in the heavy Town Sedan. Something must be wrong if you have to retard the spark so far that the power gain is lost.
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Old 08-14-2012, 05:15 AM   #13
tyler
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Default Re: Knocking

Exactly it, Terry. If I can't use the power available I might as well put the old head back on and not have to constantly worry that I'm destroying my engine. Hope I can figure something out. Thanks.

Tyler
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Old 08-14-2012, 03:32 PM   #14
Duffy1
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Default Re: Knocking

Tyler ;

As it relates to causes for overheating .Look in Les Andrews book . Trouble Shooting Chart 4-2 page 4-4 item 7 . "Cylinder compression too high - change to lower compression head " . Also with a HC head it requires less advance than a stock head. All engines are little different .So a one show fits all philosophy is hard to apply to Model A .
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Old 08-14-2012, 06:30 PM   #15
tyler
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Default Re: Knocking

New radiator showed up today at 1pm. I ordered it from Snyders yesterday at 10am. This is typical of Snyders service from what I've seen,doesn't get any better.

Course the radiator didn't fit, it's for 28-29 but I guess they don't figure that some of us dummies still use powerhouse generators and the bottom outlet is positioned for a regular one, I guess. Had to modify my generator bracket and now I will need a different size fan belt. Was hoping to run the car tonight and see if the new radiator cured my overheating but guess it will have to wait.
Thanks again for all the help. Will report back tomorrow.

Tyler
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Old 07-17-2019, 10:06 PM   #16
closedcab30
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Default Re: Knocking

hello just asking here ....when wanting to move distributor to retart do i simply from passenger side looking at the motor turn dist clockwise or anti .i have a FSI elect dist just asking as to which way to turn to retart thanks
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Old 07-18-2019, 12:20 AM   #17
Y-Blockhead
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Default Re: Knocking

Quote:
Originally Posted by closedcab30 View Post
hello just asking here ....when wanting to move distributor to retart do i simply from passenger side looking at the motor turn dist clockwise or anti .i have a FSI elect dist just asking as to which way to turn to retart thanks
You can't turn the distributor to change the timing. It is pinned to the head. You need to turn the distributor cam CW to retard the timing. I suggest you familiarize yourself with the timing procedure for the First Street Ignitions distributor model you have. http://www.fsignitions.com
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Old 07-18-2019, 07:03 AM   #18
chap52
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Default Re: Knocking

Anyone near Randolph NY that can give him a hand?
Is there a Model A club near you?
Don't blame the new head until you are certain that the timing is correct. Lot's of info on You Tube to help. ALWAYS align the You Tube posts with the manual.
Don't panic, enjoy the adventure... Chap
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Old 07-18-2019, 07:37 AM   #19
zzlegend
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Default Re: Knocking

You guys do realize that this thread is about seven years old? Hope he fixed it way back then.
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Old 07-18-2019, 07:41 AM   #20
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Default Re: Knocking

Even though this is an old thread.....just for the record, before setting the timing correctly, make CERTAIN your point gap is within the range of 0.018" to 0.022". Correct point gap is essential.
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