Heymow - Lawnmower Racing Forum
Engine Help => Briggs OHV & Vanguard => Topic started by: mightymowe on October 13, 2007, 10:37:03 pm
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My brother-in-law just bought a new mower,it said 21 hp on it so I had to look under the hood.It was a OHV single.So naturally I checked the model no. and It starts with a 33. I am thinking a C/P engine.
I sure want to take it apart to measure it up and see whats inside,but I dont think he would like that.
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Well... C/P is limited to 20 hp and below..
So unless you can find a 33" single with a 20 hp sticker on it.. your out of luck with that motor...
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I didnt realize that there was a 20 hp limit. There might be some parts that you can use like maybe a stroker crank.I am going to see if I can find out the bore and stroke of that engine.
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The real question is... is the hp change due to just a little bit bigger bore and could it jsut be jetted different.
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I was thinking if the model number is any indication,it is actually a bigger engine.I was wondering if it was bore,or stroke,or a little of both.
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Post the complete model and type.
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I'll get it later today.
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OK I got the model no. it's 331877 Type 0805E1 It also says 540cc on the sticker.
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Just curious. What brand mower did this come on?
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I think it was a Craftsman,it looked like a MTD step thru chassis.
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Doing some digging through the briggs IPLs for the 31L700 and the 331800 I see that the 31 and 33 cube engines share some of the same part numbers for the crank & rods so I think a stroker is out of the question. Unfortunatly I can't find the bore specs for this 33 cube engine.
Here are the complete piston & ring assembly part numbers
794124 Piston Assembly (Standard) $70.60
794125 Piston Assembly (.020†Oversize) $89.50
Hey George, think you can sleeve and punch a 28 flattie to 33 for me :badgrin:
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That's been done before...
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Yup been there done that!!!
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This was the first I had seen of a 33 ci engine.So that can be done to a 28? No difference in stroke? It would be a good way to increase the compression ratio in my flathead,just compress more into the same size combustion chamber.
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Its all about the FLOW in a flat head.
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Thats what I was thinking,I wanted to leave the head alone or even open it up a bit for flow,but if I compress more ci into that combustion chamber the pressure goes up and so does the power.
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but if I compress more ci into that combustion chamber the pressure goes up and so does the power.
Now ya using your noggin.
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Yup been there done that!!!
Was they much difference in power with the 33 over the 31?
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Don't know we used a piston that is not a briggs and stroked it to get right at 35 and it ran like a scalded dog but blew it all to pieces. Crank grenaded. Wasn't much left.
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I guess we need that billet crank.Any news on that?
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had an engineer in last week he cam and picked up a couple cranks. SO the process has begun.
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Cool I cant wait.
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George, Have you decided on the stroke? How much more stroke will clear with the ARC rod?
Jack Jones
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If we do what we want it will be a crank and rod kit. The wheels and minds are turning. Thats all I can elaborate on at this time.
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Is there going to be a stock stroke billet crank or just the stroker?
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Don't know yet the main topic so far has been stroker.
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Are they an estimated release date for these beasts?
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Hello, can anyone PLEASE tell me what the bore and stroke is on this 33 CI ? When I go to the B/S site and put the numbers in it refers me back to the 28. Thanks for any help. johnboy
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From what I gather,if the crank and rod are the same part no.as the 31,it must be just a different bore.I was just hoping that maybe the block was different and maybe they had moved the cam farther away from the crank to allow more stroke,and done that from the factory.That could open up a whole bunch of possibility's
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I called Briggs. It is an Intek, Bore is 3.70, Stroke 3.06 same as the 28 and 31
Briggs website is about worthless for looking up stuff like this.
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The intek doesnt have much more of a bigger bore then the 28CI (3.44)
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The intek doesnt have much more of a bigger bore then the 28CI (3.44)
.260 overbore is a huge difference. That's over 1/4" larger of a bore and there's no replacement for displacement which is why some of us are drooling over it.
28.45 CID vs 32.92 CID or 33.28 CID if you go .020 over on the 33 briggs
That's 4.47 cubic inches which could easily translate into 4.5 more HP or better if you're getting about 1hp per cubic inch or more from a modified engine.
Every little bit counts on these small racers.
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:woo: Have you seen one??? Yep I have one here for the Mad Scientist to play with.
Do you want one??? While supplies last $500 shipped to your door.
No stickers or decals. I will have pictures soon.
Let me know
Don
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I was thinking the other day and ran across a combo some of the FX guys limited to 28 cid might be interested in.
33 block w/ 3.70 bore + 25 crank w/2.625 stroke = a nice long 5.612" rod / short stroke 28.22 CID capable of 8380 RPM mathmaticly :badgrin: ....... If the crank could handle it.
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that would be one heck of a twister but how does the math do for torque? i have always liked a bigger stroke for more torque. my buddy has always liked more bore than stroke, in dragracing i actually could outrun him until he put $1400 heads on his engine. of course 406ci compared to 377ci, mine ran 6000rpm and he ran 7500rpm with different gearing. point taken on short stroke as long as there is more cam and more flow with more fuel and air.
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My math isn't that good. :lol:
I think it would be a bit of a dog on the bottom end. Like you I've always preffered the torque of a longer stroke crank but I did have a 327 chebby that I built that was very successful in short track and bracket racing so I won't discount short stroke high winding engines.
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I got a ques about the 331877 0805 e1 Is there any class you can run that motor in?
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Have you seen one??? Yep I have one here for the Mad Scientist to play with.
Do you want one??? While supplies last $500 shipped to your door.
No stickers or decals. I will have pictures soon.
Let me know
Don
Don did you ever get any pic. of them 33's?
Them 33 I am sure you can run in the ModX/CP class as long as they are 20HP and under or the Pro X with ARMA
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Anyone know the number for the piston number for the 33?
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Briggs p/n 794124
Jack Jones
Hard Case Racing
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I believe Don has a couple in stock at G-Team...
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As close as that would be cutting a 12hp block I wonder how that engine would last?
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It won't!
Unless you bolt the cylinder through the block!
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My 33ci is a 21hp motor only has 50 hrs on it. cam went out got a new cam for it, Darn i got to find another motor to put in my racer :mad:
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What exactly do you mean by bolting the cylinder to the block Rocky? Never heard of anyone doing this and I was thinking Don and George had built some 33's before and had them last.
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.260 overbore is a huge difference. That's over 1/4" larger of a bore....
Your cylinder walls are going to get waaaay thin with that bore.
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How about boring a 31CID block too 33CID?
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The 31 block may work but the head gasket surface between the cylinder and the push rod/lifter area would only be about 1/8" wide. It would be tough to keep a head gasket from blowing out in that area. Maybe with a copper gasket it could work.
Jack Jones
Hard Case Racing
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i got ya. I am sure someone will come up with something.
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33 block- upper half( no pan )- part number 794128 price-$ 162.20 at your Briggs dealer
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I got one of these 33ci motors 21hp I tried putting it in my craftsman lt4000 I lowered the hood and the air cleaner assembly rubes against the the hood, I was wondering if there is a aftermarket air cleaner kit i can use to fix this problem i do not want to hack up the hood, Does anybody got any Ideas ?????
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Air scoop like Michael A. Formentini runs ~ http://www.heymow.com/index.php?topic=5702.0
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So the part number for the 33, is the right one but, will the pistion oin fit the arc rod. Also is the skirt big like a stock 28 or short........thank joe 225 C/P
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So what would one of these 33ci OHV motors make for power with Mild Cam, upgraded valvetrain, port/polished head, adj main jet and exhaust? Easy 30hp?
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did anyone ever take the time to build a 33
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Precision Cams now stocks the 33 kit engine. It comes complete with a new PC 440 cam/spring package and all Billet parts. We also handle all the machine work, making it real easy for the engine builder. :woo:
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33 block- upper half( no pan )- part number 794128 price-$ 162.20 at your Briggs dealer
What dealer are you finding this at for $162? Best i found was over $400.
Lester
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I agree, Mike told me his cost on the block was around $450, I never checked myself just took his work for it and bought a complete engine for a little more.
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Guys that price was 3 years ago Briggs goes up 3 or more times a year
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486.85 from the briggs site.
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whats the kit price
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you could pm me with the kit price also. i tried to find it on website but no prices
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i think it was free just pay X amount for s&h
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I wish :woo:
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What dealer are you finding this at for $162? Best i found was over $400.
Lester
BRIG,794128
Description:
CYLINDER ASSEMBLY
Available Qty:
0
List Price:
$486.85
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Call Mike! He'll take care of you.