Grooved crank Journal on Alfa 164 3.0 24v

[Gussiegtv]

Hi,
I have just dismantled an Alfa 3.0 24ve engine from a 164 with the intention of rebuilding it and fitting it to my Alfetta GTV6. The mileage is unknown and by looking at what was supposed to be oil in the sump (more like black treacle) I don't think the oil had been changed very often! Mostly it looked O.K but has yet to be measured. My greatest concern was finding a deep groove running part of the way around the Crank journal for cylinder number 4 (at the front of the engine) which extends about half way around the journal. The other half looks fine and the bearing looked a bit worn but had no obvious damage. I'm struggling to find images of this journal to see if this deep groove is there to aid the flow of oil or if it is in fact damaged. Please can someone let me know?
Thanks very much.

[Pumaracing]

I imagine you aren't actually holding out a great deal of hope that the factory really felt the need to butcher just one out the six big end journals for purposes of oil flow and moreover contrive to do so in exactly the sort of way that made it look like a honking great lump of swarf had gone through the oil gallery?

[Gussiegtv]

Thanks for your reply and yes I am not holding out much hope! I know sometimes there is a groove cut in the journals on some cranks so I thought I must check for sure having got this far! I did find one photo on the web showing a similar groove on an Alfa v6 crank but it also said it was knackered! Didn't mention why this was the case unfortunately.

[Pumaracing]

I wouldn't want to use such a crank in a race engine but I wouldn't go quite so far as to say it's knackered. The journal has lost some of its load area but the engine appears to have run ok since it was last rebuilt which I surmise was its second rebuild since it left the production line.

[Gussiegtv]

Hi, Thanks very much for your view on this which is much appreciated. I intend to rebuild it to standard specification so it won't be stressed like a race engine. In a GTV6 this should be enough power! The head gaskets are the original ones with 1993 stamped on them but the sump had definitely been removed at some stage. Provided everything measures up O.K I am going to fit new bearing shells and piston rings, idler pulleys etc. Thanks again for your opinion which gives me some comfort!

[Pumaracing]

The "1993" might be a product design year rather than a manufacturing year and therefore not necessarily the original head gaskets. Ford have always incorporated the design year into the part numbers of certain components especially castings.

Are the bearing shells std or an undersize?

[Gussiegtv]

That is a good question and I can see yellow marks on the edge which shows which one of the three options was used. I really need to do some measurements to check to see if they are standard or undersize. Sorry I don't know.

[Pumaracing]

You don't need to measure the crank. The back of the bearing shells will be marked with their undersize if applicable.

[Gussiegtv]

Thanks again and I will check tonight. Sorry about my ignorance!

[Gussiegtv]

Hi,
I've finally checked the bearing shells and I cannot find anything in the workshop manual explaining the markings which doesn't make it easy! The backs of the main bearings are stamped with "CL 154" "-3A" on the other end is "MB 2638 AL". I did see something online with the same codes but no explanation unfortunately! As soon as my mike stand arrives I will be able to measure the journals but it would be great to know if the -3A means undersize for example.
Any help is welcome! Thanks very much.

[Pumaracing]

Those are going to be the original factory bearings at std size which will be graded in miniscule increments of maybe 1/10th of a thou (0.00254 mm) so that the biggest crank journals get the biggest bearings and vice versa to maintain an exact clearance. This doesn't happen in the aftermarket. Crank regrinds are at 10 thou (0.25 mm) increments and you get one size of bearing for each increment and no one frets about tiny manufacturing tolerances like the odd tenth of a thou here or there.

[Gussiegtv]

Hi That's great thank you! I was worried that perhaps the journals had already been reground. Relief! Wily Coyote was right you are an invaluable help! My mike stand arrived today so I can start doing the proper measurements and see how it checks out.

[Pumaracing]

But it's the big ends we're wanting to know about, not the mains.

[Gussiegtv]

Sorry,
Yes of course! I must wake up today!
These have the code "CL 154 and then either "3G" or it could be "8G" it's hard to tell. The other end had the number 11754. Please see photos attached.

[Pumaracing]

Well those look like OE factory bearings as well. It's a bit of a puzzler then if the bearings didn't get damaged when the journal did unless this really is some sort of machining weirdness and not a swarf issue. Let's see what the micrometer says and whether the journals need regrinding anyway but the key thing is it has clearly run ok like that for a long time and hence not an issue to overly fret about.

Main bearings have a groove in them to start with which reduces the bearing area so losing a bit of area on a big end, while not ideal on a race engine, is not the end of the world if another crank is hard to come by.

[Pumaracing]

guzzler4 said:

The above crank is unusable in that condition and it looks doubtful a regrind will get deep enough
You are best sourcing another crankshaft from somewhere

Thank you for that profound insight Guzzler, or Doctor Volt as most of us know you better in here.

http://www.pistonheads.com/gassing/profile.asp?mem...

[Gussiegtv]

Thanks to you both for your views. It is weird that the gouge only extends half way around the journal with no sign of any problems on the other side. The bearing didn't look to bad either. I do have another engine (the seller claimed it had a very low mileage) so it might make sense for me to open it up and take a look when I get time. This engine was incomplete which is why I started with a (just about) running engine with all it's ancillaries.

[CrutyRammers]

Gussie - hi we were speaking by email before.
As far as I know, all of the cranks for the v6 series are the same, with the exception of the 3.2 variants which had a longer throw; so if you do decide you need a new one then you should still be able to source one from a newer engine (from a 166 or something)

Puma is right about the bearings, they come in 3 colours (red, yellow, blue from memory) and are measured and sorted after manufacture to get better tolerances. So a colour spot would indicate that they are OEM ones. The crank should have a matching spot somewhere.

It seems odd to me how something can damage the crank like that and not completely trash the bearing? I'd guess it's already been rebuilt after the initial damage, but that is only a guess.

[227bhp]

Gussiegtv said:

Sorry,
Yes of course! I must wake up today!
These have the code "CL 154 and then either "3G" or it could be "8G" it's hard to tell. The other end had the number 11754. Please see photos attached.

What's going on with the locating tab there? It looks like it's been filed round.
CL 154 is a bearing supplied by Alfa, but not necessarily the original one put in by the factory - it could have been bought from them for a rebuild. I don't think Alfa supply oversized bearings as crank regrinding is classed as 'Proibito' by them.
So I would deduce your journals have not been re-ground, a new set of shells and some Plastigauge will be helpful here.

[Gussiegtv]

Thanks 227BHP,
I see what you mean but it is so small I can't really tell if the tab has been rounded off. I will check when I get home. Thanks for the information about the bearing references too. I didn't get a chance to do any measurements of the journals last night but will soon. Not sure quite what it will achieve unfortunately as the view generally appears to be not to use the crank. It will be interesting to find out anyway.