Race Engine Forum UK

Photos with their permission would be nice!

Let me try my best.

Certainly not a dying trade here. Alive and booming you could say.

This 'zone' is heaving with people almost every day of the week. You wait in line with a ticket to be served in some places.

In some of the smaller workshops, surrounded by old dusty gears and engines, an old grease covered grumpy man would walk to the counter blowing cigarette smoke around the place and say 'yes? or rather 'SI?''

People skills are not one of their strong points but they know their trade.

How quaint.

"You wait in line with a ticket to be served in some places." Royal Marines would love that, suckers for a queue.

G

Urbancamo:

One size in jets is 1/100 mm eg. 0.01 mm. 142 = 1.42 mm hole, 145 = 1.45 mm hole etc. Dellorto has these great dense increments, 141, 143, 146, 147, 149 and so on.

Forgot to mention that I know someone in Italy who supplies dellorto jets in smaller increments,
0.01 increments even with the mains.

142..143..144

PM me if you need to know his contact details.

Next week I hope to get the 145 mains.

Also a hotter plug for winter - as we do short journeys in town with many many stop/starts. The NGK 7 plugs tend to foul up a little during winter as we never do longer trips.
Going for B6ES or BP6ES. Will help to burn off the excess fuel on all those junction stops and starts in town every 30 meters.

Chris

Oh thanks Chris, I know this bloke you're talking about.

And what goes to NKG, never failed me. BP7ES what I use on tuned engines, and BP6ES in stock ones.

T

You never had any detonation issues with the 6 heat rating of NGK on your stock engines when under hard load/hot conditions?

But you are referring to running them in Fiat blocks aren't you?

Mine is stock as you know but tend to foul up a little as mentioned. I will try the 6 plugs when things cool down a little here and we do more town driving.

I'm used them succesfully on both Lada & Fiat engines. Currently running BP7ES on my Lada engine. Heat range seems to be spot-on, runs clean but isn't too hot.

There isn't certainly detonation if I run BP6ES with 8.5:1 compression stock Lada engine. Stock TC engine works fine with these also. Modern spark plugs can operate at very wide temperature range.
Change interwall is 15.000 kms or more...

Stock AR 1.7 has a ratio of 9.50:1

Should be ok on the 6 ratings in winter I believe. I'll give them a test and inspect their colour on a regular basis.

Thanks

Chris

Just curious, what are the fuel octane ratings available in your country?

We have 95 and 98 RON available in our country. 95 wich has max. 10% ethanol content and 98 max. 5% ethanol content.

95 and 97. I always use 97.

I think both have 5-10% ethanol now.

And the quality varies from station to station, time to time.

I'd try to use the iridium equivalent for the BP7ES. They never foul up and have an excellent spark, even on a cold engine. They also last up to 100.000 km. I've been replacing "regular" plugs with them on all my cars the lat few years and I've never regretted it.

I have a problem with the rpm.

When the engine has been working hard on the motorway and it gets up to a good temperature the idling surges to about 1350 rpm when I stop.
If I wait it may take 1 minute or so to get below 1000 rpm.

I thinking an air leak on one of the carbs - either one of the gaskets between the plastic sandwich or possilbly the carb bearing linkage(hope not this one inside).

I've had an issue with an air leak before but last time it acted differently. It would go up and down while idling.

I thought it was lean as they can 'hunt' but even when rich it does the same.

Spent several times carefully balancing them and it idles nicely for the first 15 mins, but then after some hard driving it starts surging again.

Try spraying small bursts of brake cleaner at the suspect locations. If your engine changes RPM, you know it's sucking in the cleaner and you have a leak. Be careful, brake cleaner is highly flammable and should only be used in a well ventilated area, for health concerns. Don't go sticking your head under the bonnet while you look for evidence of leaks, you can hear the RPM change just fine without putting your nose on top of the engine. If the cleaner decides to burn, you won't have any eyebrows left, if nothing more serious. Just in case, keep a few buckets of water around, extinguishers tend to have very corrosive chemicals in them.

If your engine is on contact breakers they could be the cause. If the condenser is tired the points burn and close up - this effectively changes the ignition advance.

The other possible cause apart from an leak (which I have only ever seen once) is fuel dripping into the carb from an over-full float chamber, worn needle or wrong setting - that definitely does what you are seeing. too much fuel pressure can do it too, carbs only want 3.5-4psi.

G

Thanks Guys and Whizzman.

I've heard of the carb cleaner/break cleaner method but as you said can be rather dangerous. Rather try to avoid that method if I can especially around the family house.

Guy: I have electronic ignition, no contact breakers.

I will check the floats. Maybe a little high (I do remember setting them 1.5mm higher last year when I replaced them as they were more floaty than the new ones - maybe they have settled after usage and now overflowing)?
I recently put in new needles and they were working fine before the rebuild.

The fuel pump is the same as before and worked just fine also. I wouldn't imagine the pressure could change with the original pump.

I will remove the carbs, replace the gaskets, and re-check the float heights and also the needles.
Can the needles be checked by dripped water/fuel into them while closed (on the workbench)?

Regards


Chris

You can see if the carbs are flooding by looking down the barrels once the engine starts 'misbehaving' - wear protective specs though..

Fuel will be dripping onto the throttle plates at idle if this is the case.


G