Need a Process: How to Approach Cam Snout Break
10-08-2010, 01:21 PM
#1
Rennlist Member
Thread Starter
Need a Process: How to Approach Cam Snout Break
Several of you have commented, mainly on early cars, of finding broken cam shafts.
How do you evaluate / diagnose this on a 32V car?
Set at 45 deg BTDC and remove / replace the cam gear bolts one at a time?
It is a possibility I may face this helping a friend tonight check-out an S4, noted in the Kempf/ Gates tension thread. I need to be ready, though I hope we don't need to go here. Regardless, its a machine and we will fix it. Can somebody who has faced this give some support?
(Update: In final analysis, my questions were moot. Issue was simply insufficient tensioning of new timing belt. This thread, started before I got to relook at the car, was intended to explore the possibility that we might have been facing a more dubious issue.)
How do you evaluate / diagnose this on a 32V car?
Set at 45 deg BTDC and remove / replace the cam gear bolts one at a time?
It is a possibility I may face this helping a friend tonight check-out an S4, noted in the Kempf/ Gates tension thread. I need to be ready, though I hope we don't need to go here. Regardless, its a machine and we will fix it. Can somebody who has faced this give some support?
(Update: In final analysis, my questions were moot. Issue was simply insufficient tensioning of new timing belt. This thread, started before I got to relook at the car, was intended to explore the possibility that we might have been facing a more dubious issue.)
Last edited by Landseer; 10-07-2012 at 06:57 PM.
10-08-2010, 02:03 PM
#3
Former Sponsor
I've never seen a 32 valve camshaft break, unless the drive hub breaks first. The problem is almost always the triangular drive hub "working" on the camshaft. This occurs from the bolt not being properly torqued or from the actual hub cracking right at the key.
BTW...I've never seen a 16 valve camshaft break, "out of the blue". This always seems to happen to cams that were recently worked on. The driver's snout is so long that people crack it, right at the base, when they are prying on the cam sprocket to remove the sprocket. Use a puller and this will never happen....
BTW...I've never seen a 16 valve camshaft break, "out of the blue". This always seems to happen to cams that were recently worked on. The driver's snout is so long that people crack it, right at the base, when they are prying on the cam sprocket to remove the sprocket. Use a puller and this will never happen....
10-08-2010, 02:14 PM
#4
Burning Brakes
Several of you have commented, mainly on early cars, of finding broken cam shafts.
How do you evaluate / diagnose this on a 32V car?
Set at 45 deg BTDC and remove / replace the cam gear bolts one at a time?
It is a possibility I may face this helping a friend tonight check-out an S4, noted in the Kempf/ Gates tension thread. I need to be ready, though I hope we don't need to go here. Regardless, its a machine and we will fix it. Can somebody who has faced this give some support?
How do you evaluate / diagnose this on a 32V car?
Set at 45 deg BTDC and remove / replace the cam gear bolts one at a time?
It is a possibility I may face this helping a friend tonight check-out an S4, noted in the Kempf/ Gates tension thread. I need to be ready, though I hope we don't need to go here. Regardless, its a machine and we will fix it. Can somebody who has faced this give some support?
10-08-2010, 02:19 PM
#5
Rennlist Member
Thread Starter
Just want to cover all the bases on this.
The tensioner should not have failed, either, as we were careful with that.
Actually, we were pretty damn careful with the entire job.
No, I should come there.
The tensioner should not have failed, either, as we were careful with that.
Actually, we were pretty damn careful with the entire job.
No, I should come there.
10-08-2010, 02:24 PM
#6
Burning Brakes
If it is cam related. I'm going back in with S3 cams and lifters. I'll put it int he garage until I can get these parts.
What do you want for dinner? Feel free to bring your wife if you want. It may be a long night!
10-08-2010, 02:54 PM
#7
Rennlist Member
Thread Starter
Well, if it is a camshaft, I'd recommend we find the part(s) which historically have been fairly easy to obtain, borrow the cam positioning tool, repair the car, then accumulate the other parts for later upgrade.
You don't need to be out of commission on this any longer than for the TB/WP job we just did.
Great car, very nice smooth engine, strong. I tend to go overboard with scenarios, so don't be afraid, its liable to be something very simple, too.
Even the wire.
You don't need to be out of commission on this any longer than for the TB/WP job we just did.
Great car, very nice smooth engine, strong. I tend to go overboard with scenarios, so don't be afraid, its liable to be something very simple, too.
Even the wire.
Trending Topics
10-08-2010, 06:07 PM
#8
Rest in Peace
Rennlist Member
Rennlist Member
Join Date: May 2006
Location: Bird lover in Sharpsburg
Posts: 9,903
Likes: 0
Received 2 Likes
on
2 Posts
Well, if it is a camshaft, I'd recommend we find the part(s) which historically have been fairly easy to obtain, borrow the cam positioning tool, repair the car, then accumulate the other parts for later upgrade.
You don't need to be out of commission on this any longer than for the TB/WP job we just did.
Great car, very nice smooth engine, strong. I tend to go overboard with scenarios, so don't be afraid, its liable to be something very simple, too.
Even the wire.
You don't need to be out of commission on this any longer than for the TB/WP job we just did.
Great car, very nice smooth engine, strong. I tend to go overboard with scenarios, so don't be afraid, its liable to be something very simple, too.
Even the wire.
10-08-2010, 06:28 PM
#9
Race Director
The cam failure in 16V cars is almost always the longer cam that drives the distributor....typically when the TB is under tensioned the cam wiggles a bit and over time it causes enough stress to cause a crack-failure......
10-08-2010, 06:40 PM
#10
Rennlist Member
Thread Starter
Charles says he had a widely loping idle and TB light come on after jamming on the brakes to stop for a stoplight.
He drove a bit, stopped again to a loping idle and turned the car off.
Restarted it, waited 3 minutes while idling smoothly, then drove towards home. TB light came back on about 7 minutes later. Car ran smoothly home, idled smoothly, he shut it off.
We had spent 4 full days doing a very slow, methodical TB job (all gears / pulleys, regular gates belt, oil pump orings, tensioner rebuild, new lasso, set timing with 32V'r (dialed 9 deg retard out of DS gear, 5 out of passenger). Cleaned everything
Torqued the pulleys to 45 ft-lb multiple times (couple of 32V'r iterations) and were just about at top of window with kempf.
Sorry to repeat but I'm really stymied by this.
He drove a bit, stopped again to a loping idle and turned the car off.
Restarted it, waited 3 minutes while idling smoothly, then drove towards home. TB light came back on about 7 minutes later. Car ran smoothly home, idled smoothly, he shut it off.
We had spent 4 full days doing a very slow, methodical TB job (all gears / pulleys, regular gates belt, oil pump orings, tensioner rebuild, new lasso, set timing with 32V'r (dialed 9 deg retard out of DS gear, 5 out of passenger). Cleaned everything
Torqued the pulleys to 45 ft-lb multiple times (couple of 32V'r iterations) and were just about at top of window with kempf.
Sorry to repeat but I'm really stymied by this.
10-08-2010, 11:31 PM
#12
Rennlist Member
Thread Starter
Rotors not cutting caps at all.
Gears and hubs look fine. Snug, true, no cracks visible.
Belt tension is still top of window.
Little pile of very fine rubber inside DS cover.
Slight forward tracking. About 1/16 from belt to edge of cam pulleys, maybe a little less.
Belt running towards front edge of water pump pulley making contact with its lip, sighting down the DS belt towards WP.
Tensioner adjustment bolt jam nut still in-place.
Tensioner bolt nearly buried in tensioner --- wound almost all the way in.
We must have left something out of the tensioner, that's all I can come up with.
Down she comes.
Gears and hubs look fine. Snug, true, no cracks visible.
Belt tension is still top of window.
Little pile of very fine rubber inside DS cover.
Slight forward tracking. About 1/16 from belt to edge of cam pulleys, maybe a little less.
Belt running towards front edge of water pump pulley making contact with its lip, sighting down the DS belt towards WP.
Tensioner adjustment bolt jam nut still in-place.
Tensioner bolt nearly buried in tensioner --- wound almost all the way in.
We must have left something out of the tensioner, that's all I can come up with.
Down she comes.
10-07-2012, 06:53 PM
#13
Rennlist Member
Thread Starter
Sorry, was prompted by somebody that I didn't finish this thread.
No issues with cam shafts.
I had tensioned the timing belt too loosely on the timing belt / WP / all-rollers project.
Must have misread the the Kempf ( got it in a twist ).
We retensioned the belt, which improved the tracking.
Had started another thread relative to tensioning of new gates belt and forgot about this one.
Seems like years ago. 2 or so.
No issues with cam shafts.
I had tensioned the timing belt too loosely on the timing belt / WP / all-rollers project.
Must have misread the the Kempf ( got it in a twist ).
We retensioned the belt, which improved the tracking.
Had started another thread relative to tensioning of new gates belt and forgot about this one.
Seems like years ago. 2 or so.
