Carb Question with pic

I got these carbs with the purchase of my 2500M. The owner said I might have to clearance around the heater core box to make them fit, but that they were a good setup for my car, which is having issues with the Strombergs right now.
I haven't had time to try bolting them on, but to the best that I can measure it looks like the rear carb might run into the wheelwell. These are Weber DGV-5A 32/36 carbs on Cannon manifolds. Do any of you guys know if these normally fit or not?
Thanks,
Jim

Not sure if they fit but it really isn't that great of a set up for the TR6 engine. Most people that swear by them have replaced worn out ZS's with brand new Webers and then use that as their basis for claiming that the Webers are superior.

Take a good long look at that manifold design. One common downside to DGV's on a TR6 is fuel puddling in that horrible manifold and then washing down the cylinders with fuel on start up. They are a band aid fix at best. A set of properly rebuilt/restored ZS's perform much much better than they are often given credit for.

If it were me, the only Webers that I would consider for a TR6 engine are DCOE's. Otherwise use ZS's or SU's. Weber does have a new single throat side draft as well now. Originally designed for Harley Davidsons. The current issue of Classic Motorsports has an article about them being used on a TR6.

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Thanks for the information. Here's a novice question, what's a ZS? Is the the Strombergs I have on it now?
Sounds like I should sell the webers and use that money to either get the stroms working or buy DCOE's. Do any carb's actually produce more power than others? What's the best carbs for these engines overall?

ZS is short for Zenith-Stromberg. The carbs on there now, stock, are ZS175's (1.75"~1-3/4"). They can be good for up to about 150hp. To go beyond that you will either need to go to 2" carbs (SU- HS8's or HD8's), Triple 1-3/4" carbs or triple DCOE's. Unless you increase your compression ratio and upgrade your camshaft etc... switching to different carbs, or bigger carbs wouldn't help a whole lot.

Getting your stock carbs into great shape will tell you a lot about the rest of the state of the engine. Get it up and running reliably first and then figure out which direction you want to go after that.

When my TR6 still had the stock engine I did find that it seemed to respond well to free flow air filters (like K&N) and better ignition equipment (better wires, sport coil, electronic ignition etc...). All the usual tricks of improving air flow, in and out, and optimizing the igniton. Otherwise, any real increase in power will only come from a performance rebuild or forced induction.

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You can get plenty of horsepower from a TR6 engine with the stock strombergs (Zenith Stromberg) The DCOEs will give more power at high RPM (not reccommended for long life with a TR6 engine) and will also give you a new hobby of learning to tune them properly. Tuning webers is not easy, if you really want them to work properly, and will require an investment in jets, emulsion tubes and so on. With 3 carbs, you are buying all the relevant parts in multiples. If you want to actually drive the car, and USE it, stick with strombergs, and keep the engine mods reasonable. There is plenty of power to be had without making the car hateful to drive in traffic.

DCOE's can be made tractable for regular street driving. But you have to choke them down so much that you don't really get much of a gain for the high RPM stuff. To keep the high RPM stuff you have to sacrifice driveability etc... You can get them to do fairly well at both but it is not cheap, or easy tuning. Our 'Anonymous' friend is right in that regard.

Ooops, forgot to log in. That was ME

Jesse

Now tha's funny! I read it and thinkin': "Whoever this is, they know Webers well enuff."

mehheh.

Stick with the ZS units, as suggested. They'll work quite well once sorted. The downdraught Webers on those manifolds (as Shawn says) are a funky setup. They introduce more problems than they solve, IMO. If you find you can't stand less than 150 HP, get a spare engine and build a "powerhouse" from that... and still have a TVR to drive meantime. /ubbthreads/images/graemlins/wink.gif

Thanks for the replies. What would one expect to pay for a good 2.5 engine that is good enough to rebuild?
What does it take to get 150hp out of one of these? Is it really just a matter of shaving the head and adding a cam and valvetrain? Does porting the head or installing large valves help? Are there any 2.5 specialty shops that offer performance heads or performance machined factory heads?
Are parts available to adjust the ZS's for engine modifications? Are headers available? From who?
Sorry for all the questions, but I'm really new to these cars.

A good builder 2.5 should only set you back a couple of hundred bucks. There have been enough TR6's turned into parts cars that drivetrain parts in need of rebuild (other than overdrives) just don't command very high prices.

It really doesn't take much to get to the 150hp mark. The early PI TR6's (that stayed in Europe) were known as 150hp cars. The only differences other than PI (Petrol Injection) was a more radical camshaft, higher compression and a slightly better flowing head.

Your compression ratio should be in the 7.75:1 range. Pretty low right, it was lowered for emissions purposes. Decking the block to zero piston height is your best form of compression increase. Then if you have to have more you can either skim the head or do a little more decking. The pistons on a TR6 engine can stand proud of the block a bit (a very small bit) without danger. Holding off on skimming the head retains more of the combustion chamber for a better overall performance increase. If you target a 9:1 -9.5:1 CR then you can get up to 150hp or better and still be able to use pump gas.

Flowing the head will also help, bigger valves can be tricky but are possible, though they won't be much bigger. Your better off using high quality valves and optimizing the flow characteristics around them.

As for shops. How close are you to Pandora Ohio? In Pandora you will find a guy named Ted Schumacher, check out his website TSI Imported Automotive . Another more specific TR6 performance vendor is GoodParts . Though I have never used them another possibility is PAECO . Some Triumph performance shops in England are Revington TR and Racetorations .

As far as modifying your ZS's for increased horsepower, the most you should have to do is change needles. Any other specifics and a great source for ZS or SU carb stuff is Joe Curto .


As for headers... I'm not sure but the TVR crowd might be able to help. Any TR6 header will fit the engine but I believe there is a frame interference issue when trying to fit most TR6 headers to a TVR, other than the basic mild steel version like this Moss Header The one in the back (6 cylinder, short primarys) should fit the engine and frame in your TVR. Otherwise, the stock dual downpipe manifold is good up to the 150hp range.

That should get you started. Beware though, it won't be inexpensive. It could easily be double the build cost of a small block Ford. /ubbthreads/images/graemlins/smirk.gif

If you have room, the triple carb setup nicely matches the TR6 engine when you have 'improved' it.

150hp is pretty straightforward - going for much more than that starts to get to be mega $. As a personal preference, I'd skim the head after zero decking, before letting the pistons pop up - istr all Triumph did was add material to the head to lower the CR.

Pretty much all the stock internal components are good at that level of tune (assuming they are in good condition), apart of course for a cam/lifter change.

If you have a large chunk of change burning a hole, I'm sure you can get plenty of suggestions to eke that last few hp out of the car though /ubbthreads/images/graemlins/grin.gif

I have owned TR6's and TR3's for years and found that the engine will perform very well with good stock carburetors, headers and electronic ignition.
Webers are not for the average person who wants to enjoy the car without tinkering with them at the worst possible times on a drive. Just my opinion. Thanks.
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I was actually talking about the triple ZS setup

Jim, let's hear more of the "issues" you're experiencing with the Zed-S units? What're the symptoms of the problem?

They're actually a very simple setup once you've been initiated as to their workings. Have you got any of the manuals/books explaning the beasties?

I haven't had more than about 15 minutes to work on this car since I bought it, so I don't know much yet, but I'll tell you what I know.
It's really hard to start, and sometimes impossible to start. If I can get it started, it dies many times before I can keep it running, then it won't idle. If I keep the RPM's up enough to keep it running, it spurts, sputters, and occasionally backfires. Intermittently, it will suddenly rev freely and smoothly. During this brief period, it seems to run exactly like I would expect it to, but then after just a second or two, it goes back to running rough. The previous owner was told by two mechanics that the front carb was messsed up. I'm not sure if that's the case, but I do know the carbs are synch'd and adjusted properly. But I also suspect it might have ignition problems, as there are times that it doesn't seem to have spark. When it does have spark, it seems really weak, at least compared to other cars.
I'm tempted, since I ultimately want to anyway, to convert it to an electronic ignition with a new coil and general tune up and see what happens. Obviously I can't adjust the carbs until I can at least keep the engine running. But I've yet to get any info on adjusting the carbs, so maybe I'm wrong about that?
I'm now pretty convinced to keep these carbs and sell the webers, so I just need some help with the adjustment procedure.

Buy the Haynes carb manual.
It's got pictures, and it costs about $17 from amazon.
Worth the investment imo, it'll save you wading through tons of text - the pics really help...

Agree totally with Alan... and the old saw about: "90% of all carb problems are in the ignition"... Go there and be certain that's working first. If it ~looks~ like weak spark, it IS. It should *hurt* about the same as any of your Honda's. /ubbthreads/images/graemlins/wink.gif

Good BLUE arc if you test it the "old-fashioned" way. If it's yellow there is something wrong. That all works the same as any other vehicle you have there.

Then look at fuel delivery. What pump is on there? Flow rate will be what you want to check first.

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I haven't had more than about 15 minutes to work on this car since I bought it

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Is your garage heated?

If not....An easy way to get that done would be to remove your carbs/intake & rebuild on kitchen table.

After the wife kicks you out..........

Line up Guinness outside the garage window for now.
Get a wireless router for BCF.
Pick up a "road-kill" couch.
Give the "Snappy" guy the secret knock and bolt the door. /ubbthreads/images/graemlins/cheers.gif

BTW...Tell the UPS guy to park around the corner.
(And set the boxes outside the garage door)

[ QUOTE ]
Line up Guinness outside the garage window for now.
Get a wireless router for BCF.
Pick up a "road-kill" couch.
Give the "Snappy" guy the secret knock and bolt the door. /ubbthreads/images/graemlins/cheers.gif
BTW...Tell the UPS guy to park around the corner.
(Give him the secret knock also)

[/ QUOTE ]

hehehehehehe good advise on any car project. /ubbthreads/images/graemlins/thumbsup.gif

Sometimes I lose sight of my good fortune. Then something like this thread comes along and reminds me!

'fridge inna garage is well stocked, hovel is wired with Cat-5 throughout, BCF available in every room and WiFi as well (for the back-yard 'hammock times'), my Snappy guy is a friend (!), the UPS fella wants me to do his tile floors... and dear 'Smits is an LBC nut of the First Waters. I'm good-to-go. Couldn't WISH for better circumstance.