Lets build a K321 torque monster

[ebinmaine 67,274]

2 hours ago, oilwell1415 said:

Another thing you can do to help part throttle efficiency and power is advance the ignition timing.  This is why cars had vacuum advance before computers took over.  I'm not sure you could do that easily on a Kohler, but if you could do it you would get a lot of benefit from it.

 

 

I remember reading all of this 20, 30 years ago when it pertained to small block Chevy V8 or a couple of different straight sixes I had. Very interesting stuff.

 

Sometime over the last couple years or a little bit more I was looking over a message board or website and at that time I didn't really have a full understanding of how a small engine timing system worked.

I didn't realize back then that in most cases static timing was your only timing and there was no advance.

 

I seem to remember someone theorizing or maybe digging for ideas about creating a computer-generated advance system.

I'm supposing that it must have been something about a crankshaft position sensor and an electronic spark module....

Maybe something the pulling world already does? Don't know....

 

[Greentored 3,201]

Yep, one can do every trick in the book and if the timing and air/fuel arent correct it will never perform. I have done a TON of 'super tunes' for customers on their classic cars- amazing how many are running around with carbs out of whack, and almost all of them need distributor work. A simple recurve kit and adjustable vacuum advance makes a day and night difference, especially in normal driving situations more than overall WOT power. One of my common tricks is to get all the timing 'in' by 3000rpms versus 4500ish stock, then dial in as much static timing in at idle as it will take and still start. This obviously gives it too much timing at WOT, so then Ill pull the distributor and weld up the mechanical advance slots to 'shorten' the total timing. HUGE difference! A lot of cars leave my shop with 14-22 degrees of static versus 4-8 like the factory calls for, with no adverse effects.

 Now im wondering how this could be done on our Kohlers. Maybe something out of a dirtbike and drive it off the crank- the additional spark would occur at overlap and be a 'waste' spark and shouldnt hurt anything- much like the Harleys run.

Ok, this is getting WAY out of hand now! Haha

Edited July 9, 2020 by Greentored

[tom2p 2,394]

just this past weekend was going through small boxes of assorted fasteners and parts and ran across some old distributor parts including weights and springs 

 

maybe 30 years since I've seen this stuff

 

have an old Accel coil somewhere ... thought I might stumble on to it - but still has not surfaced 

 

[oilwell1415 563]

17 hours ago, ebinmaine said:

I didn't realize back then that in most cases static timing was your only timing and there was no advance.

 

I seem to remember someone theorizing or maybe digging for ideas about creating a computer-generated advance system.

I'm supposing that it must have been something about a crankshaft position sensor and an electronic spark module....

Maybe something the pulling world already does? Don't know....

 

 

For these tractors I don't really believe there's much use in having mechanical advance.  They idle at around 1200-1400 rpm and peak is under 4000.  There's probably not much need to change the timing over that range.  Variable advance is really just there to help with starting and reduce emissions at low rpm.  If the engine is spinning to 6000 there's probably something to be gained.  If someone really wanted to try it there are tons of automotive ignition boxes out there that will do the job, but I think $500 is a lot of money to pay to get nothing back for it.  You can also get them that adjust boost based on manifold vacuum/pressure.  I think that would be really beneficial at part throttle.  Adding some timing at part throttle would probably help these tractors a lot.  It could easily make the difference between having to refuel while mowing or being able to finish the job on one tank.

 

1 hour ago, Greentored said:

Yep, one can do every trick in the book and if the timing and air/fuel arent correct it will never perform. I have done a TON of 'super tunes' for customers on their classic cars- amazing how many are running around with carbs out of whack, and almost all of them need distributor work. A simple recurve kit and adjustable vacuum advance makes a day and night difference, especially in normal driving situations more than overall WOT power. One of my common tricks is to get all the timing 'in' by 3000rpms versus 4500ish stock, then dial in as much static timing in at idle as it will take and still start. This obviously gives it too much timing at WOT, so then Ill pull the distributor and weld up the mechanical advance slots to 'shorten' the total timing. HUGE difference! A lot of cars leave my shop with 14-22 degrees of static versus 4-8 like the factory calls for, with no adverse effects.

 Now im wondering how this could be done on our Kohlers. Maybe something out of a dirtbike and drive it off the crank- the additional spark would occur at overlap and be a 'waste' spark and shouldnt hurt anything- much like the Harleys run.

Ok, this is getting WAY out of hand now! Haha

 

I've had the same experience.  I had a client with an old 351C powered Cougar that he thought ran really well, but he brought it in because he wanted more.  I drove the car and it just didn't feel as clean and crisp as I thought it should.  I recommended a dyno tune and told him that would cost about $500.  He told me he was a great tuner and there was nothing there.  Whatever.  I had the dyno scheduled for a day on another project, so I told him to bring the car by and if I couldn't find 20 hp I wouldn't charge him.  I found almost 90 hp at the wheels, so just over 100 hp at the crank.  Not only that, but he said the mileage nearly doubled.  Basics matter.
 

One of my cousins used to run pulling tractors with motorcycle engines.  He pulled the magneto off and put a sprocket for a timing belt in its place and used it to drive a distributor from a 4 cylinder car.  I'm sure you could do something similar, but it would be easier to just use a CDI box for a car.

[Greentored 3,201]

Update: heres some engine porn for ya's

The block bolted right to the base of the Sunnen valve and seat machine perfectly with a set of thick fender washers underneath.

20% larger intake valve to keep the intake/exhaust ratio somewhat correct, opened throat approx .200. Going for the 90% rule but will need to leave some material in the throat- blowing a hole in cast iron sucks- been there. Valve is a chevy Vortec 5.3 intake valve, cut down to 1.650 and cut at 30 degrees. On to the blending, port work/relieving and final valve job next!

 

Edited July 13, 2020 by Greentored

[12Horse Paladin 1,038]

21 hours ago, Greentored said:

Update: heres some engine porn for ya's

The block bolted right to the base of the Sunnen valve and seat machine perfectly with a set of thick fender washers underneath.

20% larger intake valve to keep the intake/exhaust ratio somewhat correct, opened throat approx .200. Going for the 90% rule but will need to leave some material in the throat- blowing a hole in cast iron sucks- been there. Valve is a chevy Vortec 5.3 intake valve, cut down to 1.650 and cut at 30 degrees. On to the blending, port work/relieving and final valve job next!

 

This is all greek to me.

HOWEVER:

If yer mixin' Chevrolet parts in a Kohler engine, you, Sir, are quite awesome👍🏼

Quite Possibly going to be

The

Best

Engine

Ever.😎

😆😁

 

[oilwell1415 563]

22 hours ago, Greentored said:

Update: heres some engine porn for ya's

The block bolted right to the base of the Sunnen valve and seat machine perfectly with a set of thick fender washers underneath.

20% larger intake valve to keep the intake/exhaust ratio somewhat correct, opened throat approx .200. Going for the 90% rule but will need to leave some material in the throat- blowing a hole in cast iron sucks- been there. Valve is a chevy Vortec 5.3 intake valve, cut down to 1.650 and cut at 30 degrees. On to the blending, port work/relieving and final valve job next!

Did you consider doing an undercut stem on the valve?  The area numbers don't really support it, but it's close and almost all of the flow will have to go past the stem towards the cylinder because of how the valve is shrouded.

[Greentored 3,201]

18 hours ago, 12Horse Paladin said:

This is all greek to me.

HOWEVER:

If yer mixin' Chevrolet parts in a Kohler engine, you, Sir, are quite awesome👍🏼

Quite Possibly going to be

The

Best

Engine

Ever.😎

😆😁

 

Never know, it is an experiment applying OHV rules to a flatty. It might end up being a turd that makes less than stock haha, and if it does, it was fun nonetheless

[Greentored 3,201]

18 hours ago, oilwell1415 said:

Did you consider doing an undercut stem on the valve?  The area numbers don't really support it, but it's close and almost all of the flow will have to go past the stem towards the cylinder because of how the valve is shrouded.

yes sir, just haven't gotten that far yet. 

[12Horse Paladin 1,038]

1 hour ago, Greentored said:

Never know, it is an experiment applying OHV rules to a flatty. It might end up being a turd that makes less than stock haha, and if it does, it was fun nonetheless

I love your attitude.

That is what got me into alla this in the 1st place; it is all so....interesting...ie, "fun".😊

[Greentored 3,201]

Got a bit further this evening. Port roughed in, decked, reliefs roughed in. Piston showed up today, off to punch it out next! 

[Greentored 3,201]

Stay tuned- going full 'mad scientist' and regrind my own cam

'just a little off the top'.....or base circle in this case......

[ebinmaine 67,274]

Oh man....

Don't forget to share pics!!!!

[Greentored 3,201]

Started on her after work today. Step 1- profile the original at every .050, seat to seat, lift etc...

Made a mandrel to mount cam and valve face grinding wheel to rough in, then smoothed off with a fine file and 400 grit emery. 
Nothing crazy here, just taking a little off the base circle, altering the opening and closing events, and a touch more lift. 

[Greentored 3,201]

Here’s 2 1/2 minutes if you’re bored. she’s done and I’m happy with the end results. Anxious to wrap this thing up and see if the work was worth  it. 

 

[tom2p 2,394]

dumb question - 

 

how do you get increased lift if you don't add additional material to the lobe ?  ( or was material added ? )

 

 

( how do you get your pudding if you don't eat your meat ! )

 

Edited July 23, 2020 by tom2p

[ebinmaine 67,274]

6 hours ago, tom2p said:

dumb question - 

 

how do you get increased lift if you don't add additional material to the love ?  ( or was material added ? )

 

 

( how do you get your pudding if you don't eat your meat ! )

 

Cam lift is from the base circle low point to the highest point of the lobe. 

Remove some of the base circle and you increase that distance there by increasing cam lift.

 

As to the pudding.... I've never had a problem finishing a meal ((look at me))

So I always got pudding.

 

 

[tom2p 2,394]

 

 

 

[Greentored 3,201]

9 hours ago, tom2p said:

dumb question - 

 

how do you get increased lift if you don't add additional material to the love ?  ( or was material added ? )

 

 

( how do you get your pudding if you don't eat your meat ! )

 

@ebinmaine hit the nail on the head. In the attached drawing, grinding to the thin red line reduces the base circle which increases lift, but more important- if you look at the fat red lines you see that after grinding the base circle, the line becomes steeper. The steeper line opens and closes the valve faster (fast ramps-which is exactly what the goal and benefit are with roller cams) and will also open the valve sooner and close later (duration). The blue lines are what is done with welded lobe cams, making the ramps 'fat' which opens and closes the valves very quickly, and holds them open at peak lift longer. They call this 'area under the curve' which is something i cannot do and therefore this cam will not perform as well as a welded lobe design. 

A square lobe would be ideal- it would open the valves instantly, hold them there, then slam them shut instantly. This cannot be done obviously due to more technical limitations and would stress/break the valvetrain. However, if you look up the cams hackman grinds for the Kohlers youll see what im talking about. Big power, very hard on the valvetrain.

Did I confuse the living hell out of you like myself? ha

Edited July 23, 2020 by Greentored

[Greentored 3,201]

PS- "if I eat one more bite im gonna puke" is the normal routine at meal time, followed by a hard couch crash- no need for pudding here!

Edited July 23, 2020 by Greentored

[oilwell1415 563]

1 hour ago, Greentored said:

....fast ramps-which is exactly what the goal and benefit are with roller cams) and will also open the valve sooner and close later (duration). The blue lines are what is done with welded lobe cams, making the ramps 'fat' which opens and closes the valves very quickly, and holds them open at peak lift longer. They call this 'area under the curve' which is something i cannot do and therefore this cam will not perform as well as a welded lobe design. 

I am so glad someone else understands why rollers work.  Almost everyone thinks it's because of reduced friction and there's nearly zero friction with a flat tappet; they just work like one giant journal bearing.

You could achieve the same profile as a reweld with a simple regrind.  The only time you really need to reweld is if you want to change the LSA, LCA, are grinding so much that you remove all of the surface hardness, or are at the geometric limits of the lifter.

 

I'm jealous of your access to a lathe.  When you said you were going to regrind I was wondering if you were going to do it in a lathe, grinder, or had an actual cam grinder available.

[Howie 886]

I ground a cam for a 6hp tecumseh like this. Had access to a lathe with a grinder that bolted

om the cross slide. An engine builder I knew told me the tractor pullers were doing this.

[Greentored 3,201]

7 hours ago, Howie said:

I ground a cam for a 6hp tecumseh like this. Had access to a lathe with a grinder that bolted

om the cross slide. An engine builder I knew told me the tractor pullers were doing this.

How did it work? Did you have the cam re treated for hardness afterward? Thats my next step/decision.

[Reddart 207]

How much clearance is there to the head at full lift? I wonder about that when increasing the lift and/or milling the head. 

[Greentored 3,201]

1 hour ago, Reddart said:

How much clearance is there to the head at full lift? I wonder about that when increasing the lift and/or milling the head. 

 

There's plenty in stock form, the actual increase in lift is pretty miniscule. Once the bottom end is assembled I will 'clay' it, that will determine how much I'll be able to mill the head and whether or not flat or angle mill