Running out of top end power

[Hamish]

Hi chaps

i think I have a (lackof) fuelling issue at the top end.

 tr3  2187 or less cc

1970’s warm cam

twin H6 su 

 4 branch exhaust

116bhp 5018 rpm at flywheel. Very recently done and carbs tuned.

the rolling road bloke is very used to older cars and su s

he suggested that there was a fuelling ( mechanical pump) issue at the top end in 4th and 4th od. I think he will have done the RR  in 3rd ? 

I have changed  the pump to a refurbished one done by a known reliable bloke. Mr D Davies 

Today it manifest itself as a hesitation whilst flat out. (On a private track of course)

I know of TRs running this mechanical pump with a lot more power than I have.  Without issue ?

Where do I look for a solution  ?

 

i have one of these elec fuel pumps in store

Dellorto Weber Huco 12-14v low pressure fuel pump133010 engine bay fitment https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F292015408165

 

can I add this to the fuelling system after the mechanical pump as assistance. 

Or just instead of mechanical. If so can it run straight to carbs or would it need a return line somewhere ! It doesn’t say it needs a return in the instructions. Just an inertia cut outs with that I have .

 i think su pumps don’t need this return so I’m presuming it doesn’t. 

I can take the elec feed off the coil supply this way it’s on the ignition. 

 

Thoughts welcome .

H





[Nigel C]

Hi Hamish,

The Peerless runs two Lucas electric pumps as standard and plated over the mechanical pump aperture in the block.  I picked up a pair of NOS Lucas pumps for MGB and thinking they feed about the same sized engine fitted them. Had no real issues until I had it set up on a rolling road where he found it was running dry flat out in top OD after about 30 seconds.

I have to say I have never got that high for that long! but changed them for Facet pumps. The pressure they send out meant I had to fit a filter King with a pressure regulator to reduce the pressure. Also(N/A to you) They pushed fuel past each other and filled each others tanks! so I had to put non return valves in too

One possible cheap fix (that I have done since!!) would be to fit new E type spec  floats in the float chambers. These are made form sort of black plastic and are resistant to Ethanol but where the real win is, they are smaller than standard brass ones so you get more fuel in the float chamber in the first place

[iain]

Hamish

do you have an in line fuel filter.....is it passed it sell by date?

Carb fuel line thimble filters clogged up?

fuel pump filter clogged up?

Iain

Ps Those floats are brilliant....developed for military use I believe as they allegedly can’t sink. Available from Burlen for H and HS6

Edited March 10, 2019 by iain

[Hamish]

11 minutes ago, iain said:

Hamish

do you have an in line fuel filter.....is it passed it sell by date?

Carb fuel line thimble filters clogged up?

fuel pump filter clogged up?

Iain

Ps Those floats are brilliant....developed for military use I believe as they allegedly can’t sink. Available from Burlen for H and HS6

New pump and fine brass filter

new in-line filter fitted by rolling road chap. 

No comment about carbs.

h

[iain]

Hi Hamish

just realised you have HS6 carbs......no inlet filter on the carb bowls that I can see in the manuals..unlike the H6.

Iain

[Hamish]

44 minutes ago, iain said:

Hi Hamish

just realised you have HS6 carbs......no inlet filter on the carb bowls that I can see in the manuals..unlike the H6.

Iain

Hi Iain

they are H6 carbs. 

Since the RR chap said it was fuelling /fuel pump issue. He removed the filter I had before the pump. I have since  Put in a new fuel pipe ( didn’t want to cut the original metal pipe to fit filter). Fitted a newly refurbished mechanical pump with in line filter. Pipe routing away from heat sources as much as possible. 

Still have what I believe / feels like fuel starvation at peak revs in top gear.

whilst normally this wouldn’t be a problem some of my sprints need this top end Aintree is one example.

so I would like to bottom this out.

RR chap back in garage tomorrow so will ask him again.

may try the elec pump as well ?

H

 

[ianc]

Your in-line filter seems to be mounted between tank and pump.

Not a good idea because the internal parts of the filter can collapse under the suction exerted by the pump, thereby limiting flow.

In-line filter needs to be between pump and carburettors.

From 1953 to 1964, all the competition TRs run by the Works used standard mechanical pumps, as did the uprated engines supplied by SAH and others.  Cannot see any reason why a car showing about 120 HP at the wheels on a rolling road (probably 135-140 Brake HP) should exhibit problems when using a mechanical pump.

Ian Cornish

[Lebro]

In my opinion it does not matter which side of the pump you put the filter - as long as the flow is from the inside to the outside of the filter medium.

Bob.

[Hamish]

38 minutes ago, ianc said:

Your in-line filter seems to be mounted between tank and pump.

Not a good idea because the internal parts of the filter can collapse under the suction exerted by the pump, thereby limiting flow.

In-line filter needs to be between pump and carburettors.

From 1953 to 1964, all the competition TRs run by the Works used standard mechanical pumps, as did the uprated engines supplied by SAH and others.  Cannot see any reason why a car showing about 120 HP at the wheels on a rolling road (probably 135-140 Brake HP) should exhibit problems when using a mechanical pump.

Ian Cornish

Hi Ian 

the filter is between mechanical pump and carbs now. 

RR chap removed the filter I had before the pump. DOH !

 

I agree with you regarding the capacity for the pump to deliver. 

Plenty of tr s with more power than mine (116bhp at flywheel) still on the mech pump. 

But not sure why I’m getting this apparent drop off flat out in top.

H 

Edited March 11, 2019 by Hamish
Bhp fig

[stuart]

Are you entirely sure its fuel? We used to get this problem racing Jaguars back in the 70`s but eventually found it was a spark issue .

Stuart.

[BlueTR3A-5EKT]

Off the wall here...

I can see in the photo you are running 1/4" (6mm) hose pump to carbs.  All TR2-3 ran 5/16" (8mm) rigid pipe, same as tank to pump.  TR 4/4A went to the smaller diameter pipe in production.

Could this be a limiting fuel flow factor when WOT?

Peter W

[Motorsport Mickey]

You may find you have an inlet manifold leak which is bleeding off the over bridge vacuum where the needle and jet is situated(which sucks up the fuel into the carb) in max revs constant running over 5 secs or more which will lean it out, worth a check.

Mick Richards

[stuart]

Also has the main fuel line from the tank to the pump been renewed as I did have a problem with a 250 where the line was full of sludge from standing.

Stuart.

[Hamish]

11 minutes ago, BlueTR3A-5EKT said:

Off the wall here...

I can see in the photo you are running 1/4" (6mm) hose pump to carbs.  All TR2-3 ran 5/16" (8mm) rigid pipe, same as tank to pump.  TR 4/4A went to the smaller diameter pipe in production.

Could this be a limiting fuel flow factor when WOT?

Peter W

Peter this is a consideration I will change anyway for the cost benefit.

The “but” is I had this problem with the original metal pipe.

8 minutes ago, stuart said:

Also has the main fuel line from the tank to the pump been renewed as I did have a problem with a 250 where the line was full of sludge from standing.

Stuart.

The tank appears very good inside very shiny. There is gravity free flow to the pump as well. Car has been running very well otherwise.

if I didn’t sprint it and only used it at road speeds I would never know.

 

mick

the gaskets to the head are new and I believe it all tightens up well. 

The carbs to inlet manifold look well sealed and not been separated in years. 

H

[Tony]

 

i had exactly the same problem with my supercharged 4, it ran out of fuel at 4000 rpm. the float in the bowl was to large ,more float than fuel at 4.5 psi. fitted a smaller float and now the problem has gone .rev's to 6000 with out any hesitation.

[Tony]

Should have mentioned that its running an 2" HD8 SU, the float was about 2" diameter and now using 1.5"  float

[Nigel C]

you can check for a leaky inlet gaskets by spraying brake cleaner around the edges and see if your revs go up.......along with your engine bay if you're not careful!

I've done it a few times ( once whilst a Le Mans scrutineer was stood next to me at 3 in the morning, his wide grin translated well) you have to be very careful but it does find any leaks

[Hamish]

Hi Guys. 

 Latest up date. 

(I know I have done more than one change but that’s life ) time and money has been taken up looking after our rescue dog who suffered a disintegrating  vertebrae and needs some serious back surgery and intensive post op care at home!

so I have removed the mech fuel pump. 

Blanked off the crank case aperture.

fitted the HUCO sucker pump under the bonnet. 

Fitted an inertia switch for safety.

fitted new 5/16 8mm fuel line routed to the rear of the engine - a cooler route.

fitted a screen type pre pump filter and a paper type filter post pump 

swapped the carb float chamber lids over to aid in change of pipe work direction. 

Checked the float heights and these were correct to manual. 

Blew through fuel line back to tank. 

Syphoned and filtered the fuel out of the tank x 3

added 2 gallons of fresh fuel and went for a blast- found a private runway to test it .... the same place i had the original problem  

tried in 3rd gear and it holds max revs (5k)  and more (6k) very well 

tried it in 4th and it get to max revs and holds it 

5 k in 4th seems to be the max it will do. (Just runs out of power I think  but doesn’t die as it did before)

After all this the exhaust is black. Suggesting the safety margin of running a bit rich. 

I also found this pic on the web suggesting performance of carb Aperture.

thank for all the help. The dying at the top end is no more. 

H 

ps

the pipes too and from the elec pump are long enough to connect to the original mech pump should I need to swap it back in.





Edited April 1, 2019 by Hamish

[BlueTR3A-5EKT]

Hamish,

Well done with that issue.

A couple of observations.

The type 11 air intake profile in your scan used to be supplied by K&N for use inside their air filters.  I made myself a pair out of MDF that I subsequently painted to seal the surfaces - I have no idea if they gave any benefit. They were at no cost to me that way, rather than the £30. odd the pair from K&N.  I also once bought a pair of stub stacks - type 6? https://www.ebay.co.uk/itm/Stub-Stacks-For-Use-with-K-N-or-Any-Pancake-Air-Filter-1-3-4-Inch-HS6/191904758010?epid=1090654918&hash=item2cae6a38fa:g:WpAAAOxyhlJRe4dk

Your coil is fitted to the block. Thinking says move it to a cooler vibration freer location, but keep the old one there in case the replacement fails.

The high flow low pressure Huco pump looks like a good idea as it is claimed to work as a suction unit, not needing to be below the fuel level.

Cheers

Peter W

PS Did you see my brother's ebay sale of the TR2-4 Koni rear conversion kit with shocks?  https://www.ebay.co.uk/itm/Triumph-TR2-3-4-Koni-rear-shock-absorber-conversion-kit-with-adjustable-Konis/223462443469?hash=item34076649cd:g:jYIAAOSw2EJcm4Qh

 

[Hamish]

Peter

thank you. 

I bought some of those stub stacks but found the manufacturing tolerances too poor to use. 

Yes have seen your brothers rear Koni conversion kit. If I won it I fear it may sit on the garage shelf as long as my parts to convert the front end suspension to that of the later cars with camber and castor !!!!

[ianc]

Hamish - if you are running a 3.7 rear axle on your 3A, I'm surprised the car runs out of puff at 5000 in 4th.  Or is that overdrive 4th?

In the 1960s, my old, bog standard, TR2 with 3.7 rear end would sit at 4200 in overdrive 4th on the M1 (it was legal then!), and could wind itself up to 4600 - a genuine 110 mph. It was my daily driver, with knackered engine (very little oil pressure), but seemingly almost friction-free in all areas!

With modern fuel, black exhaust seems to be the norm - my old TR2 would have light grey, almost white, exhaust after a decent run at 100 mph.

Ian Cornish

[Hamish]

Ian

i agree with you. It has a 3.7 rear end. An early tr6 gearbox with A type 22% OD. The previous owner did a lot of “in the day” (70’s) performance mods kas kastner head work on a 4a head, h6 carbs and on the longer tr4(a?) inlet manifold. It is still running whatever was the warmered up cam that Neil revington  came up withwhen he first started. Tuftrided crank. It also has an extractor manifold.  It has the original dizzy with points etc  

The max out is in 4th 

4th OD tops out at about 4600. 

This years rolling road put the flywheel figures as 

136.2 lbs torque at 3758rpm

116.3 bhp  at 5018 rpm

Any ideas where I can look to get the performance back ?

H

Edited April 3, 2019 by Hamish
Spell- change bop to bhp

[ianc]

I don't understand the 116.3 bop - what is this?

On a rolling road, the only measurements are made at the tyre/road interface - anything said to be Brake/Flywheel figure is an estimate obtained by taking away the losses through the transmission, and these losses are estimated by disconnecting the engine from the rear wheels (by de-clutching or knocking out of top gear) and letting the speed reduce.

From my point of view, the figure which matters is the power at the road, and the other matters of great importance are the shapes of the power and torque curves.  I like to see a long, near flat, torque curve through the usable rev range, as this makes for good performance on the road.

With the mods which you have listed, I would expect you to be getting 115-120 horsepower at the rear wheels, and torque to be substantially flat from about 2800 to over 5000 rpm, which is what my car (4VC) shows.

Ian Cornish

[Hamish]

Hi Ian

Bop is supposed to read bhp now corrected. 

These are my RR data print outs. 

Edited April 3, 2019 by Hamish

[ianc]

Hamish - If the 116.3 is measured at the wheels (which I suspect), then it is not BRAKE Horse Power (BHP), but Horse Power (HP).  BHP is measured with a dynamometer attached to the back end of the engine, and not many (any?) TR owners will have done that!  Kas Kastner did so in Coventry back in late 50s/early 60s when he showed ST's people that he could achieve over 150 BHP on a 4-pot TR engine without need any for "California air"!

116.3 HP is a decent figure for a modified, but tractable, road car.

If you PM me with your email address, I can send you plots for a standard TR4 and my (modified) TR4 obtained a few years ago on Enginuity's rolling road.

Ian Cornsh