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View Full Version : Exhaust manifold removal and reinstallation


Jeff d
05-03-2011, 10:43 AM
My risers have been leaking so I'm planning on replacing the manifold to riser gaskets on my LTR.

I was thinking about cleaning up and repainting my exhaust manifolds while I'm at it since they have some surface rust. Are those gaskets reusable or should I replace them? Obviously the riser gaskets are specialized since those don't exist on a car but can the manifold to engine gaskets be purchased at a regular auto parts store? Or is there something special about marine exhaust manifold gaskets?

How much trouble is it to remove and reinstall the manifolds assuming that the risers are already pulled off anyway?

Thanks,
Jeff

frosty
05-03-2011, 01:31 PM
The Vince @ skidim.com would be able to answer your questions about the manifold gaskets, but you might as well order them from him, they have the riser gaskets in stock, one stop shopping.

I personally would replace any gasket that I took apart, beats re-doing the job if it starts leaking.

There are some threads here about checking the riser to exhaust hose (dunno what it's called, they are the big black ones).
It may be time to replace them, they can collapse internally, and you can't tell from the outside. Looks to be a PITA.
Again, skidim.com can help you out there, also.

Jeff d
05-03-2011, 02:35 PM
I'm having to place an order with my MasterCraft dealer anyway for some other parts so I will probably just add them to that.

Does anyone have torque specs on the riser bolts and the exhaust manifold bolts?

wtrskr
05-03-2011, 02:37 PM
I know that the head gaskets for sure are marine only. I'm not sure, but I beleive the exhaust manifold gaskets are too.

I second skidim.com. I had shopped around online for gaskets and skidim.com prices were as good or better than I could find at the other places.

It is a pretty easy job to remove and install imo. You'll probably want a second hand. On installation the bolts should be torqued to specs and I'd use antiseize on them for future removal.

Jeff d
05-03-2011, 02:44 PM
I've ordered from SkiDim before and they were good (Water pump, impellers, SS cup holders, etc) but for some reason the riser gaskets from my MasterCraft dealer are 1/2 of the price and I've got to place an order with them anyway for an alternator bracket.

Is it normal for the manifolds to be rusty right where they attach to the block? Or has this been caused by my leaky riser gaskets?

Thanks,
Jeff

rjracin240
05-03-2011, 02:45 PM
I'm having to place an order with my MasterCraft dealer anyway for some other parts so I will probably just add them to that.

Does anyone have torque specs on the riser bolts and the exhaust manifold bolts?

Use this link to get your torque values

http://www.engineershandbook.com/Tables/torque.htm

and this link to identify what grade of bolt you have

http://www.nutsandbolts.com/v1-bolt-grade-markings.html

also will have to measure diameter of bolt and identify how many threads per inch you have when using torque chart. Also it would be helpful if you run a tap down inside of the threads of the manifold to clean them up. When you feel tap bottoming out STOP turning if you break your tap you possibly opened up a whole can of worms!! Cleaning up the threads is definitely a good thing though, just be careful and you will be fine.
As previously suggested use a antiseize when reinstalling hardware.

91.Maristar.240
06-24-2011, 10:06 PM
i'm putting new ones on mine. just in case found them for $148 each. been reading that they are supposed to only be good for 5 years or so due to the fact that they are cast iron and cast thin where exhaust meets water jackets and you can get water in the cylinder and hydro lock your motor maybe bend a rod...been advised by 3 or 4 marine mechanics that if you're worried about them then just replace them!