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Engine build

Printed From: Official Baja SAE Forums
Category: General
Forum Name: Lounge
Forum Description: Talk about whatever
URL: http://forums.bajasae.net/forum/forum_posts.asp?TID=2141
Printed Date: Oct/21/2021 at 1:38pm


Topic: Engine build
Posted By: Aztec Warrior
Subject: Engine build
Date Posted: May/14/2015 at 6:37pm
So my car didn't make it past the Oregon wait list. Time to cut all the excessive safety stuff off and make it a toy. I am looking into building up the ole Model 20. Got some parts on order...a billet connecting rod, new cam and cam gear, some valves, rockers, new carb and exhaust. Will probably mill down the head a few thousandths and port it. Has anyone done a similar build? Should make this little car a bit more interesting.

I have a 400ex engine sitting on the ground that could go in, but I think that will probably tear this chassis to pieces. Besides, the Karting guys are telling me this block will make a reliable 20 hp engine...perfect!

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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present



Replies:
Posted By: Pedro UFPBaja
Date Posted: May/14/2015 at 9:41pm
http:///www.performancevtwins.com/" rel="nofollow - This guy takes 60hp out a briggs v-twin, so he must have the parts that suit "half of that"

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Former Team Captain


Posted By: i6overboard
Date Posted: May/14/2015 at 9:48pm
Our jr. dragster motors are based on the briggs platform, flathead singe, 410cc... They make around 40hp, idle at 4500rpm, 8600 at the finish line.. I think it actually has the same bolt pattern as the intek and a similiar C to C for the cvt, so basically just a "bolt-in" motor.. 


Posted By: Aztec Warrior
Date Posted: May/14/2015 at 10:43pm

WOW, that's some serious power, I have even heard of people squeezing 50 hp out of a 305cc. But I am looking for an engine that will go hundreds of miles, not 660 feet. Reliability is most important, both for the engine and car. Going TOO big on this project will effect both.

 



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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: JeremyB
Date Posted: May/15/2015 at 2:01pm

I've thought about making a hot motor for our old car, although I'd really like to just be able to rev it out to 5k reliably, rather than make a mess of hp.

EFI is on the list before the hot motor. http://www.ecotrons.com/" rel="nofollow - http://www.ecotrons.com/
Then the same stuff as you, starting with a stock cam to see how wheezy it is at 5k.
 
If you end up building the motor, document and post it. Would be interesting to see and read about.


Posted By: Aztec Warrior
Date Posted: May/15/2015 at 7:10pm
Nice...EFI would be trick! Add it to the list. Haha.

I will definately keep this thread alive with pics and updates as things progress. Need to start a modified briggs class at one of the unscripted events

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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: johnpate01
Date Posted: May/16/2015 at 10:02pm
What a Microsquirt controller?  Maybe pair that with an injector from one of the newer dual-sports or scooters.  The Hondas are about 250cc but rev quite a bit higher so you would probably be in the ballpark.  I'm not sure about their specs, just speculating.


Posted By: jeiB
Date Posted: May/17/2015 at 2:54pm
I would forget modifying the Briggs and just use the 400ex. From the forum post below, its good for about 25HP (stock).

http://www.atvriders.com/vbb/showthread.php?17340-400EX-horsepower

Hot Briggs is cool but you are going to spend a LOT of money (unreliable, broken parts, etc...)


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Jeremie B.
McGill Baja Racing
2009-2011 Captain
minibaja.mcgill.ca


Posted By: Bettner12
Date Posted: May/17/2015 at 10:35pm
Originally posted by jeiB jeiB wrote:

I would forget modifying the Briggs and just use the 400ex. From the forum post below, its good for about 25HP (stock).

http://www.atvriders.com/vbb/showthread.php?17340-400EX-horsepower

Hot Briggs is cool but you are going to spend a LOT of money (unreliable, broken parts, etc...)

the 400ex motor is a much better starting platform, but i think the briggs would of more interest to about 100% of the teams on here. i've always wanted to test chassis, drivetrain components at about 4x hp, an upgraded briggs would allow that to happen. just ramblings...


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Penn College of Technology Alumni

Maryland 2018 Organizer





Posted By: Akron 1998 to 2004
Date Posted: May/18/2015 at 4:09pm

Harbor Freight sells a V-twin for $650 now, electric start too.



Posted By: Pedro UFPBaja
Date Posted: May/18/2015 at 5:08pm
Briggs 305cc with 31hp:



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Former Team Captain


Posted By: Aztec Warrior
Date Posted: May/18/2015 at 5:18pm
I don't believe in Harbor Freight. Besides, it won't bolt in. The sweet part of tuning up the briggs is that I don't have to make any chassis or drivetrain mods.

I'm suprised the 400ex only makes 25hp, always help like more pep than that. That gives me hope though that this upgrade will bring this car alive more than I was expecting!

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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: Akron 1998 to 2004
Date Posted: May/18/2015 at 7:15pm

Should have planed for the V-Twin.  No replacement for displacement!



Posted By: Aztec Warrior
Date Posted: May/18/2015 at 8:12pm
That's very cool, but if that is a HF, I would have a replacement ready, especially with all that displacement. Haha. j/K, I am sure it is loads of fun!

I'm opting for the name brand block, turned into a race engine with a heap of billet aluminum parts. More fun to build the power yourself, I guess.

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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: Aztec Warrior
Date Posted: Jul/10/2015 at 12:09am

BUMP!!!!   Finally got it all figured out, and a box of Horse Power just showed up today. Parts list includes:

Billet Rod-Billet crank gear-Cam-Lifters-Push rods-Dual valve springs-28mm muki carb-Billet flywheel-header and muffler.

Going to tear down the old engine this weekend, updates and pics to come...just need to figure how to upload pics



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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: Aztec Warrior
Date Posted: Jul/10/2015 at 12:16am
I try to "insert image", but after uploading and click "ok", it tells me "Error inserting opject in current location," any one know what I am doing wrong?

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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: JeremyB
Date Posted: Jul/10/2015 at 11:08am
Weird, seems to be working for me. It is inserting a link like :uploads/4/28mmTB_Top.png to the Image URL box when you upload it? What file type is it. GIF, TIF, JPG, PNG?


Posted By: Aztec Warrior
Date Posted: Jul/10/2015 at 11:38am
Yep, I switched over to Chrome rather than internet explorer...I guess it is working now...




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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: JeremyB
Date Posted: Jul/10/2015 at 12:34pm
I'm on IE10, which is probably older than everybody else is running.


Posted By: Aztec Warrior
Date Posted: Jul/11/2015 at 4:10pm
Here are a few comparison pictures of the parts that are going to make the difference...

New cam on the left, The cam lobes are measurably taller, and noticeably wider. Should let a lot more air move through this engine. 


New carb on left, 28mm bore rather than stock 25mm. pi*r^2 tells me that is 25% more flowable area; Even more than that if you count the "butterfly" that doesn't lift out of the way in the old carb design. 



Cast flywheel on left (13.2 lbs) Billet on right (4.2 lbs)=9 pound weight savings. Rotating mass! Adjustable timing also.     
*disclaimer-Weights taken with bathroom scale



New, billet rod on top, stock, cast rod on bottom. Much more strength, and a cool oiling port (for journal bearing) on the splasher arm. 


Washing parts in the ultrasonic on Monday, then the assembly begins...


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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: Richie_Dagger
Date Posted: Jul/11/2015 at 10:19pm
This will be neat. I'm assuming it's going in an old SDSU car? Would be great to get some video of racing your latest car with a legal motor.

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UNLV Baja 2010-2015


Posted By: FelixB
Date Posted: Jul/11/2015 at 11:31pm
how much did it cost you? (if you don't mind me asking)

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Felix Belanger
Université Laval


Posted By: Aztec Warrior
Date Posted: Jul/12/2015 at 2:57pm

Originally posted by FelixB FelixB wrote:

how much did it cost you? (if you don't mind me asking)


About $900 with tax and shipping. probably could have paid a little less if I would have sourced all the parts directly from the manufacturers. I went thru one company that stocks all the parts.



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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: Aztec Warrior
Date Posted: Jul/12/2015 at 3:04pm

Originally posted by Richie_Dagger Richie_Dagger wrote:

This will be neat. I'm assuming it's going in an old SDSU car? Would be great to get some video of racing your latest car with a legal motor.


Its going in last years car (This one)

Will definitely do some side by side comparisons vs. another one of our cars with a stock engine. Also, I am going to take this car to the chassis dyno before pulling the engine, to get some numbers. Want to compare the before and after.



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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: drvr5
Date Posted: Jul/12/2015 at 9:32pm
I wonder what the actual safe limit for power would be in competition. Looks like you have a fun project! Looking forward to seeing the gains you make


Posted By: FelixB
Date Posted: Jul/13/2015 at 9:38am
in competition, i think 10HP is enough... Can't wait to see how much you can squeeze out of the briggs!

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Felix Belanger
Université Laval


Posted By: Bettner12
Date Posted: Sep/27/2015 at 2:35pm
updates? 

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Penn College of Technology Alumni

Maryland 2018 Organizer





Posted By: Aztec Warrior
Date Posted: Sep/30/2015 at 1:47am

No, no tangible updates at the moment. I was just thinking about this over the weekend, but have been really busy with a few other projects. Besides, the car had to go back together (with a stock engine) to test the track for the California event a couple weekends ago.

 The donor engine is still apart on my work bench, cleaned up and just about ready to go together. I sent the main bearing, crank, cam and lifters out for some polishing and a super secret low friction treatment. I also ordered a Johnson's differential pump and Setrab oil cooler to help keep things cool. Planning to run a oil pump of the transmission (similar to ETS).

I have all the parts, and lots of motivation, just have to find the time to put it together. Once I get going, I have big plans to modify car to make it work better as a desert car for the old lady. Planning to add the oil cooling, bigger fuel cell, Tool box, spare tire, battery, alternator, lights, ect.

But the engine is first, and I will get going on it in the next couple weeks and will be sure to keep this post alive.  

Thanks for the interest



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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: kcooper273
Date Posted: Feb/09/2016 at 11:11am
Update?

I bought an old Michigan Tech car to use as a pit cruiser at TORC short course races, to haul my hot pit gear. The car weighs about 475, and 37HP will give it around the same Power to weight ratio as a Razr, so that is what I am gunning for. I have a Kohler 16HP but looking at other options, like a hot Briggs.

I am building a removable rear rack to haul stuff, but I'll to be able to put the rear cage back on it so when the county fair rolls around I can make some noise.


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Michigan Tech Baja 2010-Dec 2014 Victory Lap: Auburn 2015. 2nd Victory Lap Maryland 2015 (Peer Pressure)

CYS Motorsports-TORC Super Stock Truck #873


Posted By: Aztec Warrior
Date Posted: Jun/18/2016 at 5:34pm
So after almost a year, I am finally paying a little attention to this project. I put it on hold back then as I realized this wasn't going to be a easy plug and play deal, and life got busy, not allowing me to play with this project at that moment. 

The new, probably unattainable goal for this project is to have it completed and testing next Saturday 6/25. Then have my wife race it in the "beach buggy" class at the Del Mar fair on 6/25. It will be a push to get it there with proper testing, but if I don't set a deadline, it will never get done. So Hopefully I will find time to post some pics of progress throughout the week. 

As of right now, the engine is all assembled and bolted into the car. It will need some customization. 

I ended up having to modify the pull start drum, as it was crashing into the timing adjustment bolts on the aluminum flywheel:


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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: Aztec Warrior
Date Posted: Jun/18/2016 at 5:38pm
I had to build an intake system to accommodate the larger carburetor and air filter. 

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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: Aztec Warrior
Date Posted: Jun/18/2016 at 5:48pm
As a lot of you learned in May, Spark arresters are required to legally drive off-road in California. So, since this car will require a custom exhaust, I customized an existing Spark arrester (which was far too large for this car). Probably wont be much of a muffler, but who cares?!?






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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: Aztec Warrior
Date Posted: Jun/18/2016 at 5:51pm
As you can see in that last set of pictures, I also built a spare tire carrier/bumper that will act as a muffler hanger. Ill also eventually squeeze in an aluminum tool box in the space under the tire.

My goal for the end of the day is to build a header and mount the exhaust. 


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"To finish first, you must first finish"

SDSU Baja 2010 and 2014
McMillin Racing 2005-present


Posted By: FelixB
Date Posted: Jun/18/2016 at 7:23pm
No matter how much HP you gain, at least it won't look like a generator engine :P

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Felix Belanger
Université Laval


Posted By: Richie_Dagger
Date Posted: Jun/19/2016 at 4:24am
Originally posted by FelixB FelixB wrote:

No matter how much HP you gain, at least it won't look like a generator engine :P
It'll always look like a generator motor with the fan shroud and pull start. Good excuse to machine the inner cooling fins off and weld a jacket around for water cooling though.Wink

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UNLV Baja 2010-2015


Posted By: Nick914
Date Posted: Aug/08/2020 at 3:12am
Any development?

I'm about to take my engine apart for some rings/gaskets and carburator and that thread popped in mind.
While I'm at it I'll look for easy cheap mods. I'm thinking new carb and getting rid of the governor, ports polishing, new plug...


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Nicholas Lefebvre

Universite Laval



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