intake help
May 18th, 2016, 09:01 PM
#1
Registered User
Thread Starter
Join Date: Aug 2014
Posts: 25
intake help
well i got a 1969 cutlass with a 350 in it and the person i bought it from took the intake off so i need to know all the plumbing i will need for the new intake if anybody got pics i can see it would really help
May 18th, 2016, 09:42 PM
#2
Registered User
Join Date: Feb 2013
Location: Phoenix, AZ
Posts: 14,042
This is what I have readily available. It's an aftermarket intake but the important stuff is similar to the factory one.
I think the factory intake will also have a small vacuum nipple on a runner behind the carburetor for the air cleaner thermal valve.
manifold.jpg
I think the factory intake will also have a small vacuum nipple on a runner behind the carburetor for the air cleaner thermal valve.
manifold.jpg
May 19th, 2016, 06:46 AM
#3
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,595
There isn't really a whole lot of "plumbing" on a 1969 Olds intake.
People worry a lot about vacuum lines, but it really isn't that complex. Nearly all of the vacuum connections on the engine need straight manifold vacuum. How they get connected to manifold vacuum is really unimportant. You can run individual connections to ports in the intake runners or you can tee them together. It will work the same.
The hoses that get connected to manifold vacuum are the power brakes, PCV, AT modulator, and any accessory feed hoses (A/C or power trunk release, for example). If you have a factory intake with the thermostatic flapper, that hose also goes to manifold vacuum. The large port on the base of the carb (usually at the rear, but sometimes at the front) is also manifold vacuum and can be used for the PCV, for example. Other ports on the carb may be manifold vacuum or ported, so check with a vacuum gauge.
The only other hose is the distributor vacuum advance, and that's always good for a debate.
The factory used ported vacuum for the advance. This is a vacuum port taken just ABOVE the carb throttle blades, so it is zero vacuum at idle and then mimics manifold vacuum as soon as the throttle blades open. This was done more to reduce NOx emissions at idle than for any other reason. If you want to retain this ported vacuum, simply connect the vac advance hose to the ported vacuum tap on the carb. Note that using ported vacuum for the advance may cause overheating at idle when the engine and air temps are high. On some cars, Olds used a thermal vacuum switch to change the vac advance to straight manifold vacuum under these conditions. If your engine has this, simply screw the TVS into the coolant runner at the front of the intake and connect the hoses as indicated on the switch - "D" goes to the distributor, "M" to manifold vacuum, and "C" to the carb ported vacuum source.
Usually, the car will run better by running the distributor off of straight manifold vacuum all the time. In that case, use any manifold vacuum port, as described above for all the other functions.
And finally, as always, the hose routing diagrams for the stock systems are shown in your Chassis Service Manual.
People worry a lot about vacuum lines, but it really isn't that complex. Nearly all of the vacuum connections on the engine need straight manifold vacuum. How they get connected to manifold vacuum is really unimportant. You can run individual connections to ports in the intake runners or you can tee them together. It will work the same.
The hoses that get connected to manifold vacuum are the power brakes, PCV, AT modulator, and any accessory feed hoses (A/C or power trunk release, for example). If you have a factory intake with the thermostatic flapper, that hose also goes to manifold vacuum. The large port on the base of the carb (usually at the rear, but sometimes at the front) is also manifold vacuum and can be used for the PCV, for example. Other ports on the carb may be manifold vacuum or ported, so check with a vacuum gauge.
The only other hose is the distributor vacuum advance, and that's always good for a debate.
The factory used ported vacuum for the advance. This is a vacuum port taken just ABOVE the carb throttle blades, so it is zero vacuum at idle and then mimics manifold vacuum as soon as the throttle blades open. This was done more to reduce NOx emissions at idle than for any other reason. If you want to retain this ported vacuum, simply connect the vac advance hose to the ported vacuum tap on the carb. Note that using ported vacuum for the advance may cause overheating at idle when the engine and air temps are high. On some cars, Olds used a thermal vacuum switch to change the vac advance to straight manifold vacuum under these conditions. If your engine has this, simply screw the TVS into the coolant runner at the front of the intake and connect the hoses as indicated on the switch - "D" goes to the distributor, "M" to manifold vacuum, and "C" to the carb ported vacuum source.
Usually, the car will run better by running the distributor off of straight manifold vacuum all the time. In that case, use any manifold vacuum port, as described above for all the other functions.
And finally, as always, the hose routing diagrams for the stock systems are shown in your Chassis Service Manual.
Thread
Thread Starter
Forum
Replies
Last Post
TIM FISKUS
Parts Wanted
5
May 12th, 2013 05:17 AM
Wildcard
Small Blocks
20
December 26th, 2012 07:48 AM
Nickyloves442s
Parts For Sale
15
October 24th, 2012 04:55 PM
svnt442
Parts For Sale
3
July 17th, 2011 04:43 PM
