Hi everyone,
Are the intake and exhaust camshafts different from each other? Do they have distinguishing marks?
Back ground: I rebuilt a 1980 Fiat 2000 Fuel Injected. We started the motor but it sounded like it was about to throw a rod. We took the engine out. Removed the oil pan. All the bearing and rod caps look good.
Then we think we noticed that the cam wheels were 180 degrees off. If they were, wouldn't the valves have hit the pistons? We are very confused at the moment.
Paul
Identifying Camshafts
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PaulRandall
- Posts: 21
- Joined: Wed Feb 15, 2023 5:11 pm
- Your car is a: 1980 Fiat 2000
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18Fiatsandcounting
- Posts: 3780
- Joined: Fri Mar 15, 2019 11:23 pm
- Your car is a: 1969 and 1971 124 spiders
- Location: San Francisco Bay Area
Re: Identifying Camshafts
Early 1438cc engines had the same camshaft for both intake and exhaust, so you could in theory swap them with no issues. Later engines, like your 2L, have an exhaust cam which has the distributor drive gear between the #3 and #4 lobes while the intake cam does not have this drive gear. That's the easiest way to tell them apart: Look for that drive gear.
On all these engines, the intake and exhaust cam pulleys are different. Sometimes the intake pulley has an "A" stamped on it while the exhaust has an "S" stamped on it. A for the Italian word aspirazione (intake) and S for scarico (exhaust). Sometimes the intake cam pulley has a flange towards the rear of the engine while the exhaust has this flange towards the front, but often the 2L engines don't have flanges on these pulleys.
A stock 2L engine is "non interference" in the sense that the pistons and valves cannot hit even if the timing is off. However, if the auxiliary shaft pulley is mis-timed, the lobe on the end of the aux. shaft can strike a glancing blow on the #2 connecting rod which can cause quite a racket. If the valves are seriously mis-timed, they can also strike each other even if neither is hitting the piston. The aux. shaft issue usually doesn't cause permanent damage, but valves hitting each other will almost certainly bend a valve which isn't good.
-Bryan
On all these engines, the intake and exhaust cam pulleys are different. Sometimes the intake pulley has an "A" stamped on it while the exhaust has an "S" stamped on it. A for the Italian word aspirazione (intake) and S for scarico (exhaust). Sometimes the intake cam pulley has a flange towards the rear of the engine while the exhaust has this flange towards the front, but often the 2L engines don't have flanges on these pulleys.
A stock 2L engine is "non interference" in the sense that the pistons and valves cannot hit even if the timing is off. However, if the auxiliary shaft pulley is mis-timed, the lobe on the end of the aux. shaft can strike a glancing blow on the #2 connecting rod which can cause quite a racket. If the valves are seriously mis-timed, they can also strike each other even if neither is hitting the piston. The aux. shaft issue usually doesn't cause permanent damage, but valves hitting each other will almost certainly bend a valve which isn't good.
-Bryan