521 suspension upgrades

[domn8tr]

I've just put new tires and had an alignment done but still have a mean shimmy or vibration around 30 mph. It smoothes out some at 40. Since i wanted to convert to discs can i just use 78 620 front suspension? also where can I source bushing sets? Thanks

[izzo]

Did you seriously ask this ? without searching first?

 

No, you can't use 620 stuff, you can, but it requires some fabrication. you can buy mike klotz disk brake kit for 275 shipped. Its just the brackets and bolts tho, you will need to source the rest of the stuff. I doubt its a shimmy because of your brakes tho

[wayno]

I've just put new tires and had an alignment done but still have a mean shimmy or vibration around 30 mph. It smoothes out some at 40. Since i wanted to convert to discs can i just use 78 620 front suspension? also where can I source bushing sets? Thanks

 

Hey domn8tr, you can use the most 620 stuff, but there is a lot of fabrication, it's not worth it. I would put the 521 cab on the 620 frame before I did all that again. You need to rebush the lower bushings to a slightly wider bushing for the lower 620 arms or use washers to take up the slop, I call that jury rigging, and it always comes back and bites you in the ass, I should know, but I got threw all the R&D before I knew about "Ratsun", Also the upper A-arms are not long enough, so you need two sets of 720 A-arms to fab. longer upper A-arms, there is more involved than just that, but if you ever try this mod, we should talk, fact is the 620 disc. brakes are not that great, there are better options. As h2theizzo said, Mike K. has a disc brake conversion that uses 85-86 720 vented rotors with the better later 720 calipers. wayno

[domn8tr]

Thanks Wayno,I searched and found both Beebani's and Mike Klotz's setups, But being unemployed and having just put new tires on my 14 inch rims I guess I'll just try to perfectly adjust my drums for now. Tomorrow I'm going to check wheel bearings and try to source tie rod ends and bushings. The vibration is really bad as is the tranny. I'm going to try putting in my spare roadster 5 speed with a Z bell housing to keep the starter on the right side. P.S. I did a conversion to volvo calipers on my roadster that only involved drilling out the mounting holes ! wish there was a cheaper alternative for the 521, the volvo 240 calipers are $55.00 loaded new

[DanielC]

How are the kingpins on the truck?

After the bearings are tight, grab the top of the front wheel, and push it in and out. It should not move, with an annoying "clunking" sound

[wayno]

Thanks Wayno,I searched and found both Beebani's and Mike Klotz's setups, But being unemployed and having just put new tires on my 14 inch rims I guess I'll just try to perfectly adjust my drums for now. Tomorrow I'm going to check wheel bearings and try to source tie rod ends and bushings. The vibration is really bad as is the tranny. I'm going to try putting in my spare roadster 5 speed with a Z bell housing to keep the starter on the right side. P.S. I did a conversion to volvo calipers on my roadster that only involved drilling out the mounting holes ! wish there was a cheaper alternative for the 521, the volvo 240 calipers are $55.00 loaded new

You have a L20b engine, correct? Using the napZ case will make your shifter tilt I think, but maybe I am wrong, I know the roadster guys want the diesel case to put the Z car transmissions in there roadsters. I would think the 1980 L20b 720 series 5 speed case would be the one you need for the SRL 5 speed. But I could be wrong as I said before.

[domn8tr]

Talking to Les at CDM I believe its an early 240Z belhousing that mates the SRL 5speed to an Lseries. My son seems to think It's a later one from a 280zx, Dunno I'll finger it out

[wayno]

Talking to Les at CDM I believe its an early 240Z belhousing that mates the SRL 5speed to an Lseries. My son seems to think It's a later one from a 280zx, Dunno I'll finger it out

 

 

That's right, I had forgotten about that. That would be the way to go so the shifter stands strait up, otherwise it will be some random direction. I recall it being the early L configured 240Z case, the later ones are configured like the napZ.

[datzenmike]

FS5C71A 5 speed found in Roadsters. It has a removable bell housing. Early Z cars had a special bell made so it could be converted over for use on an L series motor. This is one such tranny.

 

 

 

FS5W71B used on '77 and up L and Z series motors. The front bell is not removable but is combined with the front of the case. Nissan designed at least 4 different front cases with different bolt patterns for use with different motors.

 

 

FS5W71B (top) and the earlier FS5C71A

You can't swap parts between these two transmissions.

 

 

 

 

 

 

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[datsunrides]

A later L series 5 speed may be a better choice. The Roadster 5 speed will fit a L series with the early 240Z bellhousing. If you do follow thru with the Roadster trans, beware the 2 common issues with these tranny's. First is the nuts holding the rear of the mainshaft tend to work loose causing a no 5th/reverse condition. 2nd is if you happen to have a non-splined 5th gear (splined 5th's are very rare), you may want to at least consider having the gear welded up as these are known to slip and created a no 5th gear situation.

 

Mark

[datzenmike]

A good Roadster transmission will command a primo price from a vintage racer. You could by several 280zx non turbo 5 speeds with it.

[Bullet_theory]

Did you seriously ask this ? without searching first?

 

No, you can't use 620 stuff, you can, but it requires some fabrication. you can buy mike klotz disk brake kit for 275 shipped. Its just the brackets and bolts tho, you will need to source the rest of the stuff. I doubt its a shimmy because of your brakes tho

 

 

technically yes he can use 620 stuff, hell he could find a full corvette drivetrain.... but like you said... FABRIATION....

[domn8tr]

The reason I wanted to use the Roadster 5 speed I have is that it was completely rebuilt by a friend I have who owned a trans shop when I lived in Hawaii. All bearings, all steel servos and welded 5th gear and a new 2nd gear were put in. I would rather this than a junkyard trans that I dont know the internals of. As a person I believe in being polite and helpful. Yes I suppose I could just google things and not be a part of this forum. So to those who have been helpful thank you very very much, and to those who would rather flame someone they don't know, I apologize and will try to do more research before posting again.

[Bullet_theory]

The reason I wanted to use the Roadster 5 speed I have is that it was completely rebuilt

 

 

hmmm thats a tough one... use a roadster trans that you could sell for quite a bit, or use a used trans with little to no known history... but ill do i bit more research on the roadster trans because im not completely sure it would be up to the task of being put in a truck, that most likely will be used to carry/haul/tow something heavy... im just concerned that the extra weight might be a bit much on the trans

[izzo]

technically yes he can use 620 stuff, hell he could find a full corvette drivetrain.... but like you said... FABRIATION....

 

 

:rofl:

 

fabrication, not for most people it seems. either want it done for free, or already done for nothing :D

[datsunrides]

The roadster trans would be plenty strong, especially the steel servo trans. Here is my opinion, FWIW. I would sell the roadster trans since you can get a nice chunk of cash for it based on 1- It's a roadster trans and 2- It's the desireable steel servo trans vs. the brass servo trans. The money you could get for it would more than cover a core Z trans and rebuild. The benefit you get is if something were to happen to the roadster trans, they are not easy to find and are expensive, even as cores. The Z transmissions, in comparision, are readily available. Use the extra cash for a nice set of wheels or something! :lol:

 

Mark

[domn8tr]

I dont' really want to sell the trans as money isn't the issue, after all if you sell a thing ,you spend the money then you neither have the thing or the money! I think I'll just keep it as backup for my srl2000 (P.S. i did have the 5th gear welded on) I realize now the roadster trans is a 31incher so I'll be using one of my 200sx doglegs in the truck. Just have to live with the big 2nd to 3rd ratio. Still trying to decide on using the Pace Setter single sidedraft and a 40mm weber or just go 32/36 downdraft. Gas is at $4.15 in my neck o the woods. Ouch Babe!