Silly Rule ??

[Randy Young]

Some of you may have noticed the Formula Continental rule stating that fasteners are unrestricted, except for those 1) connected with any moving part of the engine or 2) supporting the intake manifold. I could understand the 1st exception, but not the 2nd. I thought that perhaps someone had used plastic bolts to reduce heat transfer into the manifold, they melted, and the manifold/carb fell off and started a fire.

Well, there's an interesting "Rule Proposal - hardware" thread under "Rules Discussion" on the Formula Ford Underground forum that explains the history of the rule. Apparently some years ago, a few engine builders began using intake manifold bolts with reduced shanks to allow better alignment of the manifold with the head. [Scott Rubinzer: Was your ~'88 Runoff qualifying time in FF really tossed out because of this?] Formula Ford has the additional problem that you can't even access the stock bolts and risk leaks and crossthreading on their 1600 motors. So ...

1. How many drivers even know what a stock original intake manifold bolt looks like? I'd bet that at least half of a typical FC field could be protested because of non-stock intake manifold bolts.

2. The intake manifold bolt exception is not specified in the F2000 Pro rules. Do you think any of the Pro cars change their intake manifold bolts when they race against us?

3. The rules allow much $$$ to be spent porting the head and reshaping the intake manifold ports, but not four simple bolts that allow alignment of the manifold and head ??

Frankly, I think this is a silly rule. Formula Continental and Formula Ford are just that: formula classes, not spec classes. We should encourage reasonable innovation, and the cost of four non-stock intake manifold bolts seems not unreasonable.

Comments? Does anyone want to propose that this exception be eliminated?

Randy


BTW, Formula Ford Underground is at http://server5.ezboard.com/bformulafordunderground.html

[Daniel]

I do not know the history of this rule but I do remember something from NASCAR a year or so ago that may be related. I remember one or more teams got busted for using hollow intake manifold bolts. I don't know where the inlet and outlets were but the result was that the hollow bolts allowed more air into the engine and thereby cheated around the maximum port size rule. This type situation might have something to do with the rule but it might not.

[Daniel]

Also, one of the main reasons to port a head/manifold combination is to align the runner openings with the gasket and the head ports. Once that is done properly, you would want a bolt that does not allow any variation in alignment so that you get perfect alignment every time you bolt it together.

Using a reduced shank diameter bolt sounds like another way to pass extra air into the head. Of course, you have to drill a hole into the bolt hole from inside the head and from inside the manifold flange.

[Randy Young]

Daniel,

Drilling a hole in the intake port to let in additional air, from anywhere, would be illegal no matter what type of intake manifold bolt is used. In any case, though it would be a benefit on a Nascar motor that's always at full throttle on a superspeedway, I don't think it would work well in practice with our motors on road courses. We once had an intake manifold gasket leak - the car ran fine at high rpm, but that cylinder wouldn't fire at low rpm. Needless to say, the carb doesn't know it needs to add more fuel as revs drop.

However, you do point out another reason to allow reduced shank bolts. Six of these (not four as I say above) would be a lot less costly than the very difficult job of trying to correctly align the manifold/head with porting. Also, note that the exit diameter of the intake manifold is about 1/8" SMALLER than the intake port of the head.

[Tom Johnson]

Randy:

As you correctly point out, an engine ingesting air from a bypass source (e.g. drilled bolts) would be impossibly difficult to tune for variable throttle positions, and anybody trying this deserves the burned pistons they'd probably get.

Assuming this is the only reason to ban all but stock bolts, your original assertion that this is a silly rule is valid. So, I'd support the abolition of the rule. BTW, I know I'm illegal now since I have two different kinds of bolts on the manifold. By definition one must be illegal, but I couldn't tell you which!