Author Topic: Head gasket question  (Read 1158 times)

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Offline jamn

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Head gasket question
« on: January 25, 2018, 09:16:44 AM »
If I pull the heads for a cleanup and .030 gasket change, should I replace the bottom cylinder o-rings as well?

Thanks

Offline les

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Re: Head gasket question
« Reply #1 on: January 25, 2018, 09:21:10 AM »
If I pull the heads for a cleanup and .030 gasket change, should I replace the bottom cylinder o-rings as well?

Thanks

I never have when performing such a cleanup.  I've not had problems with leaking.  Also, if you pull the cylinders off the pistons, then having your rings seal back up without issues is nearly impossible.  This would cause you to have the cylinders de-glazed and new rings.

I would not mess with the o-rings at the bottom of the cylinders.

Offline jamn

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Re: Head gasket question
« Reply #2 on: January 25, 2018, 09:35:21 AM »
If I pull the heads for a cleanup and .030 gasket change, should I replace the bottom cylinder o-rings as well?

Thanks

I never have when performing such a cleanup.  I've not had problems with leaking.  Also, if you pull the cylinders off the pistons, then having your rings seal back up without issues is nearly impossible.  This would cause you to have the cylinders de-glazed and new rings.

I would not mess with the o-rings at the bottom of the cylinders.


Great, thanks for the info

Offline les

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Re: Head gasket question
« Reply #3 on: January 25, 2018, 11:54:20 AM »
You're welcome, and also try not to juggle around those cylinders too much if possible.  I know it's hard to break the seal on the stock head gaskets without jiggling the cylinders, but try to get a friend hold them down firm while you're doing it.  Use some plastic plumbing pieces under head bolts to hold the cylinders down (two diagonal each cylinder) if you'll be turning over the headless engine.

Bottom line:  You don't have to touch the base o-rings, but also don't go poking the bear in the nose.

Offline jamn

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Re: Head gasket question
« Reply #4 on: January 25, 2018, 04:23:36 PM »
Use some plastic plumbing pieces under head bolts to hold the cylinders down (two diagonal each cylinder) if you'll be turning over the headless engine.

Bottom line:  You don't have to touch the base o-rings, but also don't go poking the bear in the nose.

Good idea.

Offline Billy

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Re: Head gasket question
« Reply #5 on: January 26, 2018, 02:14:25 PM »
I always replace base the o-rings, my thought goes back to the EVO with paper base gaskets, they would often leak with low mileage, I would remove the cyls, replace the gaskets and reassemble, never an issue with the rings sealing back up. I carried over my process to the Twin Cam without issue, a plus is you can inspect the rings and replace if necessary.

Les, with your insight, I may change my ways.  :beer:

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Offline jsachs1

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Re: Head gasket question
« Reply #6 on: January 26, 2018, 03:24:05 PM »
I always replace base the o-rings, my thought goes back to the EVO with paper base gaskets, they would often leak with low mileage, I would remove the cyls, replace the gaskets and reassemble, never an issue with the rings sealing back up. I carried over my process to the Twin Cam without issue, a plus is you can inspect the rings and replace if necessary.

Les, with your insight, I may change my ways.  :beer:
I always replace base seals, gaskets, etc. whenever I remove the heads.
Complete nonsense that rings won't reseal when cylinders are removed, and reinstalled.  :dgust:
John

Offline 1workinman

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Re: Head gasket question
« Reply #7 on: January 26, 2018, 03:31:28 PM »
I always replace base the o-rings, my thought goes back to the EVO with paper base gaskets, they would often leak with low mileage, I would remove the cyls, replace the gaskets and reassemble, never an issue with the rings sealing back up. I carried over my process to the Twin Cam without issue, a plus is you can inspect the rings and replace if necessary.

Les, with your insight, I may change my ways.  :beer:
I always replace base seals, gaskets, etc. whenever I remove the heads.
Complete nonsense that rings won't reseal when cylinders are removed, and reinstalled.  :dgust:
John
I remember reading a post a while back that several mentioned they had not problems with the rings seating after pulling to replace the base gasket , Never had any experience in doing that

Offline HHFLSTN

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Re: Head gasket question
« Reply #8 on: January 26, 2018, 05:56:40 PM »
You could always leave the pistons in the cylinders and pull them together. I would replace the o-rings.

Offline harley_cruiser

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Re: Head gasket question
« Reply #9 on: January 26, 2018, 06:06:39 PM »
It depends on how old the o-rings are, I have pulled heads several times left the old o-rings in with no problems.
On a stock build if you pull the cyclinder you are going to find the rings at the max tolerance gap+ so expect new rings.

Offline HD Street Performance

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Re: Head gasket question
« Reply #10 on: January 26, 2018, 06:27:13 PM »
I always replace base the o-rings, my thought goes back to the EVO with paper base gaskets, they would often leak with low mileage, I would remove the cyls, replace the gaskets and reassemble, never an issue with the rings sealing back up. I carried over my process to the Twin Cam without issue, a plus is you can inspect the rings and replace if necessary.

Les, with your insight, I may change my ways.  :beer:
I always replace base seals, gaskets, etc. whenever I remove the heads.
Complete nonsense that rings won't reseal when cylinders are removed, and reinstalled.  :dgust:
John
Just pull them and replace the seals right back on, no honing!

Offline HintonTM

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Re: Head gasket question
« Reply #11 on: January 26, 2018, 07:49:47 PM »
Depends on years and or run time... if you get a upper engine gasket kit you can add those o rings for dollars on the penny. As a tech I would ALLWAYS recommend to do it all, an extra 20 min for me can save you hundreds. Now if you just doing in you garage and you donít have the oil ring compression tool getting the pistons back on the cylinders can be ... challenging ... and make sure you never line up the holes on the oil rings.. over all Iíd do it.. but Iíve done quite a few. But it not REQUIRED
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Offline Clayton24

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Re: Head gasket question
« Reply #12 on: January 26, 2018, 10:03:57 PM »
 I just did heads and thinner mls head gaskets bike has 10,000 miles i only replaced the o-ring around the dowels not the actual base orings no issue but i do think you could pull cyl an pistons an reassemble without honing etc ! Jus try to not turn the rings to a diffrent pos on the pistons .

Offline sfmichael

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Re: Head gasket question
« Reply #13 on: January 26, 2018, 10:47:37 PM »
I've done it both ways - never a problem on TC with o-ring leakage but I'm careful not to disturb the cylinder seal to the case.

Like Billy said, EVO's are another story

I'm kind of a flat rate guy so I'm not interested in pulling the cylinders unless parts are being changed...sounds too much like extra work that the customer may not want to pay for and that I'm not interested in doing for free. It's all in how you sell the job I guess.

I left them alone on my personal bike.

It's a bit of a gamble I'll admit, but a pretty safe one.
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Offline Ohio HD

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Re: Head gasket question
« Reply #14 on: January 27, 2018, 07:48:44 AM »
I always replace base the o-rings, my thought goes back to the EVO with paper base gaskets, they would often leak with low mileage, I would remove the cyls, replace the gaskets and reassemble, never an issue with the rings sealing back up. I carried over my process to the Twin Cam without issue, a plus is you can inspect the rings and replace if necessary.

Les, with your insight, I may change my ways.  :beer:
I always replace base seals, gaskets, etc. whenever I remove the heads.
Complete nonsense that rings won't reseal when cylinders are removed, and reinstalled.  :dgust:
John
Just pull them and replace the seals right back on, no honing!


 Agree, rings move around in the cylinder anyway.
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Offline Clayton24

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Re: Head gasket question
« Reply #15 on: January 27, 2018, 07:52:57 AM »
Thats a learning lesson for me ohio hd i wasnt aware that the rings move ! Thanks

Offline jamn

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Re: Head gasket question
« Reply #16 on: January 27, 2018, 08:01:23 AM »
Wow. Lots of different options here. What to do.  :emoGroan:

Offline Ohio HD

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Re: Head gasket question
« Reply #17 on: January 27, 2018, 08:11:27 AM »
It's like this, if you don't replace the base o-ring, and there is not a leak later, it's all good. If it does leak, you do it again.

It's really only about time. There's a good chance it won't leak, but guys that have said they do it, some are shop owners, and they want a good reputation and a happy customer. I look at it like this, with the heads off, you're 30 minutes or less replacing both o-rings, and the oil return o-rings, so why not?
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Online PoorUB

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Re: Head gasket question
« Reply #18 on: January 27, 2018, 08:42:28 AM »
1/2 hour now, 8 hours later? :banghead:

Low miles, fairly current year I probably would chance it. Ten year old bike, or a bunch of miles I would pull the cylinders. I would probably hone and drop in a set of rings too as long as the cylinders measured good, on a higher mile engine.
I am an adult?? When did that happen, and how do I make it stop?!

Offline kd

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Re: Head gasket question
« Reply #19 on: January 27, 2018, 08:55:50 AM »
Thats a learning lesson for me ohio hd i wasnt aware that the rings move ! Thanks



Here you go. This is what happened to me. Shortly after this discussion it happened to another well known member here. This may have corrected itself over time but finding it while tuning we ended up trouble shooting it and this is what we found. There is the evidence they rotate. I know and have a clear recollection where those rings were initially indexed. The ones that stalled in the lined up position could be related to the shape of the cylinder (that wasn't perfect but was well within spec). The other cylinder was OK but the rings were no longer where they started out.

http://harleytechtalk.com/index.php?topic=97768.msg1164570#msg1164570
KD

Offline Ohio HD

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Re: Head gasket question
« Reply #20 on: January 27, 2018, 08:59:03 AM »
I seriously doubt his bike is ten year old and high mileage. He's changing head gaskets to get more compression. And more HD cylinders get fubarred by a ball hone than if left alone. And if you use a conventional hone, you better have torque plates.
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Offline kd

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Re: Head gasket question
« Reply #21 on: January 27, 2018, 09:25:38 AM »
Ohio, my example was just intended to support the statements made about ring rotation as a real life example and not as a recommendation to ball hone or otherwise. We did the ball hone because we had rings, torque plates and the cylinder dimensions before it was run. It was a light touch to help a new set of rings and nothing more.
KD

Offline Ohio HD

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Re: Head gasket question
« Reply #22 on: January 27, 2018, 10:02:02 AM »
Sorry, it wasn't in response to you're post, look above yours.
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Offline kd

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Re: Head gasket question
« Reply #23 on: January 27, 2018, 10:12:17 AM »
That's fine Ohio.  :up: My response was mostly for the benefit of the OP. It was to show real evidence of ring rotation and I was putting the post together before your contribution popped up. The circumstance of having a blueprint of the barrels, the parts and equipment availability, and the fact the engine was only a few hours old were the deciding factors in my case. I otherwise would have no problem reassembling with the present ring set and have done it in the past with several types of engines. . 
KD

Offline hbkeith

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Re: Head gasket question
« Reply #24 on: January 27, 2018, 10:17:32 AM »
Wow. Lots of different options here. What to do.  :emoGroan:
   Reply #6 does it for a living