Hyper 7 PBS

[t2boats]

Just bought myself a hobao hyper 7 PBS off ebay, a rolling chassis, so I've been going through some old bits n bobs in the shed and making it a runner.

not having an engine i've had to buy one, so i went for an SH .28. i bought one of these a few years back and it was a belter of an engine, so i couldn't resist again. i fitted it to a GV Rex-X no probs at all and it worked really well. however.... when i come to fit the same engine to the hyper7
the back plate that comes with this particular SH.28 (it's a pull start, by the way) is MAHOOSIVE!!! so much so that it won't fit on the chassis' engine mount plates. (see pic)

question is to anyone who's experienced with this situ' out there... i have a flying point rotostart system which i'd like to fit (which is the same size as the HPI rotostart kit) but it fits the slightly smaller back plate (which i've normally seen on a nitro engine), do you think i'd be able to buy a certain back plate to fit the SH.28 from any other manufacturer without buggering things up behind the plate? can anyone recommend one? i was thinking maybe the back plate off an SH.21? they're surely not that dissimilar and it'll no doubt be designed the same way (and it won't have that massive back plate either)...

i could get around the issue by raising the engine slightly, but doing this though brings another issue, and that's where the rear prop shaft will chaff against the inner engine mount

thanks in advance!

 

[atom3624]

I suppose you'll have to be certain it seals properly, and also that the bolt holes align correctly.
What is the problem?
Is the plate catching on the chassis?
It looks identical to the back plates on my .28 and .30 engines in my LST2.
Al.

 

[t2boats]

thanks for your response mate!
yeah it's cos the back plate is so much bigger than the square-size of the crankcase that the engine won't sit properly on the mounting plates on the chassis, and if i were to raise the engine the inner engine mount then makes contact with the rear prop shaft. i've since googled "SH .21" and looked at the pics, they're indentical (as they all use the same size crankcase), and the back plate is slightly smaller. the PCD of the machined screw holes for the pullstart on the .28's back plate are alot further apart than the .21's, yet the crankcase holes are just the same. they also use the same seal! so i'm going to have to order a back plate for a .21 i think.... trick is finding somewhere. i remember rc-direct dealt with SH engines, i'll try them!

 

[atom3624]

Good luck.
Always interesting trying to make an engine fit.
I had a similar problem getting the Losi spin start to fit on the LRP engines I run - previously a Z.28Spec3, now the 'mother' of all, the ZR30Spec2.
What you read of that engine isn't hype, it is that powerful!!
Al.

 

[biggiecamp]

Could you not take a dremel and sanding drum to the plate to remove the excess material?
I put a bumpbox only RB in my Hyper7 so I get by without this issue. Good luck man.


Sent from da lower level iPhone using wanna Tapdatshit

 

[t2boats]

thanks for your replies chaps! just read your post biggie' and i thought last night about removing the chassis' engine plate and file away some of the material under where the backplate would sit - problem solved i think!! i did wonder about trimming the backplate but the mount screws for the pullstart are snug in each corner

i'll give the mount plate a little cut first and take it from there, i'll ping up a pic when it's done!

 

[t2boats]

oh, meant to say... couldn't find an SH.21 backplate anywhere....

 

[t2boats]

finally got the engine mount plate off from the chassis, there was a huge amount of threadlock on there!

here's a pic of the plate, in order for the SH.28 (with its current pullstart backplate attached) to fit the hyper7, i'd have to remove the shaded black areas of the plate.

so fingers' crossed i'll give it a go tomoz!

 

[atom3624]

That's easy with a Dremel mate, just take your time.
Stop and have a cuppa, then continue ...
Should be fine.
Al.

 

[t2boats]

it'll only take a few seconds with an angle grinder!

 

[t2boats]

all done, didn't take a few moments to get the plate to the correct shape

here's a pic showing the cut just near the mount plates' screw, it's the same on the inner side of the plate too.

so, for those who, in the slight chance, want to fit an SH.28 engine to a hobao hyper7 PBS, you'll need to remove part of the chassis engine mount plate in order for the pull start and backplate to fit properly on the chassis giving the correct pinion/spur alignment!