Problem With HOWELL V4 Plans

[Anthony R Johnson]

I am modeling the Howell V4 in cad, and I have run into a problem. The Cylinder Head has two threaded holes with a countersink that are right next to the holes for the Valve Cages. The countersink is connecting to the Valve Cage holes by a small bit, but its not suppose to. I've checked my numbers and everything looks right, but something has to be wrong. Has anyone who has built the Howell V4 had this problem?

I will attach a screenshot of the cad model, and the page from the plans. Hopefully this doesn't breach any kind of copyright since I'm only uploading the one page.

 

[stevehuckss396]

I have the plans but have not given them a serious look. If you dont get a helpful reply by the weekend ill model the head and see if i get the same result as you.

 

[mayhugh1]

Anthony,
Here is a jpg of the Solidworks head I built many years ago. I was using a different version of SolidWorks then than I'm using now, and for some reason the sketch dimensions aren't coming over to my new version or I would have included them. I'm pretty sure I made no changes, though, to Jerry's drawing. What may be happening is that you're interpreting his sparkplug hole dimensions on the wrong plane. He's using the head's plane for them. One thing I learned from building Jerry's V-twin and his V-4 is that he put things very close together but hardly ever on top of on one another. It's really difficult to make changes to his designs without creating problems for one's self down the road. - Terry

 

[ruzzie]

I have drawn it using Inventor and it comes close but doesn't break thru.

 

[Anthony R Johnson]

I have drawn it using Inventor and it comes close but doesn't break thru.

I did mine by using a 3D sketch. Its messy, but it should have worked. How did you do yours?
Having an angle in the X and Y really messed with me.

 

[Spell]

Have built heads, spark plug does connect with valve cage hole but should not be a problem as it only just breaks into.

View media item 1368

 

[lantain1982]

Hi Tony,
I can confirm the spark plug counterbore does not break into the valve guide holes.
I carried out this operation in the last 48 hours on my heads and the gap measures 0.027" to 0.035" [on my heads.]

 

[Anthony R Johnson]

Hi Tony,
I can confirm the spark plug counterbore does not break into the valve guide holes.
I carried out this operation in the last 48 hours on my heads and the gap measures 0.027" to 0.035" [on my heads.]

I've modeled the hole two different ways and got the same result. I can't figure out why some of us get one result and some get a different one.

 

[ruzzie]

I just had a look at my cad model to refresh the memory and I found that in fact it does break through with the given dimensions and that I had moved it from .350" to .370" so it wouldn't break thru.
Looking at my assembly model moving it by .02" doesn't look like it will cause any problems
I haven't machined the plug holes yet, I am waiting to finish my Trunnion for the mill so I can go 5 axis.