Vauxhall 1.2 16v engine keeps spitting out cam followers
Discussion
Looking for some advice please. I bought a Corsa C with a 1.2 16v engine with 70,000 miles and FSH.
Shortly after buying it, I discovered that the exhaust followers on cyl 3 and 4 had detatched from their proper position - i.e. the 'cup' was no longer located on the hydraulic lifter. The car was running rough with a lot of top-end noice. I took the cam out, inspected it (it's worn, but not excessively so) and refitted the followers.
All was fine for a few hundred miles, then yesterday one of the followers on cylinder 1 islodged itself and the OBD flagged a fault code P0301 'misfire in cylinder 1'.
Today I took the cam out again - and re-fitted the follower...... but what could be causing it? It's now happened on 3 different cylinders.
The only other 'sympton' is on cold startup, the top end rattles like a bag of bolts for 3 or 4 seconds while the lifters fill with oil - but that's fairly normal, right?
Here's a couple of pictures -
1. with the cam still in situ :
Untitled by Wobble Chernobyl, on Flickr
2. with the cam removed :
Untitled by Wobble Chernobyl, on Flickr
Shortly after buying it, I discovered that the exhaust followers on cyl 3 and 4 had detatched from their proper position - i.e. the 'cup' was no longer located on the hydraulic lifter. The car was running rough with a lot of top-end noice. I took the cam out, inspected it (it's worn, but not excessively so) and refitted the followers.
All was fine for a few hundred miles, then yesterday one of the followers on cylinder 1 islodged itself and the OBD flagged a fault code P0301 'misfire in cylinder 1'.
Today I took the cam out again - and re-fitted the follower...... but what could be causing it? It's now happened on 3 different cylinders.
The only other 'sympton' is on cold startup, the top end rattles like a bag of bolts for 3 or 4 seconds while the lifters fill with oil - but that's fairly normal, right?
Here's a couple of pictures -
1. with the cam still in situ :
Untitled by Wobble Chernobyl, on Flickr2. with the cam removed :
Untitled by Wobble Chernobyl, on Flickr
Mignon said:
It's possible the head was reconditioned previously and for example the exhaust valves are not std, too short, insufficient preload on the lifters. Or it could be lack of oil pressure but normally the spring inside the lifter keeps that pumped up. Valve springs weak or broken and over revving to the point of valve bounce are other causes.
I don't *think* the head has been rebuilt, on the basis that I have a pretty full set of history/invoices etc and there's nothing to suggest that. But of course you never know.... I might try some replacement lifters on the Exhaust side and see if that does the trick, £6 each it's not the end of the world if it doesn't fix it.
HRCM said:
Did you notice any movement in the cam caps before you removed the cam?
The screws clamping the cam caps in position are very lightly torqued and these are often cited as the route-cause of snapped cams and other issues with this engine's top end.
My guess is that the cam cap screws have worked loose allowing the tappet to extend beyond it's normal range and cause the top-end noise you describe in your post. Eventually the tappet guide is working free of the tip of the valve because it's all getting a bit loose in that area.
After locking up the engine with a lock-set I would incrementally back off all the cam cap screws in a spiral pattern and then clean the hole and screw thoroughly with brake cleaner. Use a drinking straw to blow the holes clear of any brake cleaner if you don't have an airline (just don't breathe in).
Then apply a dab of Loctite 243 to each screw and sequentially re-torque them in to manufacturer's spec.
Hope this helps
Hey, thanks for a great bit of advice. Yes, originally the cam caps were a little loose - but after re-fitting the followers and cams, I torqued the followers up quite tight... but the followers still came loose again :-/ The screws clamping the cam caps in position are very lightly torqued and these are often cited as the route-cause of snapped cams and other issues with this engine's top end.
My guess is that the cam cap screws have worked loose allowing the tappet to extend beyond it's normal range and cause the top-end noise you describe in your post. Eventually the tappet guide is working free of the tip of the valve because it's all getting a bit loose in that area.
After locking up the engine with a lock-set I would incrementally back off all the cam cap screws in a spiral pattern and then clean the hole and screw thoroughly with brake cleaner. Use a drinking straw to blow the holes clear of any brake cleaner if you don't have an airline (just don't breathe in).
Then apply a dab of Loctite 243 to each screw and sequentially re-torque them in to manufacturer's spec.
Hope this helps
Mr2Mike said:
Are all the rollers on the followers free to rotate? Some of the cam lobes are quite marked, and you wouldn't normally expect to get any significant wear with roller followers. If a roller is seized it might be possible that the cam lobe is dragging the whole follower off the tappet
Hmm, I *think* the rollers were rotating freely - but you've got me doubting myself. One to check I think :-) thanks
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff