Need Porting Advice

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805moparkid

805moparkid

Slant and AFX Guy
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ok so im looking to help out my whizzer engine as the ports are disgusting...

so i was going to smooth the obvious issues but as you can see the bored the hole for the valve and then for the port (90* for the exh/about 45* for the int) so around the valve guide it is just open with no radius... can i epoxy it on the intake?

any other advice...

P.S. how bout getting ride of the bump in the head and milling it to raise compression again (stock like 7:1)...
 

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Call me chicken but I don't like epoxy in heads.
 
Seems to me like it might. I mean epoxy and aluminum....no way they have the same expansion rates. Plus all that heat and gas and oil. It might be perfectly safe.....but "I" just wouldn't trust it. A .99 cent tube of epoxy could booger up your little motor.
 
I don't think I'd do much re-designing of the port. Put some smoother corners on it, don't make it much larger volume-wise. Epoxy won't come off if applied to clean metal and mixed properly but methanol/ethanol will eat it over time so you need to protect it. Honestly I try not to ever use it...lol. But if you do this is ths stuff to use and it's not cheap: A-788 Splash Zone. It's a marine product from Z-Spar. If you're going to use it with alcohol then you need clean the head with acetone, then heat it to about 150° and brush on a urethane clear coat after the port work's done. You can also use the Moroso A+B but again, if you run ethanol mixed in the fuel (pump gas) it will need to be top-coated.
 
moper said:
I don't think I'd do much re-designing of the port. Put some smoother corners on it, don't make it much larger volume-wise. Epoxy won't come off if applied to clean metal and mixed properly but methanol/ethanol will eat it over time so you need to protect it. Honestly I try not to ever use it...lol. But if you do this is ths stuff to use and it's not cheap: A-788 Splash Zone. It's a marine product from Z-Spar. If you're going to use it with alcohol then you need clean the head with acetone, then heat it to about 150° and brush on a urethane clear coat after the port work's done. You can also use the Moroso A+B but again, if you run ethanol mixed in the fuel (pump gas) it will need to be top-coated.
Click to expand...

ok thats what i wanted to know...

os a little blending will make me happy
 
I don't think that's a 2 stroke. It looks like an old European bike or something....
Regardless, ading to port volume will kill the small amount of torque it makes IMO and it's got a huge issue with fuel coming out of suspension looking at the top of the block. So it's already got weak low speed signal.
 
It is no doubt a four stroke engine since it has valves.
 
Around the guide isn't really in the path of intake flow, so I wouldn't sweat it too much. On a flathead, the bulk of the intake airflow is across the roof of the port and then across to the piston side of the valve (the valve is badly shrouded on all other sides) Focus on all the sharp edges and any obvious choke points. On the exhaust side the gasses will be mostly on the floor of the port but the same applies. As for raising compression, bear in mind that as you reduce chamber size you also move it away from the piston and increase the already bad valve shrouding. Be cautious that these castings may be a bit thin in places so don't go too nuts. Air cooled engines go through a a lot lore thermal stress than water cooled so epoxy will be risky. Also don't expect miracles a 20% increase in performance, which would be a huge gain with any engine, would take a 5HP engine to 6. That said, these little engines were built to a price (cheaply as possible) and I'm sure there are gains to be had.
 
moper said:
I don't think that's a 2 stroke. It looks like an old European bike or something....
Regardless, ading to port volume will kill the small amount of torque it makes IMO and it's got a huge issue with fuel coming out of suspension looking at the top of the block. So it's already got weak low speed signal.
Click to expand...

You're right, I just glanced and it looked like a bike motor, therfore I just assumed and completely missed the valves.=my duh.

But I still keep the same thoughts on this, leave it or...experiment with some minor relieving but in a way leaves that turbulent mixing so it's not fouling plugs at idle,low speed.

And that idea comes from the look of the burn color/travel.

I would be asking this question on a forum with experienced members in the area of messing with these particular engine's, that is If I expected to get the best advice and results.
 
I have ported one of those befor! Just clean up the port, and radius all the edges from the pocket to the port. The biggest improvement is on the short turn. the head can get some work also. smooth out the blocks above the valves, and you can open up the head around the valves also/deshroud the valves. There is not alot of power found here but probably worth the little time it takes to do. We had the head milled, flat so the part of the chamber above the piston was flat. The problem here is you lose some of the flow between the valve area and the piston. You can releive the case or mill out a little from the head to pick flow back up, similar to how people used to hotrod the old flat head ford engines.
 
moturbopar said:
I have ported one of those befor! Just clean up the port, and radius all the edges from the pocket to the port. The biggest improvement is on the short turn. the head can get some work also. smooth out the blocks above the valves, and you can open up the head around the valves also/deshroud the valves. There is not alot of power found here but probably worth the little time it takes to do. We had the head milled, flat so the part of the chamber above the piston was flat. The problem here is you lose some of the flow between the valve area and the piston. You can releive the case or mill out a little from the head to pick flow back up, similar to how people used to hotrod the old flat head ford engines.
Click to expand...

spent like an hour and for my first port job i'd say it cam out pretty good! no pics tonite but ill get some...

its hard when the hold is smaller than a quarter and your trying to avoid valve guides lol...
 
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