CHEWING OUT CAM LOBES

[DYNOED250]

Hey guys, how many of u have had a 250/200 chew a cam lobe off...


down here in geelong we been machining a flat on the side of the lifter, this way some of the oil instead of going up to youre head gets squirted onto youre cam.

Another way is they machine a grove in the lifter bore, so that oil is sprayed onto the cam on the side coming up to the lifter, both ways have neeted good results.

 

[Anonymous]

currently in possesion of a 250crossflow with a cam snapped into pieces

 

[Anonymous]

Hi guys,
Wearing only one cam lobe off a cam on the crossflow engines wasnt a great problem until the XF range came out.
The XD and XE engines didnt have any problems like that.
But with the XF came a whole lot of differences. The cams would wear out, some times before the first major service.
And a lot of other things.
This brought to our attention to the absolutely critical emphasis on lube and bedding in of the replacement cam and lifter sets.
Sometimes the same car that had one worn cam replaced, didnt make it to the next service before another was required.
At present i have a heap of crossflow 250 with worn cams. Not just abit but worn enough to stop one cylinder form working.
These are all different cylinders.
So yes, the worn cam problem has been around a long time.
Noel.
Breaking a cam must have been hard to do?

 

[DYNOED250]

to breaka cam you musta spun a cam bearing, either that or a rod hit it

 

[Anonymous]

also a nicely modifed engine block -

 

[DYNOED250]

are u running an e2 head because it looks like the pistons hit it

 

[Anonymous]

not sure its an efi head

and yes it gave it a wack, thinking number 3 inlet valve might be bent.. grr

 

[Anonymous]

Has been a long time since I seen a 250 with a leg out of bed!
Bu**ar!
Usually the head suffers as well coz the valves go crazy without the cam and the stuff going boom, big time.
Noel.

 

[xctasy]

Check this out. I have a windowed XF efi, and its had the cam broken. I don't know what happened first. Time to do a show and tell of Falcon bad breakages!

http://slantsix.org/articles/oil-pump-gear/failure-fix-report.htm

 

[Anonymous]

Check this out. I have a windowed XF efi, and its had the cam broken. I don't know what happened first. Time to do a show and tell of Falcon bad breakages!

http://slantsix.org/articles/oil-pump-gear/failure-fix-report.htm

gear also got chewed up

 

[Anonymous]

cam appears to be missing, pulling the piston out of cylinder 1

only retrieved half a piston, missing the other half and a conrod.. heh

 

[xctasy]

Conrod breakage from detonation, or cam brakage at number five from some other fault?.


I had a reall good look at my XF EFI engine, and its a chicken and egg situation. How do I know which one was first?. Rod or the cam or the lifter. Cam gear was okay.

My guess? Alloy heads and heavy rocker gear may be pre-loading the cam. And, as Gassed 260 and Dynoed250 have said, the lifters are different and could be a gauling point.

If the cam is broken, it may be the cause.

This is not a failure you hear about on non cross flows. Backlash was saying it became common on XF's. The XF had low drag pistons which limited the rev range 300 revs lower on the 250. 4500 rpm, not 4800 rpm. Iron XC and XD's could rev to 5300 rpm. My old XE with tiny cam could too. The cam has huge clearance chunks, so it may be stress risers from the cam. The head went close to the detonation threashold, so its likely the engine would be subject to more low level vibration.

Harmonics are, I belive, the reason the US 250 has a much bigger crank snout, balancer, cam chain gears and extra space between the cam and crank, along with a much stouter block.

Sorry to prattle on.

Tell me its number 5 that's holed, and we may be onto something.

 

[Anonymous]

the cause is lack of oil, due to the fact the mechanics left the sump plug loose and it ran for 30minutes.

and it was number 1 piston only

 

[xctasy]

Yep, that's right, i forgot. You emailed me.

The hydraulic lifters must run with oil, they are the weakest link. The old Blue Motor Holdens got a Wynns publicity prep-up, and ran 12,000 km in the early 1980's with mechanical lifters being the only alteration.

But a missing sump plug is a poor testimony to a mechanic.

Got any options for having them sort it?

 

[Anonymous]

just a new high performance motor

acl race pistons, 200ci rods, bored 40thou, big cam, all the bells and whistles