Vacuum line routing, timing after smog pump removal

Started by chefrob, March 11, 2021, 05:22 AM

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chefrob

I am having a problem my vacuum and timing on my 454cid after i removed the smog pumps. How do I need to set up my vacuum lines and adjust my timing on this? 1988 Chevy P30 454cid. Do i need a different carb? Help Please and thank you i??

Oz

Hello and welcome!

Other members have had to deal with the smog pump issues youre having.

Ente, smog, in the search bar in the upper right corner of the screen and select "Google" from the drop down.  That will bring up a few, really good topics which cover your questions.
1969 D22, 2 x 1974 D24 Indians, 1977 27' Itasca

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Quote from: chefrob on March 11, 2021, 05:22 AM
I am having a problem with my vacuum and timing on my 454cid after I removed the smog pumps. How do I need to set up my vacuum lines and adjust my timing on this? 1988 Chevy P30 454cid. Do I need a different carb? Help Please and thank you i??

Are you experienced in such matters? I do not mean anything negative by that whatsoever. Do you have a timing light and timing tape? There is quite a bit that can be done, and yes one's gas mileage will improve and throttle response. A new carb not at all, but a facelift (carb) may be in order, angel:

After a bit of thought, you could pull the entire vacuum line plumbing. Of course one would leave the choke pull-offs and the vacuum advance lines on but the rest is emission-related. As to timing advance the initial to 8/ 10.

There that should start a conversation.

tmsnyder

Removing the smog pumps shouldn't make any difference to the timing.

Why do you think you have a timing problem?

A little basic maintenance will go a long way.  Check all your vacuum lines for leaks or replace with new, that tubing is not expensive.   Open up your distributor and make sure the mechanical advance weights are moving free and everything is fine there.  Check your vacuum advance can with a small handheld vacuum pump, make sure it is operating and not stuck.

Then put a timing light on it.   It might be timed from #5 cylinder from underneath the front end iirc.

You might also consider recurving the distributor with a spring/weight kit and vacuum can from a supplier like Summit or Jegs.   It takes the timing back to pre-smog, nothing crazy, just proven by 100+ years of internal combustion engines.

Good luck!