Muncie M17 with the 4.9 caddy

[bse53]

What am I going to need to convert the three speed auto in the car to a manual? I've had nothing but problems keeping the auto working.

I located a donor car with a M17 4 speed-- the seller said the engine is blown, but said the transmission was working fine.

The gearing of the M17 with 275/50-15 tires will be fine-- will give me 64 mph in second at 6000.

Does anyone know offhand what axles will work? Can I adapt a flywheel (have it machined) from another GM car to work on the 4.9 engine?

SpecClutch sells a clutch kit that will work with the 4 speed. Is there any reason the Stage 1 wouldn't be sufficient given that it's rated for 340 ft-lbs torque, or should I go to the stage 2 kit?

Any and all advice is welcome.

Brian

I googled the m17 and 4.9 and didn't get anything specific. I did go to Capt.Fiero's website where he had a some info, but nothing very specific.

[Aaron]

I can really only help with what you'll need for the trans swap, but here goes:

Clutch master cylinder
Complete manual pedal assembly
The hydraulic line that runs from the front to the back
Shift cables
Shifter assembly
Trans with slave

Best I can remember that's it. You'll have some minor wiring changes to do, but since you're making a new harness anyway that's not a problem, you'll just need the plugs for the reverse lights and VSS. Swapping to the manual trans is actually really easy, assuming you have everything you need from the donor car. If I remember correctly, the pedals were a pain in the ass to get in and out, and you need the complete pedal assembly.

[The Dark Side of Will]

Pedal box is a pain to R&R.

All manual transmission Fieros use the same axles, but they are all different than the auto trans axles.

[Emc209i]

I retrofitted in a day. Collecting everything and having it ready on the workbench, I thought, was most important. There are no holes to cut, no grinding, its a cookie cutter installation. The most annoying part for me was wiring the neutral safety switch, which was more space confined than getting to the pedals. The four speed is like stepping into the 70's, but you said that's what you want. The flywheel is special to the 4.9 swap, I'm quite sure. Piffle would be the place to ask that question.

As for the clutch rating: 340 ft lbs is 60 ft lbs more than the engine is rated at. It should hold fine. The noticeable difference between stages will be engagement character and speed. I personally prefer a soft engaging clutch, but I don't race either. I'd use the lowest possible "stage" clutch that will hold the torque for street use. A more aggressive "stage" for racing. Puck disks and high pressure plates provide this snappy quality, which gets old in traffic.

[CincinnatiFiero]

I thought on the 4.9 you had to cut a hole in the transmission to put a stick behind it.

WCF used to sell 4.9 flywheels, Steven would probably know if they still do.

[The Dark Side of Will]

The 4.9 has a slightly shifted starter position relative to the V6, which may require a little bellhousing cutting around the original starter bulge.

The Northstar has the starter in the V and requires cutting away some of the webbing inside the top of the bellhousing.

[Shaun41178(2)]

Pretty sure the exhaust crossover will have to be modified or a new one fabricated to clear the 4 spd cables

[Emc209i]

Oh, that's right! Man its been such a long time since I've heard anything 4.9 related. All the more reason to use the Gestrag 282 instead.

[bse53]

Thanks for all the replies.
I'm wanted the m17 for the gearing in second. The 282 would require at least one shift in every run.
This is a dedicated autocross car so I'm not concerned with the connections that would be used in a street car. XP doesn't even require a reverse gear.
I just waned to make sure the axles from the donor car will work. It's an 85 with the 2.8. I thought the 4.9 might move the location of the tranny.

[Aaron]

Have you considered other engines?

If I were to build a dedicated AutoX car it'd have a 3500/3900. Easier swap, more power, and still plenty of torque.

[CincinnatiFiero]

I believe his existing car has a 4.9 in it already.

[bse53]

Yes, I bought the car with the 4.9. It has been modified to the extent this engine can, as I understand it.

> 4.9 Cadillac V-8
> Bored with N* pistons
> polished beams
> balanced rotating mass
> 496 regrind American Cams cam
> Allante intake

It actually pulls pretty hard to 6K.

The reason Tom went with the 4.9, I believe, was weight. The car weighs approx. 2250-2300. By going to the manual, taking off the doors and just hinging the skins, taking out the dash, which is still in the car, I hope to get below 2100 lbs.

Of course, in XP the car has to weigh 2200 lbs with a 5 liter engine. I'm shy about 150 hp of being competitive.
The 2 liter ecotec would be a good choice-- though there is no way to ever get the car to 1800 lbs.
This car will never be nationally or even regionally competitive, but at my local club, I won the top raw trophy for the year.
I would stay with the three speed auto if I could get it to last.

[Aaron]

Maybe I'm just ignorant, but I'd be absolutely amazed if that car is under 2500. No offense, I just wouldn't believe those numbers without scales. And, I don't believe it's reasonably possible to get a Fiero under 2,000.

[bse53]

The car corner weighs about 500 lbs on the front and 700 lbs on the rear with 150 lb of barbell weights in the driver's seat. That puts it close to 2250. My understanding is the manual weighs about 90 lbs vs 170 for the auto. The doors will save 50 lbs. So those to mods will reduce it about 130 lbs, putting the car close to 2120. If the dash weighs 20 lbs, and I drain the gas tank it might be possible to get it below 2100 pounds.

I was reading on Pennock's a guy was trying to get his streetable car down to 2300 pounds (edited). So I think it is possible. But yes, below 2000 would be difficult.

It's kind of funny what you have to do to get to 2300 pounds. He's figuring out how to reduce the rear tail lights a pound or two. I just take them out.

http://www.fiero.com/forum/Forum2/HTML/112942.html