water spitting out of overflow...

[kiesta00]

I just had my engine rebuilt, and had the mechanical seal changed in the water pump. After about an hour of riding in the first time, water started spitting out of the overflow tube. I changed the rad cap, so I know its not that. Could it be possible I blew the head gasket? The squish is set to .055", and the gasket is a wiseco piece.

What are tale-tale signs of a blown head gasket when I take the head off? The exhaust doesn't seem to be blowing white smoke out of it, it barely smokes at all when hot.

[250r4life]

well if it is coming out of your overflow tube, it probably isnt getting into your cylinder.

were you getting on it pretty hard? thats the only time my R ever heated up- when i was just cruising and didnt have it wrapped out...

[C-LEIGH RACING]

Little trick I learned over the years.
When you first start the engine cold, take the radiator cap off & see how much the coolant is churnning around down in the radiator. If the coolant is just kinda lazy flowing, thats good but if its churned all up & fast moving & jumpy, more than likely the head gasket is leaking.

Something else I found as well, dont know if its ever happened on anybody elses engines, but on mine the head gasket can be leaking compression into the cooling jacket, but no coolant be sucked back into the cylinder bore. I have yet to figure that out.
Neil

[86 Quad R]

as neil stated. trouble shoot it while its cold. what i do is with thye rad. cap on, drop the over flow hose in a container of water and start it. if its making bubbles from the overflow tube it will more than likely be pulsing as you throttle it.

btw: is that gasket a metal one or a paper with the metal ring at the center? :confused: i'm not too familiar with weisco's products.


neil:

i'll give ya my assessment the best i can of what could be happening.

usually what is going on as you describe is that the leak is small enough that it will only allow the static compression out and if ya think about it, the power stroke is every time the piston arrives TDC and the pressure is almost always greater than the pressure in the cooling system.

also when the piston has traveled to BDC and the cylinder pressure is at its least, the leak is small enough that it wont allow the pressure of the cooling system to force coolant into the cylinder area... this make any sense ??

[C-LEIGH RACING]

That sounds right, never thought about that.

You know something else, on the Pro-x cylinders most of the time when the inner o ring messes up & starts leaking, it will be at the front to the left most everytime.

Awhile back I was in a forum talking about that & was noted in the post, a R engine because of the angle of the carb & how the cylinder is made inside will kinda ball up the intake charge in the right side of the crankcase & cause the left side to run a little leaner & hotter.
The carb angles the same even on a stock cylinder so I guess it would have the same affects.

Sence then when I port cylinders, I try to direct the flow more to the left side to even it out a little bit, havent done any testing though.
Neil

[kiesta00]

the gasket is the one with gasket material on the outside and a metal ring near the cylinder.

86quad that makes a lot of sense, I was afraid of seizing up my cylinder with that blown head gasket, but I guess it won't hurt anything right now. I'll have to try those tricks and see if it really is a blown head gasket or something else wrong in my cooling system. Thanks for the tips

[86 Quad R]

you arent planning on running the quad in the meantime until you know for certain whats going on, are you?

i forget, what cylinder head are you running? what bore? i do remember you running a +4 tho. what psi is your engines setup and what compressed thickness is that paper head gasket?

the reason i ask such questions is... that im trying to get ya setup with a better gasket/dome cc/cr configuration. ya really need ta get away from that paper gasket. imho

[fireburns99]

Originally posted by 86 Quad R
as neil stated. trouble shoot it while its cold. what i do is with thye rad. cap on, drop the over flow hose in a container of water and start it. if its making bubbles from the overflow tube it will more than likely be pulsing as you throttle it.

btw: is that gasket a metal one or a paper with the metal ring at the center? :confused: i'm not too familiar with weisco's products.


neil:

i'll give ya my assessment the best i can of what could be happening.

usually what is going on as you describe is that the leak is small enough that it will only allow the static compression out and if ya think about it, the power stroke is every time the piston arrives TDC and the pressure is almost always greater than the pressure in the cooling system.

also when the piston has traveled to BDC and the cylinder pressure is at its least, the leak is small enough that it wont allow the pressure of the cooling system to force coolant into the cylinder area... this make any sense ??

4 years of mechanical engineering and fluid mechanics comfirms this. :) I encountered this same problem with my engine. The headgasket would just barely leak but it wouldn't suck coolant in to hydrolock the engine.

[fireburns99]

Originally posted by C-LEIGH RACING
That sounds right, never thought about that.

You know something else, on the Pro-x cylinders most of the time when the inner o ring messes up & starts leaking, it will be at the front to the left most everytime.

Awhile back I was in a forum talking about that & was noted in the post, a R engine because of the angle of the carb & how the cylinder is made inside will kinda ball up the intake charge in the right side of the crankcase & cause the left side to run a little leaner & hotter.
The carb angles the same even on a stock cylinder so I guess it would have the same affects.

Sence then when I port cylinders, I try to direct the flow more to the left side to even it out a little bit, havent done any testing though.
Neil
Thats an interesting assessment. It makes sense. I think you need to take a stock cylinder to a blow bench, or adapt a small windtunnel and compare the stock cylinder to your ported one. :D

[kiesta00]

Originally posted by 86 Quad R
you arent planning on running the quad in the meantime until you know for certain whats going on, are you?

i forget, what cylinder head are you running? what bore? i do remember you running a +4 tho. what psi is your engines setup and what compressed thickness is that paper head gasket?

the reason i ask such questions is... that im trying to get ya setup with a better gasket/dome cc/cr configuration. ya really need ta get away from that paper gasket. imho


No i'm definitely not running it again until I get some other problems fixed anyway. I'm running the stock head, rechambered. 69.5mm bore. It has 195lbs of cranking compression. Not sure on the thickness of the head gasket, the squish is at .055". This is very aggravating, engine ice is expensive to keep refilling lol. Would a cool head help any? Would an o-ring setup be any better? thx for the help guys

[86 Quad R]

yes a cool head would be better. it gives ya the ability to change domes and adjust the compression easily. you can inturn use the thin metal gasket which will eliminate potential leaks better. there are cool heads out there with/without the o-rings and can be gotten fairly cheap second hand.

if you chose to go with a coolhead and are compfy with the compression you now have. i would figure out what cc the stock head your using is with the thick gasket to help determine how the coolhead dome should be set up.

[kiesta00]

if I go to an oring cool head, do I have to have my cylinder machined for the oring setup?

[C-LEIGH RACING]

No, the grooves will be machined into the head.
Neil

[sandspanker]

I have had that problem before. My head was fine the the deck on my cylinder was warped. something to check.:)