Can't find manual - need some torque specs for 3.0

[Fishermark]

I am rebuilding my Dad's Mercruiser 3.0. I just got the block back from the shop and am ready to put things back together. I have a manual around somewhere, but cannot find it right now. Does anyone have the torque specs for the rods, mains, head bolts? <br />(It is a 1988 3.0 I believe. It may be as early as 86, and as late as 90, but I can't imaigine it makes a difference for the torgue specs.)

 

[affa]

Re: Can't find manual - need some torque specs for 3.0

Hi Fishermark<br />Headbnolt goes in the stages 45 - 90 - 136, and use a spiral patteren, start in the midle.<br />Regards<br />Affa

 

[Trent]

Re: Can't find manual - need some torque specs for 3.0

Book shows the following:<br /><br />Head 93 ft lbs (retorque in 20 Hrs)<br />Rods 11/32-24 33 ft lbs<br />Rods 3/8-24 40 ft lbs<br />Mains 65 ft lbs<br />Manifold to Head 23 ft lbs (retorque after first start up)

 

[Fishermark]

Re: Can't find manual - need some torque specs for 3.0

Thanks!

 

[Bhamil]

Re: Can't find manual - need some torque specs for 3.0

Follow Trents chart for max torque but don't take it to max immediately. Number the head bolts<br />1 to 10 (there are ten, right?) and go 3-8-6-1-5-10-2-9-4-7 in three steps; stem one, bring them to a snug torque, say 30FP, step two 45FP and step three max fp. As Trent says, after a time retorque the head bolts. Trent, if my order is wrong, please correct me. I'm assuming numbering the bolts 1 through 5 down the starboard side of the head and 6 through 10 down the port. If I'm wrong, please let this gentleman know. I wouldn't want him to wring off a head bolt because of my bad advice. Thanks.

 

[Fishermark]

Re: Can't find manual - need some torque specs for 3.0

Thanks Ben,<br />I understand the concept of torquing the bolts down in steps or stages. I'm curious at your order of tightening. In keeping with your numbering system, I guess I would do it like this:<br />3-8-9-4-2-7-10-5-1-6<br />More like the spiral that Affa mentions. (With the 93 ft lbs that Trent lists instead). Is the pattern you list what Mercruiser suggests? (Although I'm not sure it really makes that much difference to be honest, as long as they are torqued in stages to a equal amount).

 

[Bhamil]

Re: Can't find manual - need some torque specs for 3.0

You're right, the exact order isn't important except that you cross hatch. It will matter in that the gasket mustn't have pockets and even a hardened device like the head will warp to some degree. So, you start in the middle, go to the outer corners and end in the middle again. Following the bolt pattern:<br /><br /> Front of < 1 2 3 4 5 Fly<br /><br /> Engine < 6 7 8 9 10 Wheel<br /><br />3 would go first, then 8, 1, 6, 5, 10, 2, 7, 4, 9,...something like that. I live in Virginia Beach, Va., and am in New Orleans on business, so I don't have my book with me, so I'm not exactly sure of the pattern but it's something like that. Just cross hatch, it will cause a more snug installation of the head. Then, retourque. Now remember, I think there's 10, could be 12, I don't remember. And yes, engine manuals recommend a cross pattern. Trent, jump in here, if I'm wrong.

 

[Fishermark]

Re: Can't find manual - need some torque specs for 3.0

This the the first inline 4 that I have rebuilt, but I have done many small block chevies. The books I have in front of me for the heads on a small block say to start in the middle and go on around from there. Again, I'm not neccessarily disagreeing with you, it may be that these inline fours are different, but I can't really see how.

 

[Bhamil]

Re: Can't find manual - need some torque specs for 3.0

I agree with you, and follow what your book recommends. You're the guy who, in another post, found that your father thought he had a 3.0L and ended up with a 2.5L, is that right? If that's true that's a first for me. I believe they're the same block, bored a little smaller for the 2.5L, obviously, and somewhat smaller valves but, overall, they're the same. All the stuff that bolts up, will, so I don't know how you would know. Until now, that is! Well, you sound like you've got a handle on it. Keep us posted.

 

[Trent]

Re: Can't find manual - need some torque specs for 3.0

3.0 Torque Sequence:<br /><br /> <br /> 10 6 2 3 7<br /> <br /><br /> 9 5 1 4 8

 

[affa]

Re: Can't find manual - need some torque specs for 3.0

Hi<br />Yes that what the manual says, sorry but the torque specs in NM, not lbs.<br />Affa

 

[Fishermark]

Re: Can't find manual - need some torque specs for 3.0

Hi Affa,<br />Yes I figured your units of measurement were different... I knew I didn't want to put around 150 foot pounds of torque on the bolts!