Riser question

WaveRay · 06-25-2009, 03:09 PM

Do riser bolts need to be torqued? If so, to what value?
I'm speaking of the bolts that secure the riser to the manifold if I haven't been clear.

Thanks in advance.

Ray

seapower · 06-25-2009, 09:00 PM

All engine bolt's "should" be torqued. In the case of manifold's, the even torque spread's out the surface bearing area , allowing for a consistant sealing pressure. If you over torque (one side tighter than the other) you have just effectively ruined your sealing surface. Yes gasket's are used, but they are "spec'ed" with the intention of use in an evenly torqued application. I'm sure Jaw's or one of the "gas guy's" can help you out. You may have to PM them, this new forum, for me anyway makes it hard to see if a new topic (or question) comes up. Frank

nautiduck · 06-28-2009, 10:23 PM

Ray what do you have engine wise. Also are the manifolds/risers stock or do you have have something funky like aluminum or stainless, inquiring minds need to know.

WaveRay · 07-01-2009, 09:39 AM

Duck,
I believe the risers and manifolds are stock-like if not stock. The motors are 99 350 chev's. I think they were re-done in 2004. We just recently got the boat. Nuthin fancy here, only, hopefully, serviceable, functional equipment.

Also, to update, we removed the head from the port side of the problem motor. A compression test showed very low compression (30) and slightly low (150) in the middle two cylinders. We're having a valve job done. We think the riser/manifold gasket failed slightly and allowed a little water into the heads corroding the valve to the point of non-seal. Also, the spark plug in that cylinder had rust on it.
It's due to be completed today so we should have it back on soon.

Also also...Does anybody know the torque value and torque pattern for the heads on this motor?

nautiduck · 07-02-2009, 09:57 AM

Torque all the riser bolts in a cross pattern to 15lb then do it again to 25lb then finally to 40lb. Check the torque after running for 30 minutes then again after running 20 hours.

The heads are first torqued to 45 then 85. Start with the middle 2 band work your way out in an X pattern first all the bolts to 45 the do it all again at 85.

06-25-2009, 09:00 PM	#2
seapower I think Admin is going to let me have this space Join Date: Feb 2008 Location: Bath,NC Posts: 1,450 Credits: 4,826.1 Boat: 25' DownEaster Home Port: Bath, NC Best Catch: My wife Occupation: marine diesel service owner	Don't know the spec's, All engine bolt's "should" be torqued. In the case of manifold's, the even torque spread's out the surface bearing area , allowing for a consistant sealing pressure. If you over torque (one side tighter than the other) you have just effectively ruined your sealing surface. Yes gasket's are used, but they are "spec'ed" with the intention of use in an evenly torqued application. I'm sure Jaw's or one of the "gas guy's" can help you out. You may have to PM them, this new forum, for me anyway makes it hard to see if a new topic (or question) comes up. Frank

07-01-2009, 09:39 AM	#4
WaveRay backlash king Join Date: Feb 2009 Location: Jupiter, Fl. Posts: 15 Credits: 347.4 Boat: 28 Bertram Home Port: West Palm Beach, Fl. Best Catch: 7'2" Atlantic Sailfish Occupation: SONET Tester	Duck, I believe the risers and manifolds are stock-like if not stock. The motors are 99 350 chev's. I think they were re-done in 2004. We just recently got the boat. Nuthin fancy here, only, hopefully, serviceable, functional equipment. Also, to update, we removed the head from the port side of the problem motor. A compression test showed very low compression (30) and slightly low (150) in the middle two cylinders. We're having a valve job done. We think the riser/manifold gasket failed slightly and allowed a little water into the heads corroding the valve to the point of non-seal. Also, the spark plug in that cylinder had rust on it. It's due to be completed today so we should have it back on soon. Also also...Does anybody know the torque value and torque pattern for the heads on this motor? Last edited by WaveRay; 07-01-2009 at 03:41 PM.

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06-28-2009, 10:23 PM	#3
nautiduck I think Admin is going to let me have this space Join Date: Apr 2008 Location: Rock Hill SC (Charlotte) Posts: 1,272 Credits: 3,847.5 Best Catch: Duckie	Ray what do you have engine wise. Also are the manifolds/risers stock or do you have have something funky like aluminum or stainless, inquiring minds need to know.

07-02-2009, 09:57 AM	#5
nautiduck I think Admin is going to let me have this space Join Date: Apr 2008 Location: Rock Hill SC (Charlotte) Posts: 1,272 Credits: 3,847.5 Best Catch: Duckie	Torque all the riser bolts in a cross pattern to 15lb then do it again to 25lb then finally to 40lb. Check the torque after running for 30 minutes then again after running 20 hours. The heads are first torqued to 45 then 85. Start with the middle 2 band work your way out in an X pattern first all the bolts to 45 the do it all again at 85.