The Strut thread - Koni / Illumina / Tokico / Carrera / Bilstein / Ground Control

[JMortensen]

Cutlass, please do some searching, and then if you still feel you need to ask your question, post it in a different thread. This one is specifically for struts and we want to keep it on point.

[Chino 240Z]

Did you get them revalved to 300/100 also? I am considering getting them revalved to suit 240/200 springs. Is the adjustment linear? Ie, would 220/72 valving suit?

Dave

 

Yes I did the revalve 300/100, but this not on a street ride. The car is gutted or lightened, fiberglass hood & rear hatch, plexi-glass rear window, no heater core, no fan, no radio, no interior, door windows removed, race prepped car. As we learned and improved our driving on track we expected more out the car too. Just like everyone else we wanted to be faster and have better lap times too. But before we spent more money on HP upgrades in the motor we thought we should get the existing 170rwhp this 2.4L was giving us out and onto the asphalt.

 

I don't think you need to revalve or will have problems with shocks failing with lower spring rates like 240/200. Different story if you plan to get up over 300 in the future. I'm not shock and spring experienced but I'd agree with jmortensen's comments too. Cutlass, I do have 10" springs on front and I can get it pretty low, un-drivable.

 

We had a lot of body lean, and nose drop or diving as we kept braking deeper into the braking zone at high speeds. Other cars were able to hit harder & deeper into the turn without upsetting their car as much as ours did. It wasn't crazy, but just enough to see why some other car had pulled a little bit on us in a turn, after turn, after turn no matter how hard I tried.

 

We started with Tokico shocks up front & the adjustable in the rear with 275F / 225R springs. After removing the Tokicos I had found that they were basically trashed. I believe the extreme rebound rate of a 250 or 275 and 300 lbs. spring damages the internal valving in the shock. Not so much on the compression stroke of the shock but the forces of the spring rebounding seems to be too much for the shock to take and shortens it's life.

 

As for the coil overs good or bad? I would put it on a priority list of changes if one was looking for performance. It gave us the ability to play with ride height and weight. Makes changing springs and shocks easier to deal with too. Helped get the airdam lower to the ground too.

 

After swapping to this setup I dropped 2 seconds without trying. I think each driver finds what he or she is comfortable in their car. Such as, I like the feel of a welded rear out of a high speed turn. To me the rear feels more predictable time after time , lap after lap, as long as I keep the same line. And with this new spring and shock combination I was able to push that comfort zone harder and faster in these type of turns. My wife adapted to the new set up well, but doesn't trust it as much as I do (Knock on wood).

 

I'm on a budget too, I can't afford several spring & shock assortments and other mechanics to do the work for me. I need to hopefully get it right the first time though. With lots of homework and luck I was hoping that money spent would show results. We use to run 3 or 4 events after each change or upgrade. The real results of this new suspension came into play when we added the Arizona Z 12.2†Directional Vented Rotors & Wilwood 4 Piston Calipers. Dropped couple more seconds and still looking for the limit of this thing. It's going to be a combination of changes, trail & error, and driver seat time to find what improves lap times. I don't want to be the slow car on the track but understand the cars limit is directly proportional to the dollar spent. I'm just following you guys here and having fun doing it too. Thanks for your experience.

 

ok time to shut up, sorry

[JMortensen]

Does anyone have the EXACT part number for the Bilstein gland nut? I got some here, they are B30-629 Q1 and they are about 2mm too big. Might be the right one for a 280 strut, but they definitely don't fit a 240...

[MONZTER]

Does anyone have the EXACT part number for the Bilstein gland nut? I got some here, they are B30-629 Q1 and they are about 2mm too big. Might be the right one for a 280 strut, but they definitely don't fit a 240...

 

Jon,

Here is my info -

Strut part number - F4-P30-0032-MO re-valved 300/100

 

Gland nut part number - B4-B30-U232A1 M48x1.5 OST - this is what the invoice said

 

I was told the nuts people use to use are no longer available. I went back and forward with Bilstein a few times to figure this out. These work but have to be cut down in length. Check out the pictures below.

 

ps I would highly suggest getting the tool to tighten them

 

 

Jeff

 

 

number on part says B30-629 and A1

 

[JMortensen]

Thank you Jeff. The ones I have are the right length, but are too large in diameter. The Q1 makes all the difference...

[MONZTER]

Thank you Jeff. The ones I have are the right length, but are too large in diameter. The Q1 makes all the difference...

 

So your saying the part number for one that does not need to be modified to fit a 240 is B30-629 A1

 

Let us know if you get them, as I would like to order some new ones after messing mine up for not using the correct tool to tighten them:biggrin:

[JMortensen]

So your saying the part number for one that does not need to be modified to fit a 240 is B30-629 A1

Huh? That's the one you have. You had to cut them. I think mine might be the right one for a 280, and it is the correct length, but is not the correct diameter.

 

Let us know if you get them, as I would like to order some new ones after messing mine up for not using the correct tool to tighten them:biggrin:

The ones I get will be just like the ones you have, hopefully...

[Chino 240Z]

So your saying the part number for one that does not need to be modified to fit a 240 is B30-629 A1

 

Let us know if you get them, as I would like to order some new ones after messing mine up for not using the correct tool to tighten them:biggrin:

 

I second this nut for the 240Z:

ThyssenKrupp Bilstein invoice shows:

Part Number Description- B4-B30-U232B1 (Ringnut, M48x1.5 OST). I

needed to cut down this new nut in length in order to seat down

properly for my 240.

 

Tool for this Ring Nut 30MM is # E4-MS08/7. Was worth every penny of $4.40. (02/02/07 Bilstein price)

[MONZTER]

Sorry Jon, I don’t mean to confuse the issue. I thought you were saying you were going to order the same part number that you already have but with the A1 at the end instead of the Q1. I thought you meant the A1 designated the thread size.

 

The part number I ordered (B4-B30-U232A1 M48x1.5 OST) It did have to be cut down.

 

Every time I talked to the guys at Bilstein it was a real pain in the butt. I think they have so many different options, that they cant keep track of them.

[240zdave]

I just ordered the Bilstein struts and gland nuts yesterday. My 240 has 280 rear struts, and the salesman at Bilstein said the tech guys told him the part number for the 280 strut gland nut is B4-B30-U232B1, and then said it's an M48 x 1.5 nut. I told them that the 280 strut is larger (I have read either M51 x 1.5 or M52 x 1.5; I need to go measure the gland nuts I have now for the Tokico struts I am replacing to see which is correct). The salesman assured me that he had given me the correct part number. I am just as sure that it will be wrong. The salesman at shox.com told me he would compare them to the 240 gland nuts to see if they are the same size before he ships them.

 

From what you all are saying, I feel sure that I will be talking to Bilstein again to try and get the correct nut for my 280 struts.

[240zdave]

Jon,

Here is my info -

Strut part number - F4-P30-0032-MO re-valved 300/100

 

Gland nut part number - B4-B30-U232A1 M48x1.5 OST - this is what the invoice said

 

I was told the nuts people use to use are no longer available. I went back and forward with Bilstein a few times to figure this out. These work but have to be cut down in length. Check out the pictures below.

 

ps I would highly suggest getting the tool to tighten them

 

 

Jeff

 

 

number on part says B30-629 and A1

 

Clear something up for me. Are all of the photos of the B30-629 A1 nut? If so, after you cut the nut down to the proper length, did it fit the 240 or the 280 srut?

[MONZTER]

All of the photos are of the A1 and will only fit the 240 strut after being cut down. The ones Jon had Q1 are for the 280 and should would with no mods

[JMortensen]

All of the photos are of the A1 and will only fit the 240 strut after being cut down. The ones Jon had Q1 are for the 280 and should would with no mods

I ***AM NOT SURE*** that the ones I have will fit a 280. If the diameter is correct I am sure that they could be used without having to cut them down. They have 6 threads so they're just a tiny bit longer than the ones you cut down.

 

Just for the sake of argument, couldn't the strut housing be sectioned shorter and the nut left at its regular length? The nut is a lot thicker than the strut housing, so presumably there would be no loss of strength there.

[MONZTER]

I Just for the sake of argument, couldn't the strut housing be sectioned shorter and the nut left at its regular length? The nut is a lot thicker than the strut housing, so presumably there would be no loss of strength there.

 

I dont see why not, except that it would be too easy;)

[Chino 240Z]

I dont see why not, except that it would be too easy;)

 

In the case of my 240 tubes the threads inside were not very deep and left too much gland thread outside the tube and too much gap under the strut insert. I cut the gland nut threads enough so that the shoulder of the gland nut would tighten to spec and seat flush on the top of the tube. Now I don't know how deep the treads are in the top of a 280 tube? It may thread all the way to the gland nut shoulder, then you just need to section the tube test fitting everything before welding the tube back up. Careful not to make too short.

[JMortensen]

In the case of my 240 tubes the threads inside were not very deep and left too much gland thread outside the tube and too much gap under the strut insert. I cut the gland nut threads enough so that the shoulder of the gland nut would tighten to spec and seat flush on the top of the tube. Now I don't know how deep the treads are in the top of a 280 tube? It may thread all the way to the gland nut shoulder, then you just need to section the tube test fitting everything before welding the tube back up. Careful not to make too short.

I have a 240. When you're tightening struts you want the threads to tighten before the gland nut bottoms on the strut housing. So basically you want one or two threads of the gland nut showing when everything is fully tight. In this case, I'm thinking that I can just section the struts down so that the gland nut threads don't quite bottom in the strut tube.

 

You're right about erring on the side of caution. Last time I made mine about 1/8" too long and then used a washer inside the tube to bring the strut up. Better than cutting too short...

[Chino 240Z]

yea, I guess I remember seeing a slight gap or a thread left before tighenting down onto the actual gland nut shoulder. Previous owner who cut my tubes had one a little longer than the other 3. That was the side I had to take apart 2 times to get the right fit with no rattles or banging.

[JMortensen]

More weirdness... I got the correct nuts when I ordered the B30-629 A1's, so thanks to Jeff on that one.

 

I called Ground Control because I thought they had monoballs that had the correct size hole in the center and didn't need an adapter. Turns out that is wrong, but they do have the adapter. So I got those ordered.

 

I was talking to Mike over there, and he said he ran these exact struts in his Z racecar back in the 80s and had nothing but problems with them, failure after failure. I relayed Keith's ideas about them, and he basically had a "that's not my experience" type of response. So I guess we'll see how they work out.

 

In addition he said that the top hats need some machining to fit. I was imagining that the 30mm strut shaft could be a problem and I could see that needing to be opened up, but he also said that the inner shoulder (I think he was talking about the inner hole's shoulder also needs to be cut back about .120" to fit the shape at the top of the strut shaft. He said he thought he had some instructions on how to install them and he was going to try and send them. If I get them I'll post them up.

 

I haven't heard anything like that from anyone here, so I'm a bit confused as to who is right and who is wrong. I suppose I'll figure it out when they get here and I go to install them. I'm thinking another option might be to find a different top hat, there are quite a few different ones available from Coleman Racing, for instance.

 

Does it never end???

[MONZTER]

Hi Jon,

You’re bringing back memories of my install. I use the camber plates that Eric and John make with the 5/8 ball. I think I remember the top threads on the stut being smaller than 5/8 by a little bit, and I also remember the large diameter of the strut, up next to the ball would limit the amount of articulation that the camber plate could achieve. What I did is turn out a "top hat" pc that installed into the ball from the bottom. This top hat reduced the id for the strut threads and then spaced the shaft away from the ball, allowing more articulation. Wow does any of this make sense? I could draw you some pictures if it will help. These struts are not plug and play, but I like em.

 

Jeff

[JMortensen]

What I did is turn out a "top hat" pc that installed into the ball from the bottom. This top hat reduced the id for the strut threads and then spaced the shaft away from the ball, allowing more articulation. Wow does any of this make sense? I could draw you some pictures if it will help. These struts are not plug and play, but I like em.

This does make sense. Ground control did say they are sending me "top spacers" and "bottom spacers" for the monoballs. I was wondering why they would do that, but it makes perfect sense that you'd need to move the monoball up the shaft in order to lower the 30mm part of the shaft in relation to the top hat, which is the part that interferes.