Powertrain swap

[steptoe]

I have a 1964 Monza Coupe with a 140 engine and a power glide trans. Considering changing over to a 4 speed. Are there any limitations to what I can use for this project? Example: Any year 4 speed trans, bell housing, differential, and whatever would be necessary? No clue at this point but I see where it has been done. Any technical help would really be appriciated. thanks, David

[66vairguy]

I have a 1964 Monza Coupe with a 140 engine and a power glide trans. Considering changing over to a 4 speed. Are there any limitations to what I can use for this project? Example: Any year 4 speed trans, bell housing, differential, and whatever would be necessary? No clue at this point but I see where it has been done. Any technical help would really be appriciated. thanks, David

A 140HP and Powerglide are not a great match. In fact the 140HP engines used with the Powerglide are not the same as used with manual transmissions.

1) Determine if the 140HP engine is for a manual transmission --- block suffix and distributor number.

2) If your car was always a Powerglide then you'll need a number of pars. Probably best to buy a 64 manual transmission car for parts AND to see were everything goes. Take lots of pictures!

3) The 64 cars got the larger long stoke engine so the clutch, bell housing, pressure plate are different from the 60-63 cars. I recall the 65 transmission will work, but I am NOT sure!

[belaraphon]

From what I have read, the differential/4 speed transmission were the same until 1966 when a new 4 speed transmission was introduced. It was supposed to be beefier but not shift as well as the earlier transmission. Having said that, I converted my 1965 convertible to a 4 speed from a power glide. There are a number of things you will need to get. I pieced mine together over time. So a quick summary off the top of head follows:

1. Transmission, pressure plate, flywheel, bell housing, clutch disk, clutch to "Z" bar linkage and return spring, flywheel bushing, maybe a new throw out bearing. (Get the service and assembly manuals for your car. I think some people have posted them in digital format on the forum).
2. "Z" bar and mounting plate. It screws onto the bottom of the rear seat and the nuts should already be there.
3. Clutch cable, shift tube, shift coupler, shifter, shifter base shims and plastic spacer, shifter lever and base. (A nice thing to do when putting in the shift tube assembly it to replace the plastic bearing ends with new ones, or a bronze sleeve kit for better shifting.)
4. Clutch and brake pedal assembly. Clutch cable pulleys.
5. Jumper the neutral start switch in the automatic trans wiring harness to start the car. See factory wiring diagram. It will be attached to the auto trans gear selector switch.
6. Jumper (or replace the body and dash wiring harness) to get the back up lights to work. There is a switch on bottom of the front part of the trans to turn on the reverse lights. A wire will normally run to the body harness in the tunnel from the switch in a 4 speed car.
7. Recurve the distributor for best power. PG cars have a different advance curve than manual cars. 140 is initial advance at 18 and all in at 2800. PG cars don't come all in until 4,000 (at least in 1965).
8. You will need a new front top engine shroud to block off the excess power glide holes so junk doesn't get into the engine compartment. Also, there is a specific hole in the manual shroud for the differential dip stick. Alternatively you could block off and drill out the needed holes.
You will need new rubber sleeves for the shift cable at the rear of the bottom cable tunnel and for the new front shroud.

My advice is that if you go to through this kind of trouble is to replace parts that can wear out with new stuff to save you trouble later and make the car nicer to drive. Parts to replace/refurbish include:
1: throw out bearing, crank snout bushing
2: clean and re-grease "Z" bar pivots balls and put in new fiber seals
3: Install bronze sleeve bearings on shift tube, Replace shift coupler as the rubber on yours is probably hard as a rock and can introduce vibrations on the shifter and make it hard to hit the gears.
4: Get new plastic shift and brake pedal bushings, and probably new cable pulleys (and grease them up when installing)
5. Grease the shift lever and properly shim the mount bracket so it is snug but will slide forward and backward as the factory intended as the drive train moves. Shimming thickness will vary based on the thickness of the cars flooring sheet metal. You just need to remove a block off plate in the floor to install the shifter lever.

Follow the service manual for clutch and shifter adjustments. There are few parts suppliers for Corvairs on the internet. Avoid new parts from ebay as they are often incorrect unless it is from one of those suppliers. I use Clark's a lot as they are the most complete supplier (corvair.com). Also check out California Corvairs, Corvair Ranch etc. I think there is a listing on the forum someplace. Sorry if I forgot anything. The service manual will be your best friend and the knowledgeable folks on the forum of course.

PS: the block on my 140 was from a powerglide car. I rebuilt it and have no problems in the 4 speed conversion. If yours is a PG engine, check the distributor to see if it is a PG or 4 speed distributor. But seeing as how the car is so old, you must check what you have. I am running a 110 distributor in my 140. It runs fine (advance all in at 4,000) but I plan to recurve it the 140 specs one of these days.
PPS: The 140 engine uses a "heavy duty" pressure plate. You can see pictures of it on the web. It differs from the "standard" pressure plate by having additional weight cast on the pressure plate. I run the standard pressure plate on my car and it seems fine. I suspect the heavy duty pressure plate was to have more rotating mass to assist with standing starts. If someone more knowledgeable about this can comment it would be appreciated.

[66vairguy]

Great list Belaraphon.

The H.D. 140HP pressure plate is heavier for smoother starts. It is not required for the 140HP PG engine since it has a milder cam that is shifted 4 degrees by a special 140HP PG only crank gear. A little less top end HP in exchange for more torque at lower RPM. The 140HP PG engines connected to manual transmissions were popular with the Rampside/Greenbrier folks years ago. Finding a 140HP PG engine is not easy now.

Using the 110HP distributor is a good fit. A fellow in our club had a 140HP PG in his 63 wagon with the 140HP manual transmission distributor and the car ran awful. Many suggested changing the timing, but it either pinged (detonation) or had no power. He could not find a 140HP PG distributor (not common). I noticed the 110HP distributor curve is close to the 140HP PG unit and gave him a good spare I had. His car ran much better, no detonation and power and fuel mileage improved.

BEWARE about installing the 66-69 transmission on a 64 or 65 transaxle. the 66-69 transmission output shaft design WILL bottom out on the 64 or 65 ring and pinion shaft and after awhile the transmission bearing will fail in a traumatic fashion. It will fit, but won't work unless you install a 66-69 ring and pinion shaft in the 64 -65 transaxle.

[steptoe]

Thanks guys for the great information on my powertrain swap. Lots of info I wasn't aware of. Every little bit helps. This Forum is a blessing for people trying to maintain their Corvairs. My 140 engine was already in the car when I purchased it. Don't know if he changed out the engine for a 140 block or just added new heads to enable 4 carbs. He did spend a ton of money thru Clark's Corvairs. He also put a cam in it but don't have any specs on that. He lowered the gear ratio as he said the PG didn't have enough low end power to handle hills in Des Moine, Iowa. I can't read the engine number because the shroud covers it up. I'll figure that out later. I drove it home to Biloxi, Ms. from Des Moine and it took forever. That gear ratio really has it wound up on the highway. The man selling me the powertrain knows Corvairs very well so I am confident he will supply the correct parts. If I have any more questions I'll get back to you. Thanks again, you're all great people.

[66vairguy]

Thanks guys for the great information on my powertrain swap. Lots of info I wasn't aware of. Every little bit helps. This Forum is a blessing for people trying to maintain their Corvairs. My 140 engine was already in the car when I purchased it. Don't know if he changed out the engine for a 140 block or just added new heads to enable 4 carbs. He did spend a ton of money thru Clark's Corvairs. He also put a cam in it but don't have any specs on that. He lowered the gear ratio as he said the PG didn't have enough low end power to handle hills in Des Moine, Iowa. I can't read the engine number because the shroud covers it up. I'll figure that out later. I drove it home to Biloxi, Ms. from Des Moine and it took forever. That gear ratio really has it wound up on the highway. The man selling me the powertrain knows Corvairs very well so I am confident he will supply the correct parts. If I have any more questions I'll get back to you. Thanks again, you're all great people.

If the block I.D. is for a 140HP PG engine then it is possible the crankshaft has the special 140HP PG crank gear that shifted the cam timing 4 degrees. Since the cam was changed it is difficult to determine how the two work together. You would have to remove the engine and "degree the cam" to find out what the cam timing is.

When I used a 140HP PG crankshaft I removed the PG crank gear and installed a new standard reproduction crank gear. I used an Isky 260 cam with Calif. Corvair billet cam gear. As a buddy said "What are the odds the cam timing will be correct". Checking against the cam card the worst deviation was 3 degrees with most within 1 degree of the spec. Since shifting a tooth is 7 degrees and the offset Woodruff key is about 4 degrees I left it alone. The car was built for highway use with a 3.27 axle and 4 speed manual (most 140HP cars had a 3.55 axle) and the car pulls well and climbs hills easily. With a Powerglide in a Corvair there is no downshift after about 45MPH, and is the reason the 140HP PG cars got a different governor to allow higher speed in low range.

Point is ---- check the block number and if it is a 140HP PG block it probably has the PG crankshaft and the aftermarket cam timing probably isn't optimal. You should also check the ignition timing. A club buddy had a 140HP PG with a manual 140HP distributor and when set so the engine did not "ping' (detonation) it had no power. A 110HP distributor cured that issue and the car ran much better. I recall we started with 14 degrees of advance. It ran so well he just stopped experimenting and left it at 14 BTDC.