30.5 engine info wanted

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
C

Chief409

Well-Known Member
Messages
707
Reaction score
0
Location
Rosamond, CA
Where can I find out what the stroke is for the HY 30.5 engine. The CY site doesn't list this one, a Google search on HY brings up links to here. I think the 30.5 has a 2mm increase in stroke from the smaller engines, plus a bigger bore.
 
if the HY is the same as " most " 30.5 engines it will have a 36mm bore and a 2mm stroke crank.

i personally don't know of " big name " builders that have actually done anything with HY platform in the smaller motors.

you might shoot Eric Hill an email over @ Flowsystem Racing, he may know since he has done work on the 36cc motors that i believe are HY, don't hold me to that statement about the 36cc, i could be dead wrong, but it seems i had read somewhere they are...
 
After I put the OBR Prostock in the DR I'll build the stock HY 30.5 with a 2 bolt Race Ported top end. OBR has the Race Ported top end, piston, wrist pin and gasket available, also there's a Upgrade kit for $50 more with all that plus the rod, crankshaft, bearings, etc. Seems I need the Race Ported top end kit, not the upgrade kit. Just doing some checking before I whip out the credit card.

OBR complete engines, long blocks, etc. are 4 bolt. When I was ordering the Prostock I almost got the 36cc, till I looked closely at the spark plug, it'd never fit under the DR spark plug protector, and we know how hard upgrade roll cage parts are to find for Dune Runners. Scarce as "Hen's Teeth"
 
Last edited by a moderator:
hy 30.5 cc

the rod in a hy 30.5 cc engine is 30mm long. the bore in a hy 30.5 cc engine is 36mm diameter. I bolted a cy 29 top end to the hy 30.5 cc engine and love it. Its all about the way it pulls, With a modded wt 813, modded jet-pro rear- this is a really good set up for the light weight xb. These cy29 top ends can ocassionaly be bought tru ddm, large scale r-c for 30-50 bucks. Press in a set of new mains- Nachi c-6001 deep groove- fresh main seals, and your good to go.
 
I re-read the description for the 2 bolt OBR upgrade kit, it has a 2mm stroker crank, cylinder relieved and machined for the stroker without stacking gaskets, plus the Full Race porting and piston. For $149 it is interesting. After a brew or two... :)

They aren't using stroker cranks on the full builds, but one Full Race has a 3mm longer piston rod. The charts show good low end torque and a pretty linear torque curve to around 1000 RPM higher then the stock piston rod engines, and 7.5 HP at the peak of the torque curve. Would the Dune Runner drive train be ready for this? :eek:

NOTHING on wheels ever stays stock for long around here
 
Last edited by a moderator:
yup, most times when they say + 2 mm rod, it means its a 30 mm rod. You allready have a + 2 mm rod in the stock hy 30.5 cc engine. This could save you a few dollars - assuming your present crank is in good order. You would just need to buy the jug-piston-piston pin- pin spacers- e-clips, gaskets. The 36 cc engine sounds like it pulls evenly- no hit to it. This would be a good feature in a race cause ya cannot hear your own cars engine, only see what its doing.- sorta like Carrol Shelby said long ago, Horsepower sells cars- Torque wins races.
 
alfred e numan said:
yup, most times when they say + 2 mm rod, it means its a 30 mm rod. You allready have a + 2 mm rod in the stock hy 30.5 cc engine. This could save you a few dollars - assuming your present crank is in good order. You would just need to buy the jug-piston-piston pin- pin spacers- e-clips, gaskets. The 36 cc engine sounds like it pulls evenly- no hit to it. This would be a good feature in a race cause ya cannot hear your own cars engine, only see what its doing.- sorta like Carrol Shelby said long ago, Horsepower sells cars- Torque wins races.
Click to expand...
Yep, remember that Shelby saying, I was building and running Big Block Chevy's back then. Then I got married... And now have a 800 ft/lb, 400 HP Turbo diesel in my truck! 14K lb 5th wheel over Tehachapi (or any other pass, and I've pulled most of them) at 60 without ANY problem. Also something else that is a OLD track saying, "Smooth, Steady and FINISH wins the race". And someday I'll get a video of my 1/10 sorta Slash 4X4 on the track. 2S LiPo 250C power to a CC system that'll keep up with a 4S. :)

I like the OBR kit, almost everything is included. Still need the crankshaft bearings (Team Fast Eddy has ceramic), new crankcase seals, small engine tools I don't have. But it's a start and I DO have the OBR Prostock 30.5 to run in the meantime!
 
Last edited by a moderator:
Went with the OBR 30.5 Upgrade with the 2mm stroker crank. Once I get all the parts and tools together, I'll pull the HY and put in the OBR Prostock. Till then I'll be working on my Home Brew Tuned Exhaust, running, breaking things and having fun!

 
Chief where is Rosamond ? I'm in Compton once a week ..well 3 weeks out of the month..in Ga. Right now but will be there sat.
 
Got everything I can think of on order, I'm sure there will be SOMETHING I missed, there always is, to rebuild the HY as a 2mm stroker. I even watched the videos Team Fast Eddy, and OBR have put up - thanks Guys. Itty bitty engine builds are new to me!

One thing I really liked was in the Fast Eddy video, putting the piston in the cylinder. I'm used to big 'ol cast rings, a ring compressor and using the end of a hammer handle to tap the piston in. A PITA until you get it figured out.

I think I'll use the Zen torque spec and Red Loctite. I've used Red Locktite on other RC builds I've done, and things stay in place. Haven't had a problem with removing fasteners as long as both the tool and the fastener don't have any wear.
 
Last edited by a moderator:
As soon as all the parts get in, I'll pull the stocker and put in the OBR Prostock.

PS Where have you been Deluge. Lost you and RCDAD posting at the same time, thought something serious happened. :)
 
Last edited by a moderator:
I just added a new clutch bell to the list. The original is deeply grooved, shoes still had around 1 mm left. OBR installed a 6k clutch on the 4 bolt, I decided to go with that. The HY Pro Port is getting an 8K. And a 990 carb, that can wait for awhile though, the PayPal account needs to shrink a bit. :)

Good news, dogbones and the rest of the driveline show no wear, cups not spread.
 
Back
Top