4180C power valve identification

[Saturn V]

Reading BaconB8's 4180 thread made me check the power valve that came in my Holley 3-1346 renew kit. The only markings that I can find are 23 and F1 on the other side. And this power valve looks different from other Holley power valves that I've seen. Is this because this is a two-stage power valve? Does 23 mean 2.3 inHG? If so, isn't that a little low, meaning enrichment will come too late (almost at full throttle)? I tested this power valve with a vacuum pump and noted that the valve starts to move between 2 and 3 inHG and shifted all the way by about 4 inHG.

Is this the right power valve to use for a stock rebuild? If not, which is the correct part to source? I also have a new 125-105 which I believe is a single stage valve with 10.5 in HG setpoint ... would this be better, or too aggressive for a near-stock street car?

[8ballEinstein]

That's a two-stage valve pictured. I don't know what the markings mean.

EDIT - In re-reading your post, it looks like you already knew this was a two-stage valve. IIRC, in the other htread someone mentioned the points at which the valve operates.

[Saturn V]

OK, it looks like the 23 means a 125-218 power valve. Unfortunately, the 1st and 2nd stage opening points for this one aren't listed in the table below, but it looks like 1st stage will be somewhere around 10-12 inHG and the 2nd stage around 6 inHG. I don't know how reliable is this source, but I found the 125-218 power valve referenced in other places.

Now I don't understand the vacuum measurement with my vacuum pump. I know that the valve spindle started moving around 2-3 inHG, but I guess I really don't know when the ports are starting to open inside, so maybe my test wasn't valid.

Does anyone have a more solid reference? The Holley website wasn't much help. Though I did find a table of carb parts that showed the R80163 as a 4180 (80163 is the number stamped on my service replacement carb). However, the power valve part number for this carb is shown as N/S, which means not serviced. Does this really mean that this 4180 has a power valve that is not serviceable?

http://www.docstoc.com/docs/15124407...alve-Reference

[Saturn V]

That's a two-stage valve pictured. I don't know what the markings mean.

EDIT - In re-reading your post, it looks like you already knew this was a two-stage valve. IIRC, in the other htread someone mentioned the points at which the valve operates.

Ernie, thanks for your comment ... I didn't see your post until after I finished the second post. In the first post I wasn't sure what I have is a two-stage valve, but did some more research that convinced me that it is. In the post above I think I've found a table showing what the 23 means, but cannot find an official source to confirm. If my power valve 1st stage opens around 10 and the 2nd stage opens around 6, I think it should be OK. I also read that the two-stage valves are no longer made and that a 6.5 single-stage is a replacement for the 125-218 two-stage valve.

[8ballEinstein]

I didn't realize there were numerous two-stave PV's out there. One of my Holley books lists 2 of them which operates at 12" and 6" Hg or !0" and 5" Hg (for high-altitutude applications). I didn't see these combinations on your attachment. But then, I don't know how reliable my information is. I'll take a look at my other Holley books.

[Saturn V]

Yes, please post any relevant info that you find in your Holley books!

[8ballEinstein]

The other books also list just two valves with similar, but not precisely the same, openning points.

I know JA Cook approves of these PV's for our 4180's, and I don't have any qualms with them. But they were designed for fuel economy and for low power-to-weight vehicle, like RV's. So I don't know how they stack up in performance applications. I've used both types (single and two-stage) and didn't notice any major diference in drivability between them. I never checked the difference in fuel economy.

That's everything I know.

[Saturn V]

Thanks, Ernie. I plan to use this two-stage power valve in the rebuild and see how it works. Fuel economy (about 8 MPG) isn't a big deal though, since I only put a few hundred miles a year on the car on city streets.

[mustangxtreme]

I would expect a mostly stock engine to get better than 8mpg. My concern with that is putting so much fuel down the hole it washes away the oil and you get more wear on the cylinder bores.

[Saturn V]

I would expect a mostly stock engine to get better than 8mpg. My concern with that is putting so much fuel down the hole it washes away the oil and you get more wear on the cylinder bores.

Yes, I think part of the poor fuel economy is all of the idling and troubleshooting in the garage and then "airing it out". I've thought about the fuel washing the cylinder walls, but at cruise (40-45 MPH) the AFR is between 14 and 16. It's a little rich at idle, but total air and fuel flow are low then ... hopefully not washing the cylinder walls with too much fuel? I haven't tried a compression test, yet.

[84GT350CONV]

I just got my 4180c TricKit 3-1346 in today direct from Holley. The power valve that came with it is stamped 4.5. Looks like I might have to order a 6.5. to work with my stock motor. Does anyone know what number is on the stock 2-stage power valve so that I'll know for sure if I have to order the right one? I attached a flyer from the Holley kit that may be useful to others here that converts the numbers from a two stage power valve to a single stage.

[burntorange84]

I just got my 4180c TricKit 3-1346 in today direct from Holley. The power valve that came with it is stamped 4.5. Looks like I might have to order a 6.5. to work with my stock motor. Does anyone know what number is on the stock 2-stage power valve so that I'll know for sure if I have to order the right one? I attached a flyer from the Holley kit that may be useful to others here that converts the numbers from a two stage power valve to a single stage.

great info here! My last kit didn't have that...

IIRC the first stage was 11 inHg and the second was 8 in Hg. I've tested all of mine to test for leaks and it has been basically around there...my pump gauge isn't calibrated!

Saturn, you have to be very focused on the plunger to see movement. I've had a few that barely move at the first stage and the 2nd is a lot more dramatic in movement in my experience.

j

[JACook]

That's a good chart. Thanks. I have a couple original '85 carbs here, with power valves that are
stamped "8", which if I understand the chart correctly, means the 2nd stage would come in at 4.5?
Being a 2-stage valve, that may well be that they held the 1st stage that long into the throttle.

The power valves I've measured in the 3-1346 kits I've used open the 1st stage around 10.5, and I've
observed the second stage comes in around 6.5. So close enough. I know I like the way they run,
and opening the 2nd stage ~2" earlier may be why there's no moderate-throttle flat spot or ping.

I like the 2-stage power valves because they are more progressive, giving a small amount of enrichment
earlier in the throttle, before going full rich. I disagree with the assertion that they don't flow enough
for a performance application. This bit of mythology is based on the notion that performance engines
should always use the "window" style power valves. Nonsense. The power valve channel restrictions
in the 4180C metering block (and pretty much any 4150 or 4160 for that matter) are already far smaller
than the openings on the 2-stage valve.

But it appears that it may all be a moot point, since Holley isn't making the 2-stage valves any more.
I do know the last couple of the 3-1346 kits I got came with power valves that were clearly not Holley...