Buddy of mine bought a turnkey piperack with a 505. 17 runs and the cam shaft broke. He calls the seller. Seller then tells him it broke a cam with 5 runs before he sold it. Never seen a cam break before. Any ideas on where to start to fix this mess? Last week it broke a tie bar on 1 set of lifters. I had a set of crower lifters he put in got it running again. Cam broke at a idle during warm up today at the track.. Thanks

Sounds to me like there is a lot wrong with that engine. I'd pull it down and have the cam bores and lifter bores checked. Unless he's running Harbor Freight special cams, it's not that common to break one. Especially if it's a billet....

One more thought...how close are the rod bolts to the cam????

Misaligned cam tunnel, tight cam bearings, lifter bores misaligned

Just some possibilities.

Stock blocks much more likely to be a problem

Aftermarket blocks less likely

What kind of cam? Steel billet roller or ?

Never seen a steel cam break without a major engine blowup like a rod !

BB’s don’t generally have any problem with rod bolt to cam clearance but after breaking 2 cams I’d be checking for some sort of interference

No idea really. Its coming apart for sure.

quote:

Originally posted by SCDIV1:
Misaligned cam tunnel, tight cam bearings, lifter bores misaligned

Just some possibilities.

Stock blocks much more likely to be a problem

Aftermarket blocks less likely

What kind of cam? Steel billet roller or ?

Never seen a steel cam break without a major engine blowup like a rod !

BB’s don’t generally have any problem with rod bolt to cam clearance but after breaking 2 cams I’d be checking for some sort of interference

Suppose to be a comp cam roller

quote:

Originally posted by RacerVX54:

quote:

Originally posted by SCDIV1:
Misaligned cam tunnel, tight cam bearings, lifter bores misaligned

Just some possibilities.

Stock blocks much more likely to be a problem

Aftermarket blocks less likely

What kind of cam? Steel billet roller or ?

Never seen a steel cam break without a major engine blowup like a rod !

BB’s don’t generally have any problem with rod bolt to cam clearance but after breaking 2 cams I’d be checking for some sort of interference

Suppose to be a comp cam roller

Have the cam mag’ed. see if there are any other cracks. Cores that are hardened too much are too brittle!!!! If u find other cracks then that’s ur problem!

Couple years back, I had a connecting rod break my camshaft into three pieces. Took out a cylinder wall and lifter valley too. Look for that while it is apart. (insert sarcasm disclaimer here) Take care. Tom Worthington

Brian, broken cams from Comp are not so rare. Being that this engine is a 505, it’s likely it had an off the shelf grind on their black/cast core though a customs grind too could be on the black core too, which as of the past several years has a history of failure. The core he wants is the gold/copper billet core.

quote:

Originally posted by 1320racer:
Brian, broken cams from Comp are not so rare. Being that this engine is a 505, it’s likely it had an off the shelf grind on their black/cast core though a customs grind too could be on the black core too, which as of the past several years has a history of failure. The core he wants is the gold/copper billet core.

Yes 5310 cores are hard you want the 4160 gold cores!

Not sure about the 1st cam,but on this one...If the cam broke in front of the the lifters that the tie bar previously broke.The lifters turned sideways in the bore binding the cam and damaging it.You just finished it off once you got it running again...more than likely...

Am i reading that right? it broke (3) shafts? And one of them at idle????

quote:

Originally posted by TD3550:
Am i reading that right? it broke (3) shafts? And one of them at idle????

Broke 2 1 at idle.

black core? ours broke 2 years ago at idle too

sbc 8620 carbonized core just under 1" lift.

How many cams have broken?

Are they breaking between the same two lobes?

This is how you can determine if the breakage is due to a specific core (heat treat).

This is new to me. Thanks for bringing up. Roller cams for me for the last 37 years. Have some on the shelf currently. Went out to look and they all look like the one Mike has pictured. As for as I can remember all I have ever used have that gold looking appearance. So some cam company sells cams that are inferior and they know it or is it just a hit or miss.

quote:

Originally posted by SLICKSTER:
This is new to me. Thanks for bringing up. Roller cams for me for the last 37 years. Have some on the shelf currently. Went out to look and they all look like the one Mike has pictured. As for as I can remember all I have ever used have that gold looking appearance. So some cam company sells cams that are inferior and they know it or is it just a hit or miss.

Got that from Bischoff - BES in Ohio. I never even asked, I knew what he was sending good chit!

Big MotherTrucker sbc cam.

Went 5.20 off the trailer 3100lbs 200hp shot on a dot 275 radial. 1.19 60ft 4150 carb. Brand new engine & trans, converter, gear etc etc. Everything assembled in house.

Where did it break, and did the other break in the same place?

I saw a 421 smallblock that repeatedly (3-times) breaks the small base circle cam on the cylinder 7-8 end. I think it's oil pump related. Suggested an external oil pump setup.

Well the motor is a complete **** show. Bought from a set of brothers in Maryland as a turnkey dragster ready to run.. Sold as a fresh 505. Aint nothing fresh about it. Timing chain broke cams is broke every piston has hit a plug. Every intake valve has hit a piston... They looked this man in the face shook his had and probably laughed as he pulled out of the driveway. People suck. He sent pictures to the 2 and of course they both stop responding... Smfh Sad how ****y people can be..