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Discussion Starter #1
Finally I decided to replace my front struts, but when I took one out I found that it was sealed, So I little web searching and time I bougth
MONROE inserts # 73214 and boot kit #63622, rest of proccess is on attached doc.
 

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Very interesting! How'd you thread the old donor strut, and how'd you modify the top bearing area of the new insert?

Koni inserts bolt at the bottom of the donor housing, so no threading of the housing required.

I run a non stock application for my front konis. They required modification of the upper bearing ID and a few other tweaks.
 

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Chapeau fredy64l ! Very clever and clean job.

BTW that pn is for Toyota Cressida & Corolla, much lighter cars than the 164, please tell us how you find the ride/performance on the 164.

I would imagine that there is a Koni insert with the same dimensions.
 

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Discussion Starter #6
toyota cressida station wagon almost have the same weigth as the alfa , as ride , since I bougth this car front shocks wher shot. as soon as I finish the other side I will take for a spin and will let you know.
konis where out of my budget .
 

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This seems to be wonderful discovery. Besides finding an alternative insert that has a similar application, it's readily available and highly affordable, costing on ebay between $30 and $55 per strut, shipping included. A cursory search for equivalent struts turns up KYB (pn 365076) at ca. $45 per unit, and Koni adjustable Sports (pn 86-1991 sport) at ca. $160 per unit.

We await the completion of your job and your verdict regarding performance!
 

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Machining a thread inside the donor strut is a tall order for the average person. Send it to a shop and there goes the cost savings. However, it's still very cool! I'd like to hear more.

I've been running an alternate front koni for a couple thousand miles. Jason carries them. I wonder if he's sold any.
 

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Years ago, a friend on mine, with a very nice 64 Giulia Spider Veloce mentioned that he was a little tired of the soft suspension on that car. Of course, all Alfas of that vintage had soft suspension, but never the less he wanted something else. So he put on Monroe "Sport" shocks all around at seemed to be an inexpensive cost. They ended up being softer than the OEM Alfa installation. He was disappointed as he was trying to avoid spending the bucks for Konis.

My opinion thereafter was that USA Monroe "Sport" wasn't the same at all like the European idea of "Sport".

I hope that these inserts work out properly, although the price says volumes, imo. the Konis on the other hand are too expensive.
 

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Del,

I'm not absolutely sure about this, but my gut feeling is that this particular Monroe is a mono tube design. Mono tubes in general are harsher, not softer than twin tube struts, what fredy is replacing. You might recall that there is an alternate (mono tube) strut for the Alfa 164 used in Europe only, one that uses a different kind of upper bearing, one that's all rubber with some big washers on top and bottom to secure the strut shaft. (I think Chazzy experimented with a set). The purpose of that big rubber "bearing" is to introduce some serious cushioning to compensate for the rather harsh mono tube dampening. So if your experience with Monroe is softness, that may be exactly what is needed in fredy's case. From fredy's pictures it is clear that he is using the standard North American upper bearing which is quite tight. I searched high and low for the technical specification of the Monroe 73214 but could find none except that it is also called a "sensa-trac" which has some sort of variable action.

I have a Mercedes that uses Bilstein "sport" monotubes, and if it weren't for the enormous cushioning of the upper front strut mounts, the ride would be intolerable. If fredy discovers the same discomfort his only remedy might be to use the alternative all rubber upper strut mounts, luckily they are easy to get (ebay.it) and are not expensive.
 

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You very well may be correct. My recollection from many years ago was that the Monroe "Sport" shocks at that time were easy to work back and forth by hand, just not stiff in any manner. Maybe they were a sport shock for a Buick? Hopefully, the new versions should be much better. My impression of "sensa-trac" is that the shock is very soft at first, and then stiffens a little with more stroke, perhaps using a tapered pin in a valve, maybe like an old SU carb.

Meanwhile, I'm slowing screwing up the courage to rebuild the S shocks on my 91S later this Spring (I think I need Richard2 to hold my hand, lol). I think I've determined that the left front shock is way too soft now even in Sport compared to the right side, now at 174k miles. I could just throw on the spare low mileage left front shock I do have, just a day's chore as a stop gap until I actually do the rebuild all around proper like. I do have a spare set of low mileage shocks, except the right front one looks chancy and older, with some rust compared to the good looking other ones. I think that one was from a different more used car, lol.
 

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Wandering around googling I found a supposed quote from Monroe saying the sensatrac uses a tapered groove in the housing to vary damping rate with piston position.

I infer these are low pressure gas shocks, in effect a twin tube design.

A tad more googling gets you this pretty complete description:

http://www.monroe.com/en-US/support/Technical-Training/Shock-Absorbers/

Note the caution that the "comfort" zone is ride height specific. If suspension travel or ride height are not compatible with the particular sensatrac strut you will be unhappy with the result.

They claim the tapered groove is customized for each application (sure nuff).
 

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Yup, same principle as the tapered needle idea. We used to make our own needles for the SU's in our Minis.
 

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Okay, gut feeling was completely wrong. Although I couldn't find the specific wording on the Monroe website what the 73214 actually was, searching the equivalent KYB strut insert (pn 365076), indicates, clearly, a twin tube design (KYB also has velocity sensitive valving). So fredy everything should be fine, sorry for the alarm.
 

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Discussion Starter #15
My choice for that insert was based on body dia. 1 5/8" extended length 23.1/2" stroke 7.1/4" and most important body length 15 5/8"
On top of that I bought them on an auto parts store so I payed
$120. can. for each one. just because I was not sure of how there where going to fit. here is a photo of inners of strut compared to insert
 

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So, these inserts are not for the 164 specifically, ie, not necessarily matching the as designed characteristics of the suspension. I wonder just how close they will be.

I also notice that it can be bought for about $55US on line.
 

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Monotube high pressure gas dampers are not inherently stiffer. Indeed, the opposite is true: for a given damping force in bounce (jounce in UK) the gas pressure shock is more forgiving because the gas chamber acts as a supplementary spring.

The main difference is only the manner in which the increasing displacement of the piston rod is accommodated. Damping character is controlled by the same type of valving as for twin tube shocks. The difference is the displaced fluid in bounce compresses the gas chamber volume and raises the gas pressure somewhat which allows softer rate bounce valving for equivalent damping forces. On rebound the gas pressure drops as the piston rod leaves the damping chamber, again a beneficial effect permitting softer valving for equivalent damping. Then the monotube can also include (and Bilstein does) variable rate with ride height using grooving inside the fluid chamber, just as for the twin tube.

High pressure monotube dampers exhibit a slight rising rate bounce resistance and a falling rate rebound rate which are both beneficial to ride and particularly roadholding. Because of the gas chamber the valving can be made stiffer in initial resistance and usually is. The significant advantage of monotube high pressure dampers is complete absence of damper fade over a very wide range of loading.

Twin tube dampers can be made to give very stiff damper rates as easily as monotubes. The reason Bilstein monotubes are sold in uprated versions to replace OEM is the relatively low damping rates often supplied OEM to customers who fail to understand what constitutes a good ride. Bilstein also makes cheaper and lower rate monotube dampers as well as twin tubes though why you would want them is another question.

For road cars you will generally get a better ride from a monotube damper than a twin tube and the ride quality will remain constant regardless of road irregularity frequency and amplitude. Your car will also grip much better as the monotube allows the wheel movement to follow the road irregularities much better than most twin tubes. Koni is one of the better twin tube makers and their dampers equivalent to the Bilstein are stiffer, in my experience.

The compromise low pressure gas twin tube damper attempts to combine the good ride of the monotube with the resistance to fade of the monotube.
 

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I guess the key word is "inherently". But they can be and some sources say of mono tubes that there is a tendency for a stiffer ride, and of twin tubes, that because of the low gas, a tendency for a more comfortable ride. This was also the opinion of the guy who did my strut dyno testing, but it may be that most of his business is for race applications. The Boge CDS strut and Koni Sport, both twin tubes, I admit, are pretty harsh on their maximum settings.

Mono Tube/Twin Tube suspension info by 'TEIN' | EK9.org JDM EK9 Honda Civic Type R Forum
 

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The traditional view is the high internal pressure makes the monotube "sticky" in low amplitude compression. However, the larger bore eases the initial movement by increasing flow rate per unit of linear compression. The end result is the newest monotube dampers give a better ride than older twin tubes did.

I have found the Bilstein gives a smooth low amplitude ride and a firm large amplitude ride with their HD (B6) series. Best of both worlds. However, the Boge low pressure dampers I've experienced on SAABs performed well.

I think dampers are like tires and brakes, generally you get what you pay for but the basic stuff will still do the job. Do you want the pouilly fuse or just white burgundy?
 

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Discussion Starter #20
This is an update on shocks performance , suspension is not soft but not stiff either , I have get to test it on a long ride and going fast , then I will see how well this inserts perform, as I said before my front struts where shot since I bougth it , so I have no way to compare it.
but so far I am please with the results
 
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