getrag 284 driving impressions

[jmgtp]

Took a flip through the GM service manual and there is NO mention of a Pilot Bushing. SO... safe to say there is NO pilot bushing. I think juglenaut either A) is thinking of the throw out bearing or B) has no fuking clue what he is talking about. The input shaft obviously has some kind of bearing holding it, but thats gonna be inside and not a regular service item.

[Zboy]

Not to be an arrogant asshole, but if there is no pilot bushing what supports the end of the input shaft closest to the engine? Does it just ride on the clutch itself? I've never taken a manual FWD GM apart. but every manual trans I've ever seen has had a bearing or bushing in the end of the crank that the trans input shft rides in.

[brian89gp]

Not to be an arrogant asshole, but if there is no pilot bushing what supports the end of the input shaft closest to the engine? Does it just ride on the clutch itself? I've never taken a manual FWD GM apart. but every manual trans I've ever seen has had a bearing or bushing in the end of the crank that the trans input shft rides in.

Nope, and it really doesn't ride on the clutch, the disc rides on it. I'm kinda curious as to which cars had this?

Junglenaut, I have no idea how they can adjust it. The flywheel is centered on the crank by a hub and bolts on via 6 bolts, there is no way to adjust that. The pressure plate bolts on via 6 bolts and there is no way to adjust that either. The TOB snaps into the pressure plate and the arm slides in behind that, it either works or it doesn't. There is only 1 tool in relation to the clutch and that is the disc centering thingy and it is only used to center the disc while you bolt on the pressure plate. And ANY clutch adjustment you have to pull the trans out of the car, I HIGHLY doubt it is a common procedure.

skalor: The 284 is noisy...mine sounds like its got loose parts clattering around inside at a neutral idle. When you mounted the master cylinder did you modify your existing firewall plate (grind the round hole square, it is at an angle that tilts the MC at an upward angle?). It may either be the geometry of the pedal/master cylinder or perhaps that air brake hose.

[skalor]

Yeah, I sqaured the round hole that was in the firewall. I even drilled/tapped a little hole for the screw to stop it from coming out, and it's on an angle yet. I'm going to have to blame the air brake hose as is came off of the master cylinder yesterday. I'll have to see when I get it back together with the AN/braided SS lines like you used to see if it's any different. It's not exactly easy to take out the clutch master cylinder with the damn cashmasterIII in the way and I'm not looking forward to doing it.

[RidgeRunner]

My Sunbirds NVG-T550 didn't have any sort of bushing or bearing on the end of the input shaft either.

[Cliff8928]

The bearings inside the transaxle on the input shaft are what hold it up and keep it centred.. I'm not even sure whether the input shaft is even long enough to go inside the hole on the crank!

He who thought the 282/284 had a pilot bushing/bearing has just been


Cliff Scott
89 BerettaGT
89 Volvo740

[pocket-rocket]

Once again, there is no pilot bushing/bearing. There is a hole in the crank that ACTS like a pilot bushing though. They are there even on the DOHC auto cars. Reason I know is because I didn't have to take the crank out of the GTP my 284 came out of so it all would work. I used the stock crank that was in my formerly auto Z34. When you install a new clutch, they say to put some dry lube in the hole. I used powdered graphite. As for the tranny shifting better as the car got driven more, both of my cars do that too. I think the tranny needs time to warm up too, like the fluid changes viscosity like oil in the engine. I could be wrong though.

EDIT: That same "Pilot bushing" hole is the same hole that the "nub" on the back of the Torque convertor goes into when bolted to the flexplate.

[skalor]

Update: I fixed the clutch master/slave setup and the clutch pedal travel is perfect. I did the same thing as brian89gp with the SS braided flexline. It worked out very well and this way I don't ever have to worry about it again. It starts to engage at about 1 - 1 1/2" off of the floor and it's much nicer than it was before.

Now, I've noticed that in decel while it's in gear it can get pretty jerky. I have poly dogbones which probably adds to the problem. I'm just wondering if there's anything I can do to get it smoother when in decel. I thought I remembered someone talking about it and it being engine related. I'm just wondering if I'm going to have to tweak the decel values or change the IAC follower or something of that sort. I guess this should be the tuning section.

[jmgtp]

Ben worked some serious magic with the dohc computer to smooth the decel and jerkyness. I've heard that the earlier dohc manual trans (i.e. the 91s) were harsher than the later models. Don't know if theres anything to be improved with the TGP code though to smooth things out. Mine was actually smoother with the poly dogbone, so I dont think thats your problem. Maybe your lower mounts are weak? Dont think you have the accumulator in there anymore, but if you do get rid of it and clutch feel/engagement will improve a lot.

[SappySE107]

GM actually corrected their own problem with the final revision. I just base the code off that and decel is much more tame. i still changed a few things around but GM did all the decel. I was told that the issue was being too lean on decel, so you can start there I guess.

[geoffinbc]

I have a pilot bushing .

But 284/282's dont. Just did a 3400 swap and we had to make damn sure all the rust was out of the 3400 crank since it was hooked to an auto trans it got rusty since there are no shafts to go into that location.

I kinda wondered myself why there was no bushing and I even looked at the old 3.1L like 10 times to be sure there was no bushing in there. I looked in the GM service manual and sure enough there is no bushing.

[brian89gp]

A good place for you to start skalor is to find a 3.1 5spd chip and copy what you can into the TGP code. Decel, DFCO, and a good number of IAC settings.

[skalor]

I have a cavalier 3.1 5 speed .bin file, but I haven't really looked at it yet. I have a bunch of memcals that I always collect from yards. I'll have to look through them to see what I have. I think I one or two 5 speed GP memcals, I'll have to take a look tonight to see what I have to use. I gotta get this thing more driveable to get this clutch broken in.

[SappySE107]

If you can send me a copy of the .bin files from the chips you have that aren't on the site, I would appreciate it. I want to make the site collection as complete as possible.