LS4 / F40 swap - fieroguru (Page 91/216)
J Gunsett SEP 11, 07:56 PM
Last weekend I had the pleasure to meet and hang out with Fieroguru at LS Fest. He did a great job in all the events he competed in. And did I mention he blew my doors off in the 1/4 mile. I was running stock tires (215/60 14s) and on that run had real bad wheel spin that run. But as the day went on I was babying it out of the hole and letting 3rd and 4th gear do the work. Best I could do was 13.05 at 118.02 MPH. Fieroguru, hope hope we can do it again next year.

Jack
Inferno SEP 28, 03:31 PM
This is officially my favourite build thread. AWESOME!
fieroguru SEP 29, 08:59 AM

quote
Originally posted by Inferno:

This is officially my favourite build thread. AWESOME!



Thanks!

Not much new has happened, been focused on a customer car. I did get the shifter rebuilt and it seems to have helped shifting into 3rd gear, but I haven't really tested it out with a WOT 2-3 upshift yet.
fieroguru SEP 29, 04:10 PM
For the second time now, I have lost gear shift capability while driving. First time was when the c-clip fell off on a 1/4 mile pass and I was stuck in 4th gear till I limped it back to the pits. Reinstalled the c-clip and life was good.

Today while going into town, a similar thing happened and all I had was 3rd gear. I had just left the house and was only a few miles away, so I drove it in 3rd till I found a place I could turn around in and limped the car home. I thought it was the c-clip again... but it wasn't:


I broke the shift cable right where it meets the solid shaft. This is one of the few aspects of the swap where I didn't reinvent the wheel and used what others had done (modified getrag select cable for both shift and select functions). The getrag select cable is smaller than the getrag shift cable, and I think the reduced thickness and the length of the solid portion of the cable are contributors to the failure (along with all the abusive shifting).

To engage 3rd gear, here is where the end of the solid portion of the cable is. It is at the very end of the support sleeve (which I trimmed down as part of the modification) and 1 7/16" from the shifter bracket. I use the support sleeve term loosely, as the support sleeve is quite movable and would still allow the wire portion of the cable to flex/bend as the shifter engages 1/3/5 gears. This flexing/bending might be contributing the issues with the 2-3 upshift, as engaging R/1/3/5 was always more difficult than 2/3/6:


Here is the position with the shifter in 2/4/6, the solid portion is well within the sleeve of the cable:


The actual select cable doesn't see nearly the same frequency of movement with the extremes of fully extended/fully retracted. Even so, the solid portion of the cable is further into the support sleeve at full extension (Reverse) and only 1 1/8" past the shifter bracket:


Here is the 5th and 6th position:


Short term, I am just going to buy another getrag select cable and install it so I can get the car back on the road with minimal work. Winter is coming and I won't be beating on the car like I was, so it should last until I am done with the SBC/F23 swap I am working on. Once it is back with its owner, I can bring the LS4/F40 car back into the garage to redesign the whole shifter/cable setup with a custom set of cables.

Until the new shifter cable arrives, I am back to driving the 2.5/125C Fiero...

[This message has been edited by fieroguru (edited 09-29-2013).]

Jefrysuko SEP 29, 08:57 PM

quote
Originally posted by fieroguru:

Until the new shifter cable arrives, I am back to driving the 2.5/125C Fiero...




That's like going from a Ferrari to a Yugo!
mwhite SEP 30, 12:22 AM
I had the same thing happen to me. When I was far from home my shift cable failed in the same fashion. I had to drive mine 50 miles in third gear to get it home.
I don't suggest using the same part, I replaced mine with a custom cable, while I was at it I put heim joint ends on the cable to clean up the feel of the shifts.
fieroguru SEP 30, 01:14 PM

quote
Originally posted by mwhite:

I had the same thing happen to me. When I was far from home my shift cable failed in the same fashion. I had to drive mine 50 miles in third gear to get it home.
I don't suggest using the same part, I replaced mine with a custom cable, while I was at it I put heim joint ends on the cable to clean up the feel of the shifts.



Thanks for the confirmation of the issues with the cable. Have you had any issues doing WOT upshifts into 3rd gear? Mine doesn't like it at all and I am trying to narrow down the cause (may just be driver error). In the short term, I have ordered a replacement getrag select cable, but long term I will have a custom cable made... just don't have the free time or garage space to rework everything right now (if I am going to design a custom cable, I want to start with a stock 4 speed shifter base and not move the cable mounts on it.)
fieroguru SEP 30, 01:30 PM
Speaking of shifters, I went ahead and pulled the one in my car for inspection, to better understand how it works, and look for options to streamline the 2-3 upshift. Just put the transmission in neutral, remove 3 bolts and pull it out.


Within the shifter assembly, there is a pin that rides in a gated shift pattern:


There is a ball detent that helps to self-center the shifter in the 3-4 gate, but the spring pressure to go into the 1-2 gate is less than what is needed to go into the 5-6 gate, so the self-center feature isn't as strong from the 1/2 gate as I would like. Unfortunately, its cause by the countour of the bracket the detent ball rolls around on, so not an easy fix to add more spring tension.


There are two of these tabs that engage the shift rails. Notice they are tapered on one side. I might want to increase this taper (and angle the gate for the pin) to allow the shifter to start sliding towards the 3-4 gate sooner (when pushed from 2nd). I may also taper the edge that could accidentally tap 5th so I wouldn't hit the edge of 5th while trying to get 3rd.
mwhite SEP 30, 01:51 PM

quote
Originally posted by fieroguru:


Thanks for the confirmation of the issues with the cable. Have you had any issues doing WOT upshifts into 3rd gear? Mine doesn't like it at all and I am trying to narrow down the cause (may just be driver error). In the short term, I have ordered a replacement getrag select cable, but long term I will have a custom cable made... just don't have the free time or garage space to rework everything right now (if I am going to design a custom cable, I want to start with a stock 4 speed shifter base and not move the cable mounts on it.)



Prior to the cable change, the feel of the shifter was very poor for me. I am sure I hit between the gates muultiple time which helped to kill the original cable. It was much improved with the new cable. This summer I have replace the cable end on the selector with a heim joint to improve the positive feel of the shifts. Basicly I dislike the snap on connects a lot.
qwikgta SEP 30, 04:42 PM
Got about 200 miles on my F40 swap, still getting used to the shifting. My issue is I keep putting it in Reverse instead of 1st gear. One trip I did it 4 times in a row. The guy behind me was getting nervous. He kept stopping further and further back each light.

I know it takes some force to push the lever over to R but for some reason I keep doing it.

Watching your mods to see if I can get any good ideas for my shifter too.

Rob

[This message has been edited by qwikgta (edited 09-30-2013).]