Chipped Valve, Oil Consumption & Head Change - Alfa Romeo Forum
You are currently unregistered, register for more features.    
 
Thread Tools
(Post Link) post #1 of 8 Old 30-05-09 Thread Starter
Status: -
AO Member
 
Join Date: Jun 2008
Location: United Kingdom
County: Worcestershire
Posts: 275
Chipped Valve, Oil Consumption & Head Change

Some 6 months ago my 156 1.8 TS CF3 gave up the ghost. Firing on only 3 cylinders it had been using vast quatities of oil in the 8 or so months previous that I had had it and would misfire at sporadic (but fairly rare) intervals. I compression tested it and with 0 compression on cyclinder 2 I decided to get a new one and investigate the problem when I had more time.

Today I finally got around to taking the head off and the problem is immediately clear. One of the exhaust valves on cyclinder 2 is chipped in 2 places and doesn't seal. In addition every valve in every cylinder is caked in carbon deposits from the heavy oil burning.

Now I have another head, taken from a 2ltr CF2 GTV which I intend to replace this with, however since this is my first time attempting this I have a few questions I'm hoping you guys can help with.

1) Whats the likely cause of the chipped valve? Could the massive carbon deposits cause it?

2) Given the vast oil consumption and the massive carbon build up in every cylinder what should I be looking for as the cause of the oil getting into all the combustion chambers? Piston rings? I intend to fill the 4 pots with petrol tmrw to check for leakage past the pistons, will the be sufficient to eliminate the bottom end as the source of the problem? I cannot immediately see from the head any source of the problem, theres a lot of oil everywhere but I figure mostly thats from me moving the head around. If I can elimate the bottom end as the problem that would do me as if its head related I should solve the issue with a new head.

3) Skimming. Is it nessacary if there hasn't been a head gasket failure?

4) Cleaing the surfaces before fitting a new head gasket. Whats the best way?

5) CF2 and CF3 seem to have different head gasket sets, the CF3 ones being more expensive. Whats the difference?

6) Anything else I should know before I tackle this? I have a reasonable experience of DIY car mechanics but this is the first time i've delved into the oily bits!

Thanks in advance for any help!
Phear is offline  
Sponsored Links
Advertisement
 
(Post Link) post #2 of 8 Old 01-06-09 Thread Starter
Status: -
AO Member
 
Join Date: Jun 2008
Location: United Kingdom
County: Worcestershire
Posts: 275
Nobody got any pearls of wisdom?
Phear is offline  
Status: Hey Joe...
AO Gold Member
 
iainfm's Avatar
 
Join Date: May 2008
Location: United Kingdom
County: Perth and Kinross
Posts: 6,274

Member car:

Jaaaaag

Ah, go on then. I was going to wait until someone knowledgeable replied, but you'll have to make do with me!

1) Most obvious reason would be foreign body in the bore. Carbon deposits are kinda normal (they'll build up over time), can't see them causing a chip. They're a lot more brittle than steel...

2) If the head's off, change the valve stem seals. There's a special tool to pull them off, or you can (carefully) cut them off by running a chisel down the outside of them. Warning: Mistakes/slips will be costly.

3) No. Only necessary if the head's warped or damaged (eg if that bit of valve got mashed up between the piston and the block.

4) I use an old lollipop stick and meths/petrol/wd40

5) Don't know. Sorry. Maybe cos of the different exhaust manifold???

6) It's a big job. Keep a note of where everything came from. There are a lot of different (and not so different) bolts etc.

Check out Smaky's threads. There's a good 'un on head removal.

Good luck!

Iain
iainfm is offline  
Status: -
AO Member
 
zambugsky's Avatar
 
Join Date: Jul 2007
Location: Congo, Democratic Republi
County: -
Posts: 848

Member car:

None yet

Not sure about the chipped valve but mine was burning loads of oil due to piston ring-bore clearances that were way above normal. The valve bottoms had carbon deposits and the piston tops had a thick layer caked on, all on an engine with 48000 km on the clock.
zambugsky is offline  
(Post Link) post #5 of 8 Old 02-06-09 Thread Starter
Status: -
AO Member
 
Join Date: Jun 2008
Location: United Kingdom
County: Worcestershire
Posts: 275
Thanks for the responses, pretty much what I thought so far

Ok this head gasket business has got me confused. To my knowledge the head and block from a CF2 and CF3 are identical, so why do they require different gaskets. I got these pictures of the 2 gaskets and the oil channels look different (they are also manufactured from different materials). The first one is listed for a CF2 and looks like it matches the head i've got. The second one is listed for a CF3 and looks like has smaller oil channels? It is also £20 more expensive. Now whilst I am happy to fit the more expensive one if nessacary, I'd really like to know why! Especially when the head looks to match the CF2 one better.
Attached Images
File Type: jpg 3339_1.jpg (5.3 KB, 86 views)
File Type: jpg 4495_1.jpg (5.0 KB, 86 views)
Phear is offline  
Status: Hey Joe...
AO Gold Member
 
iainfm's Avatar
 
Join Date: May 2008
Location: United Kingdom
County: Perth and Kinross
Posts: 6,274

Member car:

Jaaaaag

ebspares say to phone them with your VIN when you order their gaskets sets to make sure you get the right one.

I'd imagine that either would work...but one might work better than the other. At a guess, the CF3 a refinement of the CF2 one to make them last longer. That's a wild stab-in-the-dark though!
iainfm is offline  
(Post Link) post #7 of 8 Old 02-06-09 Thread Starter
Status: -
AO Member
 
Join Date: Jun 2008
Location: United Kingdom
County: Worcestershire
Posts: 275
Ok next question. The petrol in the pot test indicates its got worn rings, particularly on cyclinder 1 but also on on the others to varying degrees. For the price of a set of rings I figure its worth changing them. So how do I get the pistons out? I know i'll need to drop the sump, but after that I have no idea! Once i've got them out how do I change the rings, do I need any special tools? Also what size bore is that 1.8 TS so I get the right rings.
Phear is offline  
Status: Hey Joe...
AO Gold Member
 
iainfm's Avatar
 
Join Date: May 2008
Location: United Kingdom
County: Perth and Kinross
Posts: 6,274

Member car:

Jaaaaag

You need to drop the sump (as you suspect), which means dropping the exhaust downpipe. You'll also need a very long ribe bit to get at a couple of the bolts, and you'll have to detach the oil pick-up pipe to drop it the last bit.

Once it's off, take the big-end cap bolts out, keeping a note of which piston they've come off (they're paired to the conrod) and which way round they go. You'll then be able to push the piston and conrod out of the top.

Last time I fitted rings (which was a long time ago) special tools weren't needed. You will need a ring compressor to refit them though. Halfords and the like have them.

Might be worth honing the bores as well...which might mean you need oversized rings. Depends what you find, really...
iainfm is offline  
Reply

Go Back   Alfa Romeo Forum > Supported Alfa Romeo Models > Technical & Vehicle Assistance > Engines (TS, JTS, JTD & V6)

Tags
change , chipped , consumption , head , oil , valve

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
OBD II Codes Smaky Alfa 145 & 146 62 14-08-19 13:36
16 important OIL questions and answers oilman Alfa 147, 156 & GT 339 03-06-18 10:39

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome