Volvo 2003 (or 2002) - anyone here ever rebuilt one (or had one rebuilt)?

[Jud]

Hi all,

Does anyone here have any experience rebuilding (or having one rebuilt) a Volvo Penta 2003 or 2002? (Note: not 2030 and 2020 - different engines.)

I've just discovered that the torque specs in the workshop manual for some of the bolts (big end-con rod and main bearing) are incorrect/confusing. (Some versions of the workshop manual had printing errors, including incorrect piston orientation!)

If anyone here has rebuilt one of these engines, or had it rebuilt by a shop, I'd REALLY like to ask a few simple questions to help me clarify the torque specs. My rebuild is at a standstill until I figure this crap out!

Thanks!
Jud

[DougR]

There were three 2001-2003T manuals published that I am aware of, the first in 1984, second one in 1986 which included the 2003T, and a final one in 1997. The last one was publication number 7730974.

In the first manual the rod bearing and main bearing torque specs which were shown in the text and photos "assembly" section were transposed when they were listed in the torque table. The second manual corrected this, and the torque specs in the assembly section and the torque table match.

The final version of the manual matches the second version, but adds an intermediate torque for the rod bearings. Specs from the final version are:

Rod bearing bolt torque- 1st step- 18 ft.lbs (25 Nm)
2nd step- 51.6 ft.lbs (70 Nm)

Main bearing bolt torque- 1st step- 14.7 ft.lbs. (20 Nm)
2nd step- 44.2 ft.lbs. (60 Nm)

DougR

[Jud]

Thanks for your detailed reply, Doug. I am actually aware of the errors and later corrections in the workshop manuals for the 2000 series engines. (I.e., differences in Assembly and Technical Specs pages). In addition to torque spec errors, there was also a bad error about piston arrow orientation - it was backwards!

These transposition errors, and the piston arrow error led to the issue I'm facing: my experienced mechanic friend helping with my rebuild doesn't yet "trust" the Volvo specs. He's being very, very cautious, for fear of ruining my big end bolts by over-torquing. (And, helpfully,!Volvo no longer sells them!)

His key concern is that 51.6 ft-lbs just seems much too high for a 9mm bolt (the big end bolt); and also why is the bigger 10mm main bearing bolt torque less (44 ft-lbs). Are these numbers still reversed?, he wonders. So I'm looking into it (hoping to get in touch with someone who has rebuilt one of these engine blocks).

A partial answer, suggested by someone here is that the main bearing bolt torques are lower b/c those bolts thread into aluminum; to torque higher (I.e., to the bolt's strength) would deform the aluminum threads. And, as for the big end bolts, the relatively high torque spec for these (51.6 ft-lbs) is the same as for the cylinder head bolts - which I've torqued before, so I know it's right.

So, now I've got to check if the big end bolts are the same diameter (9mm) as the cylinder head bolts - this would pretty much tell me that the listed spec for the big end bearing bolts, while seemingly very high, is in fact correct. I want to thoroughly check this out before torquing them and then discovering that I've stretched and ruined this now unavailable critical part!

Cheers,
Jud

Originally Posted by DougR

There were three 2001-2003T manuals published that I am aware of, the first in 1984, second one in 1986 which included the 2003T, and a final one in 1997. The last one was publication number 7730974.

In the first manual the rod bearing and main bearing torque specs which were shown in the text and photos "assembly" section were transposed when they were listed in the torque table. The second manual corrected this, and the torque specs in the assembly section and the torque table match.

The final version of the manual matches the second version, but adds an intermediate torque for the rod bearings. Specs from the final version are:

Rod bearing bolt torque- 1st step- 18 ft.lbs (25 Nm)
2nd step- 51.6 ft.lbs (70 Nm)

Main bearing bolt torque- 1st step- 14.7 ft.lbs. (20 Nm)
2nd step- 44.2 ft.lbs. (60 Nm)

DougR

[jamhass]

Originally Posted by Jud

A partial answer, suggested by someone here is that the main bearing bolt torques are lower b/c those bolts thread into aluminum; to torque higher (I.e., to the bolt's strength) would deform the aluminum threads. And, as for the big end bolts, the relatively high torque spec for these (51.6 ft-lbs) is the same as for the cylinder head bolts - which I've torqued before, so I know it's right.

Jud:

As a 2003T owner, this paragraph has me puzzled. Note that I have NOT disassembled a 2003T (yet), but I gotta ask ...

Seems to me the main bearing bolts secure into the block, as do the head bolts. Thus, both should screw into cast iron or aluminum (in the case of an al block, which I don't think we have.) Thus, as a minimum, I would be surprised that the difference would be due to different materials as suggested. That, or I am really missing something here.

[Jud]

Jamhass,

Glad you brought this up. It got me thinking, so I just checked. Someone had suggested that "theory" to me, since the aluminum oil pan holds some of the bearings (at front and rear of engine; other ones are inside).

I just looked at the parts diagram, since my workshop manual and the actual engine are not nearby, and indeed, the main bearing bolts do pass through the front and rear areas of the alum oil pan, but they actually thread into the cast iron/steel block (and not into any aluminum).

So that theory is out the window as to the "weird" torque specs (I.e., lower torque for thicker main bearing bolts, and higher torque for thinner big end bearing bolts.) Good to be able to eliminate that as a possibility.

Originally Posted by jamhass

Jud:

As a 2003T owner, this paragraph has me puzzled. Note that I have NOT disassembled a 2003T (yet), but I gotta ask ...

Seems to me the main bearing bolts secure into the block, as do the head bolts. Thus, both should screw into cast iron or aluminum (in the case of an al block, which I don't think we have.) Thus, as a minimum, I would be surprised that the difference would be due to different materials as suggested. That, or I am really missing something here.

[DougR]

Jud,

Are there any markings on the bolts which might indicate the strength class of the bolt, such as 10.9 or 12.9?

A little internet surfing for metric bolt torque values shows that a 10mm bolt of class 10.9 has a normal torque value of between 53 and 55 ft.lbs., and a 10 mm bolt of 12.9 class has a torque value of 62-65 ft.lbs. So........it seems to me that your rod bolt spec of 51 ft.lb. is within the limits of what one might expect.

I also did a bit of looking into the torque values that other VP engines of similar vintage have, and here is what I found:
MD 6&7-- Rod bolt torque= 51 ft lb Main bolt torque= 36 ft.lb.
MD 11&17-- Rod bolt torque= 47 ft.lb. Main bolt torque= 29 ft.lb.

In looking thru a half dozen manuals it is consistent that the rod bolt torques are always equal to or higher than the main bolt torque.

DougR

[jamhass]

Jud

The fact that the bolts are securing the aluminum pan IS important. The slightly lower torque spec is probably there to avoid distorting the aluminum main bearing caps. Thus, this spec is indeed consistent.

Nice to learn stuff ... even of I hope to not need to put it into practice.

[Jud]

Originally Posted by DougR

Jud,

Are there any markings on the bolts which might indicate the strength class of the bolt, such as 10.9 or 12.9?

A little internet surfing for metric bolt torque values shows that a 10mm bolt of class 10.9 has a normal torque value of between 53 and 55 ft.lbs., and a 10 mm bolt of 12.9 class has a torque value of 62-65 ft.lbs. So........it seems to me that your rod bolt spec of 51 ft.lb. is within the limits of what one might expect.

I also did a bit of looking into the torque values that other VP engines of similar vintage have, and here is what I found:
MD 6&7-- Rod bolt torque= 51 ft lb Main bolt torque= 36 ft.lb.
MD 11&17-- Rod bolt torque= 47 ft.lb. Main bolt torque= 29 ft.lb.

In looking thru a half dozen manuals it is consistent that the rod bolt torques are always equal to or higher than the main bolt torque.

DougR

Doug - very useful info. Many thanks indeed. I will pass this, along with everyone's else's insights and data, to my mechanic friend helping with my rebuild. I'm trying to convince him --and myself-- without 100% verifiable specs, that it's OK to go ahead and torque those bolts...while our stomach are in knots, hoping not to hear a "snap!" as the bolt shears...