[Irelands child]

Why does this Edelbrock 1405 carb look so ugly? I hadn't had the air cleaner off for 2-3 months or, probably 500 miles, give or take until yesterday (I put the car to bed for the winter). The carb at the last look at was nice and clean - now, covered internally through the venturis and top cover with this gummy mess. I did disassemble it to do a clean up as well as confirm the rods and jets plus change the spacer to a 4 hole phenolic. It wiped clean pretty easily. I have a "theory" but am interested in what some others think first.



Poor photo, but it does show the crud:



The car today



Getting a good cleaning plus a new alternator arrangement among other things this winter.

Dave W

[1ownerT]

My guess, overlap from the cam causing reversion. The four hole spacer may solve it.

my .02

[gmc1990rodder]

If I'm not mistaken edelbrocks says to use the 4 hole adapter instead of the Square single bore adapter...I'm unsure their reasons why they don't use the single hole adapter maybe someone else knows a lil more than I...But in my opinion the 4 hole adapter should correct your problems .... Good luck

GMC

[Runnin'OnEmpty]

I agree it's reversion, and the 4 hole spacer will help,
but what's your total timing advance?

Maybe back off on the vacuum advance a tad, in addition
to the 4-hole spacer???

[Irelands child]

I have to disagree with you folks that say reversion as the carb has been just fine for 2 years up until now - been nice and clean when I've removed the air cleaner. I am running a 288 degree cam and .529 lift so it isn't impossible.

As far as vacuum advance, I'm running a full MSD ignition, including the billet distributor which is set for ported vacuum and on their "E" curve and 8-10* initial(crappy gas!!). There is one MSD design problem that I might be experiencing with that small cap - cross firing between terminals and detonation. I'll be putting the adapter and the big Ford style cap on over the winter just to be sure.

I also went to both the Edelbrock web site as well as looked at the 1405 IB and Installation info and the only place they say not to use an open spacer is an adapter for a Q-Jet intake. Of course I may have missed something .

There is one thing that happened which I had forgotten when I originally posted this - reminded while doing the clean up when I saw the vacuum cap that blew off once. I pulled the dist. this past summer to do some other work - and put it back in way off and had two of the most amazingly loud back fires. Makes me wonder if possibly I blew incompletely burned gas back through the carb. I also cleaned up the air cleaner - and that was scorched on the inner surface.

Guess I'll do the shot gun approach and fix what I know are weak areas.

Thanks for the your responses.

Dave W

[shine]

looks like soot to me. it may have lit up when you backfired it . having lost many an eyebrow i can attest to the fact a sbc will belch fire and damnation on you.

[Irelands child]

Originally Posted by shine

looks like soot to me. it may have lit up when you backfired it . having lost many an eyebrow i can attest to the fact a sbc will belch fire and damnation on you.

Oh how well I know how a back fire will cause a flame - set the insulation paper cover on fire in my shop with a SB Ford, a 351W. Learned to put the air cleaner on when I did a first start after pulling a distributor

[eloc431962]

Originally Posted by Irelands child

I blew incompletely burned gas back through the carb. I also cleaned up the air cleaner - and that was scorched on the inner surface.Dave W

Dave this just what i was thinking and wondering if it had happened to you, and was getting ready to ask about any backfire problems,
and you have answered that, like shine it looks like soot to me also from a backfire. JMO



Cole