brodykelly

CAR: 1993 ZR-! Competition Yellow, Missed 2nd when leaving a light, hit rev limiter, kept trying to get the gear I wanted couple more times...finally got 4th. don't ask why I was in a bad mood....wife made me mad...lol...anyway after that episode I knew something wasn't right. I then noticed when I goose the gas my shifter moves up and down almost 2 inches. got it on lift and there is nothing obviously broke. all the tranny mount bolts are in place and tight, c-beam bolts in place and tight. it lifts so high that it pulled the upper rubber boot off its flange point. I took apart from the top and reattached boot. I have never noticed this before so I know it's a result of my temper and missing 2nd. it's been 3yrs since I put new clutch and hurst shifter in it. I have had no issues what so ever with it since. I visually inspected the engine mounts and all bolts are intact and bottom nuts are present. I see no visual sing of the c-beam ends moving where the bolts go thru at. I opened the hood and while in 1st slowly pop clutch and the left side of engine rotates clockwise while the shifter bounces up and down. I see know where in the shop manuals on how to check if motor mount is bad. keep in mind I have never had hood open while trying to pop the clutch so I can't verify if the engine movement is normal. I have a spare motor mount with part #172 90 on it, not sure if it's correct but does anyone know how to check to see if a motor mount is bad?? manual says it's a hydraulic mount and to check if it lost its fluid?? HOW?? so to sum it up here is what I have checked: motor mounts on both sides have all bolts/nuts present and tight, all tranny bolts present and tight, all c-beam bolts/Nuts present and tight, no sign of any c-beam movement around mounting holes on either end. car had all new clutch components and shifter changed 3yrs ago and performed flawlessly since. any suggestions send them my way, I searched and found only one other same scenario that Lee Gaffigan had and it was the c-beam bolts loose. I don't think this is my problem as it has never had an issue until I abused her over the weekend missing 2nd multiple times while hitting rev limiter and finally slamming into 4th......not proud just the facts is all.... brody p.

brodykelly

just talked to my buddy who was watching my engine as I was popping the clutch with the hood open and he said the back of the engine was lifting up not twisting clockwise as I wrote above, so maybe this is a clue to someone out there.... brody p.

74 LS4-454

hopefully the following will shed some insight into what may be wrong with the symptom you are experiencing.....the follow is from a thread I had last year after I spoke to Tim Holland (LT5 Lotus engineer) about my newly purchased ZR-1, he mentioned a lot of info which you can read here if you like....
http://www.zr1.net/forum/showthread.php?t=22910


here is the info that may help solve your problem....in my words as related by Tim....in post #7
...talking about the "tube" going from the rear of the trans to the axle,(I imagine the "tube" he was referring to is the driveshaft). Mentioned that when accelerating that you should be smooth with power delivery, and not jerk the engine in gear, such as accelerating in 1st gear, letting off, than accelerating again in same gear (jerking). This puts undo stress on the bolts that connect the joint at the back of the trans, which can come loose from that motion (think I understood him on that) which can sag when applying torque and therefore result in the gear lever (shifter) moving upwards when accelerating. This is a machined part and needs to be exact. Apparently this was discovered during testing, thus resulting in using a smooth delivery rather than a jerking power delivery

hope this helps........Tom

brodykelly

thanks Tom for your input, I will get the car up in the air and start there. I just cant understand how missing one gear after 3 years of driving it like I stole it after the clutch install that this would just now show up. there is nothing I am scared about when it comes to working on the beast.... I just got to identify the problem before I can tear into it. I was wondering if I could put a tranny jack under it and slowly raise it to help me identify where the component in question is pivoting at or even get in the car and lift it up, set parking brake and have someone under it watching as I pop the clutch to see what's moving.....???? thanks again brody p.

FU

Your C beam needs to be tightened.

Arctic91

Maybe consider C beam plates... I've heard lots of positive and have them on the wish list for both cars.

Scott

74 LS4-454

Brody, your welcome, no problem.....in all due respect, I would not even attempt to do what you have stated above......IMO that would be very unsafe for you, any other person under the vehicle, and your car, which would cause damage to say the least. Again, IMO you need to secure the vehicle on rollers, strapped down, before anyone gets under it as the clutch is released and power put to the rear wheels. Engaging the parking brake and with the rear wheels hanging and popping the clutch would not be the safest method to do or even consider. Just be safe in securing your vehicle...... Tom

oldpro

I agree you need to get beem plates from bill boudreau 602319 6575 they will solve your problems . you could take out your c beem and see if there is a problem with the mounting area either in the front or the back . the beem is made out of aluminum and maybe when the clutch was unstalled someone messed up either the front or back mounting areas. bill had a car that did this come into his shopand found someone used a hammer to take the c beem off and messed up the mounting area

Crabs

Call Bill B. "The ZF Doc", describe your problem and order up a set of beam plates.
Not hard to install, and not only will stop the shifter from lifting but also helps keep the car's rear from stepping right when spinning the tires.

'Crabs

bad-zr1

No need to have the motor running. I placed the car on jackstands (for ease of access) and used a floor jack and a block of wood under the oil pan to slowly raise the engine on the drivers side to see how the engine mounts were. Repeat on passenger side. Drivers side moved about 2 inches and I found a broken mount. Passenger side was OK. This was after checking C beam.

brodykelly

Thanks for all the replies everyone. Well after getting the car up in the air last night and doing what everyone suggested, I checked the C beam bolts at the tranny end and both of them were not finger loose but were definitely not tight. I then moved the diff. end and they to were loose, tighter than the front but definitely loose. so I rechecked alignment of the driveline according to the shop manual [took readings at the yolk end of tranny] and both readings were within the plus/minus specs listed. I torqued all 4 bolts and am now slowly working my way around the underneath of the car checking every screw, nut and bolt I see, man there are a lot of loose stuff under a 22yr old car, if you never have checked and have some spare time and a lot of Metric tools I suggest crawling around and checking all the misc. fasteners under your car. it was 145am when I finished under the care so I can only hopefully assure that this was my issue and as soon as weather cooperates I will give the ole girl a drive and see. thanks again all and my fingers are crossed!!!!! brody p.

74 LS4-454

Good luck..... hope that solves your problem....

Paul Workman

Another candidate for "You know you're a C4 owner when..." thread!

OP: Bill Boudreau's C-Beam plates are worth every cent! Not only do they solve the problem (in no small part because they're STEEL and not aluminum), but if like me your hands are average or larger, they make removing and reinstalling the C-beam no more difficult than wheel lug nuts...no kidding!

And, the rear end stays put under heavy acceleration - another benefit!

Before torquing the C-beam to the trans, make sure it is indexed properly, or your next "How do I fix it" tread will be something about strange vibrations at speed... Just sayin.