Spark nock problem solved

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vince_o
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Spark nock problem solved

Post by vince_o »

Ok so 2 years ago I built a 12 hp with help from some friends and could never get the nock out of it. I could adjust the points out, in up down and even new points and another new points rod. I took the eng back apant 3 times to see if I missed something, all ok.

When this was at the machine shop I had the blocked decked close to the top of the piston, and the head shaved. I did a little work to the exaust port, but not as much as I should have, but Im learing. Its always been hard to get over TDC and didnt know why. I talked to a bunch of people and got a bunch of leads to look for.

Well I was picking up some parts the other day and was talking to the mechanic down there and told him what was going on. He told me that I had up the compression a lot higher than what should be. There for I had spark nock due to the 93 octane not being hot enough.

So this morning I got some 110 octane and the thing purrs like a kitten!!!!!!!!!!!!!!!!!!!!!! Starts right after it passes TDC !!!!!!!

Now the bad part. Its 7.50 a gal! I wont be mowing the grass with this tractor! :lol:
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Jeff in Pa
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Re: Spark nock problem solved

Post by Jeff in Pa »

Good to hear you figured it out Vince. Maybe change the head to an uncut one to lower the compression to use premium pump gas. Worst case senerio is that it still knocks and then just put the shaved head back on.

Jeff
125 & 125 with hydraulic lift

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mmzullo
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Re: Spark nock problem solved

Post by mmzullo »

Chumlee,
See if Kolher makes a shim kit for lowering CR. I know Kawasaki has them to lower compression. It was a piece of steel like a headgasket.

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ksanders
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Re: Spark nock problem solved

Post by ksanders »

On that note, I remember a metal head gasket for Kohlers (not the regular ones, but actual thicker metal about twice as thick and doesn't compress as far). It was still a head gasket, but thicker. I used one before to get extra clearance at the time or something.
Then again, if it's a gear drive it doesn't use enough gas to worry about 7.50 a gallon anyhow and just keep the power
From the first Original to the last x82 Series... you can't beat an IH Cub Cadet!!!

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Farmallgray
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Re: Spark nock problem solved

Post by Farmallgray »

Vince,
Which style head are you running? You may be able to lower it with a different head.
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vince_o
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Re: Spark nock problem solved

Post by vince_o »

High boss head

Im keeping the power. I took it out today for about a half hour ride out back and man when you get on the throtal it runs! Wow this is nice. I am going to take it to plow day in 2 weeks Ill let you know how it dose.

By no means am I complaining!
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Chris.Woodrey
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Re: Spark nock problem solved

Post by Chris.Woodrey »

To get around paying the 7.50 a gallon you could try the octane enhancer that most parts stores sells dont know if it works or not might be worth the try...

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vince_o
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Re: Spark nock problem solved

Post by vince_o »

Chris

I tryed that but it just wasnt enough
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Cubrick
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Re: Spark nock problem solved

Post by Cubrick »

Hey Vince, try a 1/4 tank moonshine to 3/4 tank high octane gasoline! i know it has to be available in your neck of the woods! octane is extremely high in moonshine............or is that alcohol? :lol: :lol:
Cubrick

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Racenitro
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Re: Spark nock problem solved

Post by Racenitro »

Octane enhancers will not be the same as High Octane Racing Gasoline...

You still have the Alcohol present and that will reduce the octane...

A Gas Chromatograph comparison will easily show why this is true...

The number of components in Racing Gasoline is WAY less than the number in Unleaded/Ethenol based fuels.

The GC graph will have a few peaks while the unleaded will have several hunderd peaks.

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Re: Spark nock problem solved

Post by Klapatta »

Vince,
The need for 110 AV fuel in a flathead that can't possibly have a higher compression ratio than 9 to 1is something of a hard sell to me.
I run a K series that is both block decked and head shaved and it gets along on 89 octane just fine. In fact I have noticed some dropoff in throttle response when having tried 93 octane. It will complain with 87 though. The lowest necessary octane without knocking will produce the most power out of these engines.
I believe that you have something else wrong going on. I'd really like to able to help look at it with you.

Alcohol modified gasoline is here to stay and there isn't a thing anyone can do about it.
Soon it will be 15% alcohol. Mine was one of the last states where one could get straight up pump gas but that's been gone for at least a year.
It's all part of the bigger plan to get all vehicles over 10 years old off the roads. In country's such as Japan and Germany vehicles much over 5 years old with the exception of specialty vehicles or up scale classics are looked upon as something of an oddity.
Remember cash for Clunkers-

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Racenitro
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Re: Spark nock problem solved

Post by Racenitro »

The reason for the higher octane is two fold. One is the elevated compresson and the second is flame travel. The configuration of the combustion "L" type inhibits flame trave. The higher octane will help offset this disadvantage. Modern computer controlled engines manage the fuel to eliminate the knock. Most modern engines have a Knock sensor to assist the computer in looking up the correct settings that then mamages the fuel, timing and thus rliminates the knock The presence of alcohol in the gasoline reduces the rate of flame travel since alcohol burns much slower than gasoline. The "spark" knock is actually a sound wave that is created by the incorrect ignition of the fuel.

If you could change the timing then you could offset the spark knock with a timing change.

Believe it or not, but the Ford 300 CID I-6 is set to run correctly when there is a small amount of spark knock, actually non spark induced combustion.

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Re: Spark nock problem solved

Post by Klapatta »

Frank brings up some very fine points, I myself am very pleased you chimed in!
It's really good to see folks exchanging thoughts here again as we did in the old days!
ROCKWELL_Norman_Freedom_of_Speech.JPG
It was the era of the mechanical engine vacuum advance that many engines ran at their very best optimum point set so a slight ping under certain conditions (not knock) could be heard.

The topic of spark plug flame propagation concerning the flat head engine series engine goes back as far as the engine itself.
There are many who hold to the similarities of the combustion chamber between the Ford stove bolt V-8 and and the Kohler K series concerning the placement of the spark plug with the latter style heads directly over the exhaust valve. Everyone is entitled to their opinion. Both the early centrally located style and it's latter replacement offer two totally different approaches to flame propagation. I personally myself lack confidence in such 60+ year old technologies that place it directly over the exhaust valve as I have learned what works best for me. Given the choice of one over the other I know which I prefer.
Actually I would suggest that the best plug location concerning the K series falls somewhere between the two, (take a look at where Vogel Manufacturing places it for their 9 bolt re cast head to see what I mean). Oddly enough it would seem that their blueprint spec sheet has recently been removed from their pdf files but it can still be viewed on the Brian Miller site.
I must confess that I might have led others astray the other day during the discussion concerning the high head boss vrs. low boss topic-
In that post I mentioned series and types lacking some clarity, when I mentioned 3 basic series of heads I was was making reference to:
1. Open chamber (spark plug location center)
2.Closed chamber (heart type)
131721.jpg
3. Open chamber (spark plug over exhaust valve)
When I had made mention of types I was making reference to:
1. High boss 9 bolt
2. High compression (LP head)
3.Low boss 9 bolt
4.10 bolt (16hp)
I regret if I confused anybody there with that-

There are all kinds of things that can contribute to unwanted noises with these engines and many of them can be traced to the cam shaft.
Vince's cam shaft could be possibly be off by one tooth, they will run with that condition. A one tooth error works out to only 6.92 degrees out of phase, that's plenty enough to cause problems. This is no reflection against you Vince- (I almost did that myself once). Just looking at possibilities here.
Excessive cam shaft endplay will make one of these sound as it's going to grenade any second. I throw away the book when setting endplay on them and look for .002 to .004 total endplay with 3 ideal and having never had any problem in doing so at all. This always made for nice quiet running.
I will make my own shims to do this and it's really quite easy to do- the factory shims are just that too and really nothing fancy at all.

Good luck to ya Vince buddy!
That's enough outta me :roll:

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vince_o
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Re: Spark nock problem solved

Post by vince_o »

Ken

Man no hard feelings at all! Tis is how one learns, from mistakes and the help of others! The noise is back, real faint and only at high speed. I havent had a chance to play with the points today but I will tomorrow.

What is gained in putting the plug hole over the exaust valve?

Faster removal of the spent fuel?

I know that you want the exaust valve to help draw in on the intake. ( I know how it works just cant type it )

Today at 2/3 throtal its runs like a sowing machine !

Thanks
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Klapatta
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Re: Spark nock problem solved

Post by Klapatta »

Vince,
UhOh :cry:
I'm sure you realize that any increase in an unexplained noise is not a good sign.
It might be a good time to pull the head off and have a look inside, it's fast and easy to do- and it can tell a lot.
You can never know for sure what's going on inside until you do, take it from me-
DSCN0195.JPG
He looks a lot like his big brother Dr. Theopolis from Buck Rodgers in the 25th Century don't he?
theo.jpg
theo.jpg (31.05 KiB) Viewed 8850 times
So back to talking shop.
You could check for excessive piston side skirt movement by shaking it. Check for visible bore damage like deep scratches too.
This is the perfect time to check for cam shaft position. With the piston at exact top dead center on the exhaust / intake stroke both valves should be open the same amount, about or under a 1/64 of an inch. If either is open much more than that and the other is closed then the cam shaft is out of phase by one or more tooth.
With your piston at top dead center (either stroke), rotate the crankshaft slightly in both directions, about a quarter inch total should do it. If you can't see any up and down movement by the piston doing that then the big end on the connecting rod is in trouble.
Did you eat all them steaks already?
Good luck :!:

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vince_o
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Re: Spark nock problem solved

Post by vince_o »

KEn

Adjusted the points a tweek on the carb and shes nice and smooth!
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Re: Spark nock problem solved

Post by Farmallgray »

I didn't know if I should hi-jack this thread or start a new one. Since it is kind of related I'll put it here.
What are you guys thoughts on running E-85 in a flathead Kohler? I'm talking for stock class pulling
with a 4000 rpm limit.

I like the cylinder head discussion too. Some of you may know this already but I found out there is such a thing as a low boss
head with the heart shaped chamber. I bought one on ebay a while back.
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Re: Spark nock problem solved

Post by Klapatta »

Todd,
The photo I posted here yesterday afternoon is in fact a low boss heart head- this same one that can be viewed over on the other related discussion page.
It came off of an M 10 engine.
There are a couple other things worth noting on it as well, this closeup shot is somewhat blurry after cropping however-
DSCN0210.JPG
There is a raised stepped detail around the inside of the intake valve radius that is not typical of other heart heads, it must be there to improve gas gating toward the piston.
Later heads such as this one will have a series of ribs that extend outward away from the head gasket surface. These are mold knockout pin ejector extensions that help support the cast part when it is pushed off from the mold. Those ribs also help out with the flow of the molten metal. Earlier castings lacked this manufacturing detail as the casting was ejected from the cooling rib side I do suppose. If I recall correctly I looked at one of those a long while back and they used rectangular ejector knockout blades for the vent rib side. That process made this kind of mold much more expensive to build and keep in good working order. They can be repaired a number of times but after hundreds of thousands of shots they are worn out and must be replaced. Along with a new tool comes a new design. This is all only theory though but I'd bet that's how it all went.

E-85? well the goverment will be tellin me about that by themselves when they are ready.

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Re: Spark nock problem solved

Post by vince_o »

Todd

I thought of that seeing it has an octane rating of 105. But I thought that it will ruin your car if its not equiped for it I figured it wouldnt work in my cub.

Im running an autolight 216 in this eng along with the bosh coil. Should I use a hotter plug?

If so what do you guys recomend?
"It's a damn poor mind that can only think of one way to spell a word."
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Racenitro
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Re: Spark nock problem solved

Post by Racenitro »

Read this regarding E-85

http://answers.yahoo.com/question/index ... 032AALfuWW

You may want to search various sites regarding E-85 and Ethanol or methanol vs gasoline.


You will probably need to change the jet to use E-85.

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Farmallgray
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Re: Spark nock problem solved

Post by Farmallgray »

There is some info about running E85 on Brian Miller's site and he does mention drilling the main jet out.
There was also some discussion on the Yahoo garden tractor pulling forum. Some guys said it helped and others said it wasn't worthwhile.
I would think it should make more power privided the engine can be tuned to use it properly. It should also have a cooling effect. I just wanted to throw it out here to see what you guys had to say about it.
See my IH, Cub Cadet and tractor pulling youtube videos;
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