Still Hving probs with webers :-( Any ideas?

[leylandracer]

After a four Month lay-up over winter i had to start the TR7 up today, but i am still plauged with the old problem of flooding on cold start up and having to put a couple of new plugs in (It kills the plugs).

The link to a previos thread i posted is here http://www.v-8.org.uk/forum/viewtopic.p ... c&start=15 Showing the AFR's, on idle its in the high 11's could this be the prob?

Just to mention the prob again

Bring the car out of the garage, it will normally start up OK on eight, Switch it off without letting it warm up, Go back to it a couple of hours later and it will normally flood two of the cylinders Take it for a good run at norm operating temps and all will be well on the next start up, HOPE THAT MAKES SENSE one of those days today.

Another question with Webers I seem to be stuck with the AFR's around the 12 mark either on cruise, idle, or full throttle, Is that what im stuck with using webers

The carbs are Quad Weber 48 DCO'SP's

Any suggestions really appreciated, It drives me Mad It been to two rolling roads for setting up and they reckon that the best ill get with Webers. On the last visit they thought they had it sorted, there was a ledge on two of the inlets (Carb to inlet) and the thinking was fuel was pooling there which would contribute to the flooding, No such look

At the mo im using NGK BP7ES, the last rolling road visit the opperator suggested using BPR6ES for normal driving, switching back to 7's for track days etc. What do you reckon? Worth a try? Just thinking with the spec of the engine that it should be 7's? or maybe a different plug to the BP7ES which would be less prone to flooding?

Cheers
steve

[leylandracer]

Just a thought, I have another TR7 fitted with a dolly sprint engine and that was doing the exact same thing last year, cant think what make plugs it had in, but changed over to the equivelent NGK plugs and all was fine.
Suppose the easy answer is try somthing different

[Darkspeed]

Really need to know the sizes of the jets and the emulsions to make any suggestion.

The chokes at 38 look OK for the engine rate - even if getting small for a 48.

Too many tuners go very rich on the idle circuit to compensate for the progression circuit being inedequate and not having enough drillings - I dont know what the 48 SP's do in that regard.

How far are the idle screws out?

What's the colour of the 7's like, does it look like a drop of heat would cause an issue

Andrew

[Eliot]

+1 trying a hotter plug (i.e. go down to 6)

cant help re. the carbs sorry.

[bill shurvinton]

DCOEs and their Ilk I do know a little bit about. I'm up against the wall with work the next few days, but if you keep PM me I'll try and find half an hour to go through the options.

As long as you have mappable ignition (and you MUST) then you can tune webers really well. However, if you can't get the butterfly positioned correctly at idle you will always have some horrible compromises that you have to live with. I suspect one of these is causing over fuelling that, with a cold engine causes fuel puddling.

Do you have the chokes cabled up. IMO weber chokes are evil and to be ignored. 3 pumps on the pedal should do it fine.

[leylandracer]

What's the colour of the 7's like, does it look like a drop of heat would cause an issue

BLACK All of the time

1 trying a hotter plug (i.e. go down to 6)

Maybe worth a try

As long as you have mappable ignition (and you MUST)

No Mappable ignition fitted Bill (Fitted with the Mallory stuff though)

Do you have the chokes cabled up. IMO weber chokes are evil and to be ignored. 3 pumps on the pedal should do it fine

No provisions for using choke cables on the SP's, so no, Funny thing is with the webers, The 3 pumps on the throttle just doesnt work on this set-up Every other motor iv had fitted with webers is a yes, but strangley not on the RV8

[Darkspeed]

So how do you start the engine if the three three full slow pushes on the pedal does not work

How far out are the idles and do you have and jet info ?



Andrew

[leylandracer]

So how do you start the engine if the three three full slow pushes on the pedal does not work

How far out are the idles and do you have and jet info ?



Andrew

Ignition on (Pump priming) Three slow pushes on the pedal will normaly have the engine trying to fire but theres no instant start. I changed the starter last year to a Powerlite Starter thinking the faster cranking speed would maybe help, it deffo turns the engine over fast but sadly no cure for the cold flooding

Dont have any jet info, and the TR's away for four weeks for some brake mods. Whilst the TR's with them i think it will be in and out of there workshop, so iv asked them to try some BP6's as a try out

Its over at a Triumph specialist (as above) and they have mentioned that they could put it on there rollers that would be the forth specialist to have a go so i think ill miss that one, its had more miles on dynos then on the road which inc the engine builders who ran the engine in and set it up

Do you reckon the plugs could be a poss? or are 7's the norm with this spec engine

[bill shurvinton]

hmmm very odd. Looking at the setup the runners are very long and unheated, so a little like the setup I used to have on my kit car with a rotary.

When cold there were always fuel problems due to puddling, but they cleared after 10 seconds of running.

I still reckon root cause is an ignition system that forces a compromise on the carb settings. I'd love to have a week and a set of jet drills to try and really dial it in.

[Ian Anderson]

If you have flooding with 3 pedal pushes try 2 or even 1

You could easily get a result.

Or only push the pedal once you are cranking - it could help draw the gulp of fuel into the engine better.

Ian

[leylandracer]

Dont think its the knack of starting it, Iv tried all different combos even switching the fuel pump off (manual switch)

Hoping somthing simple as the different grade plugs will do it Its the only thing that really hasnt been tried As mentioned at the begining of the thread i had the exact same prob with my 16v dolly sprint engine on twin webers when it was running on Bosch plugs, changed over to NGK's and all was well, Just wondering if the different heat range might help, Suppose i can live in hope

[Darkspeed]

Are you saying that the car will start on the key from cold no prodding on the accelerator?

Please explain in detail the starting procedure you use

Andrew

[leylandracer]

Are you saying that the car will start on the key from cold no prodding on the accelerator?

Please explain in detail the starting procedure you use

Andrew

No wishfull thinking Andrew

I know normally with Webers (As on my 16V) its the three prods on the gas and it will fire up, This ones totaly different, NOTHING works for a instant cold start.

i.e.

Three pushes on the throttle, Turn the starter (Which turns it over fast) and it will try and fire and eventualy start up after a bit of turning over, (Most of the time with the flooding on a couple of the cylinders from cold)

Tried different methods like no prods on the throttle, more prods of the throttle, Switching the fuel pump off before turning the engine off, Pump switched off when first turning it over, All with the same outcome

The first time the prob started it was over at Boggs Bros for the carb conversion, They thought maybe the starter was a bit slugish turning the eng over, So i ended up putting a Hi touqe starter on, Really does spin it over fast but still no cure.

Funny thing is i posted a similar topic on the TR forum and one of there replies was;

biggest problem is the Quad Webers you got
even tony pond use to flood is engine on the tr7 v8 lol and if you watch some of the videos around about tr7 v8 rally cars you can see when they resart the engines all ways misfires with flooding probs that is y american john buffam had a holley on is tr7 v8

Re; the above quote, i think the Rally TR7 V8's used 50 DCOE's and with a 3500

Just hope it isnt a prob ill have to live with

[Darkspeed]

Re; the above quote, i think the Rally TR7 V8's used 50 DCOE's and with a 3500

That 3500 was revving to 8000rpm and developing 300BHP

They also used twin Webers on crossover manifolds a lot of the time.

Could be with a dizzy that the advance for maximum power is causing issues with the timing at idle that will not allow the car to start - Could be the idle circuit too rich - could be the plugs to cold.

Probably a factor of all of the above

Have you swung the timing about to see if you can get a better start? rather than leaving it were you get maximum power at the high RPM?

Cheers

Andrew

[leylandracer]

Still trying with the carbs (Quad Weber 48DCO-SP's) onto the third rolling road now, i reckon its done more mls on the rollers then on the road the guy thats on with the carbs now seems to know what hes on about Just having a look at the power tuning a Rover V8 book it reckons the Co at idle should be 2.6% co? do you reckon thats poss with the webers? Just got this email back from him below; Can see a BIG bill on its way

Steve

The first thing we have found is that the carbs are mounted incorrectly. They are solidly mounted rather than being flexible.
this will give rise to fuel throthing at idle.
We will need to change the studs, mounting hardware and possibly the the O ring plates. Parts are likely to be £80 with no plates and an extra £32 if they are needed. It will most likely take 3.5 hours to fit.
All plus VAT
Shall we do this or leave it.
Out of interest the CO at idle is 3.8% but the hydrocarbons are 5000!!!!! 500 would be nice.