Overheating help

[elbine69]

Ive got a pro-x 310 cylinder running on 112 with a 21cc dome. Have an afco radiator too and I cant keep it from overheating. Waterpump is pumping, there is a little play back and forth if you push on the impeller. Should that shaft be able to move? Anything else I can check or try, I dont know what else to do:(

[Dave83]

Is it pushing water out of the overflow?Possible its the cap?I know you asked this on the other forums,so I know that you have checked all the usual stuff.Mine was getting hot the last few races i ran,but the clutches were slipping some and I think that was causing alot of my problem.

[elbine69]

Yeah pushing it out the overflow. Did it with the stock rad and the new rad, so I dont think its the cap. Clutch def isnt slipping, its basically brand new, actually the whole bottom end is new, only thing I didnt touch was the waterpump. If the mechanical seal was going bad would it make it do it?

[GOTFEAR]

you might need to change your jet. i would go bigger down one clip on needle just to see what happens

[elbine69]

I can try that. Its got a 182 right now, I try jumping up to a 190. Its pretty rich as it is right now though.

[deathman53]

I'd say the main is pretty rich already, how is the pilot and needle, those have more effect on the jetting than most realize. I have a 170 or 175 main in mine(72mm pro-x-293), don't know the needle and the pilot, but both run rich.

[elbine69]

Got a 52 pilot and a CEL needle. I think the clip is on the 2nd groove up the from the bottom. Have to go look I have it written down in the garage.

[elbine69]

bump

[k265r]

is your system holding pressure? if your not creating pressure with your cooling system it will not cool your engine.

[machwon]

A 21cc dome is too small on a 110. Ditto the post above and use a new cap or pressure test the one you have. Most 310's come with a 27cc dome.

[All250R]

Water pushing out the overflow doesn't necessarily mean its overheating. A bad head gasket will do the same thing, and if bad enough pressurize the coolant system almost instantly. If that is your only symptom, I'd check the head gasket.

The impellar shaft should not be loose once torqued in against the mechanical seal. That seal needs pressure against it to keep the fluids separate. You should see other problems in the engine if that area has a problem.

[machwon]

Originally posted by machwon
A 21cc dome is too small on a 110. Ditto the post above and use a new cap or pressure test the one you have. Most 310's come with a 27cc dome.

elbine69, unless you misqouted the 21cc dome thats enough compression to run on diesel fuel (over 20:1 CR) in a 310cc motor. This is very hard on cranks, sounds like you just did the bottom end. This high of compression ratio will cause detonation which is like chaos in your combustion chamber. Detonation has many signs, quickly overheating, superheating pistons so they 4 corner sieze, blowing spark plugs out the head, destroying cranks and many other crazy mishaps.

The imprellar torques against the shaft and the mechanical seal is spring loaded. It is designed to have some movement like you described as the end of the imprellar shaft is slotted. When the mechanical seal goes bad it will leak out the bottom of the weep hole, eventually if the seal/shaft get real bad you will have milky tranny fluid from the coolant getting in the gearcase.

[elbine69]

How do I pressure test the rad cap?

Ill have to check the numbers on the dome when I get home. I know its smaller than the one I had previously, but when I talked to Allen at CT he said this was the one I should be using. I guess the dome is really the only thing left thats different.

[elbine69]

Ok the number on the old dome is 720727.
The number on the new one is 721228.

Who can tell me what these numbers mean?

[Dave83]

I think that you read them like this:
72 = stroke
07=7 degrees
12= 12 degrees
27= 27cc
28= 28cc

[C-LEIGH RACING]

Do you know what your ignition timming is set at.
Do you have an adjustable timming bearing carrier.
Do you have the 250R coolant recovery bottle in place.

When you had the water pump cover off, did you notice if the cover had the thin metal defuser plate in place & two gaskets holding it on.
With the pump impellar tight on the shaft, only in & out play would be when you push in on it & it compresses the spring in the seal. Should not be loose or have free play in & out or side to side.

If the radiator is completely full before you start a race, up to the cap, when the coolant heats up it expands yes it will blow some out.
If, when you check the coolant level, if its down about 1/2" into the radiator thats about the right level & when it heats up & expands it shouldnt push any out the over flow.

Yes, high compression is hard on cranks, realy high compression say like 250 lb or higher if you spin the crap out of it, but 210 to 245 is the norm for our big bore grunt engines.
High compression & high RPM fight each other.
Neil

[elbine69]

I dont know what the timing is set at, I just put it in the middle where I had it with the stock topend.

No recovery bottle just have the overflow running down towards the pipe so if it starts blowing it out Ill know.

Waterpump shaft is fine then only has play when you push in on it. And the thin metal plate is there.

[C-LEIGH RACING]

Ol flywheel hasnt slipped on the crank has it.
Lot of guys cant get the nut tight & then it will move, sheer the key.
Neil

[elbine69]

Dont think so. Crank was brand new, but I will check it out.

[dunatic]

Ive got a 510cc saber. Ive been chasing the same problem as well when I went to a BIG radiator. What I determined was that the BIG radiator flowed TOO much water and doesnt create enough back pressure to keep the water in the radiator long enough to cool.

So my engine guru built me a billet cork so to speak. An aluminum plug that goes into the water hose and restricts the water flow running thru the system. Worked like a charm.

Without the cork, the motor would hit 220 in less than 30 minutes of easy riding. The first run at the dunes afterwards, it wouldnt get above 160...so I drilled it out slightly and now it stays are 180 all day and night. Ive got dual temp guages coming in and out of the engine.... and they are within 5 degrees of each other all the time.

[elbine69]

Thats interesting. Got a picture of that?

[deathman53]

some of the major guys(roll design for one) say to keep the stock radiator, if anything, buy a new stock radiator at less cost than a big aftermarket. My afco, doesn't get over 190 and during the cooler months, I'm lucky to get over 150. The hybrids really need the big radiator, they run HOT. I heard the same thing, but with Oil temperatures. Alot of guys use transmittion coolers on atv's, but they can actually make the oil hotter. They are too free flowing and the oil moves too quickly to effectively cool. Fst sells modified transmittion coolers, they have resisters on the in and out ends. The pro design impeller for a banshee works better by slowing the rate of coolant, probably the implellor change in 88 for the 250r did the same thing, slowed it down.

[dunatic]

Originally posted by elbine69
Thats interesting. Got a picture of that?

I do...Ill post it up in a couple of days when I get my hands around the shop again.

Just got home from Hawaii about 30 minutes ago.

[Aceman]

Originally posted by dunatic
Just got home from Hawaii about 30 minutes ago.

A sign you might be addicted to internet forums:

"Screw the unpacking honey, I need to check for new posts!"

:D

[dunatic]

all my post in the last 7 days were from our lanai over looking the 3rd green at Kapalua resort.

great WiFi coverage and the view was unbeatable. Laying in the sun, sipping cold drinks, watching the cute golfing babes and posted ***** here....what else could you ask for ?

[elbine69]

Well I took everything apart and put it back together and it seems to be fine. So thanks to all for your help and ideas

[latheboy]

Originally posted by deathman53
The pro design impeller for a banshee works better by slowing the rate of coolant, probably the implellor change in 88 for the 250r did the same thing, slowed it down.

Do you think I may be better off with an 88 impeller now that I went big bore? Did pro design ever make an impeller for the 250r that slowed the flow rate down? Janssen said they did, but he may be confused with his banshee days....

[deathman53]

I don't know, I only have 85 and 86 motors running. I do have one 88 motor, I never ran it.