Exhaust Gasket Surface Clean Enough ?

[Horse Newbie 6,855]

Can someone who has worked on the Onan P220G engine before give me an idea of whether these exhaust gasket surfaces look clean enough to reassemble ? ( see pics)

And also would you use gasket sealer on them or just the gaskets ?

[ZXT 2,394]

Look good enough to me! I generally don't put any type of sealant on exhaust gaskets unless the surface is rough. 

[lynnmor 6,762]

I don't think I ever seen one that clean.  Be super careful tightening the bolts, they strip easily. 

[Horse Newbie 6,855]

28 minutes ago, lynnmor said:

I don't think I ever seen one that clean.  Be super careful tightening the bolts, they strip easily. 

It may have been you @lynnmor, but someone on here told me to rely on the lock washers to hold the bolts tight instead of using Loctite. I will see if there is a torque spec. in my engine manual...if I end up replacing the lock washers, would regular SAE washers do, or do I need to use the blue/ black finish washers that may be more suitable for high temps ?

[lynnmor 6,762]

Either washer should be fine but I would buy the blue/black if replacing them.  Yes, there are torque specs on the bolts and don't give it a little extra as many do.  I have repaired the threads by using Helicoils.  Another thing I do is bottom tap all the exhaust and intake holes and use longer bolts if possible.

[Horse Newbie 6,855]

50 minutes ago, lynnmor said:

Either washer should be fine but I would buy the blue/black if replacing them.  Yes, there are torque specs on the bolts and don't give it a little extra as many do.  I have repaired the threads by using Helicoils.  Another thing I do is bottom tap all the exhaust and intake holes and use longer bolts if possible.

So the holes don't go all the way through ?... I thought they did, thus I put a small piece of rag in them to keep sanding grit out...lol. I don't know if I have a bottom tap or not.

[wallfish 15,912]

9 hours ago, Horse Newbie said:

I don't know if I have a bottom tap or not.

Being a "backyard hammer mechanic" and always in a hurry, I've just snapped them off in the middle to make one. That material is hard but also very brittle. Clamp a tap lightly in a vice and sharply hit the tip horizontal to the piece with a hammer to snap it off. Some will snap off clean and even but some light grinding will flatten out the ones that don't. Very important not to overheat it while grinding, so go slow! Snap it off where the taper ends from the old tip so the new tip for the bottom is at the tap's widest point. Wa La, a hacker's bottom tap. 

 

Disclaimer-- My toolbox has a plethora of taps so converting them when needed just saves a trip to the store to buy something rarely used. But it does add a bottom tap to the arsenal too.