Series II L67/ 6 speed manual conversion

[Guest Greg Ross]

Stuck out here in the "Boonies" with nothing but "Dial-Up" I modified "Preferences" to display only two postings at a time so I could actually view some of your photos, service still times out before this last full batch you included in the one message can download. Refreshed several times and still don't gett all of the images or the complete download of many images!

From what I've been able to see so far you'll have to modify your exhaust to clear the shifter tower and cables. On my Getrag 284 I was able to just rotate the mating flange enough to allow it to bolt up and still clear the shift mechanism. Maybe if you just lose the heat shield from around that exhaust connector you can clear the shifter cables.

Haven't seen the oil filter clash yet but with mine I was able to reuse the Oil Filter bracket off the old 3.8 engine which cleared the extension jack shaft. Do you have a passenger side extension shaft? There must be since the 1/2 Shafts are of equal length.

The Oil Pressure Sender I went remote with, it's mounted up on top of the engine behind the blower. Just used the nylon tubing and fittings accessories that come with aftermarket Oil Pressure Guages.

The Drivers' side tranny mount will obviously have to go, looks like the transmission end is jacked up pretty high. You might even have to cut a hole in the subframe and insert the same piece upside down to make a pocket to let the tranny settle down low enough.

It's a nuisence not being to see your entire posting, maybe for us "Poor Folks" who live rural and are stuck with dial up you could insert just a few images at a time in a posting?

[Guest F14CRAZY]

Now I realize that piece of steel was the flywheel cover...oooops

-insert dramatic music here-

This bolts up just fine

[Guest F14CRAZY]

The trans is resting on the cradle where the driver's side trans mount is supposed to be (notice the trans side is higher than the harmonic balancer side (I'm trying not to get anyone confused, I'm known to do that)

The 4T60 does not extend out this far out; past where this mount bolts to the cradle. This is gonna take some fabrication. I dont think its extreme as it looks in this pic. I figure I can cut off the existing bracket that's welded to the cradle and come up with my own. I might actually have to get my buddy Mario (the welder) to help me with this one.

This is the G6 bracket and mount. I'm gonna ask the G6 board for some photos. Obviously the 3900 and F40 mount differently...i suppose you could say their engine is "higher" and the cradle's "lower"

Camera decided flash wasn't needed and these came out blurry, but for reference, this is the Reatta trans mount and bracket for that side. Do Bonneville's have anything similar?

[Guest F14CRAZY]

Out back, behind the engine. This is the G6 "jackshaft" to the passenger side wheel. Definitely gonna have to relocate the oil filter...I'll ask my contacts about this

Gonna have to figure out mounting this jackshaft bearing too

Couple more pix of the driver's side trans situation

This G6 mount came with the parts I bought. It shouldn't be too hard to figure out how to attach it to the cradle

[Guest F14CRAZY]

Back in the car...I wanted to retake the photos of the shifter and how it fit in the console. I don't think I'll have any problems putting the rest of the console together

Its mounted solidly. The washer stacks worked well. Drilled a few holes in the Reatta "console base" and some new steel plating (16 gauge, I believe. Whatever's really close to 1/8'')

[Guest F14CRAZY]

The G6 grommet appears to be too big but I haven't investigated this yet.

BTW, the 1 ton folding cherry picker was $100 at Harbor Freight. I'm happy I finally have one...the backhoe isn't quick nor easy nor safe

[Guest F14CRAZY]

I apologize for putting all the photos into one post Greg. I went back and split them up between a few posts. It's good you brought this up though because I would have kept making it hard for you and other dial up users. I thank you for your input though.

I plan on using "The Other Guys" exhaust manifolds so I suppose I'll hold off for a bit on the shifter cable holder.

Yes, there is a passenger side extension shaft (again apologies for the photos)

It is looking like a chunk of the cradle will have to be cut out for the trans (and reinforced after)

[Guest TommyH]

Phil, to keep your dash lights working, you should make the shifter number pattern light up. There might even be ones out there that could be easily modded to work. Or you could just short the two wires together.

[Guest Greg Ross]

Front Tranny mount looks like it might clash with the radiator?

Shifter mounting looks great, you do have some modules and electrical to build back around it/ under the dash as I recall. I had to carve/ cut some plastic parts to piece everything back together and restore the external side panel mount points.

Is this the final clutch pedal mounting, you'd mentioned a while back you had clash with the steering column? I never dismantled the dash to this extent, I just did all the underdash work more by feel!

The shift cables thru the firewall, you could drill a larger hole or, make a up a sheet metal ring suited to the size of the new grommet and screw it to the firewall to make a seal.

[Guest F14CRAZY]

Thanks for the tips and comments Greg. I'll investigate the front trans mount before I go any farther...I was thinking of it touching the radiator too

[Guest F14CRAZY]

Finally, I was able to get Mario out here and we got some stuff done. We rented a stick welder and got stuff tacked. He had to go work tonight but he'll be back tomorrow.

I scraped up what scrap steel we had laying around. I'm going to finish the edges, prime, and paint stuff and fasten it with fresh hardware (along with painting the cradle and new front suspension stuff). Don't have a clue what kind of projects this steel was previously used for...

This is our trans side "torque axis" mount

This is for the G6's front trans mount

This bad boy, near the steering rack, is the new rear trans mount (piece 1 of 3)

This is piece 3 of the rear trans mount. The smaller rubber mount with 1 stud is going to sit here, and another piece of angled steel, not pictured, is going to be bolted to the 1st and 3rd.

[Guest TommyH]

Nice work!!

[Guest jcc3inc]

F14,

In the second of your above pictures, you see the corroded end of your "A" frame rod. I'm sure you noticed that it has maybe 1/2 the diameter it once had due to rust. And you're going to replace it so you don't have the mishap that Manikmekanik's daughter had, right?

A question for you: "What kind of overall ratios does your transmission have?" It would be informative to be able to campare transmissions (including automatics), to determine what RPM to expect with various setups.

And a Merry Christmas to you!

Regards,

Jack C.

[Guest F14CRAZY]

The rust on the strut rod is pretty bad and it certainly will be replaced, not only because of that, but the threaded part broke off when trying to remove the nut. We got mad and cut it off (note the duct tape). A new A arm is about $150 from gmpartsidrect. I'm either going to have to do that or have my machinist fix it (which I'm thinking would be cheaper)

This is what I've got as far as ratios:

G6 Performance

<span style="font-weight: bold">Gear Ratios:

FIRST 3.77

SECOND 2.04

THIRD 1.32

FOURTH 0.95

FIFTH 0.76

SIXTH 0.62

REVERSE 3.54

FINAL DRIVE RATIO 3.55:1</span>

Thanks for the comments guys. Mario ought to be back today to finish up the welding

[Guest MauiWowee]

Or perhaps Jim has some rust free pieces.......................

I'm not sure I would trust one that has been welded because of the inherent weakness of steel that has been heated.

[Guest F14CRAZY]

I wouldn't quite have it welded, but made from a fresh piece of rod by knocking off the rivet that holds it to the rest of the A arm

[Guest MauiWowee]

Gotcha

[Guest F14CRAZY]

Tonight, though it took two trips to Lowes for hardware, I've got the engine/trans mounts done! I should have got pix of the rear mount I finished but you'll see it soon. I've still got to adjust its level with washers (may have to do this again when it gets time to get the cradle back in the car), but otherwise, the cherry picker's not holding it anymore

[Guest F14CRAZY]

I've got $1200 in tax money coming back...expect some progress soon

[D-a-n-i-e-l]

Glad to hear it Phil, I am very interested in how your six speed swap goes.

[Guest F14CRAZY]

Thanks Daniel. It's an exciting thought, piloting a Reatta down a quarter, deep in the 13s, or above the governed 125 limit (in a legal fashion, of course)

and putting it through all those gears. mmmmm

[Guest F14CRAZY]

Armed with a rather large tax return, work resumes! I'm going to go ahead and have the clutch setup made. I visited and talked to Dan at Clutch Dynamics and Lansing. I will be bringing the 3900/F40 setup to him along with a brand new 3800 F-body flywheel. I just got off the phone with Advance and that will be in tomorrow.

I'll soon be ordering a new hydraulic engine mount (the front one, the only stock cradle mount). I've got to do that, drill/tap my engine cradle bolt holes cuz like half of them have broken bolts in them. I'll be ordering cradle bushings from gmpartsdirect.com. The cradle will be getting new strut rods and bushings.

Work presses on!

[Guest F14CRAZY]

I ordered new engine cradle bushings from gmpartsdirect.com...$130.88. I also ordered the hydraulic fornt engine mount...an awful $168.88 from Advance. Mine's been leaking though.

On the car I removed the A/C compressor which has been dangling for a while, the condenser, the old fuel lines, the A/C lines, and the abandoned transmission cooler . I've began to deal with the broken cradle bolts which I made another thread for.

[Guest F14CRAZY]

My local bolt-house (Mid States Bolt and Screw) had similar bolts and washers for the engine cradle mounts, so I'll have fresh hardware for that.

The cradle mounts are still on their way from gmpartsdirect.com.

Clutch Dynamics will have some info for me next Monday.

Despite recent setbacks regarding my engine cradle mounts, I am continuing forward. I found a Lincoln 225 Onan powered welder on craigslist by Lake Michigan for $400 and picked that up on Sunday (and actually Mariah, owner of a '90 coupe, rode with me). It had been sitting for a few yearsl I've spent the past couple days getting it running right but it's doing pretty good. Being that I've never welded in my life I've been practicing and I'm getting the hang of it.

More to follow soon.

[Ronnie]

F14, I applaud you for your hands on approach to getting things done. I don't want to be critical of what you are doing. I have been a mechanic/machinist and welder for many years. I don't really consider myself a good welder now that I have not done much welding for a number of years. To be a good welder takes lots of training, practice and experience along with a good knowledge of metallurgy. There is more to it than mearly melting metal.

Please take my advice and hire a certified, or at the very least, an experienced welder to do the welding in critical areas on your car. It could be the best money you spend on your car. It could also save your life.

Thanks for keeping us posted on the progress of your project.

[Guest F14CRAZY]

Thanks for the advice Ronnie. Getting Mario back out here is probably my best/easiest bet...he's had two years of welding instruction. He can at least give me suggestions with the work in front of him and inspect what I'm doing. I agree that reliable welds are needed in the critical portions of the car.

[Guest F14CRAZY]

Tomorrow I should be getting a call on the status of my clutch setup from Clutch Dynamics.

Earlier I welded the retainers for the engine cradle nut-things.

[Guest Greg Ross]

Ronnie made what I thought was excellent advise concerning welding on structural members in your vehicle. And by the way, I'm going to keep this constructive.

Your response was <div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Getting Mario back out here is probably my best/easiest bet...he's had two years of welding instruction. </div></div>

Your friend Marios' 2 years of welding instruction is, at a minimum, 10 years away from being experienced if, he was working the trade and was in an environment where he got the opportunity to see a range of materials, processes and designs.

You seem to be missing the point entirely my young friend, folks here have and continue to offer you good sound experienced advise about serious, significant issues. Your quick solution is to go cheap, don't hire the welder Ronnie recommended to you, but rather "call a friend" and add another potential element of failure into what may already be a compromized structure.

I have a suggestion for you. Call the Michigan Registry of Motor Vehicles, or whatever they call it in that part of the World and ask them this question;

"What are their requirements to have a modified vehicle registered for use that has had structural repairs performed"

You most likely won't like their answer either.

Distortion would to be difficult to manage with one sided weldments on guage metal. The only potential I think for successfully repairing those areas you've cut into would be done with either GMAW or GTAW welding process, and in qualified hands. Suggest you do some research. I'll leave it at that.

[Guest F14CRAZY]

Thank you Greg. I have been out for a few days so I've been slow getting to a reply. I respect and certainly recognize what you're saying. I'm going to dwell on your advice a bit

[Guest F14CRAZY]

Progress:

Today I finally picked up a new hydraulic front engine mount. Mine was previously leaking. The first one Advance received that I ordered appeared to be very much USED so I had them get me another one.

I'm convinced the passenger side of the drivetrain need a mount to the cradle so I picked up another generic GM rear trans mount and will be working on that soon.

In the meantime I've spent the past couple evenings fabricating a jackshaft mount...the jackshaft runs from the trans, behind the engine, and terminates where a CV shaft will run between it and the hub. I'm building this out of some heavy duty steel, 1/4'' if I remember right and doing the best job I can of welding it because its going to be subject to all the torque going to the right wheel. Keep in mind it's attached to the engine rather than the engine cradle so it will move as the engine does...the splines do not allow for virtually any flexing and the bearing that the jackshaft rides on in its mounting "arm" would be subject to a lot of undue stress. It's been quite a challenge getting all the variables right but you'll soon see pix of it.

I'm meeting Dan of Clutch Dynamics tomorrow...he's going to discuss with me the measurements I need to get to make the flywheel/clutch assembly in detail.

[Guest Greg Ross]

Philip,

Have a look at the link below, this is how I configured the passenger side Jackshaft Mount on mine. The '88 had a mount which included the tubular strut running up at about a 45 deg. angle to the engine block which I also maintained. The plate with the hole in it was incorporated into that motor/ tranny mount. On my subframe this literally becomes a fixed point, it will pivot on the mount on the sub-frame but the engine cannot rise at all on that right rear corner because its' angle is locked in with the strut brace. Confusing perhaps but it appears to work.

http://img.villagephotos.com/p/2006-1/1138028/Shaftcarrier.jpg

Second link is drivers' side of the Getrag Tranny where I was able to use the correct mount for that tranny that would have been used on say a Lumina or Gran Prix. Realize your transmission is shaped quite differently but thought it might give you a few ideas.

And I only have the three mounts to the Sub-frame plus the dog bone up top. The Passenger side rear as mentioned above is more of a pivot point as is the tranny mount. The right front liquid filled mount and the dog bone allow the front of the engine to raise or compress down with torque.

http://img.villagephotos.com/p/2006-1/1138028/TrannyMount1.JPG

[Guest F14CRAZY]

Greg you're a genius. Thank you for the info and pix...I'm going to have to take a look at things again...I forgot about that trans mount back there

[Guest F14CRAZY]

Did a little more work on my jackshaft mount today. My mount is considerably different from Greg's...the bearing "carrier" has an "arm", if that makes any sense; I'll get a photo soon.

I did some analyzing of the rear trans mount. I feel I need something back there and I'll be engineering something, but the Series II L67 has its power steering pump back where the LN3 has that rod. I'll pick up a new mount and go from there.

Last Saturday I stopped to see Dan at Clutch Dynamics...he drew a good diagram for me to clarify that I needed to find out the "depth" of the crankshaft flange, where the flywheel/flexplate bolts to, to the block's trans mounting surface. I know I've mentioned this before, but once again it's a spec that he has to have as a baseline for everything.

I had the Combo off of the cradle today and fitted the new front right mount. Dan was also wondering what the "nose" of the F40's input shaft is because he suspected that the 3900's flywheel had a pilot bearing in the center. While I had the drivetrain on the cherry picker I split them. With my description of the input shaft (of which sticks out just about 3/16'' from the splines and has a considerable taper, and isn't really machined) he concluded there isn't one. There just aren't many of these G6's around with the F40 and thus he has no experience with its setup. Regardless, being that there's no pilot bearing, he said things are simpler.

I have yet to find a source anywhere on the internet that had the crankshaft flange "depth" for the 3900. I couldn't avoid it anymore, so me, my brother, and neighbor buddy Robert went to Schram's in Mason (the late model salvage yard where I got the F40). The gentlemen in the warehouse were happy to show me to a pulled 3900 and let me get the spec I needed.

According to my straight edge, the flange extends out from the mounting surface...give or take the thickness of a business card. Now I know . The L67's depth is about a business card folded in half, the difference perhaps due to the crankshaft runout? I'm not the best with internal engine stuff but I'm getting there. I'm going to report this to Dan tomorrow so he can work on the setup.

[Guest F14CRAZY]

Dan at Clutch Dynamics has been pretty busy but I talked with him today. He's be figuring out dimensions for the pressure plate.

[Guest F14CRAZY]

As I mentioned, AOL Hometown belly-ed up so the photos are not working. I'll get them back up (I still have them).

Since then I bought a project boat and am in the process of buying my first house (dang distractions). I'm considering assembling the car with the L67 in stock form...I'm wanting to do some extensive modifications to increase output but it isn't at all cheap. I could finish "GS" and get the stock L67 and six speed on the road without too much capital and work up to my "GSX" designation in the future. I'll figure something out

[D-a-n-i-e-l]

Phil,

Get-R-Done, I want to see it, pluss these cars will not make very good use of a extreme amount of power. That is with out major mods to the handeling. I am very hopeful in seeing you finish with the six speed.

[Guest F14CRAZY]

I haven't looked into it too much but I want to look into using firmer front struts, adjustable ones for a GTP might bolt up, along with a firmer sway bar and end links.

[D-a-n-i-e-l]

That will help, but the rear is where I am still stuck on. I do look forward to seeing you posts.

[page2171]

Phil, good to see you haven't given up on the project. Can't wait to see more of it.

[Guest F14CRAZY]

I definitely haven't, I've just had other distracting projects