Alfa Romeo Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
27 Posts
Discussion Starter #1
Hi I have a 2010 brera 2.4 20 valve I am having problems with . I bought this car as a non runner as a present to myself on boxing day because I just love these cars .
I have stripped and rebuilt the engine I am no pro mechanic but I have worked on cars my whole life so I've got a good understanding of engines but i am older so a 2010 cars are so complicated i might have missed something and I hope some of you can help .
When I got the car I found it had a broken air box and engine was spinning over perfectly so I stripped the injectors over spun it over and it sprayed out water so I stripped the rocker cover / cams off and found all 20 rockers broken so I believe car had been started in a deep puddle and sucked water in and hydro locked slamming all 20 valves shut at once
so I removed the head no problems with piston all in perfect.order no con rod damage as all piston rises to correct tdc .bores perfect striped head cleaned and I checked ever valve . new valve guide rubbers . New head gasket and re built engine spins over perfectly so I replaced rockets and timed the engine up with the cam belt with cam lock and crank tool and start to rotate the engine it locks up .so if I take the belt off And rocker cover cams off the engine rotate freely so the issue is valve timing
There are two screw plugs on the rockercams so that you can Insert a locking tool i assume they should both line up and lock together but mine dont engage together the cams spinning freely but can they twist .? Can the cam be 180 out how can I tell ?
 

·
Vendor
Joined
·
45,462 Posts
The cam locking tool fits into the exhaust cam, but when the cam carrier is off the engine you can also insert another locking tool into the inlet cam to ensure the inlet cam is correctly timed to the exhaust cam, did you do this? You can't fit the inlet cam locking tool when the cam carrier is on the engine as there's no room.
 

·
Registered
Joined
·
27 Posts
Discussion Starter #3
Thanks for the reply. I've got the cam carrier off and if I put the exhaust locking tool in and lock the cam the inlet cam does not line up to the hole for the other lock .. could the cam twist ?
 

·
Vendor
Joined
·
45,462 Posts
Thanks for the reply. I've got the cam carrier off and if I put the exhaust locking tool in and lock the cam the inlet cam does not line up to the hole for the other lock .. could the cam twist ?
The cams can rotate in the gears which drive the inlet cam from the exhaust cam them if there is a cambelt incident, I think they are just on a taper lock, not a keyway. Slacken the bolt on the inlet cam, re-position the cam and then re-tighten. Maybe bit of loc-tite as a precaution. Did you check to see if the bottom pulley (cambelt driving sprocket) is still OK? This is on a keyway into the crank, I have seen them fail before and then twist maybe 30 degrees or so before nipping back up again. That bolt is reverse thread too.
 

·
Registered
Joined
·
27 Posts
Discussion Starter #5
Oh I didn't know you could readjust the cams that sound like the problem . I took a good look at the cams after I posted and there seems to be a lot of wear marks where I've been spinning it over on damaged rockers so I ordered a secondhand cam carrier and cams just to be on the safe side ( well and because I thought the cams maybe twisted ) from Italian autos really helpful guy and reasonable prices they should be here for Saturday .. I have not checked the crank pulley yet is the nut super tight ? Reverse thread is that what old people call left handed .does up the opposite to normal ? thank you for your knowledge it's really appreciated after wrestling the alternator out I realised i don't know as much as I thought I did ..
 

·
Vendor
Joined
·
45,462 Posts
Yeah the crank pulley nut is super tight usually. But really you should check it, its not unusual for these 2.4s to shear the keyway on the bottom pulley. If you can't get it undone, then you could check by using the locking tool on the crank pulley to get to TDC and then confirm that it really is TDC by using a dial gauge on the top of the piston on cylinder 1.
 

·
Registered
Joined
·
27 Posts
Discussion Starter #7
Yeah the cam pulley and crank all lined up correctly so the engine appeared to be timed up before I stripped the engine . When the head was off I rotated the engine many times whilst checking every piston came up to the top of the bore to check for any bent conrods which can occur from hydrolock if the engine is running but mine happenedon start up so no bottom end damage and I always reset with Tdc on number 1 and the crank lock lined up perfectly . I've tried to pry the belt pulley with a big flat screwdriver whilst holding the crank nut and nothing moved ... thinking back I did try to bump start the car whilst towing it but unknown to me a time the time all the valves were shut so the compression pressurised the engine and locked it this may be when I knocked the cams out of alignment .
 

·
Vendor
Joined
·
45,462 Posts
That sounds like your crank pulley is fine then.. You haven't broken any of the new rockers then?
 

·
Registered
Joined
·
27 Posts
Discussion Starter #9
No after buying 20 new ones I've been very careful .many years ago I rebuilt a BMW engine and got the timing very wrong and tried starting the engine which then promptly self detonated so I've learn the valuable lesson of slowly rotating the engine by hand and if it don't turnover smoothly I stop and scratch my head like now . I am sure after talking to you that the cams are at fault so on Monday I will put the new ones on and I am hoping I will be posting the good news I will finally be driving the car I've wanted since 2006.
 

·
Registered
Joined
·
27 Posts
Discussion Starter #12
Up date ...all running fantastic ..this car is awesome I am so pleased and I really didn't realise how powerful it would be . And with a new set of prodrive 19's on it I am shocked how many people twist there heads to look as I go past .. this car make me smile every time I look at it or drive it .. does wonders for ya ego the amount of interest other people take in it .. one small issue I am still baffled about which it I assume is a rev limiter .. I have to confess to pushing her a bit but if I touch the redline it cuts the engine .. not sure if it should do that but I can just dip the clutch and restart ... you can't just dip the clutch and bump it but you can if you take it out of gear then put it back in and lift the clutch ... uumm strange one I know but I love this car some much I will just live with it don't really need to take it to the redline plenty of power anyway ... I did consider a remap but not sure if it needs any extra is it really worth remapping I am get 32 to 34 driving normally around local area so is there better mpg if I remap or maybe it's been done coz it feels very quick how could I find out
 
1 - 12 of 12 Posts
Top