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dwarfy

dwarfy

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Ive given the marder a full check over before taking it out on Sunday for the 1st time in months. Here's what Ive done:

Changed the shock oil all round for 2000wt FG oil (not sure what was in before)

Changed wheel bearings on back RH corner. They were well shot and the drive cup was moving around like a stick in a bucket.

Installed a new Bluebird 630mg servo with 14kg torque in place of the Hitec 645mg which seemed underpowered for the front tuning brakes.

Adjusted front cables brakes.

Removed the layshaft brake and rod. Going to see how it performs with just the fronts and new servo.

Set the wheel cambers and alignment using Trip's tape method! The back corner with the shot bearings was a mile out.


Its as good as its ever been now but I remember it bogging slightly at low revs before taking off like a scalded cat so will prob need a tune on the L needle. If it bogs does that mean its a bit on the lean side? I will give it a tweak & let you know how it runs :cup-1:
 
Just local to give it a run out before I chance Deeside again :scared::lol: Might have a look up to whitworth quarry on the track but don't know yet. You out Ben? You going Deeside Voo?
 
It sounds like you are about ready for some fun... But may I make a suggestion...

I blew the layshaft brake on my MT and just relied on the cable brakes, it sucked. Granted I have MT tires but they would lock up and slide while barley slowing the vehicle down... May need the layshaft brake.


Tuning..
Wait for the car to warm up before touching the needles...

Listen to the sound of the idle, if it has a popping sound it's ok or a bit rich, if it says "BLAAAA" when you hit the throttle it's too lean... Let it sit an idle for about 10-15 seconds, if it gets better, the low speed is too lean.

I would shoot a vid, but it's 9:30 pm and it's 3 degrees F (-16c) outside right now...

An easy way to tell if it's too rich is the throttle response gets better as you drive it, if it gets worse while driving it's probably lean.

If yours takes off like this or better, you should be fine...
Hear the bog at :16... That's rich, yours should do that until it's warmed up. Don't go by the smoke, go by the sound! By :25 it's starting to warm up and get clearer. By 2:00 it's about as good as I could get it with the stock 668 carb and the crappy seX-Can.

Remember, when tuning, always start with a warm engine and start with rich needles... If you are unsure, or if it's colder out than it was the last time you ran it, back the needles out (counter clockwise) about 1/8 turn. Start rich and lean for more power.

Now I have a question for you...

How thick is FG 2000wt oil? Is it thin like 20wt oil or is it thick like 200 wt or is it truly 2000wt something that you could use to fill a diff?

Trip..
 
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Trip said:
.........Now I have a question for you...

How thick is FG 2000wt oil? Is it thin like 20wt oil or is it thick like 200 wt or is it truly 2000wt something that you could use to fill a diff?

Trip..
Click to expand...

Im not sure how it compares to those you mention but it is 1 of the lighter FG shock oils so definitely not suitable for diffs. The way shock oils are rated from brand to brand confuses the hell out of me when trying to compare weights :confused:
 
Had a couple of hours out with my mate at the local park. Its on the top of a hill so was f'in freezing but was well worth it :D Needed a quick tune up to stop it bogging when going from low to high speed - I richened the high needle approx 1/4 turn from stock setting (got there in small increments!) and it was running great and sounding even better :cup-1: The x-can gets some bad press but I think it works well if you get the tuning right. I can only compare it against the stock can but it keeps up with my mates 29cc with samba so is good enough for me. The field was in perfect condition with plenty of grip but its uneven in places which caused a couple of big barrel rolls :scared: There is also a 2ft ridge at a 45deg angle so had some good jumps as well. No damage or breakages though so was a good day out!

My mate wasnt so lucky - a screw sheared on his ally engine mount but he managed to keep running ok. Towards the end his engine was playing up. He would hold the throttle steady but the engine would rev in surges on its own. Very strange, any ideas?? I will post this in the engine section too.
 
dwarfy said:
Im not sure how it compares to those you mention but it is 1 of the lighter FG shock oils so definitely not suitable for diffs. The way shock oils are rated from brand to brand confuses the hell out of me when trying to compare weights :confused:
Click to expand...

In general the lower the number the lower the viscosity, or the thinner the oil... In normal US r/c terms any oils 80wt or lower is for shocks and 1,000wt and higher is for diffs... So if the FG oil you used was about as thick as motor oil for your 1:1 car, it was probably 20wt...

Proline, Hpi and most US companies have it pretty standardized. The UK company Schumacher rates their oils with an extra "0" so 200wt would be 20wt here in the US... That's why I was asking how thick your oil was, if it were truly 2,000wt it would be thick like honey... I don't use FG oil because it's too expensive for what it is and too hard to get, but I was wondering how they rated their oils... Now I see they add a couple "0's" too.

I just filled the rear shocks in my buggy with Team Associated 40wt and it's silky smooth and doesn't hop when I drop it anymore. The stock shocks weren't filled properly at the factory so the shock only compressed less than half way, which caused the back to hop.
 
Yup, it's an air leak, could have taken a whack to the carb or the isolator (intake manifold)

Or it just ran outta gas!!! Had that happen to me once!

Did ya get any vids? I want to see that Marder run!
 
Trip said:
Dammit!

I've been looking forward to seeing your Marder run... Do you have ANY videos of it?
Click to expand...

Nope! Spoke too soon on the breakages........carb is leaking fuel :( Its not the lines I can see it dripping off the body of the carb so time for a new 1 I think.
 
Before you toss it, check the 4 screws on the top of the carb body, mine were loose on the new 813 and the primer bulb would leak back down to the tank... I tightened them back up and fuel is still holding after 2 days.

If that isn't the case and the screws are tight, don't even try rebuilding it, just toss it in the trash and get a new one! Too bad you live across the pond, I'd give you a stock 668, I have 3 extra's! Shipping would be about what it would cost you to buy a new one.
 
After the last outing when the marder was on top form Ive picked up a few more bits to improve the general performance and reliability. These are:-

New 668 carb (thanks Jacko ;))
Layshaft tuning brake set
Killer Bee V1 Kit 3
Comma LM2 grease for the diff
New 12x28x8 bearings for the drive cups diff side
New pivot post for mounting front cable brakes shaft to servo horn

The diff will be getting an overhaul and hopefully the killer bee installed tonight so I may need some assistance ;) I will get some piccys posted later :D

Its coming off the shelf this yr Voo before you start :lol::lol:
 
Got the diff done last nite. Opened it up & guess how much grease was in there.........yep......absolutely fookin none :scared: The ally sleeve has a few gouges in it and was difficult to slide off but was just ok so will do for now. The gears all looked in good shape with no signs of wear so looks like I caught it just in time :D Stuffed it full of LM2 grease then turned the gears with the drive cup & packed a bit more in to be sure! Put it back together and used silicone sealant round the ends of the sleeve to ensure the grease stays where it is supposed to & hey presto - a quiet diff :lol::lol:

Link to silicone sealing mod thanks to BtB!!
https://www.largescaleforums.com/news...-diff-sealing/

Will keep an eye on the silicone to make sure it holds but apart from that it should be good for 12 months on the shelf eh Voo :lol::lol::lol::lol:
 
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