jjacob
Member
I have been off the forum for awhile now, but am now ready to start the conversion of my 1969 500L to a 650 engine and transmission. Got a few personal emails from the Hobbler last year which were informative. I am in the USA (Nashville, Tennessee).
I was able to buy two 650 engines and a transmission out of Germany (ebay). Basically there really are no used 650 engines or transmissions available in the USA or Canada. Those people that have them here seem to think they are made of Unobtanium. Got both engines for $370 which included shipping within Germany and the transmission for $190. Shipping to USA was free as a customer allowed me to put them into their container! Both engines turn free and are 100% complete (alternator, carbs, clutch, all sheet metal).
I want to go over my general plan with the forum. I want to keep this economical so I will be keeping the stock displacement. Most benefits in torque and horsepower seem to come from cam, intake valve and compression increase changes rather than a 50cc increase in displacement.
Engines are both FSM (Polish):
Engine #1
FSM 126A1.076/8 6739534
Head: AD84M "650"
Carb: 28S1A-1-250 (has 2/98 stamped on carb. Date code?) has 2 vacuum ports in carb spacer.
Has wasted spark distributor (no cap or rotor)
Engine #2
FSM 126A1.076/8 6664664
Head: AD84M "650"
Carb: 28S1A-5 (has 10/96 stamped on carb. Date code?) has no vacuum ports in carb spacer.
Has standard distributor (rotor and cap)
Transmission
Fiat 126 AB.0C.1
4321651 10A
I have searched the internet and cannot find any information that gives a range of engine serial numbers and the year they were made or any differences. What I have been able to find out is that these engines are most likely from 1984-1994 based on the .076/8 in the engine code. These later engines should both have an 8.0/1 compression ratio? Wasted spark started in 1985, so that makes the older engine 1984 or earlier?
Any information about either of these engines would help.
My plan, other than to do a complete normal rebuild, is to maybe keep the existing cylinders and have them bored to 0.40mm oversize. I can get a new old stock Mahle oversize piston kit out of Italy for a reasonable price. This keeps costs down and slightly (very slightly) raises the compression ratio. I would increase the size of the intake valve only and keep the standard 28 carb for right now. Use a new cam with something like a 35/75 75/35 profile. Add an oil filter/cooler take off to the front engine cover. Thinking about using the wasted spark distributor and replacing the points with the Pertronix system I have already installed in the 500L. I would like to get to a compression ratio of around 8.5/1, so was thinking either milling the head 1mm or using a thin head gasket. I have a set of aluminum 12in wheels and new 145R7012 tires.
Transmission will be gone through. At a minimum new seals. Gears and syncros will be examined for wear and replaced as needed. Already have a brand new starter motor.
So please give me your opinions. Keep in mind I do not want to spend tons of money on this. Reliability is number one. Second is the ability to cruise at 80-95 kph (50-60 mph) for long periods of time and have more power for going up hills and accelerating from a stop, etc.
Also any information about the differences in the two carburetors or differences between the two engines would be appreciated.
John
I was able to buy two 650 engines and a transmission out of Germany (ebay). Basically there really are no used 650 engines or transmissions available in the USA or Canada. Those people that have them here seem to think they are made of Unobtanium. Got both engines for $370 which included shipping within Germany and the transmission for $190. Shipping to USA was free as a customer allowed me to put them into their container! Both engines turn free and are 100% complete (alternator, carbs, clutch, all sheet metal).
I want to go over my general plan with the forum. I want to keep this economical so I will be keeping the stock displacement. Most benefits in torque and horsepower seem to come from cam, intake valve and compression increase changes rather than a 50cc increase in displacement.
Engines are both FSM (Polish):
Engine #1
FSM 126A1.076/8 6739534
Head: AD84M "650"
Carb: 28S1A-1-250 (has 2/98 stamped on carb. Date code?) has 2 vacuum ports in carb spacer.
Has wasted spark distributor (no cap or rotor)
Engine #2
FSM 126A1.076/8 6664664
Head: AD84M "650"
Carb: 28S1A-5 (has 10/96 stamped on carb. Date code?) has no vacuum ports in carb spacer.
Has standard distributor (rotor and cap)
Transmission
Fiat 126 AB.0C.1
4321651 10A
I have searched the internet and cannot find any information that gives a range of engine serial numbers and the year they were made or any differences. What I have been able to find out is that these engines are most likely from 1984-1994 based on the .076/8 in the engine code. These later engines should both have an 8.0/1 compression ratio? Wasted spark started in 1985, so that makes the older engine 1984 or earlier?
Any information about either of these engines would help.
My plan, other than to do a complete normal rebuild, is to maybe keep the existing cylinders and have them bored to 0.40mm oversize. I can get a new old stock Mahle oversize piston kit out of Italy for a reasonable price. This keeps costs down and slightly (very slightly) raises the compression ratio. I would increase the size of the intake valve only and keep the standard 28 carb for right now. Use a new cam with something like a 35/75 75/35 profile. Add an oil filter/cooler take off to the front engine cover. Thinking about using the wasted spark distributor and replacing the points with the Pertronix system I have already installed in the 500L. I would like to get to a compression ratio of around 8.5/1, so was thinking either milling the head 1mm or using a thin head gasket. I have a set of aluminum 12in wheels and new 145R7012 tires.
Transmission will be gone through. At a minimum new seals. Gears and syncros will be examined for wear and replaced as needed. Already have a brand new starter motor.
So please give me your opinions. Keep in mind I do not want to spend tons of money on this. Reliability is number one. Second is the ability to cruise at 80-95 kph (50-60 mph) for long periods of time and have more power for going up hills and accelerating from a stop, etc.
Also any information about the differences in the two carburetors or differences between the two engines would be appreciated.
John