Re-Torque Head Bolts?

[mrmamiller]

Motor is 1986 Johnson 110HP. I'm in the middle of trying to diagnose a problem which could mean leaky heads. Compression is an even 120# across all cylinders. Is there ever a reason to re-torque the head bolts other than within 10-20 hours after having new gasket installed? And, could I have a leak even if the compression is good?

The problem that I am potentially looking at is water leakage causing steam cleaning of my lower cylinders. I don't want to stir things up by needlessly re-torqueing the heads and possibly stripping threads, like I did once before.

The motor was fully apart ~100 hours ago. I have no idea if the heads were re-torqued or not. I know that there was a lot of on-water testing done at the time, so maybe they did. Now you know why I'm asking the question. Thanks.

 

[hogan12009]

Re: Re-Torque Head Bolts?

If you re torque to the factory specs I don't see how you could strip any threads unless you torque past the ft lb for the head bolts.

 

[F_R]

Re: Re-Torque Head Bolts?

They are supposed to be re-torqued after break-in. Other than that, no longer necessary to do it again, unless it has been overheated. But if that is the case, the gasket should be replaced anyway.

I suspect your steam cleaning symptom is indeed from water ingestion, but probably from some other source. In fact, I wonder if that is why it was taken apart last time. Perhaps they missed seeing the problem? Hey, I've made that mistake myself.

 

[mrmamiller]

Re: Re-Torque Head Bolts?

Reason motor was apart is that it had been torn down to overbore #1 cylinder and replace piston/rings. Had issues with low motor temps after that. After finally getting the temps back up to where they should be, needed to clean out the carbon, due to LOTS of low speed operation and sooty plugs. Did a decarb and after that noticed how white the plugs were, particulary on #3 & 4 plug ground electrodes.

On the stripped bolt hole, I suppose my torque wrench must have been reading wrong (beam type), but if anything I think it was reading high, not low. I have a new wrench but have no way of checking it to confirm that it is accurate.

 

[hogan12009]

Re: Re-Torque Head Bolts?

Some torque wrenches piviot and it's real easy to go past the "piviot" and not know it... Most of em click now i think. One way I know of finding water ingestion is to pull lower unit stick a hose in the water inlet pipe check one piston at a time for water while they are all the way down on the compression stroke. I found that info on here.

I'd pull the heads and check to see if they are steam cleaned. just put new gaskets silicone and re torque when you put it together I think thats the only place water can come from other than the exhaust gasket leaking. Or fire it up let it run for a few min pull plugs and check and see if they start to rust over night.

White plugs are usually an over heat condition i think don't quote me on that.

I am going through the same thing right now leaky head gaskets and over 100 # compression in all cylinders.

 

[emdsapmgr]

Re: Re-Torque Head Bolts?

That engine can ingest water from the exhaust chest. If the exhaust gaskets deteriorate on the bubble back exhaust, water can get forced into the cylinders. Also, if the inner exhaust cover itself starts leaking. Lower cyls are more susceptible than the upper ones. (#3,#4.) Spark plugs can get a washed appearance.