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replacing riser/elbow

makomike1

Contributing Member
Hello im about to change riser and elbow on a 1989 fresh water cooled 270hp. Do I have to drain all of the antifreeze out of block or drain it from the exhaust manifold? Also can I use same studs but use new washer/bolts?? Thanks Makomike
 
if you drain the manifold itself, you will get the bulk of the coolant removed. If it is in good shape and not contaminated during removal, you can use it again. There will likely be some residual coolant in the hoses.

The studs and nuts can be re-used if they are in good shape - the copper washers are one-time use parts. that said, given their age, I'd be inclined to replace them all (in the riser/elbow areas). If you have one strip or snap off, having the replacements on hand will allow progress to continue.

Don't forget to pay attention to the gaskets - correct 'passage' count and correct orientation...
 
if you drain the manifold itself, you will get the bulk of the coolant removed. If it is in good shape and not contaminated during removal, you can use it again. There will likely be some residual coolant in the hoses.

The studs and nuts can be re-used if they are in good shape - the copper washers are one-time use parts. that said, given their age, I'd be inclined to replace them all (in the riser/elbow areas). If you have one strip or snap off, having the replacements on hand will allow progress to continue.

Don't forget to pay attention to the gaskets - correct 'passage' count and correct orientation...
Thank you. How tight do I tighten the new studs to exhaust manifold. Also what is the correct torque for the riser nuts. I think I read 25 ft/lbs?
 
Ideally with a stud tool....since they are not cheap and don't see frequent use, most use the "double nut" technique to install them...

25 ft*Lbs is shown in the manual...
 
I usually don't explicitly torque the studs but just apply locktite to the threads and run them in until 'snug'....when you install the rest of the hardware and torque the nuts, it will apply enough tension to keep it all together...
 
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