Community Forums

quikduk · 10-17-2007, 05:55 AM

We had a Rochester on our '69 Vette. I tried (unsucessfully) to have it re-built 3 times by "professional" carb shops. It seams that there are a LOT of interchangable Rochester parts from other models and only the ones for THAT particular carb on our Vette would work, not the Buicks, not the other Chevys. It was a real PITA.

I ended up scoring a N.O.S. (new old stock) that was on a dealers parts shelf. After going through it re: adjustments, it worked like a charm.

The Edelbrock is a good carb since it is based on the Carter AFB which I hae had on my 440 gas MH's before except it doesn't have the 35 different yet dependent adjustments like the Carters. With the Carter AFB, if every adjustment wasn't just so, the thing wouldn't run right. Once set up, they are one of the best carbs out there. After I re-jetted and adjusted my AFB on the 440 gasser I just sold (I also had Thorley headers, an Edelbrock manifold and had the dist. re-curved for more initial and total advance), the thing ran smooth and fast while still getting me around 7 to 7-1/2 mpg.

Most people choose Holleys for cost and ease of "tuning" since most don't know what they are doing. They are a very simple carb.

Good luck.

JimElliott · 10-17-2007, 07:50 AM

On my (sold) 87 454 the rochester was pig rich and after getting into it here is what I found.

76 jets (way to fat) sooo I finally wound up with 73s which are really in the stock range.

Next item was installing a "indexed" vacuum gauge (1 pound increments) and normal road travel @60 MPH (flat) the vacuum languished between 8-13 inches of vacuum, After a quick dial in on the distributer (22º mechanical) and 10º base the vacuum the vacuum jumped to 11-16 down the flat slab..........

Now the reason to get the ignition straight and LOCK IT DOWN FOREVER was for better power & milage and to dig back into the carb....A stock Rochester has a power rod spring that starts to open (more fuel) at 11 inches of vacuum which is NOT GOOD for the size & weight of our rigs.

Dropped in to the Carb shop (Ontario Calif) and purchased a pack of 6 inch springs (stock) and the results we're amazing with better milage, Cleaner running at altitudes and overall performance and yes that motor home (Winny 22) went from a ~stock~ 5 MPG to well over 9 MPG.

Stock ignition was 4º base 16º mechanical with a 25º vacuumm advance, Total lite footing down the slab @60 MPH was 45º.

New setup is 10º base 22º mechanical and a 10º vacuum advance for a total of 42º..And instead of climbing a hill with ZERO vacuum and 20º advance it has 32º advance, Less heat and much more power....My 83 is setup the same way.

Jim

Hemi · 10-17-2007, 09:39 AM

hollhoek

When we bought our 86 Holiday Rambler with 454 chev 3 years ago we could just hear a slight exhaust manifold leak...confirmed also by a mechanic. It got progressively worse and eventually had the sound of a dragster. I briefly considered replacing the manifolds and then came to my senses....this could be a real mess if the bolts broke off. I found a truck garage to do the job. Yes, it was tough job, two bolts broke off...they had to weld a head on the get enough meat on the bolt to turn it.

Bottom line: the mechanic did a great job....which included finding replacement manifolds etc. The engine is real quite now, except for a valve rocker arm tap tap tap....I also had he garage replace the plugs, add new distr cap ....total cost $1500. I am very glad I had this job done rather than tackle it myself.

HEMI

NeilV · 10-17-2007, 04:18 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by quikduk:
We had a Rochester on our '69 Vette. I tried (unsucessfully) to have it re-built 3 times by "professional" carb shops. It seams that there are a LOT of interchangable Rochester parts from other models and only the ones for THAT particular carb on our Vette would work, not the Buicks, not the other Chevys. It was a real PITA.

I ended up scoring a N.O.S. (new old stock) that was on a dealers parts shelf. After going through it re: adjustments, it worked like a charm.

The Edelbrock is a good carb since it is based on the Carter AFB which I hae had on my 440 gas MH's before except it doesn't have the 35 different yet dependent adjustments like the Carters. With the Carter AFB, if every adjustment wasn't just so, the thing wouldn't run right. Once set up, they are one of the best carbs out there. After I re-jetted and adjusted my AFB on the 440 gasser I just sold (I also had Thorley headers, an Edelbrock manifold and had the dist. re-curved for more initial and total advance), the thing ran smooth and fast while still getting me around 7 to 7-1/2 mpg.

Most people choose Holleys for cost and ease of "tuning" since most don't know what they are doing. They are a very simple carb.

Good luck. </div></BLOCKQUOTE>

Carter was way ahead of their time coming out of the gate. I needed a better manual for rebuilding one on a late 70's (early 80's ?) AMC and an old timer I was visiting opened up a motors manual and worked through it with me. The detailed verbiage and illustrations in the book made it a breeze. After we were done he asked me to close the book and put it back in its spot on the shelf for him. I was surprised when I saw printed on the cover "1927 Motors Manual". He said his father and grandfather had been getting them every year since they started publishing them and he was continuing the tradition. Looked like he had close to 100 the last time I visited him which was some time ago. Some 50 years had passed and that same model Carter was still in production and a very viable carborator.

Sanjay R · 10-18-2007, 10:48 AM

OK, all of this is making me think about the Carter Thermo Quad carb on my 440. I'm missing a spring clip, and the thing seems to have been sitting long enough to have the fuel in it turn to varnish. spraying heavy doses of carb cleaner down it while it was running seems to have helped, but I'm not sure if the carb is worth fixing. Should I just replace it with an Edelbrock?
Sorry for the thread hijack, by the way.

Hemi · 04-06-2008, 07:25 AM

Friends

I seem not to be getting any charge to my chassis battery; the battery (which is new) voltage when engine is not running is ~12.6 volts. When the engine is running the voltage drops to about 12.4 volt. Increasing the engine rmp has no effect on the battery voltage....I have been told that a good operating alternator system should lead to a battery voltage of about 13.5 volts when engine is running at about 2500 rpm.

I removed the alternator and had it tested at a local alternator shop; it tested good at shop. I then put the alternator back on .... still no charging.

Thinking that problem is in the battery isolator system, I disconnected the big cable on the end of the alternator and then ran a cable from that post to the chassis/engine battery + post. Still, no indication of battery being charged.

One unsolved problems are the two smaller sized wires come from a plastic clip on the side of the generator. Where do these wires go...in our unit one is left haning, the other disappears into the wiring harness.

A friend told me that I don't need these two small wires? All that is necessary is big wire that goes to the middle post on the isolator to big post on the back end of the alternator.

Any help would be appreciated...

1) how are the two small alternator wires used?

2) could the isolator be bad?

The RV is a Holiday Rambler, presidential 30 (feet), thanks

HEMI

Wallaby Dan · 04-08-2008, 05:31 PM

I can't find my GM book right now...Don't Know what pile I need to dig into! As soon as i do I will try and let you know, Dan

I think I got it and will try and post teh picture here.

In the photo, The one long wire you say goes into teh wiring harness goes to your Ignition switch1 The other wire on that plug you say is hanging should be going to the same connection as the battery wire. It should work as the votage regulator is interior The wiring diagram I have is for older vehicles to changeover to alternator. But you should be able to see where that one wire goes!

Hemi · 04-12-2008, 01:55 AM

Wallaby Dan

Many thanks for taking the time to prepare an excellent diagram. I did get the generator working very well; the wiring I used is very similar to what you prepared. I am going to store your diagram in my important items to remember.

The big wire (middle arrow) goes to the center post of the isolator. Both chassi and coach batteries are charging good now.

Again, many thanks, HEMI

Wallaby Dan · 04-12-2008, 09:39 PM

Hi Hemi, I am glad i could help Have a good one, Dan

Hemi · 04-13-2008, 05:37 AM

Dan,thanks.

I just had a look at your photoweb page; you have some serious projects underway. Good luck.

On your map, I note that you have not been to OR...try it sometime (I am from OR)...some wonderful camping and travelling, HEMI

IWD

Wallaby Dan · 04-14-2008, 11:10 AM

Hemi, I had planned to go up that way this summer and then the toad died, and now we are still behind schedule. It will be fall or next spring when we may be able to travel again. I got more things to do than I really should but, it will be nice when finished.I have friends up that way too! i have one in Washington state that i hoped to see one more time but he has Leukemia and I most likely will never to see him again. Its a shame, getting old, You make the plans and then something like this happens. He has a diesel pusher and Almost paid for.
Well i will check in later, Lunch is ready so have a good one and I will be back later, Dan