Building up intake runners - Epoxy??
Building up intake runners - Epoxy??
(OP)
Hi all, just a quick question about building up areas of the intake runners etc...
I was just wondering if anyone could recommend a particular type/brand of epoxy or another suitable substance. I know a lot of engine builders use epoxy for this but I don't know which type and I'm reluctant to do it by trial and error for obvious reasons
Also, other than weld build-up and blending, is there an easier way to fix small holes in the cylinder head?? Most of the holes are in areas between the intake and exhaust valves so I don't particularly want to weld there (the engine is a small capacity race bike engine). The holes are very small, typically 0.5-0.75mm in diameter. Should I be concerned with them at all - could they be a source of pre-ignition??
Thanks,
D.
I was just wondering if anyone could recommend a particular type/brand of epoxy or another suitable substance. I know a lot of engine builders use epoxy for this but I don't know which type and I'm reluctant to do it by trial and error for obvious reasons
Also, other than weld build-up and blending, is there an easier way to fix small holes in the cylinder head?? Most of the holes are in areas between the intake and exhaust valves so I don't particularly want to weld there (the engine is a small capacity race bike engine). The holes are very small, typically 0.5-0.75mm in diameter. Should I be concerned with them at all - could they be a source of pre-ignition??
Thanks,
D.





RE: Building up intake runners - Epoxy??
RE: Building up intake runners - Epoxy??
Are the small holes between the valves a crack? That is the usual spot for them due to the thermal stresses that are set up between cold and hot ports. You need to be concerned about valve seats dropping out of the head if cracks propagate. If the holes are just casting imperfections I'd leave them alone.
I have seen non-welded crack repair in heads performed by drilling and tapping overlapping holes. The first crack is drilled and tapped. Then a screw is coated with commercial block sealant and screwed into the hole and cut off flush. The next hole is drilled overlapping the first screw a bit and finished the same way until the crack is filled. Machining the head for new seats is usually involved.
Most of the cylinder head welders that I know of are in the tiny town of Chapin, Illinois. There are three there, I think. Chapin Cylinder Head was one place - They usually repair cast iron heads but have done aluminum repairs.
good luck
RE: Building up intake runners - Epoxy??
...Cameron
RE: Building up intake runners - Epoxy??
J-B Weld is good too, but doesn't form as easily (more liquid than A-B).
RE: Building up intake runners - Epoxy??
EHudson, no, the small holes are just porosity in the head - from the manufacturing process I'd imagine. Do you not think they are worth repairing? It's a race engine and I am concerned that tiny 'pockets' like that in the cylinder head would be a source of pre-ignition. Should I be bothered at all? I'm in Ireland so Illinois is a bit of a trek
Greenlight/Cameron, cheers - I'll have a look for that stuff.
D.