AMC 327 Holley 2300 Tuning

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Brly
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AMC 327 Holley 2300 Tuning

Post by Brly »

When I got my truck I was told all it needed was a fuel pump to run, which turned out to be true. I put a new fuel pump on and it fired up. The timing was off, so I got that straightened out and have been driving it since (not heavy ) while doing a bunch of other work. That was 3 years ago. I haven't touched the carb again until this week. It has a Holley 2300 500 cfm carb that appears to be fairly old. I got the tuning manual from the Holley website. Fuel level in the bowl was spot on. I connected a vacuum gauge and adjusted the mixture screws equally for best vacuum and ended up at 19 on the gauge. A very small adjustment was needed to obtain this. Reset the idle to approximately 500 rpm and double checked that the timing was still on (it is). I'm happy with the idle, very smooth when warmed up. The plugs that were in it were Champion RH18Y. I replaced them with Autolite 437 plugs last night before making the adjustments noted above.
The fuel economy has always been 10 mpg and the truck will stink up my garage very quickly if I let it idle inside. It does burn a little oil, typically a puff of blue smoke on start up. I haven't seen black smoke, raw fuel smell or anything else to indicate a real rich condition. I don't know any history on this engine and really don't have much frame of reference, but it seems like it's a little more sluggish than it should be. It has a T18 and 4.11 gears. I don't run it much over 60 mph, which should be around 2500 rpms.
My question is, should I dig into the jetting and power valve or look somewhere else?
It leaks oil and is in general pretty ugly. I intend to pull it someday for a refresh at minimum, but now is not the time for that. I'd just like to keep it running as good as it can in it's current condition.
Any thoughts?
1966 Jeep J3600 Gladiator - AMC 327/T18/D20
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Brly
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Re: AMC 327 Holley 2300 Tuning

Post by Brly »

Just for future reference, I did more reading and found that the 2300 carb is pretty rich, so I popped the bowl off. It appears to be in stock configuration. 73 main jets, 50 power valve and (assuming) 50 cc accelerator pump.
I ordered some parts that should help. 64, 66 and 68 jets, 75 power valve (65 was out of stock), 30 cc accelerator pump and reusable bowl and metering block gaskets. I'll put the 68 jets in first along with the rest of the parts and see how it does.
The AMC forum suggests that a 500 cfm 2300 carb is too much for the 327. I'll see what these changes do. Maybe someday I'll find a 4 barrel manifold...
1966 Jeep J3600 Gladiator - AMC 327/T18/D20

letank
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Re: AMC 327 Holley 2300 Tuning

Post by letank »

IIRC the holley 2300 is also on the IH... check it, their engines are mostly 304 so it takes a little guess

http://www.binderplanet.com/forums/inde ... ets.35044/
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
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Brly
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Re: AMC 327 Holley 2300 Tuning

Post by Brly »

Good information there. I think it can be jetted down enough, but the idle circuit is still really rich. I can't lean out the mixture screws anymore than they are right now. Read about putting wires in some of the idle passages in the metering block to restrict fuel at idle, or drill and tap the passages so the idle can be adjusted with jets. Just doesn't seem worth it for how much I drive it right now. It's running better than it was so I'll probably leave it alone until I can go to a different carb. Have 66 jets in it now. The accelerator pump made a noticeable difference in throttle response, more snappy.
1966 Jeep J3600 Gladiator - AMC 327/T18/D20
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Harry Dawg
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Re: AMC 327 Holley 2300 Tuning

Post by Harry Dawg »

Hi Brly.
I am also running the Holley 2300 on my '69 J3000, but it is about to drive me up a wall!
(Figuratively that is, this truck couldn't climb out of a wet paper bag as of right now lol)
It seems like I am constantly fooling with it, and now cannot get the truck to idle at all. (It shuts off without applying throttle).
I am wanting to swap it out for Motocraft 2100 (still a 500 CFM carb), but am unsure about what to do with the factory carb spacer.
It has 3 vacuum lines coming from it, 2 of which were plugged by the previous owner.
Any idea what these go to? From what I understand one goes to the vacuum advance for the distributor, but the previous owner installed a summit ignition box, so would this be unnecessary?
Basically just trying to figure out the vacuum system under the carb.
1968 J3500 - 1985 CJ7 - 1998 Grand Cherokee 5.9 Liter Limited - 2006 Grand Cherokee Limited
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tgreese
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Re: AMC 327 Holley 2300 Tuning

Post by tgreese »

Just a comment - a 2100 is not a 500CFM carburetor. Indeed, as an OEM carb, it's not CFM rated at all. CFM ratings are something the aftermarket carb makers apply to sell product. An OEM carb is developed and tuned for a specific application, and does not have such published ratings.

A factory 2300 on a 327 is also not CFM rated, being OEM. Comparing to an aftermarket Holley 2300 rated at 500CFM, the 327 2300 will be smaller.

Not sure what to tell the OP about his carburetor. The factory plumbing should be shown in the FSM. If you are tuning a Holley to something other than factory specs, I suggest you buy a book about Holley tuning online (Amazon, Alibris) and read up. Speed shops have all the Holley tuning parts, and the design of the 2300 is just like a Holley 4V, except no secondaries.

If you want to tune to factory specs, the FSM will have the proper adjustments, and a rebuild kit will also have adjustment instructions. Make sure you have no vacuum leaks. If the throttle shaft bore is worn out (likely on a 40+ yo carb) the carb body will need to be reamed and bushed to cure leaks around it. Wear in this area will cause an erratic idle.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
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tgreese
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Re: AMC 327 Holley 2300 Tuning

Post by tgreese »

Also, the usual problem with an old 2300 - or the 2100/2150 - is a busted power valve diaphragm. Back fire can blow out the power valve, and then the engine runs rich all the time. Engine vacuum holds the power valve closed, except when the diaphragm is broken. Very common. Take the power valve cover off and look for liquid gas. Should be dry.

Newer Holley carburetors come with a check ball that blocks backfire, preventing this problem.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

J20DAN
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Re: AMC 327 Holley 2300 Tuning

Post by J20DAN »

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tgreese
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Re: AMC 327 Holley 2300 Tuning

Post by tgreese »

The OP has not been around for more than a month. However, if he should stop by the site, I would point out that the 327 did not come from the factory with a 2300 (I had mistakenly claimed otherwise in other threads). Instead it came with the Holley 2209, which is another Holley 2V carb with the same base pattern as the 2300. It appears that some 230s came with the 2300, but not the 327. This is probably a good thing, since the unmodified 2300 functions badly on the trail, and the 2209 is probably better in that regard.

If the OP does have a 2300, it will be either an aftermarket carb (hot rod app) or from another application. In either of these cases, it will respond well to tuning according to one of the many aftermarket books about Holley performance carburetors. The 2300 uses the same speed parts as the 4150/4160 4V, except it only has one float bowl and 2 venturis. Everything regarding the primary tuning for the 4150/4160 models will apply to the 2300. There's also coverage of mods for trail use in various places online, with many (possibly helpful) suggestions.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
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