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KA24DE conversion issues

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It is a known failure. Tension rods have been broken :)

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It is a known failure. Tension rods have been broken :)

So is this in all cases or just people who bump up the horsepower, spirited drivers and/or people who race?

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Drill holes, avoid problem. Don't worry about who it MIGHT get. Just assume you're on the list. Or be super hardcore and build your own rods using inner tie rods from some rack and pinion setup.

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Drill holes, avoid problem. Don't worry about who it MIGHT get. Just assume you're on the list. Or be super hardcore and build your own rods using inner tie rods from some rack and pinion setup.

Well i guess I'll add to my list of things to do..... better safe than sorry....

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So is this in all cases or just people who bump up the horsepower, spirited drivers and/or people who race?

 

 

The way the 620 suspension is designed the tension rod travels in a large oval at the control arm end and is captured at the other end. If you don't allow the captured end to pivot (installing hard bushings) you will eventually fatigue the arm at that point leading to failure. It's not a question of how hard you drive, but how many times you cycle the suspension. 

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Makes sense....

Just love how the polyurethane ones are marketed as the better choice but clearly it sounds like they are not in this application....

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If anyone is interested carpartsmanual gives 2 part numbers...

56127-25660, 56112-09400....

Nissanpartsdirect Says replaced by....

56112-W5000.... $4each... looks like you may have to buy 10 at a time....

Not sure if actually available or not but they list them still for sale....

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Ok, the information is decent, but there is no way in hell a 5/16” drill bit is going to work in the tension bushings. That diameter bit is essentially the full width from the center of the bushing out to the edge of it. If I were to drill once in the center spacing I would be splitting the bushing open. This size drill bit may work for the 510 tension rod bushings but definitely not the ones I have for the 620!! My bushings are only 1-1/8” in overall diameter. Take out the 3/8” for the hole in the center and that leaves 3/4” of material to work with in removing 5/8” of material (2 x 5/16”). That would only leave me with 1/8” of bushing split over four points in a straight line (4 x 1/32” of support!). Has anyone used this procedure on a 620? If so do you have dimensions of the bushings that were used?

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So drill 3/16 or 1/4 holes. the dime quarterly article isnt science, just something that worked and got shared. Modify as necessary to fit your needs.

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The factory bushings cross referenced to these listed below. I bought a 2 sets because they were on closeout - but I have not installed them yet. Still in the bags. Not poly, but rubber. They look a little small in diameter, but might compress to the correct diameter. They list as sway bar end link bushings for a Pathfinder.

 

https://www.rockauto.com/en/parts/api,270074572,stabilizer+bar+link,7580

 

.

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The factory bushings cross referenced to these listed below. I bought a 2 sets because they were on closeout - but I have not installed them yet. Still in the bags. Not poly, but rubber. They look a little small in diameter, but might compress to the correct diameter. They list as sway bar end link bushings for a Pathfinder.

 

https://www.rockauto.com/en/parts/api,270074572,stabilizer+bar+link,7580

 

.

I'm a little late but the 620 sway bar endlink bushings will fit the tension rods.

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Ok, well I stuck with the bushings that I had originally gotten, without drilling them out.  So far so good, no tension rod breakage, but I haven't pushed it too hard cornering.  The tail end has been thrown around a few times, but nothing major yet.

 

One problem I did run into was regarding the transmission.  When my buddy and I did the swap, we took the bellhousing of the 240SX transmission and mated it up to the original 620 transmission, thereby not having to do any driveline modification or repositioning of the shift lever.  Unfortunately, the old transmission didn't like a hard pull in 3rd and 4th (or maybe that's just when it decided to complain after some mild abuse over the previous weeks) and started making a racket.  The following day, the sound from the transmission was almost unbearable.  After work, we started driving the truck over to my buddy's shop and in the process 1st and 2nd were unusable, and I simply stuck it in 4th and hobbled along to get it to the shop.  My buddy thinks that the countershaft bearing may have given up, and that was what was causing the noisy transmission, but then the drive to the shop may have compromised the countershaft or some other internal components (we haven't yet taken the transmission off and inspected it).

I have another co-worker who has a 2wd D21 hardbody 5-speed transmission that he doesn't need and is willing to sell it to me to help me get the 620 back on the road, but I'm unsure if the transmission will be a direct swap, or if I will need to do some additional work.  Does anyone happen to know if the D21 5-speed will directly replace the 620 5-speed (it has a dogleg shift lever) without any additional modifications (longer/shorter driveshaft, shift lever relocation)?  If not, would I just be better off trying to find a 240SX 5-speed transmission and bite the bullet to install that, cut the transmission tunnel to relocate the shift lever and then get a custom driveshaft made up?

Unfortunately I'm on a bit of a time crunch and need to get this all completed within the next week or so, as I'll be heading to Singapore for 5 weeks for work and I need to get the truck going before then so that it's not taking up my buddy's lift the whole time I'm gone, so I greatly appreciate some constructive feedback on this whole issue.  I'm very much leaning towards the D21 transmission, as I've heard that it's about the same size as the 620's but if I can find out from someone who knows 100% if it will need additional work after swapping in the D21 tranny, then that is an immense benefit.

Thanks in advance!

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You don't need to cut the tunnel to install a 240sx transmission. Just spin the plate on the top of the tunnel and drill new holes to mount it. You will probably have to shorten the drive shaft is all.

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It's not cornering that breaks them, it's constant flexing up and down going over bumps in the road. Tension rods help form a braced triangle with the lower control arm and the frame which is very stable and keeps the steering alignment correct. Without the tension rod to support the lower control arm, it will be forced to the rear when braking and hitting resistance on the road. Can't stress enough that braking a tension rod will destabilize the steering and braking with disastrous results. USE RUBBER. 

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The D21 trans should be the 31.5" long version of the longer KA 5-speed. If it does measure 31.5" from bell housing to tail shaft it will be a direct swap. 

I'm not sure when/if the D21 used the longer transmission. 

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I think the D21 was slightly shorter, the 240sx 3-4" longer than the 71B. A longer spline might do the trick.

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Thanks, guys.  So basically, if I understand correctly, what I need to do is measure the distance from where the bell housing attaches to the transmission to the end of the tail shaft.  If it's 31.5" for the 620's old transmission, then it seems like the D21's transmission should work without any modifications (except I'm not sure about the placement of the shift lever - but I am guessing that it would be close to the same) or adjustments needed with the transmission tunnel or the driveshaft.

 

We're planning on pulling the transmission out of the 620 tomorrow morning after work, and then hopefully pulling my co-workers D21 transmission out of his truck on Monday.  At that point, I'm sure it will be easy enough to determine if it will be a direct swap or not, as I'll be able to measure them up against one another.  I'll try to remember to get pictures for reference, as I'm sure someone else will have this question someday.

 

Keeping my fingers crossed that it will be a direct swap and I won't have to wait to get a new driveshaft or have something made up custom.

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It's not cornering that breaks them, it's constant flexing up and down going over bumps in the road. Tension rods help form a braced triangle with the lower control arm and the frame which is very stable and keeps the steering alignment correct. Without the tension rod to support the lower control arm, it will be forced to the rear when braking and hitting resistance on the road. Can't stress enough that braking a tension rod will destabilize the steering and braking with disastrous results. USE RUBBER. 

 

If I could have found rubber bushings when I was doing the work, I would have done so. Unfortunately, they only had Energy Suspension polyurethane bushings available, so that's what was used.  The other issue that I have is that the large nuts toward the front of the tension rods were seized in place.  We tried to break them free with PB Blaster, a vise, and some good old elbow grease, but they weren't budging.

Hopefully, I can buy the rubber 620 sway bar end link bushings that FrankRizzo and Moist Lightning had mentioned above and swap out the poly ones, but that's gonna have to wait until the transmission issue is dealt with first.

Just for reference, are the 620 sway bar end link bushings these?

https://www.rockauto.com/en/catalog/nissan,1977,620+pickup,2.0l+l4,1210138,suspension,stabilizer+bar+link,7580

If so, it seems as though I would have to go with one of the Economy options to ensure that I got rubber bushings, because some of the Economy bushings appear to be poly, as do the Daily Driver and Premium options.

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I have little use for poly but sway bar ends would be probably the only place where I would use it.

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