Cam position sensor failure
Race Director
Joined: Dec 2005
Posts: 11,885
Likes: 107
From: God's Country, ID
Thy way I can make sense of it is that the cam bolts backed out, had piston to valve contact, the engine locked up and snapped the chain. Cam has been in for almost a year so it seems unlikely the cam bolts would wait that long to back out. Hours of dyno time and 7 track days is a long time to wait to back out cam bolts...
If the chain snapped due to material flaw, think I have a shot at a reimbursement on my motor? Bought the chain from Hinson, maybe I can call them to discuss.
If the chain snapped due to material flaw, think I have a shot at a reimbursement on my motor? Bought the chain from Hinson, maybe I can call them to discuss.
Pull the valley cover off. That should give you a quick view as to what's going on.
Thread Starter
Track Junky
Joined: Jun 2007
Posts: 4,074
Likes: 36
From: Orlando Area
Tech Contributor
This was inevitable, just hoping it would have happened later than this. Only got about a year (7 track days) out of this head and cam setup. Already looking into a dry sump LS3...
Thread Starter
Track Junky
Joined: Jun 2007
Posts: 4,074
Likes: 36
From: Orlando Area
Tech Contributor
Le Mans Master
Joined: May 2011
Posts: 5,022
Likes: 18
From: Tampa FL (formerly Justinjor)
Tech Contributor
St. Jude Donor '11-'12-'13-'14
Yeah, it sucks but I told my wife I bought this car to break it. I drove the **** out of it the past two weekends. A ran a 1:47 lap at homestead on heat cycled tires that don't have much life left in them. I've taken about 5 seconds off my lap times in the past few weeks.
This was inevitable, just hoping it would have happened later than this. Only got about a year (7 track days) out of this head and cam setup. Already looking into a dry sump LS3...
This was inevitable, just hoping it would have happened later than this. Only got about a year (7 track days) out of this head and cam setup. Already looking into a dry sump LS3...
I'm honestly surprised to hear of the motor letting go so soon-that doesn't inspire confidence in my own, but I don't put quite the same amount of stress on it that you do.
I'm glad to see your attitude is on the up and up though--this is a good excuse to build it bigger stronger and faster
Le Mans Master
Joined: May 2011
Posts: 5,022
Likes: 18
From: Tampa FL (formerly Justinjor)
Tech Contributor
St. Jude Donor '11-'12-'13-'14
I can't see Hinson or anyone footing the bill for a new motor. I know the C5R is a tough chain, but I don't think it comes with any guarantee 
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Racer
Joined: Dec 2010
Posts: 418
Likes: 0
From: South Central Kansas
Not to wish the OP any bad luck.....but.....I'll bet you have cracked pistons as well as the bent valves you already know about. The problem either was broken timing chain, broken camshaft or loose or broken cam gear. I surely hope I am wrong. I think road racing is much harder on valve trains than drag racing.
Best of luck with it.
Bob
Best of luck with it.
Bob
Last edited by 1fastbob; Mar 5, 2012 at 05:40 PM. Reason: changed from engines to valve trains (my error)
Thread Starter
Track Junky
Joined: Jun 2007
Posts: 4,074
Likes: 36
From: Orlando Area
Tech Contributor
Not sure about the dry sump as they add quite a bit of $$$ to the bottom line. Called Hinson this morning - they haven't heard of any issues with the Katech C5R chain like this. Brian does have a full wet sump LS3 motor with 16k miles for $5k and a dry sump LS3 with 1600 miles for $7k - not bad prices. Kinda wanted to do this build on my own, not just swap motors. Then again, I build my last motor and look how long that one lasted, lol!
I also doubt I will see any reimbursement, but I think it would be worth finding out the cause of the failure. The motor has 15-20 hrs of track time on it (4500-6500 rpm)- not much when comparing to other successful motor builds. And I don't push rpm too high, usually shifting between 5800-6300.
The wife knew a spare motor was in the near future, she didn't know that it would be installed so quickly...
Pulled the intake and all intake valves look fine. Looks like 6 or 7 exhaust valves are bent but not broken. That is what is giving the gap between valve stem and rocker. Maybe pistons aren't too bad and cylinder walls probably ok. Heads will be off next.
I think I could sell my Spin ported FAST intake, injectors, UD pulley and headers and recoup some of the cost (maybe $1500 or so).
I also doubt I will see any reimbursement, but I think it would be worth finding out the cause of the failure. The motor has 15-20 hrs of track time on it (4500-6500 rpm)- not much when comparing to other successful motor builds. And I don't push rpm too high, usually shifting between 5800-6300.
The wife knew a spare motor was in the near future, she didn't know that it would be installed so quickly...
Pulled the intake and all intake valves look fine. Looks like 6 or 7 exhaust valves are bent but not broken. That is what is giving the gap between valve stem and rocker. Maybe pistons aren't too bad and cylinder walls probably ok. Heads will be off next.
I think I could sell my Spin ported FAST intake, injectors, UD pulley and headers and recoup some of the cost (maybe $1500 or so).
Thread Starter
Track Junky
Joined: Jun 2007
Posts: 4,074
Likes: 36
From: Orlando Area
Tech Contributor
Not to wish the OP any bad luck.....but.....I'll bet you have cracked pistons as well as the bent valves you already know about. The problem either was broken timing chain, broken camshaft or loose or broken cam gear. I surely hope I am wrong. I think road racing is much harder on engines than drag racing.
Best of luck with it.
Bob
Best of luck with it.
Bob
Just happy it did this with open field in front of me and not a wall
Racer
Joined: Dec 2010
Posts: 418
Likes: 0
From: South Central Kansas
Thread Starter
Track Junky
Joined: Jun 2007
Posts: 4,074
Likes: 36
From: Orlando Area
Tech Contributor
Thread Starter
Track Junky
Joined: Jun 2007
Posts: 4,074
Likes: 36
From: Orlando Area
Tech Contributor
Safety Car
Joined: Jan 2004
Posts: 4,974
Likes: 14
From: Pinellas Park Fl
St. Jude Donor '08-'09 & '12, '14
Because my experience, and, talking with the folks at ATI and Cloyes at the PRI Show
cheap underdrive pulley = broken chain
Some disagree, but, compile all the threads with broken chains and add up the ones with UD pullies Vs those that didn't, and they all broke the same way, usually when downshifting after high RPM
Just sayin'
Sorry for your luck
When redoing, check the Cloyes set up. They use the same C5R chain but a diffrent set of gears and it takes out the slop you get when using the OEM gear set. It's as tight as a Gen 3 set up. Greatly reduces chain whip.
But don't take my word for it, call them 479-646-1662 Ext 228 7:30 - 2:30 CST M-F
Thread Starter
Track Junky
Joined: Jun 2007
Posts: 4,074
Likes: 36
From: Orlando Area
Tech Contributor
Glen, thanks for the info. I will definitely give them a call. The guys in AutoX/RR section are saying the same thing. Good lesson learned I guess and I suppose I got lucky it happened with 100yards of grass in front of me and not a tire wall or something much harder.
I should have the heads off this week and engine cover off next week to determine the scope of damage and possible the cause.
I appreciate the contact info.
I should have the heads off this week and engine cover off next week to determine the scope of damage and possible the cause.
I appreciate the contact info.
Safety Car
Joined: Jan 2004
Posts: 4,974
Likes: 14
From: Pinellas Park Fl
St. Jude Donor '08-'09 & '12, '14
The Cloyes setup has a different pitch to the teeth. It will cause a little noise, similar to the Gen3
GMs pitch on the teeth is to reduce noise, but it makes for a sloppy chain, hence the tensioner. The Cloyes kit removes the tensioner and includes a new chain guide, like the early LS2, the dog bone looking guide that goes between the chain.
Thread Starter
Track Junky
Joined: Jun 2007
Posts: 4,074
Likes: 36
From: Orlando Area
Tech Contributor
Not from what I've seen.
The Cloyes setup has a different pitch to the teeth. It will cause a little noise, similar to the Gen3
GMs pitch on the teeth is to reduce noise, but it makes for a sloppy chain, hence the tensioner. The Cloyes kit removes the tensioner and includes a new chain guide, like the early LS2, the dog bone looking guide that goes between the chain.
The Cloyes setup has a different pitch to the teeth. It will cause a little noise, similar to the Gen3
GMs pitch on the teeth is to reduce noise, but it makes for a sloppy chain, hence the tensioner. The Cloyes kit removes the tensioner and includes a new chain guide, like the early LS2, the dog bone looking guide that goes between the chain.
I'll try to get into the motor soon so I can get to the bottom of this. I'm working 13 hour days 6 days a week so finding spare time is tough.