How does one determine the exact amount to shave off the intake manifold?
Is it a 1 to 1 ratio???????
For example:
If your deck has been cut by 0.040" then one should remove 0.040" from each side of the manifold to mantain propery bolt and port alignment.
Or put another way, shaving 0.040" off of each side will allow the manifold to drop 0.040" into the valley pocket?
I have no idea how much my deck has been cut but it has. Without any intake gasket in place, my bolt and port alignment are way off.
I have heard 0.030" to 0.060" needs to be shaved off.
Just how does one determine the proper amount?
TIA
Freddie Williams Jr.
San Diego, CA
87' White TR 11.67@118(1.80 60')
TA49, Bluetops, CAS V2 FM IC, 210/205 cam, ported stock heads
"Badgeless and Bulgeless"
Stage 1 in the works!!!
Homepage
http://www.geocities.com/turbofreddie
Brutal 6 Racing
http://members.aol.com/skooby66/index.htm
Freddie,
You need to take this a step at a time. First. you didn't say if the head deck or the block deck was shaved. Assuming you meant the head deck, you need to measure with a depth mike from the deck to the cast locator in the comb chamber on both your head and a stock head. Don't measure to the rocker rail because this can be all over the place. One you have the amount shaved, you also need to know the angle between the deck and the inlet face on the head. If the angle is 90 degrees, it's an easy problem. 0.7 is the number to remember. Multiply the amount shaved from the deck and multiply it times 0.7. This is the amount to remove from the bottom of the inlet manifold to bring it into the proper relationship again. But now the gap for the inlet gasket is too tight, so you need to remove stock off the inlet face. Multiply the amount removed from the bottom of the manifold by .07 and this is the amount to remove from the inlet face.
In your example. .040" removed from head X 0.7=0.028" off bottom manifold X 0.7=0.020" off inlet face. If the angle is other than 90 degrees, come back and I will figure it out for you. TTYL
The way we do it when building a motor is install the intake "dry" with a gasket and check the fit. The bolt holes and ports should line up. Also check the gap on the end rails so there is room for the rubber seal or preferrably RTV.
Using a 1:1 ratio for height to material removed has worked ok for us.
If you want to get it right on the money, you have to put 4 small dowel holes in the manifold/heads before you take anything apart. You drill a hole at each end of the manifold perpendicular to the manifold face, and into the heads. You can ream to size if you want to be exact. When you disassemble, you now have a guide to align the old gasket to either the head or the manifold when you do your port matching. You use a spring dowel of the proper size to align the gasket to either piece before you scratch your lines. When you're ready to reassemble, you machine your surfaces so the new dowel holes line up perfectly after the bolts are torqued. Usually you have to figure out how much to machine by using a little trig. It's in the details!