Firestorm O.S. Engine Swap  
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All Forums >> RC Cars, Buggies, Trucks, Tanks and more >> HPI Racing >> HPI Off-Road >> Firestorm O.S. Engine Swap
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Firestorm O.S. Engine Swap - 10/22/2007 1:27:23 AM   
guyelcamino


 

Posts: 12
Joined: 10/22/2007
From: Lake Hopatcong, NJ, USA
Status: offline 		I have a Firestorm and have enjoyed it, WHEN IT RUNS GOOD! It has taken a beating and the truck is tough with almost no breakage to the body/chasis/suspension. Now the motor on the other hand has been giving me trouble. I have had clutch problems, throttle return issues (the ball and cup were to tight from the factory and was binding, I sanded off the paint on the ball and works fine) and the spring in the crank that holds the drive pin for starting broke after only a few tanks of gas.
I have put about 1 1/2 gallons though the motor and it will not tune and run properly. It's time for a new one. Don't like the composite (plastic) carb either.
I want to put an O.S. engine in but can't find a direct fit. Would like to stay with a .18 but I am open to other options. I talked to O.S. but they were not much help. Original HPI motor has a rotory carb, side exhuast, sg style crank, and I installed a roto start. I would like to make the minimal amout of modifications as possible. I'm willing to change exhuast to rear exit but don't want to give up my roto start.
Who out there has done this swap and or has any info and suggestions?
       Post #: 1

RE: Firestorm O.S. Engine Swap - 11/18/2007 5:57:06 PM   
5810


 

Posts: 15
Joined: 11/17/2005
From: , TN, USA
Status: offline 		Hey i would go with a os 18 cvr motor, Its an awesome motor for under 100 bucks, starts every time. I have it in my rush, with 47-19 gearing & that thing screams. you will need some engine mounts & it should be a straight swap.

(in reply to guyelcamino)
       Post #: 2

RE: Firestorm O.S. Engine Swap - 3/10/2008 10:57:37 PM   
Gereke


 

Posts: 77
Joined: 1/14/2008
From: Cave Junction, OR, USA
Status: offline 		OS .18 CV-RX will work in a firestorm as well, however it requires that you trim down the crank about 1/4 inch and use an adapter nut for the clutch bell.


(in reply to 5810)
       Post #: 3

RE: Firestorm O.S. Engine Swap - 3/21/2008 11:14:35 PM   
gflyer_22040


 

Posts: 49
Joined: 7/5/2007
From: langley, BC, CANADA
Status: offline 		os.18cvrx w/11j rotary carb its a great engine u just need a new backplate i suggest the duratrax kwik pit supperstart one u can usually find all this on ebay or youre local hobby shop

(in reply to Gereke)
       Post #: 4

RE: Firestorm O.S. Engine Swap - 5/4/2008 2:24:15 AM   
guyelcamino


 

Posts: 12
Joined: 10/22/2007
From: Lake Hopatcong, NJ, USA
Status: offline 		Ok I finally completed the engine swap so hear is all the info to do it.

O.S. 18CV-RX 11J ABC engine p/n OSMG2104 or 11880 Tower Hobbies p/n LXGGP7
HPI Pilot Shaft M5 p/n A805 Tower Hobbies p/n LXM720
Duratrax Super Start Backplate p/n DTX6031 Tower Hobbies p/n LXHPS2 (this is optoinal if you hate pullstarts)
Team Assosioated Carb Return Spring p/n 7562 Tower Hobbies p/n LXUP98 (optional but would recommend it even
with the original motor)

The O.S. motor is a ROTORY CARB with SIDE EXHUAST just like the original HPI motor. It comes with a pullstart which means the back of the motor will except the Duratrax Super Start adapter. Non pullstart motors have a different back and therefore a different bolt pattern.

The Modifications I had to do to install it were to cut about 3/16 (.187) off the crankshaft so the HPI pilot shaft would screw on all the way. Yes thats right cut the end of the crank on the new motor you just spent over $100 bucks on!!! I was'nt to happy about the thought of it myself. A cut off wheel in a dremel made it a piece of cake. The shaft is hardend and I didnt have to dress the end of the threads much to remove any burrs. Don't buy the Team Assosiated clutch nut that I saw recommended in the other forum. The snout is to long.

The original motor mounts will work if you file or dremel clearance in them. The back of the O.S. motor were the bolts for the pullsart go interfear with the mounts. They are soft aluminum and were no problem to file. You do not need to use the motor mount spacers supplied with the O.S. motor or buy the HPI 20mm purple engine mounts either. They don't fit the Firestorm chasis so don't waist $20 like I did.

You will need to cut the bottom chasis plate. The back of the O.S. motor is larger then the original HPI motor and hits when you try to bolt it down. You have to cut right up to the mounting holes for the motor mounts in the chasis. You can cut it all the way across with a cut off wheel even though I just cut a notch for the back of the motor. You may need to trim a few threads off of the scews for the pullstart/Super Start if they protrude through the back plate.

The original exhuast will bolt up but you need to cut the bolts down to 25-26mm (1 inch long) or buy shorter ones. They will hit the header pipe when you tighten them all the way.

I chose to rotate the carb slightly so I could get to the LSN. If you turn the carb to much the throttle lever will contact the head. Especially since it is plastic and deflects under full braking. I also added a Team Associated throttle return spring to asure full throttle return to idle. I had problems with the original motor not always returning all the way and driving me nuts trying to figure it out.

I have just finished bolting it up and have not yet broken it in to work out any possible bugs or give any porformance data. I did port my exhuast header and tightend up the servo saver so the car will finally turn. My next upgrade will be a Hitech 645 servo for the stearing.











(in reply to gflyer_22040)
       Post #: 5

RE: Firestorm O.S. Engine Swap - 5/5/2008 1:49:56 PM   
guyelcamino


 

Posts: 12
Joined: 10/22/2007
From: Lake Hopatcong, NJ, USA
Status: offline 		Well I got to break in the O.S. engine today. I used the heat cycle method. I had a hard time starting it and when I did it would'nt idle. She was PIG RICH from the factory. I had to lean out the LSN to get her to idle. When I ran the car it had those gargling sounds due to a super rich HSN setting and was limited in rpm's. Once I started leaning that out she woke up. I never got her over 210 deg. so I know my settings were safe and I always saw a trail of smoke. I guess I'm still used to the original G3.0 settings. The manual for the O.S. motor has different high and low speed needle settings by a few turns. Made me a little nervous at first thinking everything was going to be to lean until I was spurting raw fuel out the exhuast. I haven't got a chance to fine tune the engine yet to evaluate it's performance though.

(in reply to guyelcamino)
       Post #: 6

RE: Firestorm O.S. Engine Swap - 6/2/2008 9:54:28 PM   
guyelcamino


 

Posts: 12
Joined: 10/22/2007
From: Lake Hopatcong, NJ, USA
Status: offline 		This engine rips!!! I have pro line m2 gladiator tires on the rear and I can't keep the front wheels on the ground when running in grass. I have the 21 tooth clutch bell , slipper clutch turned 6 turns out ( factory spec) and tunned slightly rich. It has pick up like a bat out of hell. My street tires aren't that sticky so the rear end kicks sideways when I take off. When I do get a good bite on the street I have to let off to keep in under control.

(in reply to guyelcamino)
       Post #: 7

RE: Firestorm O.S. Engine Swap - 6/25/2008 12:15:30 AM   
Nesal


 

Posts: 61
Joined: 6/13/2008
From: , SPAIN
Status: offline 		Hey nice one man! looks pretty cool!

(in reply to guyelcamino)
       Post #: 8

RE: Firestorm O.S. Engine Swap - 6/25/2008 7:46:35 AM   
standupclothing



Posts: 127
Joined: 11/14/2006
From: Austin, TX, USA
Status: offline 		WELL i was wandering what happened here... I cut my shaft 3/16" off and then removed the friction plate that came with the motor, placed the flywheel collet over the square key, put flywheel on the collet, put the clutch shoes on, screwed in the pilot shaft, put a washer then bearing then clutch bell on the pilot shaft and screwed that on with the bearing and 4 washers. My problem is that the clutch bell tightens up against the flywheel... isn't it supposed to spin freely?? Did I put it on in the wrong order??

Thanks!

_____________________________

.:Stand Up Industries:.

(in reply to Nesal)
       Post #: 9

RE: Firestorm O.S. Engine Swap - 6/25/2008 10:08:27 PM   
NitroNate



Posts: 818
Joined: 7/31/2007
From: Honeybrook, PA, USA
Status: offline 		Which CV-R do you have??(S) or just the standard CV-RX?

_____________________________

My Firestorm is anti-breakage;
My MLST2 is garbage.>:(

(in reply to standupclothing)
       Post #: 10

RE: Firestorm O.S. Engine Swap - 6/25/2008 10:56:27 PM   
standupclothing



Posts: 127
Joined: 11/14/2006
From: Austin, TX, USA
Status: offline 		The standard one...

_____________________________

.:Stand Up Industries:.

(in reply to NitroNate)
       Post #: 11

RE: Firestorm O.S. Engine Swap - 6/26/2008 5:49:39 PM   
NitroNate



Posts: 818
Joined: 7/31/2007
From: Honeybrook, PA, USA
Status: offline 		Hmmmm ,I never encountered such a problem.Are you sure its against the flywheel?If you over-tighten the clutch bell screw,it will have quite a bit of resistence.I put the collet and the flywheel on,then the pilot shaft,then the shoes,then the CB.Other than that I couldn't guess what the prob is.

_____________________________

My Firestorm is anti-breakage;
My MLST2 is garbage.>:(

(in reply to standupclothing)
       Post #: 12

RE: Firestorm O.S. Engine Swap - 6/28/2008 4:42:20 AM   
standupclothing



Posts: 127
Joined: 11/14/2006
From: Austin, TX, USA
Status: offline 		ah thanks nate but i got it! it was all those dang washers that came off the g3.0... they wouldn't let the bearings spin so i just put three before the screw head and it works perfectly and i was able to complete mounting the motor tonight :-) just gotta get a z-connector extension for the new receiver and i will be ready for break in... oh yeah and should i get a new exhaust gasket probably? the paper one was junk after taking the header off...

_____________________________

.:Stand Up Industries:.

(in reply to NitroNate)
       Post #: 13

RE: Firestorm O.S. Engine Swap - 7/2/2008 6:29:49 PM   
standupclothing



Posts: 127
Joined: 11/14/2006
From: Austin, TX, USA
Status: offline 		well i got it in and everything all together... i will post pictures when i get home tonight if i remember... what do you guys recommend for break in? what is the normal running temp for this thing?

_____________________________

.:Stand Up Industries:.

(in reply to standupclothing)
       Post #: 14