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440 Six Pack Sucks (Vacuum Leak)
#1495125
09/02/13 12:26 PM
09/02/13 12:26 PM
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Joined: Jun 2012
Posts: 43
Pacific Grove, CA
black68gtx
OP
member
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OP
member
Joined: Jun 2012
Posts: 43
Pacific Grove, CA
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My Six Pack is a 1970 factory setup and is mounted on a 1968 440. When the engine was rebuilt they machine shop shaved the deck and a purple MP cam P4452993 280/280 - 60 duration 474/474 lift centerline 110. I put this in my 68 GTX(4 speed).
I have since installed this in my 71 Challenger (automatic). From day 1 it never really ran right. I always had to feather the gas and brake at stops signs and lights fearing it would stall.
It finally stalled at a car show cruise and now I'm determined to get it running right or put a 4 barrel setup in it (god forbid).
So far I have changed the outboard base plates and metering plates with Promax. Currently running 64's jet in center with 4.5 PV, changed the torque Convertor to a 2400-2600 flash stall.
Bought a brand new Center carb. MP electronic ignition curved and ignition timing at 18 and 36 @ 2200.
I've at the conclusion that I have a vacuum leak. I sprayed starter fluid around the intake and appears to have a leak around the 5 and 7 intake port.
Last night I began installing these felpro gaskets hoping to put 1 set between the heads and the valley pan and the other on top between the intake and valley pan.
After 4 hours of trying to line up the 8 bolts. I could only get the 2 under the valley pan on for the bolt holes to line up.
I guessing that 1 of 2 things is going on here 1) because the deck was shaved I won't be able to install all 4 gaskets or 2) I should only be installing only regardless of the deck being shaved.
Any thoughts?
Last edited by black68gtx; 09/02/13 04:49 PM.
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Re: 440 Six Pack Sucks (Vacuum Leak)
[Re: black68gtx]
#1495126
09/02/13 12:50 PM
09/02/13 12:50 PM
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Joined: Jan 2003
Posts: 4,720
Moved to N.E. Tennessee
GomangoCuda
master
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master
Joined: Jan 2003
Posts: 4,720
Moved to N.E. Tennessee
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The felpro paper gaskets are way too thick. Even if nothing is cut they often will not fit. There are gaskets available that are only .015" thick. Look on ebay or someone here probably will jump in and say they sell them also. Even these may not fit if alot was taken off the decks. The correct solution then is to take some off the intake side of the heads or the head sides of the intake. Personally I go for doing the heads so that any intake will fit. If by chance your intake is warped (like one that I have) then kill 2 birds with one stone and machine the intake instead. I would check the manifold for straightness first. If it is ok I would reinstall it with a new tub and some Hitack, Coppercoat or maybe hylomar. No paper gaskets. Do not use RTV (silicone rubber) to seal around the ports because it turns to snot when exposed to gasoline. If it wont seal then reuse the tub and try to get the .015 paper gaskets in there. If that won't fit then I guess your going back to the machine shop.
You have already put alot of money into this so don't give up now. Many people here (probably most) have been down the manifold doesn't fit road before. It is fixable and you will like the results. Nothing feels quite like a properly running 6pk.
Last edited by GomangoCuda; 09/02/13 01:00 PM.
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Re: 440 Six Pack Sucks (Vacuum Leak)
[Re: black68gtx]
#1495134
09/02/13 04:02 PM
09/02/13 04:02 PM
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Joined: Feb 2005
Posts: 4,313
Prospect, PA
BSB67
master
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master
Joined: Feb 2005
Posts: 4,313
Prospect, PA
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Quote:
Quote:
You need to check the fit of the intake on your motor, especially the heads to the intake manifold. Take the valley pan off and scrape the intake and head mating surfaces clean, set the intake on the motor and use a feeler gauge to see how much clearances you have between the intake and heads on each corner, front and rear, top and bottom   If you have say .030 on the left rear(drivers side) and .035 on the top left rear corner and zero on the drivers side top front and .007 on the front bottom driver sides and similar measurements on the other side the intake or heads will have to be machined so they are parelel and align properly with the head maounting surfaces  I like to see .000 on the bottom sides on both sides and .001 to .003 clearances on the top so the manifold will pinch the bottom tight against the intake pan and gaskets so no oil will be sucked into the intake ports  BTW, once you make the sixpak seal up and get it tuned properly you will love them 
When I do this, I'm guessing that I can use a couple of the manifold bolts (finger tight) just to hold the manifold in place while I take the reading.
Doing what Cab says is certainly a way of getting right. But it simply does not need to be perfect to seal. They are all misaligned, some more than others. With paper gaskets, it will seal. If you are just looking to get it sealed up, a shorter and easier path is:
1) Use the thinner paper gaskets. You probably have the 0.030" thick ones. You can get them 0.015" thick, or
2) Open up the bolt holes slightly , or
3) Just take the manifold off and have it milled 0.060".
#1 may work, #2 and #3 will work
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Re: 440 Six Pack Sucks (Vacuum Leak)
[Re: BSB67]
#1495135
09/02/13 04:36 PM
09/02/13 04:36 PM
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Joined: Jun 2012
Posts: 43
Pacific Grove, CA
black68gtx
OP
member
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OP
member
Joined: Jun 2012
Posts: 43
Pacific Grove, CA
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Does anyone have a part number of name for the thin paper gaskets?
Last edited by black68gtx; 09/02/13 04:47 PM.
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Re: 440 Six Pack Sucks (Vacuum Leak)
[Re: black68gtx]
#1495136
09/02/13 06:32 PM
09/02/13 06:32 PM
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Joined: Jan 2003
Posts: 9,436
Blair County,PA
62maxwgn
master
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master
Joined: Jan 2003
Posts: 9,436
Blair County,PA
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Quote:
Does anyone have a part number of name for the thin paper gaskets?
How about a set of these !
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Re: 440 Six Pack Sucks (Vacuum Leak)
[Re: black68gtx]
#1495140
09/06/13 01:22 PM
09/06/13 01:22 PM
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Joined: Dec 2007
Posts: 18,157
Mass
DAYCLONA
I Live Here
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I Live Here
Joined: Dec 2007
Posts: 18,157
Mass
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Quote:
I still have a leak.
I'll assume you've checked the intake for cracks?
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Re: 440 Six Pack Sucks (Vacuum Leak)
[Re: BSB67]
#1495143
09/13/13 01:33 PM
09/13/13 01:33 PM
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Joined: Jun 2012
Posts: 43
Pacific Grove, CA
black68gtx
OP
member
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OP
member
Joined: Jun 2012
Posts: 43
Pacific Grove, CA
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Quote:
You need to check the fit of the intake on your motor, especially the heads to the intake manifold. Take the valley pan off and scrape the intake and head mating surfaces clean, set the intake on the motor and use a feeler gauge to see how much clearances you have between the intake and heads on each corner, front and rear, top and bottom If you have say .030 on the left rear(drivers side) and .035 on the top left rear corner and zero on the drivers side top front and .007 on the front bottom driver sides and similar measurements on the other side the intake or heads will have to be machined so they are parelel and align properly with the head maounting surfaces I like to see .000 on the bottom sides on both sides and .001 to .003 clearances on the top so the manifold will pinch the bottom tight against the intake pan and gaskets so no oil will be sucked into the intake ports BTW, once you make the sixpak seal up and get it tuned properly you will love them
When I do this, I'm guessing that I can use a couple of the manifold bolts (finger tight) just to hold the manifold in place while I take the reading.
Doing what Cab says is certainly a way of getting right. But it simply does not need to be perfect to seal. They are all misaligned, some more than others. With paper gaskets, it will seal. If you are just looking to get it sealed up, a shorter and easier path is:
1) Use the thinner paper gaskets. You probably have the 0.030" thick ones. You can get them 0.015" thick, or
2) Open up the bolt holes slightly , or
3) Just take the manifold off and have it milled 0.060".
#1 may work, #2 and #3 will work
I have since removed the intake and what it appears is that the bottom of the intake is not as flush with the head and the top of the intake is. (I really could not get a feller gauge to do much for me)
I looked at the paperwork from the machine shop and the deck is at 10.720 and I found that the initial height should have been 10.725.
Would I be good at having the manifold it milled 0.060"?
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I'd have to look at the paperwork to see what if anything it tells me.
