I'm reversing some new Grubee GT5 motors, and found some nice metal surprises inside:
What's Inside Your Grubee GT5?
- Thread starter bairdco
- Start date
it's hard to tell from these pictures, but the head gasket was unevenly "torqued," but if you look closely, you can see it's crushed more in two opposite corners than the others.
it also had a different amount of washers under the crappy acorn nuts to take up the space. one had 2 flat washers and a lock, and the rest had one flat and a lock.
it also had a different amount of washers under the crappy acorn nuts to take up the space. one had 2 flat washers and a lock, and the rest had one flat and a lock.
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here's a before and after shot of the combustion chamber on the slant head.
the casting is super rough, which could cause hot spots, as well as a nice surface for carbon build-up to stick to.
in the secod pic, i also lapped the head with sandpaper on glass. you can see the uneven-ness in the before pic.
the casting is super rough, which could cause hot spots, as well as a nice surface for carbon build-up to stick to.
in the secod pic, i also lapped the head with sandpaper on glass. you can see the uneven-ness in the before pic.
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here's a shot of the stock steel, shorty intake.
all the welds inside should be dremeled smooth, as well as port matching the flange (no after pics, because i haven't done it yet...)
all the welds inside should be dremeled smooth, as well as port matching the flange (no after pics, because i haven't done it yet...)
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My gt5 needs a new jug, piston and rings because of those bits. My first major learning experience with China Gas quality control. Oh well. Now I know.
if installed un-touched, right outta the box, you could have some serious problems, including premature engine failure, lowered compression due to metal shavings gouging the cylinder walls and piston, and just all-around poor performance.
i'll post pics of the finished product soon, after i get some new nuts for the head. i ain't using those lousy acorns.
i'll post pics of the finished product soon, after i get some new nuts for the head. i ain't using those lousy acorns.
You're tellin me. I was lucky it lasted as long as it did. On the bright side, I get to tear into it and do some hands on learning. I'm going to replace the acorns, too. But yeah, that's exactly what happened. I was riding, then ting, ting, no compression.
Thanks for the pictures, Bairdco, this just reaffirms my 100% anti anything from Grubby Grubee (feh) stance.
It might be a good idea to do a complete engine disassembly. Who knows what kind of nuts and bolts might be bouncing around inside of the crankcase.
It might be a good idea to do a complete engine disassembly. Who knows what kind of nuts and bolts might be bouncing around inside of the crankcase.
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i don't think the problem is Grubee's alone. i've heard of many other engine manufacturers with the same problems.
and, it looks like the skyhawk's gonna be the only engine available (except for old stock) unless the other factories pay off the EPA.
and, it looks like the skyhawk's gonna be the only engine available (except for old stock) unless the other factories pay off the EPA.
Wow. They went all out on yours. Mine only had lock washers on three of the studs.
I had one that had a newspaper or magazine stuffed in the crank case. I have no clue why that was done, just to mess with us I guess.
Maybe one of the assemblers did not want to get caught reading on the job lol.
Maybe one of the assemblers did not want to get caught reading on the job lol.
I have heard of shady used car lots filling automotive differentials and manual transmissions with saw dust to conceal and quiet worn out gears and bearings.
Perhaps it was one assembler's idea to sound deaden the internal racket?
Still......newspaper in the crankcase? Wow! That's pretty bad.
Here's some photos to show what happens if you don't go through your entire engine before running it.
That gouge is enough to render an engine useless.
That gouge is enough to render an engine useless.
Here's the piston...
This engine has about 600 or so miles on it, btw. So they don't last very long if you don't prep it properly. I think this should be brought to the attention of people looking to buy these, because I had no idea when I bought this one, obviously.
This engine has about 600 or so miles on it, btw. So they don't last very long if you don't prep it properly. I think this should be brought to the attention of people looking to buy these, because I had no idea when I bought this one, obviously.
I don't quite know how to put it... integrity is something many of have learned not to expect when purchasing any number of products.
Warranty and reputation of the vendor become more important than specifics of the product itself.
Seems like it's all a crapshoot!
Somewhere along the line I have come to a dubious conclusion that a used item is a proven product.
I recently invested in a 3 in 1 welding machine on the bay.
Blue and red were far out of reach, don't mind saying...
With only two flaws, it functioned ok... The vendor contacted the service person and I made a wiring switch to rectify one problem, the second problem required replacement of the main control board.
Luxorgoods got me that part within a week. I'm happy!
Vendor reputation is very important to me.
Best
rc
Warranty and reputation of the vendor become more important than specifics of the product itself.
Seems like it's all a crapshoot!
Somewhere along the line I have come to a dubious conclusion that a used item is a proven product.
I recently invested in a 3 in 1 welding machine on the bay.
Blue and red were far out of reach, don't mind saying...
With only two flaws, it functioned ok... The vendor contacted the service person and I made a wiring switch to rectify one problem, the second problem required replacement of the main control board.
Luxorgoods got me that part within a week. I'm happy!
Vendor reputation is very important to me.
Best
rc
Hey Bairdco,
That head you are lapping, it needs to be lapped until the ring that you have surfaced is flat with the rest of the head surface otherwise the head will distort when you torque it down.
Sit the head gasket on the head where ever the head gasket covers this needs to be flat. Did you lap the top of the barrel as well? I even lapped both of the inlet and exhaust manifold surfaces and both the inlet manifold and exhaust manifold as well, there was not a flat surface anywhere.
The metal inlet manifold that came with the Gt-5 kit was not round where the carby bolted on so when I tightened the carby one of the tabs broke. I ended up getting a aluminum manifold. The area where the carby bolts to on the aluminum manifold is machined and is perfectly round. No broken tabs.
I also washed out the crank area with fuel/2 stroke mix to make sure to wash out any swarf.
Regards,
DaveM.
That head you are lapping, it needs to be lapped until the ring that you have surfaced is flat with the rest of the head surface otherwise the head will distort when you torque it down.
Sit the head gasket on the head where ever the head gasket covers this needs to be flat. Did you lap the top of the barrel as well? I even lapped both of the inlet and exhaust manifold surfaces and both the inlet manifold and exhaust manifold as well, there was not a flat surface anywhere.
The metal inlet manifold that came with the Gt-5 kit was not round where the carby bolted on so when I tightened the carby one of the tabs broke. I ended up getting a aluminum manifold. The area where the carby bolts to on the aluminum manifold is machined and is perfectly round. No broken tabs.
I also washed out the crank area with fuel/2 stroke mix to make sure to wash out any swarf.
Regards,
DaveM.
With the quality that these kits have nowadays, it is wise to disassemble and inspect your engine internals before use. At this point perhaps the vendors should start shipping these 'kits' with the engine completely disassembled. It seems that the buyer ends up taking everything apart anyway, so it would save us the trouble of initial disassembly, and maybe save them some labor costs of putting the engines together in the first place.
do you just shake it up? I'm doing this right now to my engine and I'm debating on cracking the crankcase open or just washing it out as you described. I don't want to half ass it, but if I can avoid taking it apart, I wouldn't mind at all.
does it get everything out?I am kind of intimidated when it comes to getting into the lower end, plus I lack some of the tools needed to do it...
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That would be nice...at the very least they could let you know it needs to be done. But then I could see some people being turned off from diving into a complete engine build on there first time around. I think there is a business opportunity here for someone that could sell these engines after they have gone through them, clean up the castings and such. It would cost more, but the reassurance of your engine longevity would be worth it IMHO.
Isn't that what ThatsDax does? IDK? Seems like good idea...
