2.0 Pinto Tuning Tips

[Guest marknickson]

Just rebuilt a 2.0 Capri engine of unknown vintage.

 

INGREDIENTS...

Head bought from Ian Harwood from an RS2000 (perhaps originally Cortina though) with rimflow valves and light porting. Cam is a Piper 285; vernier pulley installed. Inlet manifold and Weber 32/36 DGAV is from the same Capri as the block. Electric fuel pump and pressure regulator fitted. Distributor is from a Y reg 1600 OHC Sierra (the original donor). The auto choke part of the carb has been removed as it fouls the cam cover, so choke is operated by hand at the moment! Vacuum advance is now fitted too. Timing has been set at 8 degrees BTDC at 1000rpm.

 

THE PROBLEM...

Needs full choke to start, and once warm it idles nicely without choke. No black smoke. No nasty noises. So far so good.

 

The pick up is terrible. The engine hesitates when the throttle is opened. So much so that you can stall the engine by opening the throttle quickly. The car is almost undriveable because under load it is even worse. Seems to run quite hot too.

 

I have stripped the carb down, as that was the obvious culprit. The float level is spot on, the jets are all clear (now!), the accellerator pump seems to be working OK, and all the fuel has been drained from the tank and replaced with fresh.

 

I've tried everything I can think of, including altering the idle mixture (both ways) with little effect on the hesitation.

 

ANY IDEAS??????

 

One more thing. With my set up, what jets should I be using?

[Guest Kieran]

Not sure about jetting but I had a similar problem witha 40 DFAV carb fitted to my pinto. Tickover was fine but touch the throttle and it would die. Could only rev the engine up by either choking the carb with my hand or flooring it. Anything else and the motor wouldnt pick up. Turns out the mains were too small.

 

The haynes book should list jet sizes, but if the engine has run on this carb before, it seems to point to an airleak somewhere?? Try spraying around the inlet manifold etc with wd40 whilst the motors running and look for white smoke from the exhaust.

 

HTH

 

Kieran

[Peter Bell]

Mark it is called the progression stage and is the most difficult bit to get right. It is the change over from the idle jets to the start of the main jets. If you look at Jims NW Hoodies site there are jets for the DGAS set up it will be a good place to start and probably will not be far out. You will have too small air jets, possibly too small idle jets and mains. It won't cost much to try them but the best bet will be to go to a rolling road that knows what they are doing. You will need to advance the ignition too, try about 12-14° if it doesn't pink give it a bit more.

Peter.

[Guest MrSandman]

Peter beat me to it.

 

With a modified engine you will need more advance at low rpm to compensate for the poor volumetric efficiency cause by the valve overlap.

 

This is not your problem, it is carb as others have stated but will certainly be an improvement on your current advance.

 

It does beg the question why you still have a single twin choke when your engine probably needs more breathing.

[Guest salty_monk]

32/36 should be ok, it's only a mild tune, not that much difference between that & the DGAS....

[Guest marknickson]

Peter beat me to it.

 

With a modified engine you will need more advance at low rpm to compensate for the poor volumetric efficiency cause by the valve overlap.

 

This is not your problem, it is carb as others have stated but will certainly be an improvement on your current advance.

 

It does beg the question why you still have a single twin choke when your engine probably needs more breathing.

Thanks for the advice fellas!

I'll have another go and let you know how I get on.

 

I've actually de-tuned to a twin choke. I used to run a 2.1 Pinto, with the same head and twin 40 DCOEs, but soon got tired of the excessive fuel consumption. With the small tank, and sub-20mpg, it got to the point where I was reluctant to go for a drive! Whn I originally built the car (many years ago) it was fitted with a 1.6 Pinto which was very economical but underpowered. Also that damn VV carb was a real pain!

 

I figured the 2.0 would be a sensible compromise.

 

Mark

(AKA Wizzy)

[Guest salty_monk]

Sounds like you need fuel injection... Zetec or XE will produce loads more power & still return the mpg.

 

I got under 20mpg with my 2.0 on a DGAS, I drove it "enthusiastically" though...

[Longboarder]

Put the twin 40's back on and get them set up by someone who knows what they're doing,

or bike carbs and megajolt to give 3D ignition map

or bike TBs and inject it.

 

Nigel

 

or engine change time.

[Big Jim]

Put the twin 40's back on

Round spherical objects! Gas guzzling fuel disposal buckets! (well on a Pinto, anyway!)

 

Get your ignition sorted out, unless you've altered the ignition curve (go see Dave Andrews web site, there are links to it from our site) then you'll never get the performance that the cam is designed for. once you've sorted the ignition, get someone proper to set up the carb, once done, it'll fly.

[Guest marknickson]

Put the twin 40's back on and get them set up by someone who knows what they're doing,

or bike carbs and megajolt to give 3D ignition map

or bike TBs and inject it.

 

Nigel

 

or engine change time.

Change engine? Again? It's taken me a year to get this one finished!

The DCOE carbs were set up properly. Jim's right - they just guzzle fuel.

Bike carbs? Megajolt? I have neither the time nor the money.

 

I have a new set of jets and a service kit on order, so I'll try that first.

 

Mark

[Longboarder]

Maybe DHLA's are better but I always got 30mpg on any journey, docile round town and responsive to throttle. Rev limiter was set to 6500 and it would pull hard all the way and bounce agressively off it.

Changing from 2.1 to 2.0L pinto wont make any odds to the fuel consumption.

 

Nigel

[Guest MrSandman]

I have heard that Dellortos are better than Webers for fuel efficiency. I think Bike carbs are even better if set up properly as there is no accelaration pump to assist with fuel 'disposal' when opening the throttle.

 

Whatever fuelling you have, economy will always be compomised without correct ignition timing and a good spark. That's why I am going with Megajolt.

 

I agree that a later engine would provide both power and ecomony but obviously that will be more work than sorting what already have fitted.

 

I wouldn't build a new kit with a pinto but neither am I prepared to start swapping the engine in this one. YET!!

[Guest Bob Green]

Round spherical objects! Gas guzzling fuel disposal buckets! (well on a Pinto, anyway!)

 

Get your ignition sorted out, unless you've altered the ignition curve (go see Dave Andrews web site, there are links to it from our site) then you'll never get the performance that the cam is designed for. once you've sorted the ignition, get someone proper to set up the carb, once done, it'll fly.

I don't know if I agree with heavy fuel consumption theory if the carbs are jetted correctly. I had a 172bhp Pinto on 45's, maximum size valve flowed head by Mike Tanski and a Piper 285 camshaft.

 

After using a wideband digital gas analyser to get the jetting correct (and this was acheived by soldering the jets then re-drilling with jet drills), the car went like hell but on a run and driven "normally" would return over 30 mpg.

 

The ignition timing was set at 17.2 degrees at idle on a standard distributor to give 37 degrees at 3,700 rpm. I found however that after fitting a MegaJolt ignition system, I could set the ignition so the progression in the carbs was spot on.

 

Working with DCOE's is not a black art, just a case of understanding them

[Guest marknickson]

I appreciate all the replies, thanks.

Perhaps my carbs weren't tuned correctly!

 

Anyhow, the work is done now, so if I can get the current set up running smoothly I'll be a happy-chappy! I'm not looking for rocket-ship performance, just a useable, efficient and reliable engine that means the tank doesn't need filling 5 times to get to the South coast!

 

I've had a quick look around and can find no signs of Bob Vincent, Ian Cairns, John Trickett or Graham (don't forget your toothbrush) Holdway(?). Are you out there somewhere?

[Guest marknickson]

OK

Fitted a service kit to the carb today, and new idle, air and main jets as per Jim's DGAS.

Big difference - great.

Apart from a little hesitation that could be down to ignition or cam timing, it's great. Starts well and idles beautifully.

Much better throttling...almost perfect!

 

Aiming to get it MOT'd next week.

Roll on Summer!

 

Next jobs......

 

Washer bottle & pump to be fitted (about time too!)

Coolant catch-tank

Small leak on rad to solder up

Fresh sikoflex around screen

Replace perspex on O/S sidescreen (damn wind!)

Fabricate new O/S nerf panel (help!!! Any advice?)

Re-calibrate speedo for bigger tyres

 

Thanks again for your help guys

 

Mark