Measuring deck height

[Denny]

Just use a carbide cutter with WD40 and leave it rough. Polished intake ports cause the fuel to fall out of suspension on the way to the valve. Also leave the chambers rough to promote mixing. Polish the heck out of the exhaust port though!

 

[atlantazombie]

make it pointy at the top and fat at the bottom, shape it to a tear drop pointing to the runner.
Some others make it a high shark fin, some with a shark fin with a slight curve.

Alright so there should be a lip at the end near the bowl area. I got an image, the red line is the edge, and where the slop finishes, and it set farther back so that the blue lines which slopes up to it is more gradual.

Should that edge curve back again, or do you think it’s better to have a sharp edge? Second image is bob58o’s port job on “predator 212 port and polish” where he leaves it sharp.

I think leaving it sharp points the air into the valve, maybe you’ve tried this combination

Predator 212 Port and Polish (Or Not)

Been reading a lot about upgrades and opening up and let the engines breath. Already built a Predator from parts my friends gave me but am still looking at more upgrades. Years ago (before forums) they use to say that porting and polishing heads on the old Briggs engines helped on top end but...

www.diygokarts.com

 

[BrownStainRacing]

That's a nice job Bob has done to that head.

I lay those edges down.

Air/fuel mix is heavy, and it's also harder to move because it being pulled in by the piston going down.

Unlike the burnt exhaust, which is lighter and easier to move because the piston is pushing it out.

I try to keep the intake as straight as possible keeping the mix moving. Any sharp edge or turn slows it down.

I'm by no means a porting expert, but working that area around the valve guide, is where I found the best results.

On your head. I would reshape that guide, and move those slopes back a lil farther, maybe about .010"-.020" passed the middle of the guide and lay them down some more.

I tried to keep up with some guys around here when porting heads, but they got more time then I do. And they told me some horror stories they ended up with jus experimenting. So I try to not get so aggressive with the dremal, .

 

[atlantazombie]

Did a little tweaking on the intake side, here’s what I got:

 

[BrownStainRacing]

Did a little tweaking on the intake side, here’s what I got:

In pic 1, work the edge of those sides a lil more.

Kinda hard to explain, but you want em more round then squared. Not too big, jus changing it to round shaped.

Like a funnel shape, if you was pouring water in from the valve side.

 

[atlantazombie]

I think I cleared out the right side a lil too deep but I see I managed to get that funneled look for both. I cleared out a little bit of the wall on either side so that the air has a straight shot. I just want to be careful not to remove too much, though I might have gotten a too crazy with the Dremel already

 

[BrownStainRacing]

I think I cleared out the right side a lil too deep but I see I managed to get that funneled look for both. I cleared out a little bit of the wall on either side so that the air has a straight shot. I just want to be careful not to remove too much, though I might have gotten a too crazy with the Dremel already

Leave it there.

That's plenty.

I think that dam dremal starts singing a mermaid song after a lil bit, and I can't seem to stop.....until there's a hole out the side,

 

[atlantazombie]

!! NUMBERS !! Alright I got an update, put in new piston with ring end gaps top is .012 bottom is .013 so almost perfect best I’ve gotten so far. Deck height being .024(all in inches)

16cc displacement with plug and valves in, giving me a CR of ~~9.8:1 with my current .009” head gasket.

Piston to head clearance is really close!! I’m not gunna unshroud the valves for the time being.

Next up is getting the valve train back in shape.

 

[BrownStainRacing]

!! NUMBERS !! Alright I got an update, put in new piston with ring end gaps top is .012 bottom is .013 so almost perfect best I’ve gotten so far. Deck height being .024(all in inches)

16cc displacement with plug and valves in, giving me a CR of ~~9.8:1 with my current .009” head gasket.

Piston to head clearance is really close!! I’m not gunna unshroud the valves for the time being.

Next up is getting the valve train back in shape.

Good job, on the measurements, .

You'll be fine at .031", piston to head.

I meant to ask, which 26# spring broke, intake or exhaust, and did you see anything bad with the valve or retainer???

I know you got most of your valve train parts from Dyno Cams, and if you see a bad part, get with them, they will fix the problem.

They can't fix a bad measurement or calculation, but they are good people and will do all they can to find out if it was a bad part.

 

[atlantazombie]

Good job, on the measurements, .

You'll be fine at .031", piston to head.

I meant to ask, which 26# spring broke, intake or exhaust, and did you see anything bad with the valve or retainer???

I know you got most of your valve train parts from Dyno Cams, and if you see a bad part, get with them, they will fix the problem.

They can't fix a bad measurement or calculation, but they are good people and will do all they can to find out if it was a bad part.

Hmmm no nothing on the retainer, valve got a good whacking but the stem looked fine otherwise. Spring broke right in the middle, this all happened on the exhaust side. That stud was bent a good 3, 4 degree.

Actually I rolled the stud on the intake side on a flat surface to check if it was bent and it actually also had a very slight bend. Pushrods are straight.

I’m left wondering why that stud was bent from before I even touched the valve train. Doesn’t make sense that a bone stock motor would have an issue like that

 

[BrownStainRacing]

Hmmm no nothing on the retainer, valve got a good whacking but the stem looked fine otherwise. Spring broke right in the middle, this all happened on the exhaust side. That stud was bent a good 3, 4 degree.

Actually I rolled the stud on the intake side on a flat surface to check if it was bent and it actually also had a very slight bend. Pushrods are straight.

I’m left wondering why that stud was bent from before I even touched the valve train. Doesn’t make sense that a bone stock motor would have an issue like that

I hear ya.

These engines are so inconsistent.

It's funny, I have never seen a piston set .040" down in a stock 196. And when you started this, I thought where did this 1 come from, .

They usally around .010"- .020", being all stock.

Makes me wonder if theres a tall deck and short deck version,......idk. but it surely wouldn't surprise me.

Jus double check your work, you will fine out what caused it.

That .300" lift cam should have no problem with 26# springs and those LD rockers, unless the valve is too short.

 

[atlantazombie]

I got some work done on the valve train, and also finished off the exhaust porting. The valve train photos are stock length valves, shorter -.04” pushrods, thin light lash caps. AND also same setup but stock pushrods

Installed height on the exhaust is already at .840” when I need to be around .850” so cool bind could be issue, I’ll put up some photos of that.

 

[atlantazombie]

This is exhaust rocker arm on stock pushrods

And this one is same setup just with -.04” pushrod. Hopefully you can see it’s at a bit of an abgle


Possible coil bind?


Intake side before(Stock pushrod) and after (-.04”)



Possible coil bind on intake side

Exhaust porting job . It could be smoother but I don’t have the bits to polish it, only grinding stones

 

[BrownStainRacing]

What's the underside of the rocker slot look like at max lift, valve lash set at 0" ?????

 

[BrownStainRacing]

Another thing, try them with the stock rockers.

They might have less ratio.

 

[bob58o]

Alright so there should be a lip at the end near the bowl area. I got an image, the red line is the edge, and where the slop finishes, and it set farther back so that the blue lines which slopes up to it is more gradual.

Should that edge curve back again, or do you think it’s better to have a sharp edge? Second image is bob58o’s port job on “predator 212 port and polish” where he leaves it sharp.

I think leaving it sharp points the air into the valve, maybe you’ve tried this combination

Predator 212 Port and Polish (Or Not)

Been reading a lot about upgrades and opening up and let the engines breath. Already built a Predator from parts my friends gave me but am still looking at more upgrades. Years ago (before forums) they use to say that porting and polishing heads on the old Briggs engines helped on top end but...

www.diygokarts.com

Not sure which head that was. If it’s the head I’m “using” now, I knocked down those edges eventually

 

[BrownStainRacing]

Champion old style rockers might be your best bet.
They are 1:1 ratio and you will give up some lift, but coil bind is more important then lift.

They are strong rockers, I haven't tried the new style Champion rockers.

Shaft Rocker Arm Ass'y

www.doverpoweronlinestore.com

 

[atlantazombie]

What's the underside of the rocker slot look like at max lift, valve lash set at 0" ?????

How would you check that?

It’s kinda hard to see. I tried marking out the edge with a sharpie with no luck

 

[atlantazombie]

Champion old style rockers might be your best bet.
They are 1:1 ratio and you will give up some lift, but coil bind is more important then lift.

They are strong rockers, I haven't tried the new style Champion rockers.

Shaft Rocker Arm Ass'y

www.doverpoweronlinestore.com

Those look like some nice rockers without breaking the bank like some of the others.

I calculated that 1.333 ratio would get me right on coil bind. I can’t find any other good options besides a stock style stamped rocker arm on 1.3:1 ratio. But I’m afraid that’s getting real close to max coil bind.

Honda GX200/Clone/Predator 1.3:1 Ratio Rocker Arm (NON-HEMI ONLY!)

OMB Warehouse - Go Kart Parts and Mini Bike Parts. OEM and Aftermarket supplier of Outdoor Power Equipment Parts, Arborist and Landscape Supplies.

www.ombwarehouse.com

 

[Denny]

Or you could have a machine shop cut the spring pockets deeper. It can’t be that expensive.