Black804speed

Guys

I found coolant leaking from the rear passenger corner of my 1980 L48 intake manifold. It looks like I am going to have to reseal it. I have never pulled an intake manifold before and need some advice and walk thru on how to do it and what to avoid. I have a shop manual as a guide ,but I am especially concerned about the following:

1 . Procedure for removing and marking distributor and reinstalling
2. Where do I disconnect carb linkage
3 Some of the manifold bolts look rusted.. I dont want to break them off... whats the best way to avoid breaking them.
4. How do I separate the intake from the block. I ve heard with a hammer and block of wood but where do I hit it to prevent damage to the aluminum manifold. Is there another way?
5. What is the best gasket to use. I plan on using RTV to seal the front and back.
6. Whats the best way to remove old gasket and sealant from intake and heads.

Any advice from some who's done it before would be greatly appreciated

PatG

If you do not have a timing light to re-time the car then clean the base of the distributor where it sits on the manifold and mark it with a marker or scribe. Remove the distributor cap and make note of the rotor position. Then remove the bolt and distributor hold-down. Slide the distributor up and note that the rotor will turn a bit when the gear disengages from the cam. Take very careful note of the position. When you go to reinstall it is exactly opposite. If you mess up you will likely have to set to the motor to TDC on #1 cylinder just like a new motor. There are probably better guides than this - perhaps someone else can chime in.

At the carb. Just the throttle cable, and it may be anchored on a bracket that will come off when you remove the manifold bolts. If you have cruise then that will come off as well. You will have a few vacuum lines, the gas line and the PCV hose that will have to come off as well.

You can try some various penetrating oil as best you can get it in there. Let it sit for a day if a bolt gives you trouble. Although the bolts may be rusty on top I doubt there will be much problem getting them out, make sure you are using a good wrench that is properly sized to avoid slipping on the bolt head.

You can usually find a tab or leverage point on the manifold to start a corner. Once the initial break is made it should come off fairly easy. A gasket scraper is actually pretty good for this and a screwdriver can work. Beware that you can mess up the machined face of the manifold, so use proper caution (don't go all crazy with a screwdriver)

I am a Felpro fan. Definitely use RTV for the valley seals.

I usually use a razor blade but they do sell gasket scrapers. Be careful on aluminum as you can gouge it. Also take care to not get the gasket into the lifter valley. Position rags/towels in the valley when scraping and use a shop vac to clean up when done scraping.


Of course you will want to drain some of the coolant before starting.

A great book that will explain all of this in detail can be found here This will help you to prepare for your future rebuild as well

Ed_78Vette

Vette79C3

Good helpful information from Pat. I would suggest using a camera to document what you are doing as well as using it for remembering exactly where the dist and rotor position before removal. Don't use the gaskets provided for the front and rear block rails. Just a good amount of RTV and definitely use this around the water passages. Use brake cleaner to clean the intake and to wipe down heads.