85 Fiero manual tranmission shakes/shimmies after chevy 350 install (Page 1/1)
svocal SEP 15, 03:38 AM
Hi guys
I had my 85 5 speed upgraded to a 350 Chevy engine. I have notice 2 issues.

1. As I put it into 1st gear or reverse, the car starts to shake or shimmy until I pick up some speed.
2.. When driving it onto the inclined tow truck flat bed in 1st gear, the car barely moves even when the clutch is fully released. I feels like the clutch is not engaging completely.

I already had a mechanic look at it and was told the clutch needs to be worn in to address the shaking issue. Not sure about the 2nd issue. Please help.
olejoedad SEP 15, 08:08 AM
You say you had it upgraded, I will assume you did not do the install yourself.

What does the installer say about your issues?
wftb SEP 15, 09:20 AM
You need a new clutch. Especially when you are having issue #2. I have never had a new clutch that needed to be bedded in. Brakes yes but a clutch no.
fieroguru SEP 15, 10:10 AM
For item #1:
  • What clutch did they install? Brand & model?
  • Is it a 4 or 6 puck version or a solid ring of friction material? The 4 & 6 puck versions are known to have chatter on engagement.
  • Does the shake or shimmy happen with the car just rolling - most SBC installs shift the engine and transmission to the driver side, which reduces tripot housing clearance on the driver side. So it is very important to verify that there is no binding as the suspension is a full droop and full compression - or you will break the axle and likely the transmission.


For item #2:
  • What brand SBC kit? Zumalt based kits have very little room for the flywheel, clutch, pressure plate combo. Depending on the combination of parts you might not have enough clearance for the throwout bearing to fully release and let the pressure plate reach full clamp pressure.
  • What transmission? F23s have lots of install issues with mis-matches of parts.
  • Did the shop check the height of the pressure plate fingers with the flywheel, clutch and pressure plate installed and compare that to the available range of motion?
  • Did you mix and match pressure plates and clutch disks?
  • If running a Fiero 4 speed or 5 speed transmission, did the shop install a longer slave cylinder pushrod? If so, compare its length to stock as it might be too long. Mark the location of the clutch release lever, then remove the pushrod. If you can't put the release lever back to the same position by hand, the pushrod is too long. Cut it down 1/4" (but keep it slightly longer than stock) and try it again.

fieroguru SEP 15, 10:21 AM

quote
Originally posted by wftb:

You need a new clutch. Especially when you are having issue #2. I have never had a new clutch that needed to be bedded in. Brakes yes but a clutch no.



While slipping on a new clutch rarely improves with time, most high end clutches do recommend a 500 to 1000 mile break in period for smoother clutch engagement and maximum holding power.

Brakes and clutches are very similar in how they work. Pressure applied to a friction material to reduce relative motion between the clamp and a center component that is able to spin. With brakes the clamp is stationary, and the goal is to stop the rotor/wheel combo from spinning. With clutches the clamp spins and the goal is to make the input shaft of the transmission spin get the car moving and keep it moving. To get optimal performance, rotors and flywheels need to start with a properly machined surface to aid in the bed in procedure.
Dennis LaGrua SEP 15, 11:12 AM
If the car barely moves with the clutch released, it sounds like I would go with fieroguru's idea about the slave pushrod being too long.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

svocal SEP 16, 12:08 AM
The SBC was done by V8 archie about 5 years ago when he was in Illinois. He used the original fiero 5-speed tranny in the engine swap. I did test drove the car when he completed it and i did notice the shake a little bit. But I didnt notice the incline issue until I had it towed to local shop recently. I haven't driven the car since the SBC upgrade 5 uears ago. The car has been in storage since. I just recently decided to get it out and running.
Since Archie did the install himself, I can assume he knows what he is doing....right? Who am I to question his work. I've heard all good thing about Archie, so that is why i took my car to him for the SBC upgrade.
Or maybe i just got a faulty clutch? defective parts?
I know he is semi-retired abd lives in las vegas. By no means am I a fiero guru or mechanically savy.
I haven't ran across any fiero mechanics here in San Diego Ca,(where i reside). The best I can do is take everyone's input/suggestions to the local mechanic and hopefully he can make sense of it. I think i'm better off taking it to a guy who knows fieros..right?
Are there any good fiero guru mechanics in Southern California or close to Southern Ca that you guys an recommend? (Besides West Coast Fieros).
I am more than willing to ship my "Baby" to someone who can get it fixed.

I
viperine SEP 16, 01:21 AM
Rusty flywheel. Sat 5 years?