I need a shock less than 1" diameter and about 12-14" at half extension. It's for an engine shock absorber. I found one about 1.5" diameter and it was too fat. Trunk struts need to be mounted in an opposing arrangement because of the pushing action, and there's only room for one. Any ideas?
Ideally I want something not too hard to find, for example bicycle shocks, as a product category, are too much of a niche item for me to get locally.
I know of no mtb shock that comes even close to meeting those specs - all will be too fat and too short - except maybe - maybe - a fork leg, but you'll needto find an older fork that uses a removable arch and an air spring (older Rock Shox; some Marzocchis) although I fear you won't get enough air pressure for your required spring rate. What is the required stroke length? What are you trying to do again?
The third thing I thought to try after succumbing to failing to listen to your main points a couple of times was to google "linear damper". I still can't think of anything you're going to find at the local hardware store, but you may at least come up with something in the particular size range you're after... The first result I found was from an aircraft parts vendor, but hopefully there are some from a less pricey category...
I'm also having trouble with the idea that an engine could be located by mounts soft enough that a hatch strut would be capable of shoving the engine around and not just be all over the place if you rely on that damper to keep it from moving excessively, but then I don't know anything about your project...
mcmaster-carr...
2" stroke length would be enough.
Trunk struts do push out VERY hard. If you try to compress them with your hands, you might as well be trying to compress a piece of rebar.
The damper is really just to extend the life of the engine's mounts, the car works fine without it, for 6-9 months at a time in my experience.
Are you trying to make a DIY "Engine Torque Damper"? If so, just know that the aftermarket ones use rubber inside them to resist motion, and VERY few if any will use an actual damper.
Oh... one of those. Google "MINI engine damper". A modified/extended version of that should do it. I can't see how the top of the engine moving 2" would be considered normal.
It doesn't move that much, 2" is a number very much on the safe side. The TSW Mini engine damper is just like what I want...I'm looking for something about half as expensive though.
I think the Porsche 928 and some Mercedes use them stock so you could probably get broken ones from the junkyard. 
I guess stiffer engine mounts aren't an option?
MrJoshua wrote: I think the Porsche 928 and some Mercedes use them stock so you could probably get broken ones from the junkyard.
Thought about that already, no Porsches or Mercs in the junkyards (and no Porsche 928s in the country). When you wreck a car like that around here it either gets turned into scrap metal or used as a lawn ornament, the junkyards can't get customers for those things.
I already urethane-filled all the engine mounts except one (driver's side with an aluminum attachment point), it still eats mounts like this. There's a good bit of vibration too. People with urethane-filled mounts who have added a damper said it reduced vibration and made the car more solid at the same time.
Old school hot rodding trick, chain the engine down. Run a chain like you would a dogbone mount someplace, leave just a touch of slack so the mounts still do what they should.
I much prefer using a chain in the form of welding one to the block and head in an effort to keep the head on the block when presented with eleventy billion pounds of boost.
There's an adjustable spring preload coil over under the seat of seadoo xps 97-02 and seadoo hx from 95-97ish. Lose the spring and it might be what you're after.
Swank Force One wrote: I much prefer using a chain in the form of welding one to the block and head in an effort to keep the head on the block when presented with eleventy billion pounds of boost.
Is that to keep the head from flying too far when it blows off?
Moped rear shocks should be easy to find, otherwise maybe shocks from a suspension seat?
Depending on how much and how your room is configured maybe a knee-action or friction shock?
Really saving the chain thing as a last resort, but if shocks aren't an option that's what I'd go for. Probably put some bushings on each end to have a little give.
I'll check out the seadoo shock and moped shocks.
You say "urethane filled" what about just complete poly mounts.
x2 on the Mercedes engine shocks. All of the 80s 300 diesels use them. Any you find in the junkyard will probably be worn out though.
This is relevant to my interests as well. Once I discovered that the eBay engine torque dampers were just poly bushings in a tube, I kind of gave up.
The Mercedes ones look promising. Only $25 on Rock Auto for a 300 D "torque strut" but I can't find dimensions for it.
The 240D version is about $30 and there's compressed and extended dimensions listed but there's no way that's overall length. Rock Auto
Anyone know the overall compressed/extended dimensions on these?
z31maniac wrote: You say "urethane filled" what about just complete poly mounts.
I'm not quite ready to turn the car into a paint shaker
Man I just ordered some stuff from RockAuto, wish I'd seen those earlier.
Did some more digging around for OEM options, looks like the '80s to early '90s diesel Mercedes used a gas strut type belt tensioner that might also be an option.
A little over $20. Rock Auto
Looks like the right size, does that push out like a trunk strut or is it just a damper?
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