3.0L valves

[gorman]

I've just picked up a late SVT 2.5L engine with the extra oil drain heads. Considering the heads....

Can someone who has fitted 3.0L valves to 2.5L heads, give me some feedback about doing inlets only vs both in and ex.

Also; i have a vortech, so the valve configuration should figure in the decision I make ... experience on forced induction breathing would be a plus too ... thanks ... G.

 

[captastic]

I had conversations with Warmonger back in the day, and he felt that 3L valves on the exhaust side would give the best results for scavenging the cylinder. He felt that the intake side flowed pretty good with a little work on porting.

 

[gorman]

I had conversations with Warmonger back in the day, and he felt that 3L valves on the exhaust side would give the best results for scavenging the cylinder. He felt that the intake side flowed pretty good with a little work on porting.

yeah, that is what Kinger says about FI engines in the old forums too.

As well as unshrouding the heads around the valves, it goes on to say that it has to be done using a flow bench to see if what is being machined is beneficial or not

...surely once you've done one head you know pretty much where to work the head ..... G.

 

[Not so wild Bill]

Could somebody clarify that some SVTs have the 3 oil drain holes in the heads. I was under the impression that it was only late cougar heads that matched the 3 ltr block?
When would the change have been? Thanks

 

[gorman]

Could somebody clarify that some SVTs have the 3 oil drain holes in the heads. I was under the impression that it was only late cougar heads that matched the 3 ltr block?
When would the change have been? Thanks

I don't think the car is the deciding factor .. more likely the MY.

The engine I have, came from an ST200 Mondeo and has a large yellow sticker on the valve cover saying it is a 2001 long block and should be serviced accordingly. This sticker was put on there when it was rebuilt by Fords ... G.

 

[gorman]

Hey Guys;

can someone tell me please,

Do you need to replace the valve seats to fit 3.0L valves ? or do the 2.5L heads have enough material in the seats to accommodate the 3.0L valves ?

I found this thread http://www.contour.org/ceg-vb/showt...es-in-2.5-heads-on-a-Hybrid.&highlight=valves an opinion was offered but nobody confirmed that there was enough material in the seats.

Also; considering I have FI... the loss of compression ratio from unshrouding is not as critical ... would someone care to voice an opinion on the power gain from the valve swap ?

...thanks ...G.

 

[bnoon]

When Kinger and I ran our heads, they all had the valve seats machined/replaced because of not enough material. Unshrouding the combustion chamber was key to increasing flow.

 

[gorman]

When Kinger and I ran our heads, they all had the valve seats machined/replaced because of not enough material. Unshrouding the combustion chamber was key to increasing flow.

Hey bnoon; thanks for that info. i'll bear that in mind if the heads come off at some stage.

i'll have to go thru the NECO forum and see if I can find the threads on this. Vaguely remember seeing pictures of combustion chamber unshrouding, hope the pictures are still hosted.. G.

 

[bnoon]

If you're using the 2.5 heads with 3L valves on a 2.5, lay a 2.5 head gasket in place on a block and note any difference in circumference to the gasket bore size. Then trace/scribe that onto the head. Gently lay back the combustion chamber walls out to that scribe line with your favorite porting tool (sanding rolls). To make the scribe lines visible, use machist dye, magic marker, paint, etc on the head prior to the scribe. If you're using the heads on a 3L, use a 3L head gasket.

FYI, I know all of my pictures and Kinger's pictures are pretty much gone since he and I both have let our websites expire long ago.

 

[Heywood]

If you're using the 2.5 heads with 3L valves on a 2.5, lay a 2.5 head gasket in place on a block and note any difference in circumference to the gasket bore size. Then trace/scribe that onto the head. Gently lay back the combustion chamber walls out to that scribe line with your favorite porting tool (sanding rolls). To make the scribe lines visible, use machist dye, magic marker, paint, etc on the head prior to the scribe. If you're using the heads on a 3L, use a 3L head gasket.

FYI, I know all of my pictures and Kinger's pictures are pretty much gone since he and I both have let our websites expire long ago.

Wouldn't this create uneven compression between the cylinders since the combustion chamber for each cylinder will end up slightly different?

 

[bnoon]

It's not something for everyone. If you're not handy with a die grinder, leave it to the professionals. It's not like it's brain science or rocket surgery or anything. Cylinders and intake/exhaust ports are rarely 100% equal.