I replaced the front lower control arms with brandnew ones from Mazda $500 per side. No more groaning rackets like a wooden battleship tacking into the wind.

Visual inspections of the JimLab bushing show plenty of grease as per the zerk fittings. The stainless steel pin was loose enough to fall out of the bushing.

Based on the fact that the bushings were noisy only when hot, I'm guessing that the thermal expansion of the stainless steel pin was not optimized for the Nylon bushing so there was too much slop leading to noise. That's what happen when you have a software guy (a Microsoft certified one too!) do mechanical design.


What a F*cking waste of money ($500 + install cost (another $500) plus $1000 for new Mazda control arms and two alignments ($250 each time) for a total of $2000 (my cost)).

Be warned. I shouldn't have put these POS bushings in when I found out that he doesn't run exactly the same bushings in his project car. In fact, he runs some kinda of steel bushing rather than nylon.

 

Thanks good to hear!
That's not good to hear.

ouch!

OUCH!!!

note taken

 

Poman! You disappeared, what have you been up to?

I am still running my original bushings, 112k and counting. I have pillow ball heim joints waiting to be installed, but havent seen a need to install the bushings (no creaks clangs etc).

 

Poman,

can you take some pictures. I'm just really surprised (and slightly disheartened as I have the same bushings installed) as they became problematic for you after <1000 miles IIRC??

 

Wow, you're back! I haven't seen you for a while. It doesn't seem like you're the first one to report these wooden battleship issues, either.

 

I will post pictures tonight that I took of the bushing as they came off the car.

I've disappeared for a while as I haven't driven the car (problematic cosmo fuel pump, the damn clunking was embarrasing pulling up to ferraris (there are 200+ ferraris in Scottsdale).

Also, I was looking to get a Lotus Exige or Cayman but that would mean no food for Wife version 1.0 and 3 Kids Version 1.0. So no replacement for RX7.

Northern CAL may be in the future too.

 

First 1500-3000 miles no issues: felt great. Then it got hot and as I moved to AZ (110 is normal and 115-118 in August - there is a reason why 3 major religions came out of the desert) it got worse.

Not only is the noise the issue, the steering feel changed as it got hot the harder I drive it. So the supposed benefit of Nylon bushing wasn't there.

Note that I still have the JimLab bushings in the upper control arms but they don't seem to cause the problem as the lower control arms. I'm guessing the reason is that the lower control arms are designed to rotate and SLIDE with the Mazda Bushings whereas the JimLab bushings do not allow the lower control arm to slide.

On the bright side, I got 280 whp at roughly 4800 rpm until the Cosmos Fuel Pump couldn't keep up. Reason was the O-ring and the plastic sleeve (mounted on the fuel pump outlet) supporting the O-ring was bad. I guess the pump was still good but no one had those parts.

Replaced that with a Supra pump from RP in TX. Now I need to get Steve Kan to finish tuning.

 

What kind of mods do you have that require the upgraded fuel pump? I've been tossing the idea of getting the Supra pump for a while, but I have read a lot of conflicting data that states that my setup is limited by the injectors.

 

Can you guys confirm if I'm seeing stock Mazda Bushings in Jim Project Car?


Out of his posts, he does run OEM bushings as per the list below:

Suspension Component Changes
1. Original OEM components
2. Polished original components
3. K2 trailing arms and toe links - changed my mind and sold without using
4. M2 Performance trailing arms and toe links - sold without using after bad reviews on longevity of rod ends
5. Used rear components - sold originals to DClin when I was investigating a stronger IRS differential conversion
6. Polished used rear components
7. Rotary Extreme trailing arms and toe links - powdercoated "near chrome", sold without using
8. Sold polished rear trailing arms with FEED pillow bushings - exchanged for used stock trailing arms
9. Polished used trailing arms

Final Configuration:

* Original front upper and lower control arms
* Original rear toe links
* DClin's rear upper and lower control arms
* GoodfellaFD3S's trailing arms


What a LaPrick!! Sold me POS bushings while he runs OEM bushings. If this is true then so much for the grand old man of RX7.

May be there is still one last utility for these bushings? Like up someone's **** cavity so that he won't have an incontinence problem after I ebay a contractor to pay such person a visit?

 

I can't stand Jim as much as the next guy, but get over it. Yeah, Jim's bushings are loud and stiff...what did you think bushings made out of a material as hard as nylon would feel like? Not trying to start a pissing contest, but that's what you get from dealing with small operations business with limited R&D.

 

I wouldn't have such a problem with Jim if he hadn't resort to a playbook by dumbshit corporations (like GM, Microsoft, Ford etc) by blaming the victim: (1) no lube (2) incompetent installer and so on.

Guess what, the guy with the supposedly unobtanium bushings himself doesn't practice what he preach.

I know suspension noises. This was beyond it.

I still have them but at a lower and livable volume and probably because of the upper control arms with the POS bushings in them but this was really loud with the bushings in the lower arms. Enough that you can hear it over the exhaust while making a normal turn on a smooth AZ highway (101).

 

I always thought that the loose fit between the bushing and the pin was a disturbing behavior. I thought the point of these bushings was to reduce play, and here you have bushings that have play starting on day one.

 

yea my car has his bushings on it........ i hate them, they are loud as **** and make all sorts of noise i feel like my car is gonna fall apart somtimes and i've only had them in for 2k miles or so

 

on a related note, what other options do we have? who else makes a *kit* that will replace them all? i'm to the point where i want to rip them all out over winter.

 

Ask and ye shall receive... https://www.rx7club.com/group-buy-center-69/possible-gb-fd-delrin-suspension-bushings-506081/

 

On a side note: Sweet *** AP brake kit!

 

Guys, if the Jimlabs litterally fell appart, or developed unacceptable play in too short a period of time, that may be considered a design fault, but the reality is, there's no free lunch.

Solid bushings are just that: Solid bushings. They will make noise, they will ride rough, and they will likely wear quickly. Thise are probably the reason the car came with rubber from the factory.

If you're "upgrading" to acheive some performance end... such as more precise feel with a solid bushing... there will be some tradeoffs, like the ones everone is complaining about. It's just like stiffer springs, more aggressive shock valving, lower-profile tires, chassis stiffening, sound deadening removal, etc, etc, etc.

Did Jim claim that they would be as quiet as stock? Ride smoother? Last longer? No, I believe he claimed that they would be more precise and cost less than Mazdaspeeds (which are incidentally just harder rubber).

AFAIK, Jim is going to use Wanklins new polyurathane bushings.... but you'll note that Jim's project car is being done as a STREET-ONLY car. IMHO, JimLab bushings really weren't intended for a street car where a little more comfort and longevity are valued over absolute slop-free precision. I don't blame him. It's a street car. I wouldn't use Nylon bushings on anything but a dedicated track car... on which I would expect to replace them fairly often.

Just my 2-cents. I'm sorry for anyone who had bad results, but really, there shouldn't have been too much of a surprise there.

 

I don't have jim's bushings, but I have some of basically the same design that I made myself. Nylon (not re-enforced) with bronze pin inserts instead of stainless, and zerks. I've had them for about 30k miles now.

The bad: They are loud and started making all kinds of moans and groans after only a couple thousand miles. It's embarrassing having to explain why my car sounds like an old wagon everytime someone new rides in it.

The good: Night and day difference at autocrosses. Prior to installing them, I always did decent, but I knew my car was capable of better (I know, driver vs. car ) But after I installed them, I started cleaning up! The car feels like it handles about the same, but I have no other explaination why i vastly improved so quickly. Plus, they only cost me about $125 worth of materials and a couple days in front of a lathe.

If I keep my car much longer, I will definately be looking into stockers or wanklin's.

 

The difference between the bushings and the items you listed is the R&D put into products so the manufacturer will know exactly how the product will behave over a period of time and is able to pass that info on to the consumer up front or improve the product to overcome the problems that arise.

 

Theirs the Delrins, Autoexe, SuperPro, MazdaSpeed, Pillow ***** (from many many companies), new stockers probably more that I cannot remember...

 

thanks for the help HDP and eyecandy

 

WRONG.

No amount of R&D will change the fact that if you put on stiffer springs, more agressively-valved shocks, and replace your 50-series tires with 30 series, your car will not be as quiet and comfy as it was.... and you accept that tradeoff for the performance enhancement.

Ask people with a rollbar or roll cage, or a diff brace, or a trans brace, or a torque brace whether or not the car makes alot more noise or transmits more vibration.

WTF did everyone THINK solid bushings would do?

 

Who said anything about quiet and comfort? The original post was about the quality and longevity of the product and the only way to determine how it behaves and how it will stand the test of time is through R&D. I think he and everyone who purchases stiffer bushings know there is a trade-off of ride comfort, but no one expects the performance gains to only last several thousand miles. Now the question that you should be asking (or trying to answer since you are such a Webster of knowledge) HTF long did everyone THINK solid bushings would LAST?

 

Nylon bushings are going to be pretty nasty on ANY street car as has been stated several times in this thread. I don't think it would matter much who the manufacturer is.

On a side note, why would it matter if Jim uses the bushings or not? To the best of my knowledge his car has been a continual project and has not been driven for years.

 

Are you sure the installer did it right? Were other mating components checked for play / clearance? If there was any prior damage to the mating components, it would aggravate wear in the new components. You paid $250 for one alignment? Caveat emptor!

You have issues regarding Microsoft software guys? I know several software guys that are brilliant and quite competant as mechanics (they do their own work on their cars) and as mechanical designers (they research and collaborate with experts for product development).

chuck