Can cams be installed incorrectly?

[graphikg]

Except for obviously snapping them in half, can they be installed incorrectly? My car tends to shut off under load only at around 2800-3200rpm, and the shop is attributing it to possibly the head having the wrong cam, or it being installed incorrectly. Everything else has been checked and is good - vanos, ecu, oil and fuel pressure, spark, etc.

[erik325i]

It's possible to not set the cam timing correctly.

[graphikg]

Isnt that the same as just setting the car's timing correctly at TDC? Or does the cam have to be set seperate from the actual Vanos timing? It could be that the timing is off because the shop says that the valves are JUST SLIGHTLY hitting the top of the pistons - but no valves seem to be bent.

[Van Westervelt]

the two cams can be off, or just one, or neither. All scenarios are possible, but its a little hard to say without having the car.

[erik325i]

Isnt that the same as just setting the car's timing correctly at TDC? Or does the cam have to be set seperate from the actual Vanos timing?

Yeah, same thing. There is no "VANOS timing". When you install the VANOS, you have to set the cam timing for both cams.

It could be that the timing is off because the shop says that the valves are JUST SLIGHTLY hitting the top of the pistons - but no valves seem to be bent.

Unless your rods somehow streched, or your crank decided to bend, then I'd put my money on the cam timing being off if you are experiencing piston-valve contact.

[ChaseN]

...the shop says that the valves are JUST SLIGHTLY hitting the top of the pistons - but no valves seem to be bent.

I don't know how long you've had the engine together, but that can seriously impact the health of your rod bearings. A buddy of mine's 5.0l Mustang spun a rod back in high school, and when his Dad pulled the motor apart, they found the valves had been ever so slightly kissing pistons and forcing the piston/rod assembly down against the crank.

[graphikg]

I don't know how long you've had the engine together, but that can seriously impact the health of your rod bearings. A buddy of mine's 5.0l Mustang spun a rod back in high school, and when his Dad pulled the motor apart, they found the valves had been ever so slightly kissing pistons and forcing the piston/rod assembly down against the crank.

It hasnt been together for too long, maybe 20 miles or less running with this problem.

Unless your rods somehow streched, or your crank decided to bend, then I'd put my money on the cam timing being off if you are experiencing piston-valve contact.

G DAMN! It could be a bent crank. I would be devastated if it is that.

[ChaseN]

It hasnt been together for too long, maybe 20 miles or less running with this problem.

Ahhh! Lucky :)

G DAMN! It could be a bent crank. I would be devastated if it is that.

Argh! Unlucky

[graphikg]

Shop says it cant be a bent crank or stretched rod because the car wouldnt idle as well as it does and it would be vibrating; the car doesnt vibrate.

[BrewCity11]

How does the motor respond outside of 2800-3200 rpms?

[e30s50dan]

Possible bad ECU!?

[Sagaris]

Since the cam bearing caps are line-bored you must use the exact bearing cap from the exact location it was removed from. I made this mistake on another car. I had installed the bearing caps from another head in the correct order the 1,2,3,4 markings on the caps corresponded with the correct cylinders, but even torquing the cam bearing cap bolts to 15 ft-lbs could cause the cam to seize up and the engine couldnt start. I was so confused. I doubt this is your problem but it is an answer to "can cams be installed incorrectly"

[Jason89i]

cam timing.

did you install schrick cams? schricks are notorious for the timing blocks to be off. you cannot just install them "square up." you need a dial to install them.

this happened to a buddies s50. exact same symptoms. unplug your vanos and see if the it continues. my guess is that when the vanos engages (advances the cam 7deg) it is too far off and pistons kiss the valves. (we unplugged the vanos solenoid and the car ran above 2800. plugged in the vanos and the car would not run above 2800.)

jason

[JGood]

you cannot just install them "square up." you need a dial to install them.

You mean the sides are not perpendicular to the heads? No m/s5x cams can be installed "squared up" where the top of the cam square is parallel to the head surface... instead the sides have to be basically perpendicular to the head (I'm not even sure if that's 100% true, I've never measured my cam block tools, maybe it's more like a 95 degree angle?). So you're saying Schricks take it one step further and aren't even perpendicular on the sides, and require their own installation technique other then the cam blocks? Just curious... I've never messed with Schricks. If so, that sucks!

[Jason89i]

correct. stock bmw cams are installed by the factory "square up." you use the little cam block tool (see pic below) to install stock cams. HOWEVER, schricks have a few batches of cams where they were not a "square up" install. Johns in perticular were 8-13 degrees off .... cant remember if the intake was off by 8 or 13...... but you get the idea.

Also note in pic, the top edge (unmachined) is NOT parallel with the face of head. The side edges (machined) ARE perpendicular to the face of head. the "square" ends are actually parallelograms (sp?).

cheers, jason

(thanks e36-tech.com for pic.)