how often rebuild carb?

66gtk · March 16, 2009 at 10:48 PM

How often would you recommend rebuilding your carb with a kit? Consider a seasonal cruiser with about 1K miles a year....

C6ZZKGT · March 16, 2009 at 11:03 PM Official Post

Troy, Are you running a Ford or Holley carburetor?

-Fred-

65Rangoon_old · March 17, 2009 at 8:37 AM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

How often would you recommend rebuilding your carb with a kit? Consider a seasonal cruiser with about 1K miles a year....

I did my rebuild back in '99 as I recall inconjunction with the major overhaul of the engine. The car has been on the road since Mar 2000, and driven very close to 20k miles since then. To date, no internal/external leaks, performs extremely well, maintains its' adjustments and there is no rebuild planned anytime soon. I reckon what I'm saying is; I don't consider rebuild a time sensitive necessity. Instead I believe that when its performance starts to degrade, then that is when to act.

[Blocked Image: http://s4.tinypic.com/30w2jyw_th.jpg]

66gtk · March 17, 2009 at 9:25 AM

Unfortunately, it's not an Autolite, but I have a 600 CFM Holley in service on my K. I noticed last season that my car would want to die when braking to a stop at times. It was intermittent, and worse when it was warm. Sometimes, I noticed it was more difficult to start after doing these things as well. I had gone through everything including new points, condensor, plugs, wires, timing, valve adj, and this problem still remains. I'm having a Ford guy go through the carb right now, but am also considering ditching the coil and points and getting new Pertronix units. I should also put an inline fuel filter in there as well. It just pains me to deviate too much from stock, but I do like to drive and enjoy my Kar, and I want it to be a reliable top performer as well.

66gtk · March 17, 2009 at 9:27 AM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

How often would you recommend rebuilding your carb with a kit? Consider a seasonal cruiser with about 1K miles a year....

I did my rebuild back in '99 as I recall inconjunction with the major overhaul of the engine. The car has been on the road since Mar 2000, and driven very close to 20k miles since then. To date, no internal/external leaks, performs extremely well, maintains its' adjustments and there is no rebuild planned anytime soon. I reckon what I'm saying is; I don't consider rebuild a time sensitive necessity. Instead I believe that when its performance starts to degrade, then that is when to act.

[Blocked Image: http://s4.tinypic.com/30w2jyw_th.jpg]

That's AWESOME!!

289kford · March 17, 2009 at 2:24 PM

My Kar never ran better than when I took off the Holley and installed a Pony Carb unit.

The Holley was a pain in the butt.

I think you will get 3 of your wishes granted, 1)good performance, 2)reliable and 3)not deviated from stock, by going with a 4100.

I am also running the Petronix, most people can't tell.

66gtk · March 17, 2009 at 2:41 PM

I tried a rebuilt 1.12 Autolite 4100, and it was a nightmare. Sent it back twice and couldn't get it to work. My dad had a similar experience with his, and never got his restored 4100 to work either. Bad luck? I don't know, but it seems with the money these are exchanging hands for, there is a lot of opportunity for bad carbs to enter the market place in hopes of making a buck. The most knowledgable Ford mechanics I know have nothing good to say about the current popular "restored" carbs available on the market, and my own experience is in line with this. Maybe the 3rd time I'll get lucky, but is it worth the chance??

Kman_old · March 17, 2009 at 3:14 PM

My original 4100 had the soup to nuts rebuild and cosmetic restore by Pony Carbs in 2005. Never touched a thing on it - went right out of the box and onto the car. I put 1,000 to 1,500 miles a year on the car and have had zero issues so far from then to now. I also use the original Pertronix and Pertronix coil

Jack

zray · March 18, 2009 at 12:21 AM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

Unfortunately, it's not an Autolite, but I have a 600 CFM Holley in service on my K. I noticed last season that my car would want to die when braking to a stop at times. It was intermittent, and worse when it was warm. Sometimes, I noticed it was more difficult to start after doing these things as well. I had gone through everything including new points, condensor, plugs, wires, timing, valve adj, and this problem still remains. I'm having a Ford guy go through the carb right now, but am also considering ditching the coil and points and getting new Pertronix units. I should also put an inline fuel filter in there as well. It just pains me to deviate too much from stock, but I do like to drive and enjoy my Kar, and I want it to be a reliable top performer as well.

lower the floats.

Z. Ray

C6ZZKGT · March 18, 2009 at 9:33 AM Official Post

A typical Holley problem, even more aggravated by todays gasoline, is the power valve failing. That will cause idle problems. Z.Rays suggestion of lowering the floats is also a good one. Symptoms of a high float level are more pronounced on hard braking.

I run 4100's on my Kars with no issues for years. The power valves tend to hold up reasonably well and the first problems are usually a leaking accelerator pump. The 4100 is a really good carburetor and I do not find it difficult to diagnose and repair.

-Fred-

289kford · March 18, 2009 at 11:01 AM

the 4100 is so good in fact, Summit now sells a version of it. maybe made by Holley, I seem to remember a marine version from Holley years ago. this will give you the best of both worlds?

http://store.summitracing.com/partdetail.asp…15&autoview=sku

dunc289_old · March 18, 2009 at 11:57 AM

The first 4100 I put on the 347 wouldn't idle well or run smoothly, long hesitation..... then I put a freshly restored pony restored 4100 that I paid to have done, not one ' someone said was restored by them' and it runs quite well, my distributor needs some tweeking 'cause it jumps the advance too far at low rpm's, but thats not the carbs fault.<img src=images/icon_smile_big.gif border=0 align=middle><img src=images/icon_smile_big.gif border=0 align=middle>

s2ms · March 19, 2009 at 10:25 AM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

Z.Rays suggestion of lowering the floats is also a good one. Symptoms of a high float level are more pronounced on hard braking.

It would make sense to me that a low float level on a Holley would also cause stalling when braking as the fuel surges to the front of the bowl and momentarily leaves the jets dry.

66gtk · March 19, 2009 at 10:35 AM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

Z.Rays suggestion of lowering the floats is also a good one. Symptoms of a high float level are more pronounced on hard braking.

It would make sense to me that a low float level on a Holley would also cause stalling when braking as the fuel surges to the front of the bowl and momentarily leaves the jets dry.

So you guys are saying 2 very different things?? I wish I knew more about carb tuning, but I simply don't.

cobraboy · March 19, 2009 at 11:02 AM

Hi guys, what jets do ya all run on a standard HiPo motor ?

dunc289_old · March 19, 2009 at 12:16 PM

I think they are mixing things up a bit. If the level of the FUEL in the float chamber is too low, hard braking would cause the small amount of fuel in the float bowl to surge forward, uncovering the outflow point. fuel starvation momentarily. If the floats are set LOWER, they will shut off incoming fuel with the level of fuel in the float bowl too low to keep fuel over the outflow point under hard braking. Setting the floats HIGHER will allow the fuel level to be nominally higher, eliminating uncovering the outflow point. Have I got this right, guys?<img src=images/icon_smile_big.gif border=0 align=middle><img src=images/icon_smile_big.gif border=0 align=middle>

zray · March 19, 2009 at 8:38 PM

On a Holley, if the fuel level is too high (floats set too high) gas may come out of the vent tube of the secondary bowl during braking and out of the primary bowl vent tube during acceleration. When all this un-metered gas hits the combustion chambers, the engine may flood & die. Even with the vent baffles or whistles, gas can still come out the vent tubes. For this reason, vent tube extensions are common on drag racing or off road racing cars.

If the fuel level is set way too low, as mentioned above, the jets may become uncovered during braking (primary side) or acceleration (secondary side). Or you can even run the bowls dry during full throttle if the float level is too low. The bowls are pretty large so this is more rare in my experiences.

I personally have more trouble with the "gas level too high" scenerios

Z. Ray

s2ms · March 19, 2009 at 9:49 PM

Z. Ray and I are talking about two seperate, but related and equally problematic scenerios. Both based on personal experience no doubt.

I have had more issues with an engine trying to stall on hard braking due to the float (and fuel) level in the primary bowl being too low and uncovering the jets, especially on steep hills.

Holley offers tube extensions that attach to the secondary jets so they can scavage fuel from the rear of the bowl under hard acceleration if that is an issue.

I guess the bottom line is if you are using a Holley make sure the floats are properly set.

zray · March 20, 2009 at 8:55 AM

When heavy braking caused my car to die, I was never certain whether my fuel level was too high causing flooding, or too low, as mentioned above, causing fuel starvation. But when I re-installed my Paxton I bought a wideband air/fuel ratio gauge to help me with jetting.

http://www.aempower.com/ViewCategory.aspx?CategoryID=67

Now I could see the mixture richen during heavy braking, and knew which direction to take to try & correct the problem. A very good tool to help diagnose fuel issues.

Z. Ray

6hypo5conv_old · April 9, 2009 at 8:50 AM

66gtk: I would also suggest that you get a good repro 4100 HIPO directly from PONY-(Jon Enyeart) I just got my Kar back from the restorers with the one I purchased from Pony on it and its perfect, perfect from the first start up perfect now, you had a very bad experiance with that former employee of Jon's attempt at the 4100 for you, don't let that experiance make your mind up to keep the non-original holley on your otherwise stock engine.

On the other hand I had a Holley specialist custom build an OLD OLD Holley 600 carb for my 302 in my 1978 F150 with the Ford auto trans kick-down lever, I put it on the engine almost 15 years ago set it and drove it about 75k miles then recently sold the truck with the carb operating flawlessly-never touched it in 15 years execpt to change the aftermarket in-line filter very regularly.

Participate now!