Tuning TRIPLE STOMBERGS ?

[Blown_FC]

Can anyone point me in the right direct or maybe drop a few names or references, to show me how to properly tune my Triple Stromberg CD150's ?

Yeah Yeah, I know.....I'm the stupid one for wanting Triples, but get them right, and they look and go fantastic.

Cheers

Mark

[craiga]

Hi Mark,

I had a set of triple 175CD's on my Torana when I was younger and my experience is as follows:

1. Buy yourself a Carby balancing tool. They are fairly cheap (about $50.00) and are used to measure the airflow through each carby. Any good tool or auto shop should be able to supply one.

2. Use the carby balancer to adjust your linkages, spend plenty of time here because it's critical to get all three carbies adjusted EXACTLY the same. On the Holden linkages its very simple to make this adjustment using the knurled nut on the accelarator linkage of each carb. You should check the adjustment at about 1200 RPM where any effect of a cam will be minimized. When you're done check it at higher revs just to make sure that the accelerator rods are bent or something silly.

3. Once you've got this right loctite the things up. There should be no need to fiddle again.

4. Adjust the idle mixture using the adjustment nut on the lower body of each carby. Do each one at a time. Turn one out until it starts to run rough (you can use a vacuum gauge connected to the manifold to monitor this) then turn it back in until it smooths out. Keep going until it leans off and starts to misfire, then go back out again until you get the smoothest idle (or the most stable and highest vacuum reading). Repeat this on each carby and all should be OK.

5. I ran a fairly large cam and had lots of head work done, so I didn't run oil in the carby damper so the piston raised very quickly to get maximum air into the engine. The downside was the thing was very hard to start because the pistons would bounce around and heaps of air would be drawn into the engine. On a street engine you should run auto transmission fluid, which will work fine and is easily obtained.

Too easy

Good Luck,

Craig.

[Blown_FC]

Thanks very much Craig....you obviously have had a fair bit of experience with these......my experience only extends to Twin SU's on my Mini Cooper.
I didn;t know a great deal about them, so I had a mechanic come and try and tune them for me.......he brought a screwdriver and a bottle of LPG gas ( Camping bottle )......I looked puzzled.....he started the car, and then opened the gas bottle as sprayed a small amount of gas into the air filter.....if the engine revved higher, it meant it needed the extra fuel, and hence was running to lean.....or if the engine bogged down and spluttered, it meant it was running too rich, and needed leaning off.......as far as balanceing them goes, I used a piece of plastic tube down the through of the carb and listened for the heartbeat of the pistons revolution, then tried to balance both carbs so that the hearbeat was the same....but I'm not too sure I want to use either of these methods on the FC.

Thanks again, you've been a big help........so tell mem how did the torana run ?

Mark

[craiga]

Mark,

Glad I was of some help. You can use the tube method but its a bit rough, the carby balancer will get a perfect result and fairly quickly and easily.

I've heard of the gas trick before, you can do much the same by just partially covering the air intake, if the revs go up it's lean, if they drop its rich. Again a pretty rough method, but I reckon a vacuum gauge is the way to go.

I spent over 10 years fixing expensive automotive diagnostic machines and one of the older training guys showed me how to tune a car just using a cheap vacuum gauge. It was incredible how accurate he could get a timing setting just from monitoring the intake manifold vacuum levels. He also used it to very effectively set mixtures.

You made a good choice by buying your CD Strombergs - they might not go as good as webers or SU's but they certainly hold their tune a lot longer and give great fuel economy.

The Torana did go OK, used to pull one front wheel up if you gave it a bit   It was twisting so much the part of the A pillar at the bottom of the windscreen where it meets the cowl cracked quite badly. The car died a horrible death when I ended up running it into a tree.   That really f*&cked the A pillar.........

Cheers,

Craig.

[fccool59]

Hey Craig, that sounds like a sweet mill you were running there, this is this sort of weaponary you wanna wack in the poo mobile when we finally run at Eastern creek.

Mark,
I don't think it's stupid to have triples. some children are happy playing with lego basic and duplo while others need a more sophisticated and exciting challenge like lego technics.
its a bit the same when you get older but we play with real cars now.
they say small things amuse small minds, so I guess he who says one is stupid for running triples must be running either dual quads, six or eight single barrels or triple two barrels or have a small mind.
I had a four cylinder for my first car with twin SU's and enjoyed racing my friends after school so I would always make sure the carbs were synched before I left in the morning, I enjoyed going in to roll call with greasy hands and smelling like petrol and knowing that no one with a car and liscense could beat me in my school. this created some good times and memories and I am glad I didnt leave my car stock.  Its not stupid to want to have fun and excitment in your life for the small price of extra tuning and a couple of extra bucks in the tank, after all you only get to live once. I love the look of triples too, I currently only have a 2 barrell holley but it goes great and runs better up top than any factory holden carb, it also is pretty good on fuel but I still get strange bastards tell me to put on a single barrel stromberg, I had a single barrel stromberg on a red for a week and hated it, it went like I was carrying a ton of bricks in the back and used as much fuel as the holley.
When I was at tech my rather elderly and conservative teacher explained the efficiency of multiple side druaght carbs compared to a downdruaght single, the only advantage a single carb had was its ability to stay in tune and lower cost to make.  Rolls Royce is one example of a car that used multiple stromberg CD's in a time that toyota cressidas and nissan skylines had EFI.
if Rolls Royce engineers were stupid why do people pay more to buy the cars they designed.
unless you are a fuel economy freak or hate mucking around with old cars, I think you have made a good
choice. with better looks, sound and efficiency and fun than a single stromy wich is the common choice by those who bag bigger or multiple carbs.

[Blown_FC]

Well, I guess that would kill the A Pillar for sure !

I went for Triple Strommies, as I couldn;t afford a Blower as originally planned, so I decided to keep within the era and the tech level of an old holden, hence I'm going for a 202 rebuilt to XU1 specs.......plus an auto for the wife to drive.

I'm thinking my 202 Red, a stage 3 Yella Terra Head, XU1 Manifold and Triple Strommies, an XU1 Cam, Extractors, and Light Optical Dizzy...may run with a 2500 stall converter and a 3:08 or 3:36 diff.

If it looks half as good as the pic of your torana bay, I'll be stoked !

Cheers

Mark

[Blown_FC]

Thanks for that FCCOOL59...it's good to hear some re-assuring stories......and you are right......if you are a fuel economy freak, or don't like tuning carbs and tinkering on the weekends, that you shouldn;t be playing with old cars like FC's....no offence to those Microchipped V6 techno FC's running around.....no doubt they would piss all over my old 202 set up, and cost half as much to run...but for me, if I wanted my FC to sound like a commodore, I'd just by a commodore.....like I said....no offence intended.

Having said that, when the time comes and I finally get my car on the road, and the carbs are pissin me off and I miss a club run because the cars not running right, I'm gonna want to wish I had gone for a V6 ..........then again.............................NEVER !


Cheers and thanks for your thoughts !

Ok....all you V6 guys can now start hunting me down !
I'll be easy to find...I'll be in my shed tuning my carbs !

[fccool59]

Dont worry, you can luagh when they are broken down in the middle of no where with a fried computer. Or there late for a meeting becuase they have been up all night trying to rectify why there car wont start.
I was working in a car yard once were we had a VN just stop, all 4 mechanics and 2 auto eleco's had a go over 4 months, with the heads on and off and about 4 different computers and heaps of head scratching they decided to change the whole motor before it cost more than it was worth in wages, it was also quite common to have the V6 commodores come back with major engine problems.
I think a warm old holden 6 is one of the sweetest sounds in the world and adds well to the feel of a FC and has been well proven, Victor Brays set up in the worlds fastest sedan looks pretty primitive compared to some of these new skylines and stuff running around but the ol Aussie tomato farmer would still blow there friggin hi tech doors off in his 57 chevy and he isnt running a RB26DETT or 20B turbo wich many young ricers are mislead to believe are the worlds fastest engines.
I dare any Honda spoon car to take the challenge.
no offense to the hi techers but there is nothing like the feeling of hammering along with a nice old warm all aussie six banger, its like comparing the feel of sitting in a FC to a hyundai excel.
I bought a FE of a guy who had another one wich was running in the 11's onm the quarter with a naturally aspirated 186 running a alloy head and triple webers, it looked pretty serious but it was still based on a 186, how many V6's are doing this?