Alfa Romeo Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
235 Posts
Discussion Starter #1
Greetings!
I'm in the process of getting my Verde's engine back together (see my thread Verde going under the knife). This engine has a 'red' crank, and according to the book, the crank measures out fine for diameter & taper. I ordered a set of standard main & rod bearings from IAP. Now that I've torqued the main caps down, just how tight is the crank supposed to be? It's impossible to turn by hand with the crank pulley. Obviously I need to get some Plastigage and check clearances. And what should they be? And which Plastigage size range should I use?:001_unsure:
Thanks in advance!
 

·
Premium Member
Joined
·
26,992 Posts
Alfa engine bearing clearances

Use Green PG-1 plasticgage

Main bearings 0.0019" or less
Rod bearings 0.0024" of less

Reference source Spider 2.0L engine ovehaul manual Oct 90 PA 8777

I have used these specs on my 164 V6 engines.

Do these checks with engine, bearings, crank and rods dry and do not rotate crank.
 

·
Registered
Joined
·
235 Posts
Discussion Starter #3
Thanks Steve!
I figured the bearing clearances would be in that range based on rebuilding other designs in the past. And thanks for the heads up on the Plastigage!
 

·
Registered
Joined
·
235 Posts
Discussion Starter #4
With the assembly lube carefully cleaned off, main bearing clearances are way less than .001" according to the Plastigage reference marks on the package. It's a confirmation of the obvious. I haven't removed the rod bearings from their package. I won't even bother checking. They'll go back to IAP. So, now what? Are there any suppliers still offering bearing sets according to the size ranges these cranks come in? Or do I open the clearances up the old fashioned way by carefully using a hone? :001_unsure:
 

·
Registered
Joined
·
235 Posts
Discussion Starter #5
After poking around the 'net, I've found nothing. Checked with my mechanic this morning. His advice is to turn the crank down and re-nitride to get the clearances right. Apparently specific bearing sets to suit the different machining tolerances no longer exist. Back to the machine shop..............
 

·
Registered
Joined
·
235 Posts
Discussion Starter #6
Yeah.... checking more closely, main bearing clearances are around .00006. Yep..... definitely time to fix this.
 

·
Premium Member
Joined
·
13,983 Posts
I would call DiFatta Brothers in Baltimore. They service Alfa's and they sell the parts that they use in customers cars. They are more aware of aftermarket parts quality than the folks who just sell parts.
 

·
Registered
Joined
·
235 Posts
Discussion Starter #9
Took the heads over to Santo so he could set the valve lash for me. He found a couple of cam lobes have gone bad. Time for a set of S cams!
 

·
Premium Member
Joined
·
982 Posts
I got a set of bearing from Andy at Performatek and they miked up smaller than the Glyco's I usually use. They are the AE brand.

Here is the shell thickness for the different bearings.

Main shells
Used OEM 0.0721
New OEM 0.0724
Glyco 0.0722
Glyco 0.0721
AE 0.0717
 

·
Registered
Joined
·
235 Posts
Discussion Starter #11
The 'standard' set I bought from IAP were Glyco. They're apparently a generic set but who knows what parameters they used? My crank was locked solid with something less than .00006" clearance. Green Plastigage squeezed out to about 1/4" after torquing. Basically, for a 'red' crank, way too small.
 

·
Premium Member
Joined
·
982 Posts
The 'standard' set I bought from IAP were Glyco. They're apparently a generic set but who knows what parameters they used? My crank was locked solid with something less than .00006" clearance. Green Plastigage squeezed out to about 1/4" after torquing. Basically, for a 'red' crank, way too small.
What I am saying is that the AE set is .0004 to .0005 thinner per side than the Glyco set. That will give you an additional .0008 to .001 additional clearance.

I have an unused set in my parts collection if you want to try them. Send me a PM.

Greg
 

·
Premium Member
Joined
·
26,992 Posts
Alfa 12 V6 main bearings:

60568882 Red std
60568883 Green
60568884 Blue

Rod bearings:
60513381 red std
60513382 blue
 

·
Registered
Joined
·
235 Posts
Discussion Starter #14
Thanks, but I have a factory set on the way. They should fit fine, but I will keep your offer in mind if they don't work out.
 

·
Registered
Joined
·
235 Posts
Discussion Starter #15
Success!
Finally had a chance to work on the engine today. New main bearings fit perfectly, as do the rod bearings. New liners are in place. Next up is to assemble the rods and pistons and install them.
Thanks for all the help and offers!
 
1 - 15 of 15 Posts
Top