Idle rpm drops substantially when putting car in gear

[Michael_]

Did they use RTV and/or paper gaskets at the factory? What exactly did the factory use/do?

 

[WileE]

And... what are your vacuum readings ?

Yes, sure sounds like a vacuum leak to me; at least that’s the first thing to check.

Buy some tools. Start with a vacuum gauge and a timing light.

Basics first would be looking for vacuum leaks/leaking hoses etc:
- disconnect & plug brake booster
- plug ALL vac fittings to the carb or intake manifold
- check spark plugs & cracks in the insulators
- etc. Look for things that age or mileage could cause deterioration.

Do this, do that. Check here, check there. Try this, try that. Replace this, replace that. And yet you don't even know where you started. See these ^^ posts. That's where you start.

 

[RemCharger]

Did they use RTV and/or paper gaskets at the factory? What exactly did the factory use/do?

The factory never used the paper gaskets on standard port B/RB engines. They didn't exist. Nor were they needed.

yes, use a thin smear of ultra black rtv in the crush beads of the valley pan. The factory used the old indian head stuff. Torque to spec 40 lbs. Depending on yr they changed the spec , but 40- 50 is lots. If you cant get a torque wrench in there, the spec is damn tight. It has to be so you crush the ribs as designed.

 

[threewood]

So i watched a couple videos and these people seem to use RTV together with the gasket:


Is this necessary/good?
If necessary also if you use the additional paper gaskets or is this basically the alternative to using the additional paper gaskets?

I suggest Hylomar on both sides of the metal gasket and under the clamp bars.

 

[Geoff 2]

Edel recommends 25ft/lbs on the intake bolts because their intakes are alum. Do not use silicon where it can come in contact with petrol or petrol fumes, which would be the intake ports. Use Permatex cement on the int ports, silicon everywhere else.

 

[Michael_]

Do this, do that. Check here, check there. Try this, try that. Replace this, replace that. And yet you don't even know where you started. See these ^^ posts. That's where you start.

Well i already found two vaccum leaks (the intake even leaks on both sides) so i don't think that further diagnosis is needed at this point.
I mean sure maybe there is even more wrong but i will start with those two leaks. Personally i don't really expect more to be wrong (timing, carb tuning etc.) because the engine runs great apart from this idle rpm issue.

 

[AR67GTX]

Back to the booster - are you sure the booster is bad or is the check valve bad? The check valve is an easy and cheap fix. You can have your current booster rebuilt. I used Booster Dewey (actually Power Brake Booster) last year and it’s working great. Turn around was very reasonable too.

Vacuum Brake Boosters | Power Brake Booster Exchange, Lynwood

Power Brake Booster Exchange rebuilds vacuum brake boosters and supplies hard-to-find booster parts. Find out more about our services online today.

www.powerbrakebooster.com

 

[Orig69]

Well i already found two vaccum leaks (the intake even leaks on both sides) so i don't think that further diagnosis is needed at this point.
I mean sure maybe there is even more wrong but i will start with those two leaks. Personally i don't really expect more to be wrong (timing, carb tuning etc.) because the engine runs great apart from this idle rpm issue.

Did you diagnose the cruise control for a vacuum leak?

 

[Michael_]

Back to the booster - are you sure the booster is bad or is the check valve bad? The check valve is an easy and cheap fix. You can have your current booster rebuilt. I used Booster Dewey (actually Power Brake Booster) last year and it’s working great. Turn around was very reasonable too.

Vacuum Brake Boosters | Power Brake Booster Exchange, Lynwood

Power Brake Booster Exchange rebuilds vacuum brake boosters and supplies hard-to-find booster parts. Find out more about our services online today.

www.powerbrakebooster.com

Did you diagnose the cruise control for a vacuum leak?

I think it will be a good idea to disconnect the cruise control unit and replace the check valve just to be sure.
I just ordered parts but it can take a while until i get them.