Author Topic: Head sealing problem  (Read 4572 times)

nuke em

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Head sealing problem
« on: March 16, 2006, 07:55:02 PM »
I am starting to get pissed. I don't know if everyone knows yet but I am building up a 350 Odyssey engine to a 420CC. Its a Leckich water cooled jug and head with an 88.5 MM ceramic coated Wiesco(YZ490) piston. I have a nice dust covered 102C and heel clickers, rebuilt driven with white spring, to put in her. I also just rebuilt the starter, pull start, ported and polished the jug, and have a big exhaust pipe for it. I put new seals in the bottom end too. I have several different reed cages(Vforce,Boysene rad w/ straight inlet,G-3,cr-4,6,8 petals) and carbs(34,36.5,38,39,40mm) to play with until I get the right combo.

 Here is my problem, during  the first leakdown test it had a bad leak into the coolant system. I could hear it. I Yamabonded the head gasket and it still leaked. I went out and got new O-rings(the old ones were Yama-nastied). Still leaks bad. OK, I did the glass/600 grit oiled sand paper redneck lap job. Looks great. Slapped it back together, pumped it back up to 7lbs, seems fine. Came back in 10 mins and its down to 3 lbs. I retorque the head down a little tighter, re pumped it back up and now I can hear the seep again in the coolant areas.  :evil:  I am not sure where to get more head gaskets. My head gasket "looks" OK. The CR480 dirt bikes used around a 88mm bore gasket with a 7 stud setup. Maybe the jug and head are slightly warped still? I can go back and remove more material(I didn't remove much before, just cleaned it up) but my squish band is already pretty close.  Any suggestions? Punt? LOL

Gary

Moskito

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Head sealing problem
« Reply #1 on: March 16, 2006, 10:18:17 PM »
O-ring on the outside, but what's in the inside around the cylinder's hole?

Most o-ring setups have two o-rings.  A buna (black rubber one like you have) around the outer sealing edge and a Viton (redish brown colored - can take the heat and nasty stuff gasoline has in it/makes when blown up) around the inner edge.

Do you have enough room around the combustion chamber to cut another o-ring groove?  If you do, place it so that it's right there on the edge of the sleeve where it's pressed into the jug.  That should solve the issue.
Moskito - Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming \'WOW-What a Ride!\'

nuke em

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Head sealing problem
« Reply #2 on: March 17, 2006, 05:03:21 AM »
Thanks Moskito. I does have an inner ring already. You can't see it because the head gasket was stuck to the head in that early picture. It did not however have a o-ring in it. There was just white RTV smeared everywhere. I put a regular O-ring in it. Where is a good place to find a viton ring? I'll check a few places here in town.

Gary

Moskito

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Head sealing problem
« Reply #3 on: March 17, 2006, 07:30:40 AM »
Quote from: "Nuke Em"
Where is a good place to find a viton ring? I'll check a few places here in town.

Gary


Two ways to find the o-ring would be:
Local bearing supply house - they should be able to get seals, bearings and o-rings.

The other is a bit more of a long shot - look into a sled engine, such as Arctic Cat.  Find a cylinder that has a similar diameter piston and then order an o-ring set for that.   May take more homework than just going to some place that would carry what you need.
Moskito - Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming \'WOW-What a Ride!\'

LiveWire

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Viton O-rings
« Reply #4 on: March 18, 2006, 02:01:38 PM »
The viton O-rings I use with my water cooled heads are black. They are 3 1/2" x 3 3/4" x 1/8". I use a buna for the top one that is away from the actual combustion chamber and a viton one for the lower one that seals the shell to the combustion chamber. The lower one is much closer to the direct heat of the engine and has more material between it and the water. I could have probably used buna, but better safe than sorry.

nuke em

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Head sealing problem
« Reply #5 on: March 25, 2006, 05:58:32 AM »
Yesterday before I left for work, I removed the o-rings(both) and bolted the head on with ONLY the head gasket(like we discussed on the chat the other night). It leaked just like it did before. At least I have all weekend with nothing else to do, unless the ol war wagon made plans for me. LOL

I'll post back later with pictures and progress. I plan on trying a new 350 3 layer gasket to see if see will seal then. If it does, I will trim it to size. Wish me luck.
Gary

ludedude

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Head sealing problem
« Reply #6 on: March 25, 2006, 06:30:40 AM »
good luck ;)  :P

nuke em

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Head sealing problem
« Reply #7 on: March 25, 2006, 07:33:42 PM »
No dice!   :evil:  I went as many as 5 layers of gaskets. I got pissed and started reassymbling  the ATC. I will start fresh tomorrow.

ludedude

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« Reply #8 on: March 26, 2006, 04:18:51 AM »
You said you lapped it....did you lap both, the cylinder and the head?...just asking  :oops:

On another note...I see you have spider tracs on the rear....how do you like those? We had a 13" wide set on Ted's pilot....too much traction...it steered like a dozer with bad braking clutches! LOL

nuke em

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Head sealing problem
« Reply #9 on: March 26, 2006, 08:08:36 AM »
Ya, I did a very light lap job on both surfaces. I didn't want to remove much material because the squish band is very close now. Seems I don't have much of a choice now. I can add more gaskets to raise the squish, I guess?????, just doesn't sound like a good practice. The leaking hiss sound is the same everytime so the gaskets didn't make any difference and in any order. I ran a small pump to keep about 3lbs pressure in it with the piston up and head off. I took a rubber tube and listened for leaks inside the coolant areas of the jug. The only leaking was around the piston rings. Made me feel better, I was begining to think there may be a crack from the tranfers into the coolant area. I am going to lap it again and we'll see. I'll get some fresh pictures too. I am going to get on it today when it starts to warm up(28 deg now). Feel free I you have any ideas to what I may be forgeting.

I really like the 22X12.5X10 Spider Tracks for the type of terrain we have here in Wyoming. They are a little wide for my rims but I have discovered that it actually protects the lip of the rims and keeps it on the bead nicely. During hard cornering, the sqare knobs alond the side wall really bite in. They also have great wear, still in great shape after 2 hard years. 6 ply makes them almost bullet proof. As far as the bad, they are a fairly heavy tire. I also run a very agressive 22X8X10 up front with that tire.

 The 3/4 mile track at my house has alot of "S" areas and hair pin corners. If you go in wrong, it will not turn worth a crap( like a dozer, LOL), but when you figure out when to hit the throttle and when to hold it steady, no one can catch me through the corners. My friends bring their quads out and get spanked. We normally run 2 laps for time.

ludedude

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Head sealing problem
« Reply #10 on: March 26, 2006, 09:40:36 AM »
You using soapy water in a spray bottle to isolate where it's leaking?

If you don't have that nailed down...figure out where first.

nuke em

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Head sealing problem
« Reply #11 on: March 26, 2006, 11:12:29 AM »
Thats the whole problem. It is leaking past the head gasket and into the the coolant passages (between the jug and head). I removed the head, then used a palm sander with a rougher grit to rough up the surface. Next, I used a fine grit on the lapping glass to give the surface a shiney appearance where the head is contacting. It looks like the inner mating surface is not making good contact(still rough), thus not keep the pressure in the combustion chamber(leaking past the gasket). I will do alot of lapping today to see if I can get her trued up.

ludedude

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« Reply #12 on: March 26, 2006, 11:30:04 AM »
color the surface with a black marker before you start (or at any point while lapping). Lap a bit and look for any spots of marker left (low spots).

Do not push hard when lapping..let the paper and/or compound do the work. Keep moving the parts in figure eights, keep the paper wet (WD-40 or similair)

You probably know all that....but in case not, or someone else is reading ;)

nuke em

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Head sealing problem
« Reply #13 on: March 26, 2006, 06:19:42 PM »
I lapped until I couldn't do it anymore, then did a little more. Covered the surface with red perm marker,quick lap, I have a perfectly flat head and jug top. Put it back together, the exact same HISSSSSSSSSSSS. S.O.B. !! *%#$@%&$!##@ !!!!!!!! Went in, had a beer and thought about it. The tone of the hiss into the coolant area has not ever changed. It has to be somewhere else. I desided to fill the coolant area of the jug. Went out, pulled the jug yet AGAIN. Pulled the head for the 40th damn time, set the jug on the bench, added water to the jug, nothing. SOB, maybe I need to figure a way to pressurize it. Gathered up several items, came back and low and behold there was a single water drop hanging inside the exhaust port wall. I shined a bright light on it. There the bastard was, a tiny tiny pin hole from my porting, I guess. You don't know how happy I am to find a hole, I was dancing a jig! I have been fighting this for several weeks and added a few more grey ones too.

OK, now I need to weld it up. I have never welded aluminium but I do have a MIG and have a small spool of alum wire. I DO NOT want to F it up. I probably should have someone fill it and I can go back and blend it back in. Any thoughts or suggestions? Kicking back with another beer knowing I will be riding this beeeotch very soon now. :D

Gary

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Head sealing problem
« Reply #14 on: March 26, 2006, 06:26:05 PM »
Quote from: "Nuke Em"
I guess. You don't know how happy I am to find a hole, I was dancing a jig! I have been fighting this for several weeks and added a few more grey ones too.

OK, now I need to weld it up. I have never welded aluminium but I do have a MIG and have a small spool of alum wire. I DO NOT want to F it up. I probably should have someone fill it and I can go back and blend it back in. Any thoughts or suggestions? Kicking back with another beer knowing I will be riding this beeeotch very soon now. :D

Gary
CONGRATS!!! Sometimes the itty bitty things are the worst and will drive you INSANE...

Have someone weld it up for you - don't use the MIG...

Make sure they fill it in fairly well then go back and blend - but be careful about how deep this time!  :shock:
Moskito - Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming \'WOW-What a Ride!\'