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Shocks - a Tale of Woe and Sorrow  Rating:  Rating
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 Posted: 04-27-2005 07:51 pm
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Ron Earp
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As you fellows probably know I'm getting ready to race a JH in SCCA Improved Touring. First time one has been raced in IT road racing as far as we know.

I've had a hell of a time with the shocks.  As you also know, JH's have enough clearance stock to ride over logs. Way too much and the ride height is way high resulting in a roll center way off the ground.

I fixed that by having http://www.coilspings.com make me a few sets of 3.25" ID springs in various lengths at 650lb rates. I finally settled on 8" springs as being perfect, 3" shorter than the stock 11" springs.  Mocked the springs on the car with no shocks and they seemed perfect. But wait.

I had been having a hell of a time with the Koni's that came on my JH. I had had them rebuilt twice by TrueChoice, and finally thought I had them correctly valved for the 650lb springs. But, when I got ready to install them I noticed they were still leaking and sent them back for a third rebuild.

In the meantime my buddy Jeff got so pissed off about hearing me complain about shocks that he called the JHPS and order the Blistens for the JH. Thanks I said, shocks solved.

Well, I put those on the other day and now I have a problem. The springs lowered the car, true, but they lower the car so much that the shock is basically entirely compressed. No travel that I can tell.  I'm not sure the Koni's would have had this problem but I'm going to check them.

If both types of shocks have this problem then I am in need of some suggesitons to fix this. I cannot legally move the suspension pickup points but I thought it a simple matter to weld plates to the bottom from arm and lower the shock mounting point.  Or, if there is room, drill another top mounting hole higher on the subframe to move the top up a bit.

Anyone have any ideas? I just discovered this early in the AM, so I still need to think about it and explore. I'll put up some pictures for those having trouble visualizing.

The neat thing is the springs I finally settled on had the car at a great ride height and had the suspension perfectly setup - lower arm was parallel to the ground, upper parallel to the ground with a little travel to stops - ready to go.  Just running into a seemingly pesky dampener situation.

Thanks,

Ron

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 Posted: 04-27-2005 10:45 pm
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Mark Rosenbaum
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Just a thought -- looking at the bits, I think you could raise the upper shock pivot point about 1/4" or so, after filling the original holes, but it's probably not too good an idea to modify (and weaken?) the upper suspension arm of the crossmember, so if it were my car I'd want to keep that pivot point where it is.

You can gain a great deal of compliance by welding down-pointing tabs on the shock mounting brackets, then drilling new holes for the lower pivot bolts -- probably several sets of holes (see the rough sketch below).  Design for strength, as the shock bracket sees the full force of the spring.

Alternately, to avoid modifying any suspension parts, you could gin up some spacers of whatever thickness seems appropriate, and use these, and longer bolts, to lower the shock mounting brackets as desired.

Edited for clarity: first paragraph, "upper suspension arm of the crossmember" was "upper suspension arm".

Attachment: brkt.gif (Downloaded 287 times)

Last edited on 04-29-2005 03:00 pm by Mark Rosenbaum

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 Posted: 04-28-2005 02:09 am
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Ron Earp
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Mark that drawing is precisely what I envisioned - thanks for putting that out there. Excellent piece of work and if I have something made we'll owe you royalities.  That is perfect.

It can't go up at all, you are right on that, just not enough room.  But down it can come and I am going to start some measuring. I DREAD having to mess with the shocks and get something different - honestly, the shocks have been the most expensive piece of the car - hell, I put together an entire panhard rod system for the rear with improved trailing arms and roll bar for much less money than I've messed with shocks. 

I just got my head back from the machine shop so it is valve adjustment time and all that happy stuff, but I'll re-visit this issue shorty.

Ron

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 Posted: 04-28-2005 09:49 pm
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Judson Manning
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Ron,

Any reason why you didn't go with coil-overs mounted to the stock p/u points?  It seems you would have had a lot more flexibility with mounting, shock travel and spring rates?

With the bump-stops in place, the front can only be lowered ~3/4", so I assume you've removed them?   Also, the stock ride-height at the front x-member is about 5" or as I remember VERY close to the IT minimum.  Have the rules changed to allow basically a 2" ride height?

The JH front swing-arm length is about 50"-70" in stock form, I figure if you lowered the car 3" your swing arm length is in the 30"-50" range?  I read in a chassis book somewhere  that 100"-125" was fairly desirable.  Can you confirm?

Judson

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 Posted: 04-28-2005 09:56 pm
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Judson Manning
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Ron,

Sorry, but you're actually not the first guy to run a JH in ITS trim. 

There are at least (2) cars here in Atlanta that retired from ITS many years ago.  The 4sp I have was actually built for Jack Smith's ITS car circa 1998, during the 4sp rebuild he found a 5sp.

To my knowledge Jack's car actually never finished a race due to bearing and oil sloshing/starvation problems.  It is quite possible that you could be the only ITS JH to finish, or dare I say, win an ITS event!

Best of Luck,

Judson

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 Posted: 04-28-2005 11:05 pm
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Ron Earp
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Judson,

What tracks did he run? I looked through SCCA data back to 1993 and the only JH I found running was the old Huffaker car in 1995 for Prod. Where is this IT trim car, and, is its' owner still around? Be interesting to get some info from them.  I'd heard rumors of it, maybe from you last year and Jeff too, but I have not met a soul who has actually seen the car nor remembers seeing it run - and I know some 20 year IT vets from Atlanta and Northern Florida.  I'd just like to see the car and talk with the fellows to get some solid race info.

5" is indeed the ride height minimum for JHs. Not sure what is up with mine, but I've got that in spades.

We didn't do coilovers based on conversations with Joe Huffaker back in Novemember of last year. Basically, his advice was to use the springs we are using, approprate dampeners, get the car low, weld the diff, use a panhard rod, and go like stink. They won Prod again in 1995, so they must know something.  Looking back on it I wish I did go with coil overs since it'd help a bunch with setup., a whole bunch.   Still might do it, but I just need to get the car going first and see how it goes. $$$ figures too.

R

Last edited on 04-29-2005 01:51 am by Ron Earp

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 Posted: 04-28-2005 11:39 pm
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Ron Earp
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Actually, just measured mine. The tow tab on my subframe is 7.5" from the floor and it is the lowest point on the subframe (arms don't count).  So, if I go down 2.5" more then that would lower the body 2.5" more on the tire and be just about perfect.

On the chassis swing radius 80-100" is good. But, most cars racing in IT today don't hit that.  Z's are a good example, typically running around 40-50" but you can't complain with results - consistenty in the top five for ITS and still a contender for the AARC at the end of the year, getting beat this year by the BMW overdogs. 30 year old cars still in the hunt! Light makes right!

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 Posted: 05-03-2005 02:50 am
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kart54
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Hi Ron,

    There was a JH running in IT out of Texas about three to four years ago. I looked into buying it but passed due to the poor condition of the car. It was advertised on race cars for sale if memory serves me right. The SCCA results you mentioned are only normally complete at the national level.  I bought a 914 that was raced extensively in Cal Club and Nor Cal SCCA as well as PCA from 1993 to almost 2001 and there are few, if any,  results for it listed anywhere. When I contacted national and the two clubs all I got was the year the car was first registered with SCCA. (1993) and the name of one of the owners. Fortunately, because of the web, one of the former owners heard I was looking for information and contacted me with the details.

    There is another jensen running in IT or Production here in California. I've seen it at Willow Springs ( a road course) a few times but never had time to follow up. I always though that individual was on this list. If your serious about finding out call Richard at West Coast Racing Cylinder Heads. His number is in the JHPS book and probaly in another area on this site. he has raced Jensen Healey's for years and I believe did the heads for the Huffaker cars.

KART54

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 Posted: 05-03-2005 01:21 pm
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Mitch Ware
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The parts manager for the local Saab dealership near here races a Jensen Healey in one of the production classes. His name is Fernando Gra I believe and works at Saab of Half Moon in NY.

 

Mitch Ware

1974 JH-5 #111119670
1971 TR-6 #CC66950LO

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 Posted: 05-03-2005 05:46 pm
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Ron Earp
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I've traded emails with that fellow.  Actually, one of his "Prod JH to be" cars was up for sale.  Not a bad deal either, but I don't want to race production due to preference.  Fields are too small, you end up racing against the 2,3,4 or 5 guys in your group that show up. Plus, production gets really expensive since engine modificaitons are much more extensive.  If you attend a Spring National Opener you can start counting production motors that go "boom!" on your fingers you'll typically need both hands.

IT on the other hand is milder, more stable from a reliability standpoint, and have very large fields with lots of competition.  We're racing VIR this weekend and the IT run group has got 56 cars pre-registered into my run group, ITS and ITA. 

Regarding the other IT JH car that supposedly ran, I've got feelers out (and Judson might have talked to him by now) to find that fellow and chat with him about his experiences.  Of the people I met that saw/knew him they said the car never ran a competition race, only in practice due to sorting issues.  That is too bad since it would be nice if one was running now to see and to learn from.  There are not that many Brit cars running in IT (lots on production), a TR8 in the mid-west in IT,  the TR8 I wrench on here in the SE in IT, and that is about all I know of.  We're trying to increase the count!

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