I'm trying to research the percentage of flow difference (stock of coarse) between the 2.0L head and the 1.8L. Does any one how much?

What kind of difference running the larger valve set-up on both heads? (%)

TIA

KP

It's not just head flow..

A lot of the 2L head power comes from the combustion chamber shape and plug location.

After all, the 2.0L head is the only production head designed by the factory racing team...

The answer to your questions is it depends.... It really depends on how big are the valves, how big is the intake (carbs EFI), what cam, what exhaust, what cylinder size, what rpm range, etc... In some cases smaller is better and in others bigger is better. So, head flow rate is good but not all the pieces to the puzzle.

Sorry for the vague answer, but don't just go by head flow. Len and Jake have modified new 1.8's to have the 2.0L plug location. Check their web sites.

Ken

I have the data, but its not something we share.

I'll tell you now thet the plug location of the 2.0 is good for 5% more power than the flow differences.

Thats a huge percentage of my engines receive relocated spark plugs.....

Bigger is seldom better.

Jake - no specifics required, but do the sodium filled valves make a big difference?? (5% is a big diff in my mind ).

Sorry for the hijack.

QUOTE (fiid @ Dec 22 2005, 03:16 PM)

Jake - no specifics required, but do the sodium filled valves make a big difference?? (5% is a big diff in my mind ). Sorry for the hijack.

they were that way to help them last longer due to the cam timing being setup to run the engine hot.

The idea is that the sodium melts (which it does at pretty low temperatures) and then sloshes back and forth inside the valve stem. When it is at the valve head end, it picks up some of the heat from the head. When it is up inside the stem proper, it gives off that heat to the valve stem, which then goes into the valve guide. Effectively, this gets some of the heat from the head of the exhaust valve (one of the hottest places in the engine) into the cylinder head, which is also pretty warm but has cooling fins and forced air flow to keep it from getting overly hot.

Now you know why having decent valve guides is important--they are one of the main cooling paths for the valves!

--DD

Sorry, gang I think you might have misunderstood my post. I was only intrested in the difference in the flow rates, not percentage of power between the two heads.

Pretty much common knowledge the 2.0L head has a better flow rate. The info is just a ball park figure not a exact average CFM rate. It just saves me from putting the two on a flow bench , doing the math and seeing for myself.

Why, I'm a Motorhead! and just plain curious.....

KP out

QUOTE (KevinP @ Dec 22 2005, 07:50 AM)

I'm trying to research the percentage of flow difference (stock of coarse) between the 2.0L head and the 1.8L. Does any one how much? What kind of difference running the larger valve set-up on both heads? (%) TIA KP

A machinist I know back in Sacramento once told me that it would take 8 hours of work on a 1.7 or 1.8 head to match the flow of a stock 2.0L head.

I don't know if that answers your question.

Sodium filled valves suck... They were technologically advanced in the 1970s, but now we have stainless steel valves that FAR supercede them in durability... When the sodium filled valve break, they take out the entire engine with their own "Mini explosion" that makes the wallet open VERY far in a split second.....

Hey Jake,

I haven't never seen what kind of damage a sodium filled valve will do to a engine if it ever came apart or kissed a piston and broke, but I can only imagine this is an awsome site!!!
Don't have any pics of these kind of melt downs do you?

Thanks'

KP out

Yeah, I have a few... email me.

Hi Jake, merry xmas...wlecome back after the short break...


I have a polish question....

Is it worth the effort to polish the chamber and ports...not change the shape...just polish...?

Or, is that gonna change the heat exchange of having a rough port?

Rich

A super smooth finish can actually cause issues in the ports, especially the intake on carburated engines due to fuel mixture...

good, another thing I dont have to do.

Rich