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Quadrajet Carb Talk and Tips / Re: 4MV Marine swap
« Last post by LouC on Today at 07:36:16 AM »
Agreed I have no problem with points and do keep spares, and a feeler gauge on board with the small screwdriver needed to change if I have to. In my case the boat has an OMC Cobra drive system which uses an Electronic Shift Assist module that lowers the idle speed to allow the clutch dog in the lower unit to release. This is what allows you to shift to neutral with a load on the prop.  This module only works with points, it will not work with the electronic system unless you use a diode fix (might not be reliable in a marine environment) or a properly set up new Assist Module made to work with electronic ignitions (CDI electronics in Alabama makes such a unit). The Mercruiser system actually momentarily shorts out the ignition on the dog clutch Alpha drive and if the shift cable is a bit sticky it will stall the engine. The OMC system is more sophisticated in that it lowers the rpm from about 600 to 450 and will not stall the engine, if its in good enough tune to run at that speed.

I wish they had made a marine version of the old Delco window style points distributor. The easiest ever to set the points on. I still have that flex allen wrench tool from the 70s! Worked great on Chevrolets, Oldsmobiles and Pontiacs  with the distributor all the way in the back.
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Quadrajet Carb Talk and Tips / Re: 4MV Marine swap
« Last post by Cliff Ruggles on Today at 02:54:06 AM »
Points are preferred for Marine use simply because if/when they take a crap (which isn't often) you can have it back up and running in a few minutes.

I recommend installing a set of points into the distributor for each engine, set the dwell, then remove them, seal in zip lock bag with new condensors and put them in the boats storage box in the console.

Install another new set of points/condenser, set the dwell, ignition timing, and sleep better at night.

If/when they take a dump you'll be back up in minutes, and don't forget a good fitting screwdriver on board in your tool kit or put one in the bag with the spare points.  If you have the type of distributor where you have to completely remove the screws than hold down the points/condenser grab a few extras and put them in the back with the spare parts.  Most of those screws will be #8 or #10 and either 24 or 32 pitch.  You can get a hole bag of them for a couple bucks at most fastener stores.

I'm not fond of electronic conversion kits, even for automotive use.  You will NEVER break down in front of Summit or Jegs and require a flat bed back to the house.  Contrary to what companies selling "bug zapping" distributors will tell you, there isn't a single ounce of power waiting for you by converting them.  You may get a little quicker cold starts with MSD stuff, and slightly improved idle quality IF your carb is a little lean at idle, but from idle to the shift point they make the same power as anything else provided the timing curves are exactly the same.

With a boat you can get stranded miles from the dock and become a SAR case, or even get injured or killed if a storm comes up or you get ran over by a barge.

I was a Coast Guard boarding officer for several decades.  As far as inspections and carriage requirements we typically only look at the flame arrestor to make sure it's still in place, and a working ventilation fan for enclosed engine compartments on small craft as far as the engine bay is concerned.  So you woln't get a violation for converting your points distributor to electronic or replacing it with something aftermarket, but as mentioned it's not a good idea......Cliff
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Quadrajet Carb Talk and Tips / Re: 17059241
« Last post by Cliff Ruggles on Today at 02:41:46 AM »
Add the holes to both sides by drilling down from above in the bypass air channels......no worries.....Cliff
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Quadrajet Carb Talk and Tips / Re: 4MV Marine swap
« Last post by LouC on February 16, 2019, 02:24:08 PM »
I believe this is correct, the most commonly used one is the GM EST system, used by Volvo Penta and others. Merc has their own system Thunderbolt IV and V. I am still running an ancient Prestolite points distributor with full mechanical advance. Works just fine actually.
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Quadrajet Carb Talk and Tips / Re: 17059241
« Last post by mcx on February 16, 2019, 04:42:32 AM »
Cliff..thanks for clarifying what I dont have here, ...any issue with adding a second corresponding hole in that drivers side base plate channel for bypass air?. Adding the passenger side seems fine...Mike
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Quadrajet Parts and Numbers / QuadraJet Choke Pull Off Bracket Repair
« Last post by 4ever18 on February 16, 2019, 04:15:49 AM »
I have a couple of choke pull off brackets and the tabs that hold the pull off to the bracket have been broken off.  I ordered a wire repair clip from QuadraJet Parts. com but the part was out of stock and they don't know if or when it may be restocked.  Any idea where else I may be able to find this part?
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Quadrajet Carb Talk and Tips / Re: 17059241
« Last post by Cliff Ruggles on February 16, 2019, 02:15:36 AM »
Both are closed.  That hole supplies full manifold vacuum to the port on the drivers side of the main casting.......Cliff
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Quadrajet Carb Talk and Tips / Re: cam selection
« Last post by Cliff Ruggles on February 16, 2019, 02:14:24 AM »
The ICL method can be confusing and difficult to obtain good results especially if you are going back and forth with the crank instead of in one direction only.

As many engines as I've done over the years I just check the intake open point of the #1 intake lobe and leave it alone if it's at or close to where it needs to be.

I do NOT use double roller or multiple keyway timing sets, only factory link belt type and source out the 3/4" wide sets for my engine builds.  This makes moving the cam around a little more difficult, but well worth the effort, IMHO.

EVERYONE out there since WAY back in the 1970's when I got into this hobby runs right out and buys a "double roller" timing set like it's some sort of upgrade.  Most are just OK some are a little better and some are just plain JUNK.  The ones that fall into the decent category will have billet sprockets, seamless full roller chains and multiple keyways to move the cam around.  I still woln't use them here in my own engines.

One of my mentors ran a very successful Stock Eliminator Camaro and told me decades ago that the factory timing sets and much stronger than the roller variety, and they have constant tooth contact, absorb some harmonics, and will last the life of the engine.

So jump ahead to 2000 when I built my first 455.  The company I sourced all the parts from highly recommended that I purchase a 9 keyway Rollmaster timing set, so I went off course from what I typically do and bought one.  It did fine for a few years but I was driving the car almost every day and racing it as often as I could get it to the track. 

I was racing in Northern Ohio one evening and the car started to slow down, WAY down, but oil pressure was fine, fuel pressure was fine, no internal noises, etc.  I put the car on the trailer and pulled the engine over the weekend.  Figured I freshen it up and restore power.  Turns out the ONLY thing wrong with it was that the very expensive double roller seamless timing chain had failed.  It was so loose you could just about walk it right off the gears!

I replaced it with a Melling 3/4" wide set and the engine was fine till I replaced it in 2009.  The new engine has a Melling timing set in it and just happened to have the water pump/timing cover off recently to repair a coolant leak and the timing set looked perfect........FWIW......Cliff
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Diagnose a Quadrajet carburetor problem / Re: Ping when secondaries open up
« Last post by 77cruiser on February 15, 2019, 03:53:47 PM »
What hanger do you have?
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Quadrajet Carb Talk and Tips / Re: 17059241
« Last post by mcx on February 15, 2019, 02:05:56 PM »
...here is a pic of the base plate and what I think are the idle air bypass...one open and one closed?
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