How do you do a leak-down test?

[pastorbud]

Post a picture with the new gasket in place.-------I think it will seal just fine.----Too much overthinking here.

Exactly! But next to boating, overthinking is my second favorite hobby. I hope to re-assemble today.

 

[pastorbud]

SUCCESS! Got it re-assembled and torqued down this afternoon after church. I haven’t fired it up yet, but compression test showed 120 on three cylinders and 130 on one. #4 was at 30 psi before, so 120 is a lot better, LOL.

That was a cold compression test. I will warm it up tomorrow, Lord willing, and torque the bolts to 225 inch pounds at operating temperature, and re-run the compression test.

Thanks for all the help, guys. I had my doubts for a while as to whether I could get this old girl running again.

There’s no way I could afford to have a boat, if it weren’t for the guys at iboats.com.

Pics tomorrow, I hope.

 

[jerryjerry05]

Cold/hot??
I never noticed much difference.

 

[pastorbud]

Cold/hot??
I never noticed much difference.

I know, right? But all the time I hear “Ya gotta warm it up!”

 

[pastorbud]

Fired up pretty good today. I didn’t have time to put it on the water. But after it warmed up, Compression was about 130 on all four cylinders. I still need to think that head, I guess. Here are some pictures with close-ups of the gasket, as best I could get

 

[pastorbud]

While it was warm, I also re-torqued the head bolts. Couple of them moved about an eighth of a turn tighter.

 

[pastorbud]

Meant say I still need to PAINT that head.

 

[jerryjerry05]

Re-tuorqe
I loosen the bolts and redo them(one at a time)
Not just tighten them more.

 

[racerone]

Just retorque the bolts once the powerhead cools.----Not sure why one would take the bolt out before re-torque.

 

[pastorbud]

Just retorque the bolts once the powerhead cools.----Not sure why one would take the bolt out before re-torque.

Well, in my case, I forgot to coat the bolt shafts with grease before installing them, So I might go that route. But with my skills I might snap another bolt or strip some threads.

Old boat. If it works, maybe don’t fix it.

 

[jerryjerry05]

Take em out and start again.
Myself, I've never re tuorqed.
Never had a problem.
Once it's tightened down, re tuorqe is just adding more tuorqe.

Use marine grease, no anti-seize.
Anti-seize and salt water makes perma seize.

 

[racerone]

I guess torque on a bolted joint is also not well understood then !!----So what does a torque wrench actually measure ?----What does torque do to a bolt / gasket ?------How does the heat from the aluminum cylinder head affect the torque on a steel bolt ?

 

[jerryjerry05]

What do Torque Wrenches Measure?



Mostly friction!

Torque is simply a measurement of the resistance to force when a nut is turned down the fastener's thread. Most of this resistance is friction. Therefore, torque cannot and should not be used in the context of a fastener's "tightness".

Friction consists of five parameters:

1. Material at the bolt-to-joint interfaces
2. Surface finish at the bolt-to-joint interfaces
3. Lubricants at the bolt-to-joint interfaces
4. Thread condition
5. Lubricants at the thread

90% of the resistance you feel on your torque wrench is caused by friction.* Change the friction by 10% and you get a 100% change in bolt tension with the same setting on your torque wrench!

When a torque value is given, lets say 40 foot pounds on a bolt, an assumption is always made as to how much friction there is between the bolt, nut, and joint surfaces. This is why a torque specification must specify the Conditions of Torque.

 

[racerone]

Part of torque measurement is the bolts going into tension -----Stretching of the bolt !!

 

[pastorbud]

Boat went 30.2 MPH at 4500 RPM with three adults onboard. That’s the fastest I’ve ever seen it go! I could have cranked it up to 5400 RPM, but I didn’t feel like pushing my luck! Brand new, this model tops out at 35 MPH, (I think) so not too shabby. New head and head gasket.

 

[jerryjerry05]

YEA!!!!!!!!!!!!!!!!!!!!
Now go fishing!!

 

[pastorbud]

YEA!!!!!!!!!!!!!!!!!!!!
Now go fishing!!

Took it out after church yesterday. Plenty of power in rough seas with me and three passengers on board, and we caught keeper sea bass and porgy.

 

[jerryjerry05]

Where?
We're going this week and the keeper seabass sounds good?

We haven't had a good seabass catch in a long time.
5 years ago we caught limits for 5 guys and very few throwbacks.
Nowadays everything is a throwback

 

[pastorbud]

Heh. Little north of you! Southeastern CT, off Groton Long Point, in the Fishers Island Sound, at the eastern tip of the Long Island Sound.

 

[pastorbud]

I can’t get link right. Second effort

https://marine.weather.gov/MapClick.php?lon=-72.10784&lat=41.29862#.XXeDpCUpDYV