Cdaniel
Undocumented Mechanic-I Am Not CDAN
This is the gasket to use.
Builds The Clustertruck Rides Again - Refurbishing a 1975 Chevota
- Thread starter RWBeringer4x4
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- #802
Is there any DISADVANTAGE to using the completely enclosed bracket, vs. the open one. I agree it seems like a no-brainer to ensure that all the passages are covered, but it seems odd that everyone wouldn't provide this.
Cdaniel
Undocumented Mechanic-I Am Not CDAN
I'm not sure what brackets you mean.
as I said before, GM had design differences - since the carb pre-dated and then survived after the emissions standards came, there were going to be changes. The Cadillac one, for example, was a heat riser that went across the manifold. If the gasket was wrong, exhaust gas got into the vacuum port via the brake booster port...
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- #805
Sorry, I meant gasket.
- Thread starter
- #806
Correct - but the "four hole" gasket above seems like it would cover every possible vacuum passage, leaving only the throttle plates exposed. Seems like it's a "one size fits all" gasket.
nope - but that's my point, you need to pull the carb and check the gasket against the bottom of the carb and against the intake to be sure you've covered all the vacuum ports and channels.
Working my way through your thread and couldn't resist a comment on this post. As a fellow compulsive spreadsheet-er let me just say
!I too have a spreadsheet of all parts and the source. Between ToyoDIY and some amazing help from @beno I've created a monster. It's a beautiful thing as I'm sure yours is as well.
Spreadsheet love over... Moving back on with your thread.
- Thread starter
- #809
Working my way through your thread and couldn't resist a comment on this post. As a fellow compulsive spreadsheet-er let me just say
I too have a spreadsheet of all parts and the source. Between ToyoDIY and some amazing help from @beno I've created a monster. It's a beautiful thing as I'm sure yours is as well.
Spreadsheet love over... Moving back on with your thread.
Thanks, and welcome aboard! It's been slow going lately. Wedding/House purchase seriously affected the cruiser fund but I'm hoping to get back on track this winter. Glad someone else appreciates documenting the brutal truth of that these things cost!
reddingcruiser
Practicing for retirement
Keeping a spreadsheet of what you spend on your 40!
That's like someone walking around with their mistresses name and number in their shirt pocket. When the wife
finds out it's gonna get ugly
. BUT, that's what diamonds are for.
- Thread starter
- #811
Keeping a spreadsheet of what you spend on your 40!
That's like someone walking around with their mistresses name and number in their shirt pocket. When the wife
BUT, that's what diamonds are for.
Way ahead of you! The wife has a horse. That's basically the financial equivalent or restoring 2-3 FJ40's. I'm in the clear
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- #812
Ok @SuperBuickGuy - the carb is off. Baseplate gaskets are below. The first two shots are of the manifold, gasket and no gasket. Seems that this gasket would be ok on this side:
On the carb side - it seems more questionable. There are two channels exposed, one up by the primaries, which could be an issue, and on back at the secondaries, which I think is supposed to be open. Looks like the passages in are plugged, not sure it goes to the carb internally or if it's a "vacuum out"
It seems like just by the shape of this channel, it would always be open to the manifold.
Seems strange to me that the rebuilder, especially one with as good a reputation as SMI, would provide an incorrect baseplate gasket. What say ye?
reddingcruiser
Practicing for retirement
Same here - wife with a horse. Let's see, horse, barn, feed, fencing, vet bills, tack (how many saddles do you need!?), riding 'apparel, horse trailer, pasture irrigation, round pen/arena.....what do I forget?
- Thread starter
- #814
Wow, you went whole hog! My wife is still boarding elsewhere. Still 2X more expensive than the FJ40
I think that forward vacuum line should be covered.... I'll look in my stash of gaskets tomorrow night (I'm taking classes all day tomorrow)...
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- #816
Awesome, keep me posted! I also shot an email to Sean Murphy @ SMI wth the same pictures. We will see what he says as well.
I did notice many of the rebuild kits for 1978 Chevy Q-jets (which is what this one is) come with both the 4-hole gasket as well as the open one.
I think you need to put a 4 hole gasket on it along with an adapter. I know the intake looks like one that works with either Holley or Quadrajet carbs - but there is a holley that has the same base as a quadrajet and that might be why it doesn't work right.
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- #818
Ok, so the follow-up question(s):
1. What do you mean by an adapter? I was under the impression that the Holley Spread-bores were a direct Q-jet replacement, and would bolt right in where a Quadrajet used to be.
2. The 4-hole gasket would go above the open-face gasket I currently have, to block the vacuum passages on the carb baseplate, right?
The only thing neither of these address fully is the split plenum. Without a "center" piece of gasket running between the bores, it seems like air could cross between the two sides of the intake. There would be a gap just over the split plenum, as thick as the gasket.
I'd agree the intake is the problem - it's a universal open bore and without a specific adapter the Quadrajunk won't seal correctly . Seen this plenty of times , best option is to find a carb specific intake manifold .
Sarge
Sarge
- Thread starter
- #820
Why not just get an adapter, as opposed to a whole different intake manifold? What do these adapters look like? Everything I've been able to find is a square-bore to spread-bore, or something otherwise drastically different.
The Quadrajet seems to seal EXTERNALLY just fine on this manifold - I can spray carb cleaner all around the base gasket and not see a change in idle.
