C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Help, distributor install when block is decked+aftermarket heads??

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Old 09-15-2007, 06:24 PM
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bogor
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Default Help, distributor install when block is decked+aftermarket heads??

I am about to make the first start of my renovated engine but I have some concerns about my HEI distributor: I have decked the (L98) block to 9.005 deck height and switched to AFR 210 Eliminator heads. I´ve had some trouble aligning the ports of the intake and the heads (ended up epoxying the floor of the intake ports) and I suspect the contact surface between the distributor and the intake has moved vertically (not clear in what direction though...). Is there a way to check if the position of the distributor is correct (vs the oil pump drive pin and the cam gear). I can imagine a lot of problems if the distributor has moved to much... The engine is in the car with the oil pan on. If it is of any importance, the intake is an Edelbrock TPI high flow baseplate, the drive pin from ARP and the oilpump a Melling M55a.
Old 09-15-2007, 06:38 PM
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billybonesmusic
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there should be a little room there for play with the ARP, no?
Old 09-15-2007, 06:50 PM
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_twisted_
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dis gear mess should be a concern - for abou 5 bucks mr gaske has a shim ki o ge he proper hiegh - bad o have he disibior bomed ou on he cam gear
Old 09-15-2007, 06:57 PM
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corvette1989bham
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hope you remembered to check the oil pump rod retainer.
Old 09-15-2007, 07:00 PM
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billybonesmusic
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i forgot my shaft when i put the oil pump in and put the pan on....duhhhhhhhhhhh. you only forget once! just like forgetting to put the plug in after you launch your boat, just once!
Old 09-15-2007, 07:19 PM
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bogor
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Originally Posted by billybonesmusic
i forgot my shaft when i put the oil pump in and put the pan on....duhhhhhhhhhhh. you only forget once! just like forgetting to put the plug in after you launch your boat, just once!
He,he-that is at least one thing I´ve got covered.

corvette1989bham: The rod retainer is integrated in the pin to my understanding.

The engine builder (not the same as mine) put a big block drive pin in a friend of mines sbc, not much play at all...Took him almost a year to find out why his ignition was not working as it should

Anyone know the factory recommendations regarding play in a sbc (drive pin-distributor)?

Maybe just use a marker pen on the distributor gear tooths to check the gear mesh pattern?

Last edited by bogor; 09-15-2007 at 07:21 PM.
Old 09-15-2007, 08:16 PM
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billybonesmusic
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checking gear mesh would be good, mine was decked .015 i haven't tried to put the dist in, (figured i would put it in after i installed the eng/tranny because i didnt want to break it, but........I think ill go have a look and set mine and see how it all lines up, i have the ARP shaft also. better find out now before i put it in i guess..
Old 09-15-2007, 08:18 PM
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billybonesmusic
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my FSM is on the way as we speak, but i don't have it now, so hopefully someone will chime in that has one and let us know how much it is.....
Old 09-15-2007, 08:54 PM
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Originally Posted by bogor
I am about to make the first start of my renovated engine but I have some concerns about my HEI distributor: I have decked the (L98) block to 9.005 deck height and switched to AFR 210 Eliminator heads. I´ve had some trouble aligning the ports of the intake and the heads (ended up epoxying the floor of the intake ports) and I suspect the contact surface between the distributor and the intake has moved vertically (not clear in what direction though...)..
When you deck the block, mill the heads and/or use thinner head gaskets, the intake ports in the heads, move lower into the "Vee" of the V8 engine configuration. Because it IS a vee, the intake ports in the heads as they moved down, lower, into the vee, also move closer together. With the heads closer together, the original width intake manifold now rides too high in the vee to mate up with the intake ports in the heads. That is why you thought you had to epoxy the bottom of the ports in the heads. When heads are milled more than a certain minor amount, or equivalent machining is done, the intake side of the heads should be milled to let the intake manifold drop far enough into the vee for the intake ports to align. Also, the bottom of the intake manifold has to be milled so it doesn't bottom on the china walls of the block before the intake gaskets are properly compressed against the heads. Different engines are comprised of different angles and there are no hard and fast, universal, rules for the amounts needed to be machined in all cases. The machine shop has charts for the various engines. For instance, if more than .xxx" is removed from the deck (head milling) then for every so many thousandths off the deck, .yyy" needs to be removed from the intake face of the heads (or manifold) and .zzz" from the bottom of the intake manifold. Properly done the intake ports will align, again.

It sounds as though neither the intake sides of your heads nor the intake manifold have been milled. If so, even though the manifold sits high in relation to the ports, it is still where it used to be, in relation to the block. That means that you should not have an issue with the distributor. If you have any doubt, drop the distributor in, with out a gasket. If the distributor housing flange bottoms on the intake manifold, then everything is OK with the dist. Neither the cam gear nor the distributor gear are tapered. It doesn't matter how high or low the distributor sits, within reason, as long as the clamp bolt isn't forcing the bottom of the distributor gear against the oil pump drive shaft. Did you follow all that?

RACE ON!!!
Old 09-15-2007, 10:52 PM
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Last time I checked epoxying the floors of an intake means it's sitting lower than the heads. Sounds like AFR has raised the runners on the Eliminator heads.

On the distributor, drop it in without a gasket and make sure the collar bottoms on the manifold. The distributor should sit up ~.030" from being bottomed. That ~.030" is the gasket thickness. If the distributor doesn't bottom on the manifold you'll need a shim like Twisted above mentioned, the thickness that the collar is sitting above the intake, plus the gasket.

From what's being described I doubt there's going to be a distributor height problem but it never hurts to check.
Old 09-16-2007, 01:20 PM
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bogor
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Thanks for the input everyone! I did a quick check and it looks like the distributor is not sitting flat on the intake surface. This activity have previously been associated with a lot of cursing and testing of my patience (lack of) so I will do a more thorough investigation later this week.

Last edited by bogor; 09-16-2007 at 01:33 PM.

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