Starting from hot 246GTS

My car always starts from cold - never had an issues, no matter how long it is left

A couple of times recently however I have stopped for 5 mins after running it for 20-30 mins (e.g. getting petrol) and it had trouble restarting. It did start after letting it cool but obviously this is annoying. Any ideas?

 

There are many threads on hot starts you might want to review. It seems that everyone has a "procedure" for hot starts; you're not the only one who has experienced a problem. I find that letting the fuel pumps work for several seconds and then depressing the throttle about 1/3 to 1/2 while cranking usually does it. Good luck.

 

Switch to a gear reduction starter, no more problems!

 

Thanks!

Sorry what is a gear reduction starter?

 

A gear reduction starter will greatly reduce the effort required to turn the engine over. The original factory unit draws a huge current and turns over very slowly. During a hot start it is quite easy to quickly drain the battery if you are not careful with the factory set up. A gear reduction starter plus a new alternator with inbuilt regulator will be like a breath of fresh air.

These people can supply a unit suitable for the 246 and I've used them on all my cars Starter Motors - WOSPerformance There are other similar solutions out there, especially from the US but by the time you factor in import duty etc they often work out to be more costly.

 

A few years ago I had the same issue and switched to a gear reduction starter works great now ..

 

Great thanks, I don't get the impression that it's not starting because it's not turning over fast enough or that the battery is drained. On the occasions the issue occurred, after I let it cool it was fine. I assumed it was a problem with the carbs, maybe vaporising the fuel?

 

vapor lock is a possibility, especially if letting the car cool helps. Sooo . . . leave the engine compartment open to cool faster when you're stopped, or, do the 1/3 to 1/2 depressed gas pedal.

And, add a gear reduction starter. The added rpms, plus less drain on the batter greatly aids in the starting process.

Certainly you can get by without one, but yours, if original, is creeping up on 45 years old and may need a rebuild, or to be replaced to optimize your starting.

D

 

Correct, the fuel bowls are directly above the engine especially the one over the thermostat housing. It evaporates very quickly in these circumstances.

In my opinion the way the engine fuel system is designed it should be self venting and no vapour lock issues should occur.

for me its a starting technique and always has been. The GR starter is a good option and greatly assists in engine turnover and less drain on the battery. It all helps but isn't a 100% cure

 

Great thanks guys, I checked and they aren't particularly expensive so, as you say anything that helps is better than an embarrassing hour kerbside

Any particular brand or supplier you would recommend (I'm based in the UK). Is it something I could fit myself?

 

The Dino has a continuous flow fuel system short of the last bit of line to the carb, so letting the fuel pump run before trying to start should help because at least the fuel in the crossover line will be cool.

I also open the engine cover after stopping so I don't get so much heat soak, as dm_n_stuff suggested.

 

I think it also helps to keep the tank topped up; circulating a small volume of fuel doesn't help.

 

when I had my dino I remember I had a different procedure for starting warm vs cold. Once I learned this procedure it was never a problem. The only problem is I don't remember what that procedure was !

 

What ignition system are you using?
The stock AEC-103A Marelli perhaps?

 

The correct procedure has never failed me.

For those without a handbook see the attached.

Mark Shannon
Image Unavailable, Please Login

 

As some of you that have read posts from me about my ignition system in the past knew about the issues I had. We rebuilt the ignition back to complete stock including an NOS S125BX Marelli distributor and Winterburn CD ignition unit (I love this unit. I can't say enough good things about it. It is effectively a new Dinoplex without the issues. Truly a plug and play replacement and designed for a points system). We also installed iridium NGK spark plugs as per Corbani's recommendations. We rebuilt the DCNF Weber carbs. Since then I have had fantastic immediate start ups from cold (even after sitting a couple of weeks), straight to unassisted idle. When driven in Calfornia heat, it has no problem restarting when hot. I find that putting the gas to the floor really helps on hot restarts but doesn't really need it but is good insurance to not flood the motor. I mention this only because my experience has been great with a stock points ignition system. With the iridium plugs it has never fouled.

Freeman

 

Great thanks! will try that! I don't know what starter it has (the car is at our weekend place at the moment) but it doesn't have a choke - (unless I've managed to not notice that in the 15 years I have owned it - which is unlikely but not impossible...)

I usually try to keep not very much fuel in it as I don't use it that much and I don't like the idea of running it on old fuel so I try and fill it with fresh stuff when I drive it

 

There are some people on this board that have a lot of experience with the DCNF carbs such as Rob Calisi. Since we rebuilt my carbs I never use any choke (not hooked up). In the past, before the carb and ignition rebuilds, I had to use the choke to start it but we found that it was some clogged idle jets. Normally you shouldn't have to use the choke. Now my Dino goes straight to a smooth 700RPM on start up cold or hot. If your Dino is stock with points, my suggestion is to get your Dino to start up and run correctly with the stock components before changing anything as a baseline. I am by no means an expert. I speak from my own personal experience with my Dino working on it myself with my friends that I trust.

Freeman

P.S. If your car goes long periods between driving I would put in a fuel stabilizer or racing fuel. Racing fuel doesn't get old and varnish like normal fuel.

 

Thank you Freeman for the vote of confidence but my experience has come from a very systematic approach of trying to understand how each component in the fuel delivery system works and how its operation contributes to the bigger picture of fueling the engine.

In the case of the Dino I don't really buy the theory that the carbs overheat and that the fuel bowls evaporate empty. While this may physically happen, it is good practice to turn the key until the fuel pumps run and you can normally hear a change of sound when the carbs are full. Once the carbs are full a cold engine normally needs a bit of a priming which is achieved through a few pumps of the throttle to get some raw fuel into the intake via the accelerator pump. When hot, the engine will need less fuel so opening the throttle part or full without pumping is the way to go. The first opening will squirt fuel in (unavoidable because of the accelerator pump) but then as the engine turns over it will draw mainly air until it fires.

This is not a Honda where you just turn the key and go. Starting one of these cars has a certain sense of occasion and it is to be savored. Understanding what the engine needs when it is hot or cold makes a big difference to avoiding problems with starting.

 

Here is how I installed mine, the photos show you how compact the gear reduction starter is
http://www.ferrarichat.com/forum/206-246/265858-dino-diy-replacing-starter-gear-reduction-unit.html

Ignition needs three things; fuel, O2 and spark
While fuel is an easy path to go down many times the Dino's weak spark can produce similar problems which is why I asked about your ignition system.
Are you running a stock Marelli box?

I have two Dinos; one with and MSD and one with an original AEC103A which failed after a few years and replaced by Permatune, which was not much better. The MSD has had absolutely no starting issues in 10 years of ownership and it really doesn't care which type of spark plugs I use (copper/platinum, Bosch/NGK). The AEC103A and the Permatune can be finicky in hot start situations.

 

Thanks, I have changed the plugs a few times and it generally seems to start much better with new plugs (currently it has ngk iridium I think) but the do seem to get black and tarnished very quickly even when it seems to be in a good state of tune

I keep meaning to clean the old ones and swap them back but I can never be bothered

 

In my opinion for what its worth is the Iridium plugs are no good for the Dino or it depends solely what ignition system you are using. Some swear by them so it seems they are not the definitive answer to plug fouling.

Certainly with my set up these plugs are useless, standard NGKBP7ES are perfect.

Recent re-jetting of the carbs have transformed the car considerably as the dino wasn't designed for the modern fuels we get today.