18HP Briggs
 

Ok, you all know that I have this motor in my cart. Here is what has been done to it so far.
High performance cam
Billit rods
advanced timing key
high rev kit
two barrel conversion
copper gaskets

Now on that note, a while back a member gave me a set of 16HP heads with aluminum rockers. I have read it seems that I would need to run premium gas on this setup but I would like some opinions on this setup and if there would be any concerns in regards to this? Currently the backlash on is set at .004 and .006, would this remain if the 16hp heads were installed as well?

Re: 18HP Briggs
 

87-octane is fine.
Depending on the cam, you may have to get creative with the valve adjusters.


I run .004" on both valves.

Re: 18HP Briggs
 

No enough room for the valves to lift?

Re: 18HP Briggs
 

There is room.

If you look at Boke's build thread, you'll see what I did with the adjusters.
It depends on the cam grind.

http://www.ddturner.com/boke58.jpg

Re: 18HP Briggs
 

The lope on the cam is right at .300.

Re: 18HP Briggs
 

It's not so much the amount of lift that causes the issue.
It's how the cam is ground to achieve the lift that causes the issue.

You can grind a cam with the same base circle as a stock cam, but that will only allow a certain amount of lift until interferences occur.

To get around the interference issue, a cam is given more lift by reducing the base circle diameter. What this can cause is that the pushrods(while on the low side of the cam) are not long enough to reach the adjusters in the stock configuration.

http://www.ddturner.com/camlobes.jpg

Re: 18HP Briggs
 

Nice rockers!!! Are the 16hp heads hard to come by?

Re: 18HP Briggs
 

16hp heads are easy to find.
16hp heads with aluminum rockers are harder to find.

Re: 18HP Briggs
 

Would longer pushrods work?

Re: 18HP Briggs
 

Yes. You can buy adjustable pushrods, made-to-length pushrods, or just move the adjuster lock nuts.