Author Topic: Coolant Disappearing (Read 10396 times)

swanitalia · « **Reply #15 on:** May 29, 2015, 12:04:59 PM »

Jerry,

I will check my squish and my UCCR this weekend so i can provide more accurate data.

My bore x stroke is 66.5mm x 76mm

How much does it usually cost to get the oem head grooved for O-rings? I have several heads so I may send one out and have it machined and grooved.

The engine was set up to use a thin gasket from the 3-piece oem gasket.

The head was relieved about 2mm I believe, i would have to double check.

I am running a .195" spacer plate with a OEM base gasket on each side.

Jerry Hall · « **Reply #16 on:** May 29, 2015, 04:54:49 PM »

I did not realize that it was a stroker motor. It looks like the head has had a lot of material removed from the dome and squish area. Sometimes heads will flex due to the combustion pressure and leak when too much material has been removed. How much has been removed from the gasket surface?

swanitalia · « **Reply #17 on:** May 29, 2015, 05:43:45 PM »

I will have to check and measure the distance from the gasket surface to the bolt area. I had a builder in Michigan port and design the head.

swanitalia · « **Reply #18 on:** June 05, 2015, 08:38:19 AM »

Sorry it took so long, but working with a broken shoulder makes work slower.

I got the head off to measure. The distance from the gasket surface to the flat surface (bolt area) is 16.75mm, and the squish using the cr250 head gasket is .045".

Jerry Hall · « **Reply #19 on:** June 05, 2015, 05:33:24 PM »

Quote from: swanitalia;54993

Sorry it took so long, but working with a broken shoulder makes work slower.

I got the head off to measure. The distance from the gasket surface to the flat surface (bolt area) is 16.75mm, and the squish using the cr250 head gasket is .045".

Was the piston to head clearance measured at the bore or where the squish ID intersects the combustion chamber?

swanitalia · « **Reply #20 on:** June 05, 2015, 05:38:16 PM »

It was measured at the bore.

wilkin250r · « **Reply #21 on:** June 09, 2015, 02:33:33 PM »

Quote from: Jerry Hall;54791

Acorn head nuts and copper washers need to be used to prevent coolant from seeping around the wet head studs.

While we're talking about heads, o-rings, and leaking, I've got a question and a problem.

On one of my spare motors, I've got a cylinder that is cut for o-rings. My problem is, when I throw my cool-head on there, the studs are too tall to allow the acorn nuts to seat, even with copper washers.

So my choices seem to be:

1) find tall acorn nuts. I haven't really looked, but I don't like my chances of finding them.

2) find really thick copper washers.

3) use normal copper washers and standard hex nuts with an anaerobic sealant (like a liquid teflon tape, for those that don't know). This is my current solution, and it does work.

4) I could grind down the stud height, but I'm worried about corrosion. I imagine they are at least zinc coated, and the exposed tip will corrode if I grind that coating off.

5) My question for YOU, what do you think about machining a small grove, like a counterbore, at each stud location (either into the head, or into the cylinder) for individual o-rings on each stud?

jimcarrier · « **Reply #22 on:** June 09, 2015, 03:03:10 PM »

i mean... i never used copper whasher and never had a leak on my 3 oring set up...

just find some nut and copper if you can..

Btw if your stud are installed backward, you will have too much stud "lenght" getting out of the head.. .that maybe why you have this trouble..

swanitalia · « **Reply #23 on:** June 09, 2015, 03:15:18 PM »

You could use flanged hex nuts instead of acorn nuts, I know a few people who run their bikes like that.

Jerry Hall · « **Reply #24 on:** June 13, 2015, 12:51:05 AM »

Quote from: wilkin250r;55074

While we're talking about heads, o-rings, and leaking, I've got a question and a problem.

On one of my spare motors, I've got a cylinder that is cut for o-rings. My problem is, when I throw my cool-head on there, the studs are too tall to allow the acorn nuts to seat, even with copper washers.

So my choices seem to be:

1) find tall acorn nuts. I haven't really looked, but I don't like my chances of finding them.

2) find really thick copper washers.

3) use normal copper washers and standard hex nuts with an anaerobic sealant (like a liquid teflon tape, for those that don't know). This is my current solution, and it does work.

4) I could grind down the stud height, but I'm worried about corrosion. I imagine they are at least zinc coated, and the exposed tip will corrode if I grind that coating off.

5) My question for YOU, what do you think about machining a small grove, like a counterbore, at each stud location (either into the head, or into the cylinder) for individual o-rings on each stud?

Any of the 5 choices should stop the leak around the studs. I have used all of these at some time or another over the years.

On some engines there is not enough room to put o-rings around the studs without interfering with the inner or outer head o-rings.