New Grave Digger owner

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haha yeah I had to use a bit of 2 stroke oil to get everything in place. Was really tight with the 3 hole stopper; there’s no way the bloody thing will leak anything now haha
 
Bought a couple upgrades. First, I'll be tossing the stock Primal servos. Had enough servo glitching. The 100KG Primal servos do seem strong, but not smooth, and a noticeable amount of play and they can be a bit twitchy when going through the full steering range sitting on the bench.

Will keep those two 100KG steering servos as backup brake servos, or for another build or something. They seem OK on their own for something like a brake servo but too sloppy for accurate steering or at least with more than 1. Bought a couple of the AGFRC 78KG servos which in hindsight, I hope are enough and I'm not kicking myself for not getting the 100KG ... I ordered from TaylorRC and picked up a couple other things while I was at it, and they only sell the 78KG for a decent price. I figure those will be enough and the 100KG rated Primal servos are probably overrated specs anyhow.

Also purchase the JS Performance lower trailing arms. Noticed one of the stock rod-ends was a bit sloppy, and rather than just replace it I figured I would upgrade the 4 lower arms, and use the stock lower trailing arms in place of the upper arms and get rid of the excess exposed threads for both in that way.

On a side note... I have a DBXL 2 I just upgraded the fuel tank on; damn Horizon! Leaky gas tanks from the lid, and a hole that likes to wear in the side of the stock tank. Bought an aftermarket tank meant for the V1, so had to re-drill a couple new holes and get the tank fitter but well worth it. It's definitely a fun car when you work out all the stock issues. Debating whether I give that one the works, or stash away money to fully upgrade one of the Kraken Vekta.5 LSE kits ... 2 cars is enough for me, but I like having something fast and something more for show / cool factor like this Grave Digger. This truck is definitely not a bring out every weekend and bash on it hard type deal. There are better 1/5 scale cars for that :)
 
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Shimmed everything up and got rid of any slop in the drivetrain. There was a lot of back and fourth play on the front output shaft from the transmission front and back in specific. Also re-did the diffs now. They of course started to come loose so I bought new M4x16mm screws so I was making full use of the available threads. The supplied M4 screws are too short! No wonder they back out. Red loctite and evenly cross snugged the bolts then really tightened it down. Tried to back one out after letting it sit for 12 hours … good luck without a ton of heat lol

Also received the upgraded shock seal kit. Seems much better but not impressed they didn’t use a plastic guide washer as the last insert into the lower shock cap. The way it is now there’s still too much lateral play and now it attracts dirt inside that area. As long as it seals better I guess but a half-arse fix in my opinion!
 

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I didn’t, I’ll definitely do it next tear down with a bearing replacement. I couldn’t find what size bushing despite finding the Amazon link. Which size exactly do I need? Also said it wouldn’t deliver for 3-4 weeks so I said “forget” it for now
 
Thanks Bizzer!

Now to find some 100cst shock oil. Damn it, ran out with 3 shocks left to fill.

Finished the rebuild for now. The 100KG Primal Servos I was wrong about in terms of the torque and definitely aren’t underrated torque wise. I installed the 78KG AGFRC servos and while they are miles more accurate and much less deadband and slop, the servos stall when you sit the truck still. That’s annoying …

I wonder if I can just buy a gear set from the 100KG servos and drop them in the top case of the 78KG. I'm positive its the same servo with a slight gearing tweak
 
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Here she is ready to run again. Using the JS performance lower links, and the stock lower links as upper links. Had to use a thinner M8 nut on one side of the upper links to obtain the proper length; luckily the JS performance lower links had 4 right hand threaded thin M8 nuts, so I used the stock thicker nuts on the JS links and the thinner on the stock lower links. Worked perfectly, and no more slop/wiggle because of too much exposed thread with the stock setup.

I'll try the 78KG but I'm thinking I'll now move those to something else, and upgrade to 100KG so I can turn the wheels sitting still again for peace of mind.
 

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Well, I always think the upgrades are complete. Not the case. Re-did the harness; my switch kept flaking out and the truck sometimes would sporadically lose power and it'd take a good 10 toggles of the cheap stock switch to get it to power back up again. Not very confidence inspiring.

Purchased a 30amp rocker switch meant for a welding machine, and ripped out the stock 18awg wiring and re-soldered the servo wire leads to it while shortening it a little. Used 14awg instead. Didn't have any interference issues at all, but you definitely pull some amperage through that switch and wiring harness. Better to have a bit larger gauge wire run down the truck closer to the servo plugs to handle the power draw a little better.

Already noticing less voltage sag under hard braking and especially if you're full on the brakes and giving any steering input as well the voltage can drop so far you get close to browning out the receiver - and that's running a beefy 5,200Mah 60C LiPO. Never mind the stock NiMH battery ... yeah right!

Also have some carbon fiber brake rotors coming to avoid having to toss the brake calibers after wearing them out completely after 3 tanks of gas or so. Will see how well they work to stop the truck, and I'm betting the overall brake wear is much much less.

... and last but not least, received the brass bushings. Will have to do another tear down of the axles which maybe I should do anyhow, to see how the longer screws and red thread locker are holding up on the diffs.
 
Photo of the carbon fiber brakes installed. Fingers crossed they both help the truck stop well, and last a good while. Installed a set of red brake calipers front and back. It think that should do it for reliability upgrades I'm hoping.
 

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Good to know Rick; maybe there was an issue with the grey pads delivered with the GraveDigger, who knows but the front pads were really worn down after 3-4 tanks of fuel, and the rear pads while not half as bad were also worn in. I'm not confident it was just these pads in particular as I know others who tend to purchase a "box full" of brake pads to wear through on their trucks. Me on the other hand, look for a proper solution rather than a couple hundred on extra pads :) haha

Honestly I think it's more that on a 80lbs + truck, the pads and calipers are pretty small, and further to that aluminum on metal for brakes is obviously an issue generally speaking. Not sure why anyone would think that's a good design personally, but clearly I guess they're working OK enough for some.

For the carbon rotors, it set me back $60 for a couple sets but they're not really "for sale" in retail at the moment. Was considering copying the disks and making my own, but there's a guy I found who makes a couple parts for the Kraken Vekta as well as this truck that had a 'revision 1' he had just completed working on but not fully tested; so I'll report how well they hold up after a few runs. If they hold up, maybe he will be putting them up for sale on a shop and I'll for sure share that then.
 
To report back ... the carbon brake discs work perfectly. I can't get the kind of stopping power that puts the truck up on its nose (could be brake balance as well as I try to bias them evenly) but after you work the carbon fiber discs in and put a little heat in them they stop this beast of a truck from a high speed run without issue and predictably.

Much needed upgrade IMO and way better than steel on aluminum. I've asked the guy who made a set for me whether he's looking to sell more and if h his, I can post info for anyone interested.
 
One more upgrade .... beautiful JS aluminum fuel tank. I couldn't get the old bloody tank with the 3 hole tank stopper to stop leaking no matter what I did. Every bloody run I'd have fuel dripping off the tank and causing a mess.

Bought a JS Performance tank, with a good new 2 hole stopper (which btw the holes were MUCH smaller on ... used the high flow fuel kit without fuel tube on it inside the stopper holes) and tossed the damn Kraken 3 hole stopper and kept the stock tank just as backup. Happy to say, not a single drop of fuel anywhere it's not supposed to be now.

Only 1 fix left for this thing for now in terms of reliability. The darn white plastic shock-end bushings seem to randomly screw themselves out and get destroyed. Another stupid design on this thing. Going to put my thinking cap on and come up with a solution so I don't have to buy a lifetime supply of the F'in things.

So far I've solved / upgraded:

  1. poop stock engine
  2. Servos
  3. Entire wiring harness and large rocker switch switch (which BTW is 100% worthwhile, not a single issue now after multiple runs)
  4. Upper and lower arms and heim link upgrade
  5. Diff screws
  6. brass bushing mod
  7. Shimmed out the transmission
  8. Entire radio / electrical components supplied short of the kill switch which I find decent
  9. Brakes (stock metal on aluminum is plain stupid ... carbon fiber discs, keep getting better with every run and virtually no wear)
  10. Fuel tank and fuel setup
  11. The components required to bump this truck from 'Standard Edition' to 'Collectors Edition'
  12. Primal supplied upgrades shock seal setup (though, I ended up paying for this myself despite them saying they'd send a set free ... go figure, partially my impatience as I wanted to get the truck working and not leaking shock oil sooner than later)

Pretty poop for the amount of money these things cost new, but regardless ... I can officially say short of the shock bushing issue I'll get sorted out somehow, this is a reliable truck now and I can run it for an entire afternoon, clean it with an air compressor, put it away and not have to wrench on the damn thing every time I run it. Perfect, and this engine keeps getting a little snappier with every run. It's got to be fully broken in at this point now ... awesome engine; matched perfectly to the truck and not snapping anything in the driveline.
 

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Update... I tried to fix the plastic shock bushings from backing out, and no such luck. I tried using a plastic 10/32 washer drilled out to 1/4" to fit between the plastic bushing and the shock holder on the axle and it managed to back out slightly, and subsequently destroy the threads on the plastic bushing and still snap it. Not even running the truck hard ... I guess I'll have to use a dab of silicone sealant on them or something and let it dry, so I can remove it later if I need.

Officially this truck is 10x worse than even a Losi DBXL out of the box to keep running without an issue. Absolutely a pain in the ass for the money. Anyone looking to purchase one has to be prepared to sink several thousand dollars more into one of these to enjoy at least a couple 15 minute sessions in a row before something breaks. Horrible actually ... if the truck wasn't so cool to look at, I'd be tempted toss it in the trash by now. It's not good for jumping, it'll break quickly even just there, it's not great for handling corners (it's a monster truck!) etc. it's basically good for doing glorified figured 8's around your backyard and it still manages to fall apart in some fashion. Although ... again, it's really damn cool to see and watch while it's working which is the kicker and real annoyance it's so fiddly.

I keep the damn thing in mint condition after every run as well. Shame ... but it keeps me busy with something to do at least if that's any sort of consolation.
 
I mean, you're right in alot of aspects it needs work out of the box or needs to just come with better electronics to help. One of the easiest things to remember is no matter what you do, it will never be 100% reliable or flawless. That goes for any rtr or home built.

Other than engine, and servos mine hasn't been bad yet. I've broke the bottom shock mounts as you have said, definitely a poor design but they are easy to change. Uniqueness is definitely a key factor here why most put up with the sub-quality parts lol.

I think they are pretty awesome, probably a bit on the over priced side but when you control the market like this you can do what you want. Plus primal is very good with replacement parts when asked.
 
Mostly easy to change, except if the ones that keep busting are the front two and have to keep pulling apart the steering arm and C hub to get at and completely remove the bolt that holds the shock in on the bottom :) The rest take less than 5 minutes. The key takeaway though, is "why"? These trucks have been through 3 revisions; my only conclusion is they make money off these spares so they don't care to do it properly it seems.

For sure and I would never expect 100% reliable; but reliable enough to me is to be able to at least make it a handful of tanks before you have to do anything other than a quick checkover for bolt tightness and changing air filters as needed etc. Not every single time you take it out which is ridiculous.

They are pretty awesome in general, but man there are so many little corners cut and little gotchas. Don't forget as well, not everyone has money perhaps like you and I to constantly toss at this stuff. I'm not hurting for money, but this is just annoying at this point haha it seems you're not exactly hard up for cash either judging by how often you post new builds on here from what I can tell. So I don't think in general we're the "average". Primal must get a poop-ton of complaints on a regular basis about parts quality.
 
Ill just say this...I have a V2 Raminator and have had it for almost 3 years with close to 8 gallons of fuel through it. I spent time to set it up correctly, took time to go over the rig when assembling and did the basic mods most of us identified or saw a need for. I had a couple small hiccups with my rig but have been blessed. While I did upgrade things and add things..this was done out of my own liking, not because it was needed in most cases. Truck is reliable, runs amazing and is a blast to run.

Yes I fully agree the plastic bushings suck on the shock ends...especially up front by the steering and in the far back by my rear steer. But respectfully the statement of, you must be prepared to spend several thousands of dollars just to run a couple 15 minute sessions is ludacris.
I run my rig for 45 min sessions when I run it. I jump things, I crush other rigs, I do high speed donuts with my rear steer...basically I make a mini Monster Jam session every run. I clean it up at the end of every run and put it away for the next session.

Every 6-10 months depending on how hard I ran it, I tear it down and go over the rig. I take that time to deep clean, replace grease, fluids and check wear parts for wear. I fully documented my build, any struggles I had and my success as you also have.

In following your endeavour, very respectfully, it seemed like from the beginning you were trying to hunt for and engineer solutions for issues that had not arouse yet or things you just didnt like. As far as the money aspect....that is up to the consumer and the wallet they own. Most RC enthusiasts that are spending $500 on a Traxxas or Arrma rig are not in the 1/5th scale gas game..nor are they going to pop $3,500 on a Raminator. This truck is for a niche market. Owning one of the earlier V2 editions, Primal was always open to feedback and follow up. They are not a huge company selling thousands of rigs with huge profit margins, thus the fact they are attempting to update/upgrade as they go is appreciated. If they did full retooling for stuff..the costs would be much more to us and the chances of a company's P&L flipping and then going belly up rises. Which would then leave us all hosed that own these rigs.

The best thing we can have is companies like JSPerformance, Taylor RC and others making aftermarket parts to close the gap on things we have issues with. Also input from owners like yourself is huge as not only Primal but aftermarket companies, hear and see a need then help us.

In closing, I am not saying you are wrong, just saying its a perspective thing...and yes..there have been issues...but this has not been the total group consensus.
Pic of my rig after last bash just to close out my soap box. 🏆🏁🏁🏆
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