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help.XX4 rear pivot blocks breaking every race.

Posted: Wed Jan 13, 2016 5:07 pm
by vintage racer
Heres my trusty XX4 fresh off the track from last night.I havent raced it much in the last 5 years but just moved close to a track and started up again and really enjoying it.Trouble is Im breaking a rear pivot block every meeting,some snap and some pull past the screws like the one in the pic.The car is fast and Ive got it working well so dont want to just buy a modern car.Is there alloy or any other stronger one made for this car?Thanks in advance.

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Wed Jan 13, 2016 6:02 pm
by RichieRich
I just restored one of these. I think some people have replaced the block with the one in this thread: http://www.rc10talk.com/viewtopic.php?f=27&t=30840&start=30

It may be a longshot trying to source one.

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Wed Jan 13, 2016 6:12 pm
by vintage racer
That Trinity one would be nice. I just bought a2208 3 degree rear block that looks similar but in plastic from OLDRC.I was wondering how it would fit as it says its for the XX4,looks like Ill need to do some mods but with the front section removed I cant see it being any stronger.I really need to find the trinity one.

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Wed Jan 13, 2016 6:34 pm
by klavy69
I had one I had bought for parts awhile back that must have done this with the PO. It looked like they drilled out thru the top part of the rear bulkhead and installed longer screws with lock nuts on the top. Looked wierd and I have never really ran one of these all that hard so I really was only guessing that it was for a reason similar to yours with the screws pulling out. Now I have another one sitting here lookin alot like your picture with one broken eye on the pivot and the other sided pulling out thru. It doesn't fix the broken ones but it will keep it together until it gets broken if that helps.

Todd

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Wed Jan 13, 2016 7:33 pm
by aip47-2008

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Wed Jan 13, 2016 9:12 pm
by Beau S
you have to run a rear brace! And if the screws seat loosely in the pivot-block and rear tower, it can break the chassis...

do you have a rear almn brace? and are you running 3deg rear blocks for the xx4?

There is an option, to run a mod that use more modern xxx(t) pivot blocks, but it narrows the rear hingepin distance.

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Wed Jan 13, 2016 10:39 pm
by aip47-2008

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Wed Jan 13, 2016 10:39 pm
by vintage racer
Wish I would have saw those alloy ones before buying 6 plastic ones,I didnt even think of searching for street weapon ones.

I was running the 2 degree ones but ran 0 degree last night as was all I had left.There is some alloy braces with the 3 degree conversion a2208 I bought so I will definetly be running them but they allways seem to break out at the front for me.

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Wed Jan 13, 2016 11:07 pm
by Beau S
One of the ways I bulletproofed mine, using 3mm flatheads screws instead of the 4-40 gear.. The molded holes are already a little loose for the 4-40 hardware & will easily strip. The slight wiggle can cause the screws to backout, or increase the chance of impact to break.

This is why I keep my pivot blocks where the screw would thread into them, then continue to thread into the rear tower.

I found that the 3mm screws fit just right, no wiggle, & do easily strip.

Wiggle causes the front chassis supports (that hold the steel insert) to chip or break also. I use a tiny drop of Thin CA to glue the insert into the chassis.

I have a few other things I do too..

Plus, I water boil ALL plastic parts for ~1hr, and let them cool in the water. Re-hydrates the nylon.

Boiling fixed my constant caster block breakage.

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Wed Jan 13, 2016 11:11 pm
by Beau S
Great collection of xx4 tips.

Arno even gathered all the tips that Dyno Dan posted on rctech xx4 forum.
He studied the xx4 all the way from Jukkas designs & notes... To evolve the platform into the 22-4.
http://site.petitrc.com/setup/losi/SetupSheetsLosiDoubleX4WE.html

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Thu Jan 14, 2016 12:25 am
by RichieRich

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Thu Jan 14, 2016 3:08 pm
by klavy69
Not as of yet but have a set coming my way to beat down. After ordering them I looked thru my box-o-xx4 crap and found a street weapon with a trinity set up in it like the one pictured in the thread you posted above :oops: .

Todd

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Thu Jan 14, 2016 8:02 pm
by slapshot1979
The one I used in the first link provided above was a xx brace trimmed out. never had a problem

Image

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Fri Jan 15, 2016 11:45 am
by isles1
XX or XXX rear pivot block used for the XX4 mod?

Re: help.XX4 rear pivot blocks breaking every race.

Posted: Sat Jan 16, 2016 9:00 am
by slapshot1979
Not sure about xxx but xx for sure.