gasket, intake manifold to cylinder head ??
looking through the February 2016 GCR, the only reference I could find for the intake manifold to cylinder head gasket was:
s. Miscellaneous
1. The timing chain/sprocket cover may be altered or replaced.
2. The use of the following non-standard replacement parts is permitted provided their use does not
result in any unauthorized modification of any other component:
A. Fasteners - nuts, bolts, screws, studs, etc. Intake manifold fasteners may be of either a socket
head or hex head configuration, and must be 5/16” diameter.
B. Gaskets, except head gasket.
C. Washers.
D. Seals.
E. Connecting rod, crankshaft, and camshaft bearings of the same size and type as original. Normal
oversize/undersize bearings are permitted. This does not allow reducing the........
does anyone see any other rules that impose constraints on what's used for a gasket between the intake manifold and the cylinder head??
while looking for the intake manifold to cylinder head gasket rule, I couldn't help noticing the very curiously written rule at the beginning of the Kent section. by my count there's five gasket surfaces on a Kent cylinder head:
1.) cylinder head to cylinder block interface
2.) cylinder head to exhaust interface
3.) cylinder head to intake manifold interface
4.) cylinder head to valve cover interface
5.) cylinder head to thermostat housing interface
wonder how much can be removed from which interface or interfaces before it's non-compliant??:confused:
12. Kent Engine
a.General
1. Components shall not be interchanged between the Kent and
Cortina versions of the engine unless specifically authorized.
2. The engine shall not be altered, modified, or changed in any
respect unless specifically authorized herein. When a system
is specified to be “unrestricted” (e.g. paragraphs p and q), the
restrictions of this paragraph do not apply.
3. The gasket face of the cylinder head may be resurfaced provided
the maximum compression ratio is not exceeded.
Art
artesmith@earthlink.net
gasket, intake manifold to cylinder head rule(s)
my principal interest is the intake manifold to cylinder head gasket rule(s). when you start thinking about the ports in the cylinder head and the ports in the intake manifold as four(4) ports and not eight, the thickness and the ID of whatever constitutes a compliant intake manifold gasket gets real important. if the ID is too small, the gasket creates a sharp edged orifice (ie: a restrictor); if the ID is too large it creates an unwanted "trench" around the circumference of the port that destroys the boundary layer. the union of the 5/16-18 tapped holes in the cylinder head and the clearance holes in the intake manifold define the maximum amount the intake ports can be compliantly raised assuming something smaller than BOTH the 1.50" OD maximum allowed cylinder head intake port size and the 1.340" maximum allowed intake manifold dimension is the real answer...................!
the authorized milling of an undefined gasket surface is at best an amusing observation. it only serves to illustrate that the closer you look at the rules, the more "gray areas" you find. the five enumerated gasket surfaces are the minimum! anyone feeling a little more pushy could make a strong case for nine, the five listed above plus four spark plug seats. inclusion of spark plug seats meets the suggested criteria for effecting compression ratio and open a fascinating example of the difference between reality and the compliance with the rules as written. the last time I could find a copy of the approved/official compression checking procedure for Kent's, it said something to the effect that if uprated valves were proud of the cylinder head certain numbers were required to be used in the formula without making a measurement. my memory says, and it's important to remember it's an old guy's memory, that the two predefined numbers covered valve volume and spark plug volume below the deck of the cylinder head......
Art
artesmith@earthlink.net
Excellent question, and I would add another
I would also add the gasket/transition between the carburetor and the intake manifold, though there are some more specific rules and guidelines for that. Your "trench" comment is making me ponder, indeed...
While you are on the topic, someone who looked at my intake manifold took the plug out that was blocking the "fifth hole" in the cylinder head face of the intake manifold. Has current wisdom changed on the blocking/filling of this hole? Is the modern gasket without a hole enough to block it? I wouldn't think so, but...
And, if the hole should be blocked in addition to the gasket not having a hole there, what is the material of choice these days? Epoxy? JB Weld? Something else?
But back to the question at hand, would you custom make an intake manifold gasket, or buy one that has holes too small and cut back from there? Where would you buy high quality gasket "stock?"
David
failed attempt at Dark humor.............
there continues to be comments posted here and also privately via e-mail along the lines of "clearly the rule as written refers to the head's cylinder block interface surface since compression ratio was referenced". clearly my attempt at dark humor was flawed and far too subtle!! if resurfacing any, some, or all of the cylinder head's nine gasket surfaces did NOT effect compression ratio, would more people see the attempt at dark humor??
for reference, the rule in question as written:
3. The gasket face of the cylinder head may be resurfaced
provided the maximum compression ratio is not exceeded.
"The" implies one, when in fact there's nine. AND if resurfacing any, some, or all of the gasket faces doesn't effect compression ratio, surely there's a valid question which one and how much can be machined compliantly. "face" is singular suggesting the competitor in fact has a choice............
before starting the explanation, it's critical to remember (or realize) the reality of the real world can have nothing to do with compliance with the rules as written!! translated for this example, it means if the compression ratio didn't change per the rules as written (and all of the required written verification procedures in place), the compression ratio didn't change in the compliance verification world.
the Kent (uprated) cylinder head is FLAT from both Ford and Pierce. since no "flatness" criteria is included in the rule as written, the competitor is in charge of flatness. flat cylinder heads (ie: cylinder heads without combustion chambers) take almost all of the complexity out of calculating compression ratio in the real world. flat cylinder heads contribute three components (ie: numbers) to the typical compression ratio formula:
1.) a negative volume for the intake valve protrusion above/below the cylinder head deck
2.) a negative volume for the exhaust valve protrusion above/below the cylinder head deck
3.) a positive or negative volume for the spark plug installation
for reference, the valve protrusion rule as written:
C. Maximum valve protrusion from head surface: .040”
in the real world, measuring the volume of the the two protruding valve heads and the spark plug on a flat head is a pain in the ass requiring serious precision. for compliance with the rules as written in the compliance verification world, the numbers for the two protruding valve heads and the spark plug are specified/provided/mandated for inclusion in the compression ratio formula in the Kent compression ratio verification procedure (ie: they're NOT measured)! someone more skilled than me at finding things on the club's web page should post the compression ratio verification procedure. since the web page was improved, I struggle every month to just find the latest Fastrack.........
therefore, in the compliance verification world it should now be obvious that resurfacing ANY of the cylinder head's nine gasket faces does NOT effect the static compression ratio! in the real world, the four spark plug's contribution are changing by a trigonometry function of the spark plug's installation angle with respect to the cylinder head's cylinder block interface surface (ie: something less than 14mm OD).
Art
artesmith@earthlink.net
ps: the compliance question which was the point of my original post has been answered
