Savage X Bulk Head/Diff

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guinnessdublin

guinnessdublin

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Hi people, have got the newer savage x top excess gearbox coming to fit/update my savage 21 & was now looking at updating at some point the easy excess/maintenance bulk head/diff housings to it also.
Have looked on HPI w/site & cant work out what other parts from my original parts will also have to be updated also, aim I right in thinking the shock towers & bumper support arms will need to be also please?
 
I know the towers and bumper mounts differ and I think the skids do as well. Also the tube-nut that goes through the bulkhead halves is hex shaped vs round like the old one, so it's keyed into the bulkhead and less likely to turn on you if one side is stuck with locktite.
 
Hi olds97-Iss, okay thanks for that the parts list is growing then!
How sure are you about skid plate as they look the same unless bumper post ends engage differently?
 
That’s agood move on the bulk head tube fixing being hex shape now, remember that well now how annoying it was when undoing other side & it kept spinning round! ??
 
They may only be different in the fact that the X/XL have an X molded into them. I never had the 21 parts and X parts side by side. I've had the 21 style and I have the X, but never had them at the same time.
 
guinnessdublin said:
That’s agood move on the bulk head tube fixing being hex shape now, remember that well now how annoying it was when undoing other side & it kept spinning round! ??
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Yep. that was very frustrating. Reminds me of the stupid steering posts on the current model 6S arrma's. lol!
 
What about the diff bearings are they a different size, have not got my size to hard have to look them up in manual later?
 
Pretty sure they are the same as before. 8x16 on the ring gear, 10x16 on the cup. I hate the 10x16... It likes to die and take out ring/pinion gears if you don't pay attention.
 
Okay thanks for info, if there’s anything else you can think of be grateful if you could pass on! ??
What about the lower/upper bulk head braces & wish bone pins (suspension arms) can I reuse my existing ones, the list goes on?
 
With eacy access diffs you need the newer shock tower and hex shaped joint posts and upper arm brace, any skid plate and bumper support will fit them.
 
Thanks Iokky, do I not need the bumper support posts as they are different design from mine held in place into shock tower with C clips?
 
Looking at Savage X manual why did they start using a short spring coil Pt Nu 6561 with longer coil like I have always had fitted?
 
guinnessdublin said:
Thanks Iokky, do I not need the bumper support posts as they are different design from mine held in place into shock tower with C clips?
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The easy access diff housing has the 2 holes where you attach the older bumper supports.
 
guinnessdublin said:
Looking at Savage X manual why did they start using a short spring coil Pt Nu 6561 with longer coil like I have always had fitted?
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The big bore shocks use 2 springs per shock as standard, the older shocks, 2 per corner instead of 1, use 1 spring per shock.
 
Thanks Iokky, but if using older bumper posts how do I fix them to shock tower as newer type is held in with C clips?

What was the point of having separate coil spring, was it to give you more tuning options with different thickness of coils?
 
The old bumper support screws into the same place as older diff housing.

I don't know why 2 springs maybe they were using some springs from other models such as Hellfire.
 
Pretty sure the "dual springs" were just that, dual rate. One that was softer than the other so the smaller bumps would get absorbed via the softer spring and big bumps/jumps would compress the soft spring fully, then compress the heavier spring.

I'm not sure if the old bumper mounts work on the newer bulkheads or not. Looking at mine, there are holes on the side of the bulkheads where they might go, but the hole isn't in a raised boss like the older ones for the bumper mount to key into, it's just a hole on a flat surface.

These are the upper hinge pin braces, they are thinner than the old ones to allow clearance for the now removable diff cap:
https://www.hpiracing.com/en/part/105891
 
Okay thanks guys, those dual springs seem pointless to me unless I’am missing something!
Yes did think my existing ones would foul the removal of the screws being wider.
 
guinnessdublin said:
Okay thanks guys, those dual springs seem pointless to me unless I’am missing something!
Yes did think my existing ones would foul the removal of the screws being wider.
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It was an attempt at a progressive spring rate like you find on many vehicles these days. Although, most use a single spring, more coils on one end than the other, so the further you compress it, the stiffer it gets. Same purpose, to absorb small stuff without upsetting the truck and to absorb big jumps without bottoming out so hard.
 
Okay thanks olds97 for clearing that up makes sense as a HPI light purple colour spring set I got 14 yrs ago for savage has exactly that with the coils spread out more one end, did wonder if they should be fitted at top or bottom of s/absorber!
 
It really doesn't matter which end is which. The softer part of the spring will collapse first regardless. Although, might be better if the softer end is at the top so that it has the shock body to keep it in form as it collapses.
 
Okay got some complete s/hand savage x bulk heads which came with shock towers at a price I could not pass by.
After fitting them today noticed that at front of TVPs the bulk head is fixed in different fixing hole then my original ones & even though there is a hole in bulk head & TVPs there appears to be no existing thread to take any screw.
Looking at Savage x manual it shows two fixing screws in exploded diagram though, can anyone explain this?
 

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To add just remembered that on my original bulk heads the second hole was to accommodate a plastic stud which was moulded onto original bulk head, just strange why in Savage X manual it shows two fixing bolts each side?
 
guinnessdublin said:
Okay got some complete s/hand savage x bulk heads which came with shock towers at a price I could not pass by.
After fitting them today noticed that at front of TVPs the bulk head is fixed in different fixing hole then my original ones & even though there is a hole in bulk head & TVPs there appears to be no existing thread to take any screw.
Looking at Savage x manual it shows two fixing screws in exploded diagram though, can anyone explain this?
Click to expand...
guinnessdublin said:
To add just remembered that on my original bulk heads the second hole was to accommodate a plastic stud which was moulded onto original bulk head, just strange why in Savage X manual it shows two fixing bolts each side?
Click to expand...

Looks like most of your questions have been answered so far, but here's the answer for the 2 screws. Screw Z613 goes through the top of the 2 holes in the TVP into the bulkhead. Screw Z632 goes through the hole at the bottom of the TVP into cross brace # 102272. Some TVPs have a second hole @ the bottom to install an additional lower cross brace. It adds extra stiffness to the TVPs.
 
Okay thanks, so screw Z632 fixes cross brace lower down not in second hole, would help if HPI added direction arrow like in my old Savage 21 manual.
I wonder why HPI did not include this plastic stud on bulk head moulding to go in this second hole like on my original bulk heads strange?
 
guinnessdublin said:
Okay thanks, so screw Z632 fixes cross brace lower down not in second hole, would help if HPI added direction arrow like in my old Savage 21 manual.
I wonder why HPI did not include this plastic stud on bulk head moulding to go in this second hole like on my original bulk heads strange?
Click to expand...

Not sure. The X style easy access bulks that I have have the alignment tab (I checked) which I was wrong about the upper mounting screw. It actually goes in the lower of the 2 holes.
 
They must have released two versions then as mine have just a hole in bulk head where this moulded plastic stud should be to then snugly fit into second hole like my original savage 21’s did, just the holes are swapped round!
 
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