Crane Hydraulic Roller cam failures
09-15-2004, 02:15 PM
#1
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Crane Hydraulic Roller cam failures
Replaced the cams in my HP500 carb motors with Crane 168731. These are just slightly larger than the original HP500 cams. Also replaced the cam bearings, roller lifters and timing sets (used Cloyes hexadjust sets that have the billet gears) and the oil pumps.
The motors run great with these cams. But, after 60 hours, the cam in one of the motors broke just in front of the distributor gear. On a positive note, this was the best place for it to break since it did not cause any valve to piston interference-the motor just simply shut off because the distributor stopped turning.
These cams have the iron distributor gear and Crane installs this gear by turning down the rear of the camshaft to a smaller diameter and sliding the distributor gear onto the shaft, probably a friction welding type process. Anyway, this is where the camshaft broke. I was fortunate to have Crane cover it under warranty and I got a new cam.
Now, after 75 hours the new cam broke in exactly the same place. I haven't talked to Crane yet, but something is obviously wrong. I will be having the motor completely disassembled and everything checked over to see if the cause can be determined. When the cam broke the first time, the cam bearings looked fine and so did the distributor gear. The cam spuns nicely in the motor. There was nothing obvious.
One guy I talked to said it may be caused by some weird harmonics going on in the motor. Any thoughts out there?
The motors run great with these cams. But, after 60 hours, the cam in one of the motors broke just in front of the distributor gear. On a positive note, this was the best place for it to break since it did not cause any valve to piston interference-the motor just simply shut off because the distributor stopped turning.
These cams have the iron distributor gear and Crane installs this gear by turning down the rear of the camshaft to a smaller diameter and sliding the distributor gear onto the shaft, probably a friction welding type process. Anyway, this is where the camshaft broke. I was fortunate to have Crane cover it under warranty and I got a new cam.
Now, after 75 hours the new cam broke in exactly the same place. I haven't talked to Crane yet, but something is obviously wrong. I will be having the motor completely disassembled and everything checked over to see if the cause can be determined. When the cam broke the first time, the cam bearings looked fine and so did the distributor gear. The cam spuns nicely in the motor. There was nothing obvious.
One guy I talked to said it may be caused by some weird harmonics going on in the motor. Any thoughts out there?
09-15-2004, 08:22 PM
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Re: Crane Hydraulic Roller cam failures
I can't offer any explanation on what has happened to your motor. I would just like to say that it seems that the problem is in the same motor. Has the other motor had any cam related problems?
I am putting together a 540 for next season. I used the same type of cam you have described but I used an Isky. As you said, Crane cuts down the back of the cam and presses on a distributor gear. Isky does the same only they pin the gear on as well. Isky told me that they have never had a gear failure. But, what else would they say..
I am putting together a 540 for next season. I used the same type of cam you have described but I used an Isky. As you said, Crane cuts down the back of the cam and presses on a distributor gear. Isky does the same only they pin the gear on as well. Isky told me that they have never had a gear failure. But, what else would they say..
09-15-2004, 09:05 PM
#3
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Re: Crane Hydraulic Roller cam failures
I had a crane solid roller also break in that location. I also has the steel gear option. I probably had 100 hours on the cam. Word I got is that it isn't the first time they have broken 
Had Crower do me a similiar grind. Time will tell.
Had Crower do me a similiar grind. Time will tell.
09-15-2004, 10:02 PM
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Re: Crane Hydraulic Roller cam failures
I have the exact same combo 100 hours 0 problems. What springs are you using. I know they had nothing to do with the cam breaking at the gear I was just curious.
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09-15-2004, 10:18 PM
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Re: Crane Hydraulic Roller cam failures
Checkmate454, the cam in the other motor is fine so far with 130 hours. I have run these type cams in other boats with no problems. As far as Isky pinning the gear on, it wouldn't have made a difference in my case since the shaft itself actually snapped right where it is necked down, probably the weakest point in the shaft. The gear is in perfect shape. I am thinking that if the shaft wasn't necked down it wouldn't have broken, but on the other hand something must be causing it to break.
Bob, is the Crower made the same way? I would like to use a hydraulic roller again and also have the iron gear for reduced maintenance. What about Comp or Lunati? Also, what do you think of having two different brand of cams in your motors?
Bob, is the Crower made the same way? I would like to use a hydraulic roller again and also have the iron gear for reduced maintenance. What about Comp or Lunati? Also, what do you think of having two different brand of cams in your motors?
09-15-2004, 10:23 PM
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Re: Crane Hydraulic Roller cam failures
35/25,
I wasn't suggesting that pinning the gear would have prevented this problem. I was just passing on information. As far as using 2 different cam companies, I suppose you could get away with it providing that both cams have the exact same grind. The motor wont know what brand is stamped on the cam, it just cares about the bumps on the stick.
I wasn't suggesting that pinning the gear would have prevented this problem. I was just passing on information. As far as using 2 different cam companies, I suppose you could get away with it providing that both cams have the exact same grind. The motor wont know what brand is stamped on the cam, it just cares about the bumps on the stick.
09-15-2004, 11:03 PM
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Re: Crane Hydraulic Roller cam failures
Scott, I am running Comp 929 springs and they are holding up well in both motors.
Checkmate454, I appreciate your fyi on the Isky design. Didn't mean to sound challenging. I am really frustrated with this experience however. I have been playing with motors for many years and can't put my finger on this one. Hopefully, the engine shop can find some hidden gremlin inside to explain it. Should have the motor in the shop by early next week. Wonder if I stand a chance with Crane as far as another warranty claim. Even if they give me one, wonder if I should switch just for piece of mind.
Checkmate454, I appreciate your fyi on the Isky design. Didn't mean to sound challenging. I am really frustrated with this experience however. I have been playing with motors for many years and can't put my finger on this one. Hopefully, the engine shop can find some hidden gremlin inside to explain it. Should have the motor in the shop by early next week. Wonder if I stand a chance with Crane as far as another warranty claim. Even if they give me one, wonder if I should switch just for piece of mind.
09-16-2004, 04:53 AM
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Re: Crane Hydraulic Roller cam failures
Just a thought,
Are you using the Gen VI style cam retaining plate in front of the cam? That works real well. If so, disregard below.
If its a old style Gen V or Gen IV cam you need a cam button. Crane tells you to set the lash on the button to the timing cover to a few thousands. Setting the lash is important. What Crane does not tell you is the stamped steel timing cover will flex way too much for the cam. I have watched that cover push out over a 1/8". Just rev up the motor from an idle and look. That is pulling the distributor and oil pump shaft with it. When everything is new there is not enough clearance in the gears to have a problem. After some wear comes in, it binds and breaks the cam. I would look hard at the wear problem on the cam. Can you find one tooth that looks like a bind point? It could be just a Crane flaw but we run them a lot and do not have your problem.
If you are using the circulating water pump, take some liquid epoxy and stick it on the water pump back about the size of a silver dollar directly over the cam button location. Install the water pump and tighten. When the epoxy gets hard, The cover can not flex. If you are using a crossover you will need a stronger cover.
Have you checked the distributor installed height? If the heads have been cut, the block decked, or a new intake you will need to check that. You measure down from the cam surface on the intake to the top of the oil pump shaft. Measure from the bottom of the distributor gear up to the housing of the distributor. Measure up the distributor where the oil shaft goes in. You want to have at least 1/16" or little more clearance from the shaft bottoming out in the distributor gear base when installed. I have had to use up to three gaskets under the distributor to get this on modified stuff.
Good Luck
Are you using the Gen VI style cam retaining plate in front of the cam? That works real well. If so, disregard below.
If its a old style Gen V or Gen IV cam you need a cam button. Crane tells you to set the lash on the button to the timing cover to a few thousands. Setting the lash is important. What Crane does not tell you is the stamped steel timing cover will flex way too much for the cam. I have watched that cover push out over a 1/8". Just rev up the motor from an idle and look. That is pulling the distributor and oil pump shaft with it. When everything is new there is not enough clearance in the gears to have a problem. After some wear comes in, it binds and breaks the cam. I would look hard at the wear problem on the cam. Can you find one tooth that looks like a bind point? It could be just a Crane flaw but we run them a lot and do not have your problem.
If you are using the circulating water pump, take some liquid epoxy and stick it on the water pump back about the size of a silver dollar directly over the cam button location. Install the water pump and tighten. When the epoxy gets hard, The cover can not flex. If you are using a crossover you will need a stronger cover.
Have you checked the distributor installed height? If the heads have been cut, the block decked, or a new intake you will need to check that. You measure down from the cam surface on the intake to the top of the oil pump shaft. Measure from the bottom of the distributor gear up to the housing of the distributor. Measure up the distributor where the oil shaft goes in. You want to have at least 1/16" or little more clearance from the shaft bottoming out in the distributor gear base when installed. I have had to use up to three gaskets under the distributor to get this on modified stuff.
Good Luck
09-16-2004, 09:30 AM
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Re: Crane Hydraulic Roller cam failures
Linster,
Yes, these are GEN VI motors with the cam retaining plate on the front of the block. I never actually measured the distance from the oil pump shaft to the distributor flange, but always make sure the distributor is not bottomed out when I install it. You can tell if it is bottomed if the gasket remains loose after you insert the distributor and push down on it by hand. I have run multiple gaskets, as you say, to correct this situation.
Yes, these are GEN VI motors with the cam retaining plate on the front of the block. I never actually measured the distance from the oil pump shaft to the distributor flange, but always make sure the distributor is not bottomed out when I install it. You can tell if it is bottomed if the gasket remains loose after you insert the distributor and push down on it by hand. I have run multiple gaskets, as you say, to correct this situation.
