Hi, everybody,
I have a Holley 6619-1 carb, and some time ago I asked on this forum if I could use an 1850 metering block in it. I got some really good advice on why it wouldn't work. Now, I would like to know if the base plate from an 1850 could be used on my 6619 (I snapped the pass. side rear ear off of it tightening it down on a homemade adapter that stuck out a little to far) I checked the Holley numerical listing, and they list the 6619s base plate as N/S (not serviced) I hope this doesn't mean it is so different that it can't be substituted with the 112-20 base plate. I really had the 6619 tuned in nice, I would like to avoid going thru that process all over again. If I can't get any word on this, I'll take 'em off and compare 'em, but I would like to know first if it's even worth doing, or should I just look for another 6619 to rob the baseplate from, or what. Thanks,


Scott

 

Looked on ebay and found this :

http://www.ebay.com/sch/i.html?_from...All-Categories

Prices seem reasonable, but I didn't look at shipping. Maybe that would be a better alternative, and you'd have a parts carb

 

$35.00, including shipping. Normally, this is what I would do, but I am starting classes in Sept, and money is pretty tight right now, and I have this 1850 laying around. If it's do-able, I'll use the 1850 baseplate. If not, thanks for the heads-up!


Scott.

 

My pleasure, hope you get it worked out

 

I would imagine that the 1850 secondary metering plate is a lot richer than the one for the 6619-1 which was Holley's attempt at a lean, emissions compliant carb in the 70's. Unlike the front metering block that use a reverse, "lean" idle system and had larger Power Valve Channel Restrictions to use with two-stage power valves, the secondary metering plates were 4160 compatible although calibrated for leaner A/F ratios.

Go ahead and swap the two out for the time being. The carb should still run like a champ even if the secondaries are a little richer. You can always find a "donor" 6619-1 secondary metering plate at a later time to put the correct part back into the carb.

Good Luck!

 

I think you may have misunderstood my post. The secondary metering plate is fine, I broke the baseplate, or the throttle body may be a more accurate term. The aluminum base under the carb main body.
I am wondering if the passages between the main body and the base plate will be the same. I ask because I learned last month that I couldn't substitute the metering block from an 1850 on this carb, because of the reverse idle. The passages between the metering block and the main body are different.

On a side note, I looked into the secondary metering plates, and found something which may surprise you. The 1850 uses a 134-9 metering plate, which has a .067 main orifice, and a .031 idle orifice, while the 6619 uses a 134-39 metering plate, which has a .073 main orifice, and a .029 idle orifice. So, the "main jet" size, so to speak, is actually larger on the 6619! Maybe to compensate for the lean primaries? Anyway, just thought ya might get a kick out of that little tid bit of info, it surprised me.


Scott

 

Why don't you take off both throttle plates and compare them side by side?

 

I'm hoping I can get some info from an expert on whether or not it will work before I bother, plus, ya never know, there may be some difference that can't be seen, or won't be noticed by me. That's probably what I'll end up doing tomorrow, take 'em off and compare 'em. I'll probably just break down and buy a core 6619 of ebay, in the end.


Scott

 

Sorry about the misunderstanding. Major difference between the throttle plate and secondary metering plate. To be honest, I don't know of any differences between the throttle plates for the universal 600 cfm 1850 and the 600 cfm "lean idle" 6619-1. All the major differences were in the primary metering block and the main body to achieve the "lean idle" feature. I guess that a side by side comparison is the only way to verify compatibility.
Interesting...the 6619-1 has a leaner idle orifice, but larger mains. Guess Holley didn't want the carb to lean out at WOT. BTW, I had a 6619-1 on my '67 327/350 replacing the stock 585 cfm Holley with fixed float levels (lead plugs replacing the adjustable portion of the needle and seat assemblies). Engine ran extremely well with the 6619-1. Better response at all rpm and better fuel mileage although the engine did run leaner (light gray exhaust pipes). Hope things work out for you!

 

OK, here's the update:

Holley says yes, it will work. However, I took the broken baseplate from the 6619 and, without even removing the baseplate from the 1850, I can see that the idle orifices in the actual venturi of the baseplate are much, much larger on the 1850, and also are in a different spot. On the 6619, they are very small, and are directly below the transfer slot. On the 1850, they are very large (the red straw on a can of carb cleaner would almost fit) and they are not directly below the transfer slot. So, I pulled the trigger on a parts carb on ebay. Drawmain, thanks for the tip on the ebay carb. Mr. Beachcomber, nice try, but a swing-and-a-miss! Seriously, tho, it caused me to learn a little bit about how the metering plate actually works, so thanks.

Scott

 

Happy I could help

 

A little late in the game, but have you tried using JB Weld to re-attach the ear that broke off? I've had excellent results in the past using this product to repair carburetors. Once it sets, you can use a Dremel to touch up the join patch as well as making sure that the bottom portion of the throttle plate is flat and level. Good Luck!

 

Really? JB Weld? I didn't think it was THAT strong.......


Scott

 

Tensile strength is close to 2 tons (3,960 psi). Just give it 24 hrs to fully cure. Their JB Kwik has a tensile strength of 2,424 psi and cures in around 4 hours. I prefer the original. Take Care!

 

If I glue it back together, there will be a "bending" force (I am no engineer, I'm not really sure what the technical term is)on the join when I tighten the nut on the stud. If it was a crack, maybe I could see it, but it's broken right off! And it has the vacuum port for the pcv running thru that part, so there is very little surface area to glue back together. (pretty sure that's why it broke right there) Ehhhhhhh...........I'm still skeptical. If I didn't have a parts carb on the way, I would try it, but I think I'll just wait for the parts carb to show up. Thanks, tho, I'll keep it in the back of my head as an option in the future.


Scott

 

Scott, I hate to disagree with another forum member but I honestly think that you'll be removing your carb again of you attempt to fix a broke-off baseplate ear with JB anything. When they claim that it has 3900-odd lbs of 'tensile' strength, that means that somebody in a lab glued two pieces of CLEAN, FLAT metal face-to-face together with a square inch of bonding surface then pulled on the two pieces at right angles to the bonded surfaces until the joint failed, which happened to occurr at somewhere around 3900 lbs. of pulling force. You are correct in surmising that you would be applying a bending load to that 'repair' which would very likely fail as soon as you applied anything approaching recommended torque to that nut. JB Weld is very useful stuff that no self-respecting mechanic should be without, but it just won't work in this instance.

 

Sorry for the late response. Hurricane Irene got in the way at first, and then I had a senior moment...I couldn't remember the name of the thread! (Finally had to go back and look at all my previous posts to find this thread.)

Anyway, I thought that using your response would be a good way to reiterate the correct way to mount a Holley (or any other carburetor). First of all, the aluminum throttle plate is mounted in a clamping force provided by the tension of the nut & washer on the the stud anchored in the manifold. Since Holley only recommends 60-80 inch-pounds of clamping force, the stud is not fully stretched to it's maximum strength.

If the mating surfaces between the throttle plate and manifold are not flat, torsional (bending) forces result with the weakest component yielding (deforming/breaking) if excessive force is continually applied, e.g., a broken mounting ear/bent throttle plate for Holleys or recessed, sunken front bolt holes in the upper carburetor main body for Q-Jets.

Holley recommends a criss-cross pattern on mounting their carburetors. The torque is applied incrementally starting with the rear passenger side moving diagonally across to the front driver side then back to the rear driver side, and finally diagonally across to the passenger front.

Personally, I use a beam torque wrench and do two passes to bring the torque up to 70 inch-pounds. (I use the middle recommended torque value since I calibrate my torque wrenches every two years now.)

The main point to remember is that low torque should be used to mount carburetors. After all, 70 inch-pounds is slightly less than 6 foot-pounds.

Hope you get your 6619-1 back together soon!

 

I have another parts carb on the way, so I'll just use the baseplate from it, but I will definitely keep that in mind, I am sure it will come in handy someday, sooner or later, to get me out of a jam.


Scott