Porting Cast Iron head

(quoted from post at 14:17:00 02/26/20) Wondering if anyone knows of someone who could port a cast iron cylinder head for an Oliver. Thank you in advance!
You might check in with the younger guys at your local auto parts store. Find out if there's anyone in your area that builds drag racing engines. They would know where you can get a head done.
 
Porting helps but going to larger valves really gives it a boost. don,t know what engine you are working on but larger valves will help.
 
(quoted from post at 18:02:29 02/26/20) Porting helps but going to larger valves really gives it a boost. don,t know what engine you are working on but larger valves will help.

Only if the valves are the restriction and not the port .
Valve and valve seat angles and widths are as important as valve diameter .
In small bore, long stroke tractor engines. Large valves can hit the cylinder wall and flow is shrouded by the cylinder wall.
 
(quoted from post at 23:46:22 02/26/20)
(quoted from post at 18:02:29 02/26/20) Porting helps but going to larger valves really gives it a boost. don,t know what engine you are working on but larger valves will help.

Only if the valves are the restriction and not the port .
Valve and valve seat angles and widths are as important as valve diameter .
In small bore, long stroke tractor engines. Large valves can hit the cylinder wall and flow is shrouded by the cylinder wall.
Exactly. That's why the work needs to be done by someone with a flow bench.
 
Without a flow bench, anyone would be shooting in the dark.

Generally on old tractor engines the port is already too big.
The biggest area to improve on is the valve seat area, seat angles and the area on either side of the valve.

The trouble with certain heads, especially gas engines with chambered heads is the chamber severely shrouds the valve, to the point a very large valve might flow worse.

What model Oliver? Waukesha installed larger valves and made the ports larger as hp increased through the years. It s not uncommon to install valves from a 880 into a 77 head.
 
Where are you located? I go to Albion Il. Harrison Automotive. He has a flow bench. Also holds some NHRA records. Mine flows 40 % more. 618 445 2405.
 
(quoted from post at 08:49:13 02/27/20)
(quoted from post at 23:46:22 02/26/20)
(quoted from post at 18:02:29 02/26/20) Porting helps but going to larger valves really gives it a boost. don,t know what engine you are working on but larger valves will help.

Only if the valves are the restriction and not the port .
Valve and valve seat angles and widths are as important as valve diameter .
In small bore, long stroke tractor engines. Large valves can hit the cylinder wall and flow is shrouded by the cylinder wall.
Exactly. That's why the work needs to be done by someone with a flow bench.

It is usually safe on any cylinder head . To match the ports to the manifold . Grind port casting flashes off . Blend rough edges in the valve bowl . And the perform the classic valve and seat angle/width .
Without a flow bench . Indeed it s not about removing any significant amount of metal, just work with what is there .
 
Air flow is one thing, but velocity is just as important. I have filled bottom of some ports up to 1/4" with no loss of flow, but the engine made more power because of the increase in port velocity. On the intake ports the increase of velocity helps keep the air/fuel mixed better thus you get better combustion. On an exhaust port the increase in velocity help draw out more spent exhaust gases out of the combustion chamber, and it also helps the intake draw in more air/fuel.
Another thing is how much valve lift you have, most also look at the airflow with the valve at it's maximum opening, and not at flow at half open (remember a valve reaches full open once, but it reaches half open twice).
I mentioned filling the bottom of ports can increase port velocity without reducing flow, but also if you can fill a port floor you are reducing the radius of the turn that air has to flow. The straighter you can make a port the better it works.

Before good aftermarket heads were available for the Ford 351 Cleveland the extreme bend in the exhaust port was a real power killer so what was done back in the day was modifying the exhaust ports with port plates. A section of the exhaust ports were milled away, and new exhaust port plates were put on to straighten out the ports, and it increased flow, and velocity dramatically.
Stock 351C 4V exhaust ports.
mvphoto49959.jpg


351 C 4V with port plates installed (note the ports are now smaller than the stock ports).
mvphoto49960.jpg


Hopefully this shows that it's just not about making ports bigger. A lot goes into cylinder head port work!
 
Without use of a flow bench to measure actual progress it is recommended to only remove the casting flash from the ports. The most important part is the 1/2 inch before the valve seat. This can be worked with Cratex rubberized wheels [work to a nice radius enhancing the 3 angle valve job.] With the right abrasives you can do it yourself. There was saying about making ports to large " don't play Jerry Branch unless you are Jerry Branch" . Mindless porting will just make too large ports.
 

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