Re: [2cylinderhondas] Re: oil leaks

[dealadayray]

Yea Know Miles, you brought up an interesting point, all the head nuts
have washers but also are open which allows them to torque past the stretch
of the stud. I too was looking for a reason the rear area of the head was
always developing a leak after several thousand miles. Not only the stretch
of the studs makes it harder to torque but the fact that every time I
rebuild a head it's surfaced lending to the loss of another 3 to 5 thousands
coupled with possible over torquing which can cause warping. But all this
aside we can torque the cap nut only so far while the other nuts will still
pull the head down enough to seal but also allows the rear two studs to
lift. My torque wrench only shows pounds feet applied, not the stretch of
the stud. A washer and cap nut would do the trick, unless the stud has
stretched past this limit, rather the width of the washer, also.
Speaking over torquing, this does cause the cam box to warp on the
outside edges. The 6mm bolts on the four corners will curve up and leak
when the head studs are over torqued. Torquing the four corners to 120 inch
pounds before completing the final torque on the studs will maintain even
pressure across the cam box to head area. And the gasket for the cam box
should be 1/32 thick, thinner material will work but the surface and torque
requirements must be more critical.
Bill

[d.vallejo]

Bill is the subject of this letter mostly concerned with over torquing the
the head or sealing a leak? I found that a a generous application of permatex
copper spray to head gasket just before installation helped prevent leakage.
all the other gaskets received the gray gasket sealer that use to be known as
Yamahabond. I beleive it it called three bond or triple bond now. Once
applied to the gasket and torqued down there wasn't any leakage. I only
retorqued the head once, after the first 1500 miles, There was no leakage or
any compression problems. The engine didn't leak at all for the next 20,000
miles. With the next rebuild, due to a shattered oil pump drive wheel, I was
able to remove the gasket sealer with some spray on gasket remover and a putty
knife and minimal elbow grease. Needless to say I repeated the use of these
gasket sealers on the last rebuild.
Don Vallejo

[dealadayray]

Hi Don;
Really it's both, retorquing the head should be done and it only takes a
single warm up, like the first time you start up your engine after rebuild
to gain the necessary results from a retorque. I used to wait for 500
miles or so, and change the oil at the same time and remove any chips or
sealant picked by the oil. I used to use the High temp copper RTV, but it
takes up to 48 hours after application for it to cure and that's from
Permatex. What Permatex suggested is the RTV Silver which is like your
Honda or Yamaha Bond sealants. It Cures in several hours when the
temperature is at 70 or above. On the Head Gaskets I have made a higher
quality gasket material is used than what other after market head gaskets
are made of. I did this to try and solve the leak problem at the rear of
the engine. But I think Miles suggestion on the rear center cap nuts is the
answer.
Bill