Thread:

How much cam for a 540 with Lightning Headers?

Keep the LSA at a minimum of 112*. Probably 113.5 would be quite nice with minimal-to-no reversion at all.

I know it's a complicated subject, isn't valve overlap as important as lsa???? For example I had a cam that was like 108 lsa with 15ish degrees overlap and no problem (tt bassett headers).

I doubt there could be a proper answer without seeing the entire list of specs on the cam in question.

Sledge hammer, are ya still there? Cam specs? Or did ya figure it out??

There's a lot more to it.

Rate of fall from collectors to end of tailpipes. This is huge !

Reduced water option ?

How far back water enters the exhaust

Idle speed including in gear

overlap as H20MOFO said (not just LSA) (before and after TDC). As another note, some cam spec'rs don't have a good record with reversion.

Header specs themselves (primary ID and length - collector ID and length including tails)

Valve jobs

Cylinder head sizing

================================================== ======

No matter what you do, even if you think your 100% safe, pull the headers (manifolds) right after first firing up with water going thru exhaust. Check your exhaust ports for signs of water.

Originally Posted by Sledge Hammer

I am getting a 540 built now. I have Lightning headers. Website says 240 duration or reversion may be an issue. Builder is planning about 248. Has anyone had any experience with a 540 and Lightning headers?

If the builder has selected the cam and you both have set a goal in power then complete the build and see if the goal it met. If so then the build was a good combo, if not then you have grounds to question the builders selection.

I kind of agree with Chris here. Build ytour engine to make the power you want, then deal with the water. There are other ways to control water issues than with the cam grind.

Originally Posted by steelcomp

I kind of agree with Chris here. Build ytour engine to make the power you want, then deal with the water. There are other ways to control water issues than with the cam grind.

please elaborate on the water control, I will be running IMCO powerflows
with the s pipes and water reversion is a concern

Originally Posted by cfm

So, spend $$$ and question nothing, and then if it breaks (from sucking water) you 'now have grounds' to question it ?

Good thing you don't work on aircraft.

The thread is a question about reversion with the headers he has and the engine he's building. if it makes the power but reverts exhaust water it's still a good combo ?

================================================== =======



Steelcomp - these are water jacketed headers. You can't just turn the water on at a higher rpm like you can with single wall water injected headers many of the jet boaters use. The integrety can be deeply sacrificed if run dry for periods of time. Some in a very short time.

Plus - he already has them, so some mods to make water harder to revert can be diffcult or impossible to perform depending on what's needed.


Sledgehammer - Are these the standard Lightning headers or did you have some options done like: having water introduced further back or their reduced water option or ???

Do these run thru transom or over the traansom ?

If thru transom, are the tails seperate (joined by rubber couplings) from the headers ?

Do you have any pics of them in the boat or atleast pic of back of the boat and how they enter over the water (lake) ? Pics (or very exact description) of exhaust + water routing in the boat will tell us very important info.

Any noise laws to be concerned with ?

Complete engine build info will be needed also.

==========================================

There are a lot of questions that need to be answered here. The more likely an engine will suck water back, the more safeguards have to be put in place.

Again, always pull the headers/manifolds when first run with water going thru the exhaust.

With most water jacketed systems you can not simply ignore what effect a cam will have with it. Depending on the set-up It can make you compromise a lot.

Scott,
Apparently the customer and the engine builder have talked about this build. The engine builder has selected a camshaft that he feels will work or has built the combo in the past. Giving the customer the benefit of doubt I am sure they talked about a HP goal and if not met what they would do. The years I have been doing this . . .this is what happens.