Mercruiser exhaust manifold bolts

jonny rotten

Petty Officer 1st Class
Joined
Jan 8, 2012
Messages
366
98 5.0 Will 5 inch bolts work on the exhaust manifold? OEM is 4 3/4. Will the extra 1/4 inch bottom out before tightening up. Thinking not and it will work. 4 1/2 doesn't leave much meat comparing to wear marks on old bolts
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
42,699
Think it might be to long
To check screw the bolt all in without manifold and measure distance. Do this on every hole to see if it will tighten up before bottoming out
 

crazy charlie

Vice Admiral
Joined
May 22, 2003
Messages
5,588
If you are stuck on using the questionable bolts you may want to consider using extra washers to make up part of the space.Charlie
 

ESGWheel

Chief Petty Officer
Joined
Aug 29, 2015
Messages
646
One thing to consider is to run a thread chaser (not tap) down each hole. Use WD40 when using it followed by a cleaner like Brake Clean (or compressed air) to clean out any debris. This is the best way to ensure you are getting the proper torque on the bolts especially if the new ones are longer then the old ones
 
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