318 and 1.6 Hughes roller rockers

[lomchivok]

Here is a link to the rockers.
http://www.hughesengines.com/Index/products.php?browse=browse&level0=QS0gU21hbGwgQmxvY2sgIkxBIg==&level1=Um9ja2VyIEFybXMgJiBBY2Nlc3Nvcmllcw==&partid=26579

I have a built 318 stock stroke with Keith Black 1.81 CH forged Piston. The pistons sit in the hole .002. The heads are Indy RHS LAX with 1.92 & 1.62 valves and 62cc chambers, sporting a Comp XE268H cam with stock stamped rockers. The head gasket gives me around .050 Quench area.  The Cam is a 106 intake center line installed as close as I could get it at 105.5
The stock stamped rockers may be giving me 1.5:1 but I would like to step up to the Hughes 1.6:1 roller tip rockers.

My question is, Do you think there may be valve to piston contact with the higher ratio rockers?

[Beekeeper]

I'd be tempted before you buy to mock it up now with the 1.5s and check the clearance. Then do the math on how much more lift the 1.6s will give and subtract the difference. There are always going to be subtle variations in how everything was built which make guessing dangerous.

[lomchivok]

I know your'e right. I just wondered if anyone out there has done a similar upgrade to a similar motor...Similar being the crux...I know, no guarantee and there's not much better than clay to tell the story.

[jimynick]

If you have ready access to compressed air, you could roll it up to TDC on #1, remove the plug and if you don't have a plug adapter for air you can make on by knocking the guts out of an old plug and brazing in a airline connector, hook it up to the air and then compress the valve spring- there's a variety of ways to do that- which will allow you to remove the keepers and retainer and lower the valve and measure it's travel and contact height. Do the math for the new rocker ratio and subtract to see where you are. The quick and dirty way is to pry the rocker arm down when the valve is open at it's max and see how much it's got before it contacts the piston. Virtually everything I've read, says that 1:6's are not a problem, it's when you go to 1:7 and up that you've got to be careful. Measure twice and take it easy on the egg nog if you're bored today and decide to give'er a go. LOL 

[Chryco Psycho]

even a soft rope fed in the spark plug hole will hold the valve up while you remove the spring & use a checker spring , you can measure the drop to tthe piston to make sure you have enough clearance

[lomchivok]

I think I'll look at it with checker springs to find the closest position in the rotation.
I found that I have a bad wrist pin in my 318...ugggh..such a sweet motor too.

Now I'm thinking of sticking a 360 in there...probably what I should have done in the first place...gonna go with the same zero deck and my indy heads with roller rockers on a roller cam this time.

I'll fix the wrist pin and keep the 318 for a rainy day.

[Chryco Psycho]

if you are going to 360 might as well built it to 408 CI