Topic: New head gasket leaks.... both sides?

[kidrcth]

So i rebuilt this motor a couple years ago. It has just completed its 2nd hour of run time(started about a week ago). The bike has not moved however(still a work in progress). At first i had a valve cover leak which i fixed. I cleaned the engine and ran it for a bit to get rid of any kind of residual oil.

Today i finally put my muffler on and a few other things get it running great and decide to just run some fuel through it and let it run.

After a while i start noticing smoking and its from the sides of the engine. I can almost see bubbling. Looks like the gasket has swollen as well. Not sure why. The motor is coming back out soon enough. Once the bike is all fitted together i will strip it back down for powder-coat. All other signs of health look good for the motor. No noise, no metal, No oil burning, so the rebuild went well, except for this head gasket.

What should i do with the head gasket deal? Are there better gaskets to use? Could my gasket be at fault?

[Dunk]

Did you measure height of the dowels and ensure they were at least a few thousandths shorter than the space available in the recess in cylinders and head? I recall having this issue when I put mine back together, had to file a few down to ensure it would seat fully.

[kidrcth]

Ya know, I did not and this is the first time I am hearing about that potentially being an issue.

I torqued everything at least twice to do with the head gasket. My torque wrenches are calibrated annually. I am surprised at the way in which these gaskets are swelling. It doesn't inspire confidence.

[Jerry Rxman Griffin aka MuthaF'er]

I like the first reply but also how about those 4 6mm bolts in the center line of the head?

[kidrcth]

Which bolts again? The head gasket is not leaking from the center from or rear. It's leaking from the sides. The very side parts. I can almost see the oil bubble out.

[Jerry Rxman Griffin aka MuthaF'er]

There are four 6mm bolts in the center line of the head that bolt to the cylinders. They can be seen from the spark plug openings. 2 of these are located near the 2 ends of the head close to your leak. I doubt this would cause the leak but thought I'd mention it. I'm going along with the dowel theory in light of you torquing down all the cylinder stud bolts. Now this makes me ask, did you use the properly torque value and sequence?   

[kidrcth]

Sequence was followed. I have not kept my notes from the build from 2 years ago. So being able to tell you the torque I applied to each bolt will not be possible. I did however follow he manual.

I think I will just proceed as I intended with figment, upon dissassembly I'll replace the gasket with a higher quality gasket and display my notes.

[scottly]

Was the head or block resurfaced? This is usually what causes the need for shortening the dowels. Are you sure the gasket is actually leaking? Some of the smoke may be from burning off the paint or gasket resin (or whatever it is that composition gaskets are made with).

[HondaMan]

The #1 culprit here is: the combination of too-thin O-rings in gasket kits, and too=thick head gaskets in ALL of today's kits.

The OEM head gasket compressed to less than 1.00mm when torqued down, while all of today's are more than 1.1mm in the same situation. Also, the old ones were impregnated with sealant, none of today's are like that.

The 2 O-rings that supply oil to the head (on the 2 studs at the back of the cylinders, in the middle) were originally 11mm x 2.4mm thick, with a head gasket to settle at 0.85-0.90mm at 200 in-lbs torque. With today's head gaskets, this leaves less than 0.05mm O-ring seal, which won't hold back the 60 PSI oil. To solve this, you can use the 2.62x10.77mm Parker O-rings (a common SAE size, available even at Ace Hardware) in these 2 holes. I do this on EVERY engine I build, now.

Also, the rubber pucks that seal the quarter-sized holes under the Rocker Towers that were sold until about 2 years ago were all too thin. After several contacts with PartsNmore and some other suppliers, the correct thickness versions are in our vendors' inventories today. When installing these (or the O-rings), always lay them in place and measure how far proud of the surface they are: with the O-rings, you must lay the head gasket in place, then the O-rings, then measure how far the O-rings sit above the gasket. The gasket will not compress more than 0.4mm max (at 20 ft-lbs, with HD studs), so these O-rings must stand more than 0.2mm above the untorqued gasket surface, or the oil feeds will leak. This oil moves forward until it reaches the metal rings around teh cylinders, then travels outward as the engine is "tighter" in the center than at the edges.

If you can't find the O-rings where you live, PM me for a couple of them. I have 100 or so on hand.

[scottly]

Mark, the o-rings wouldn't cause leaks at the side of the gasket?

[kidrcth]

When I get back to the motor I will thoroughly document the process.

Read surfaces were not reground. They were flat and clean. Might not be the same this time tho.

[flybox1]

There are four 6mm bolts in the center line of the head that bolt to the cylinders. They can be seen from the spark plug openings. 2 of these are located near the 2 ends of the head close to your leak. I doubt this would cause the leak but thought I'd mention it.

Do these really have an sealing qualities when torqued to 104inlbs max? 

[Jerry Rxman Griffin aka MuthaF'er]

Doubtful

[kidrcth]

Those two bolts also, i remember having the use a super thin Crowsfoot wrench to torque them. PITA.

When i disassemble again in a bit ill know where the issue is. My worries are with source of manufacturers for gaskets. Seeing that oil leaks from the head are so common i like the idea of trying to prevent that. Should i use cyclex again or is there somewhere better i can source from?

[calj737]

If you opt for an MLS gasket, milling and decking is generally recommended. And dowel trimming.

[kidrcth]

Yeah after this has happened i don't think the next  build will be risked without a resurface.

[alacrity]

If you opt for an MLS gasket, milling and decking is generally recommended. And dowel trimming.

I wouldn't hesitate for a second on this.  Pull the head and block, get the two faces milled so they are perfectly flat, removing the minimum amount of metal.
Then call Grumpy Mike over at CycleExchange after the machine shop tells you how many thou they needed to remove to get the surfaces flat and correct.  He'll talk to you about compression, squish, or he may just not take the call.  I love the guy... others ... maybe not so much. He know a ton about these engines though... So even if you don't get him on the phone, pick their basic mls gasket and install that and you'll be golden.  Also what works for me with these it to let the studs/nuts rest for 24-48 hours, then re-torque (breaking one loose at a time and immediately re-torquing it to max spec before moving to the next one, following original pattern as described in your manual).  A little 90 weight on the stud threads is a good idea too for a variety of science-y reasons.  It's a bit pricier than your off the rack crap head gasket but you will not have leaks or worries afterward. Whats your time worth? What is the risk of busting a stud because you had to re-re-re-do the head when it leaks again?

[Duanob]

The #1 culprit here is: the combination of too-thin O-rings in gasket kits, and too=thick head gaskets in ALL of today's kits.

The OEM head gasket compressed to less than 1.00mm when torqued down, while all of today's are more than 1.1mm in the same situation. Also, the old ones were impregnated with sealant, none of today's are like that.

The 2 O-rings that supply oil to the head (on the 2 studs at the back of the cylinders, in the middle) were originally 11mm x 2.4mm thick, with a head gasket to settle at 0.85-0.90mm at 200 in-lbs torque. With today's head gaskets, this leaves less than 0.05mm O-ring seal, which won't hold back the 60 PSI oil. To solve this, you can use the 2.62x10.77mm Parker O-rings (a common SAE size, available even at Ace Hardware) in these 2 holes. I do this on EVERY engine I build, now.

Also, the rubber pucks that seal the quarter-sized holes under the Rocker Towers that were sold until about 2 years ago were all too thin. After several contacts with PartsNmore and some other suppliers, the correct thickness versions are in our vendors' inventories today. When installing these (or the O-rings), always lay them in place and measure how far proud of the surface they are: with the O-rings, you must lay the head gasket in place, then the O-rings, then measure how far the O-rings sit above the gasket. The gasket will not compress more than 0.4mm max (at 20 ft-lbs, with HD studs), so these O-rings must stand more than 0.2mm above the untorqued gasket surface, or the oil feeds will leak. This oil moves forward until it reaches the metal rings around teh cylinders, then travels outward as the engine is "tighter" in the center than at the edges.

If you can't find the O-rings where you live, PM me for a couple of them. I have 100 or so on hand.

Good point if he even put them back in in the first place. I've heard of guys thinking they weren't necessary and left them out or if they didn't come with the HG kit they never put them back in. I had an aftermarket HG that never fit quite right around the oil gallery holes and even with the new o-rings it still started leaking. I went with an OEM Honda HG and oring kit and also used copper spray on both sides of the HG and voila! No leaks.

[HondaMan]

Mark, the o-rings wouldn't cause leaks at the side of the gasket?

Yep. In the last 3 years I have repaired 2 engines myself (one was a K4, the other F1) that leaked at both the sides of the engine and at the back, between the middle 2 cylinders. Both of them had the too-thin O-ring situation, following the owner's [otherwise-correct] rebuild. The oil forces its way along the edges of the metal rings around the cylinders, which is the thickest site(s) in the compressed interface between the head and cylinder deck, until it reaches the middle of the outer edges, then out. Most of the time, I find the center 4 head nuts to be looser than the outer ones when this occurs, which also suggests the head(s) was tightened down to spec in the published order, but not re-torqued 24 hours later: I always find these same nuts to be much looser when I go back the next day, back off all of the nuts 1/4 turn or so, then re-torque: the inner ones go down about 3/4 turn to recover the same torque, while the outer ones go only about as much as I loosened them.

Then they don't leak, if the right O-rings are used.

Just this year alone I have received over 15 "calls for help" with this very issue, and it has been this head-gasket-scenario every time. i have to go get another batch of these O-rings already!

[SKTP]

I am commenting s I can find this again...lots of good info here