ozzy

In the past year more and more (respected) people have said that det is the biggest killer of scooby engines; hence why everyone's going on about fitting a knocklink.

I ran my car for 3yrs with no gauges at all and never had any bother. I recently fitted a knocklink and could see more *noise* between tanks of Optimax or SUL AND I could also see some det warnings at high-revs.

Is it that much of an old wives tale or is there more too it?

Stefan

johnfelstead

current situation is i have rebuilt the engine, run it in, changed the oil then gone for a blast and its detting.

I have tried it with Optimax - it dets, Optimax plus 75ml NF - it dets, ESSO SUL - it dets, ESSO SUL + Millers Octane plus - it dets. Tried it with a standard STi5 ECU and standard rated plugs - it dets, tried it with an ECUTEK remapped ECU plus 7 grade plugs - it dets.

So i think its safe to say the reason my engine failed wasnt down to the fuel, wasnt down to oil, wasnt down to oil surge, wasnt down to oil temp (it was only 90 degrees C), wasnt down to oil presure, wasnt down to charge temp (yes i monitor that too). Something i havnt found yet is causing this det and caused the engine to fail in the first place.

Friday i am putting the car on the rollers at Prosport in stockport and getting some det cans on the engine to check i am not chasing a red herring if the knocklink is playing silly buggers. I will find the reason why mine failed and seems to now be detting, its just a case of elimination after testing.

When i get to the bottom of this i'll do a proper write up of what was involved with the rebuild and all the testing being done right now with conclusions. You can read my rebuild thread and the saga to date in the engine section on 22B.COM JohnF Rebuild

cheers
a tired JohnF

johnfelstead

Stefan, you will get some Knocklink activity as the revs rise, especially above 6500rpm as it will be picking up natural engine noise and displaying that. UK's tend to light up the first two greens at high rpm, STi's tend to light up the 2 yellows too if you are really nailing it at the top end. As the revs rise so does the background noise being displayed.

When you have det the knocklink gives a very fast display lighting all the LEDS up in one big pulse, efectively you are seeing the optical equivilant of a noise spike when you get det.

johnfelstead

mine was a big end failure, it did #1 and #3 big style, took out the crank and 2 rods. It did that in under 43 seconds! When i left the start line of the sprint course at TOTB2 it was perfect, when i came through the timing gate at the finish 43.45 seconds later it was fcuked.

Even with a knackered engine and one run it beat 2/3rd's of the entry. LOL

Chicken Man

John,

Its a good job you don't "drive like a *** on the roads" and always do dozens of things regularly to ensure your car is kept in tip-top condition!

I genuinely feel sorry for you for the grief that you are going through, not to mention the incredible expence.

But come on, you've got to be feeling a bit of a **** after saying that lot!

johnfelstead

there is nothing wrong with the heads or anything internal, i rebuilt the engine myself with some help from Pat and the guys at Prosport and its spot on mechanically.

johnfelstead

no Chicken Man, i dont feel a ****, as you so elequently put it. As of yet i dont know the reason for my failure, when i found out i'll let everyone know.

If you follow what i wrote earlier you are far more likely to have a safe engine, that is not going to protect you from every eventuality though.

When my engine failed, my knocklink was not working, but i didnt know that, so had it been working i most likely wouldnt have had the expense of a rebuild. I now check everytime i start the engine that the knocklink detects the starter hitting the flywheel ringgear and displays a slight spike, i sugest everyone else does the same.

Mad Gypsy

Both Roger Clark's and Barrett's advise an uprated oil pump.

Both have said that Optimax by itself is fine to run on an import.
Neither advised an uprated fuel pump.

GC8

If you can get an exhaust gas reading as its detonating it will help you to pin-point the cause. Assuming that the car is fueling correctly; if its lean it will be an air leak. If the mixture is good then Id look at the ignition advance. Because the pre-ignition caused 2 cylinders to fail; which indicates massive detonation, Id discount a highpoint as its unlikely to affect several cylinders at once.

Simon

johnfelstead

Like i said Simon, its early days. It is nothing to do with ignition timing as i have tried two diferent ECU's on the car with 2 diferent maps and still get det, it didnt det for 52,000 miles either.

We will be doing thorough testing at Prosport and will find out what the problem is (if there is now a problem and it is real det i am detecting). It could be fuel related, it could be a knackered MAF, it could be lots of things right now, i wont know until its tested properly though so we will have to wait until friday to see where we are at.

johnfelstead

lean running can be caused by lots of things, Faulty MAF, Fuel pump breaking down under load, poor voltage supply to the fuel pump, blocked fuel filter, pinched fuel line.........etc etc. It's a case of test and measure now.

scooby_si

wasn't there the suggestion sumwhere that following an oil change the engine should be turned over manually so the oil gets a chance to get round the system rather than running for even a split second with no oil in certain parts?
I will try & dig out chaps details who put many failures down to this but he was a knowledgable chap (unlike me fire away if i got all me terms wrong lol) who works largely on engine rebuilds & who didn't appear to just be doing the pub talk thing....
Si (scoobless mongol)

Leviathan

If theres one thing that sticks out from all of this and previous threads over the months its excess heat.
Not so much in Johns case but the majority of these failures,
prolonged high speed is involved= heat.
I am convinced that the shape of the classic (especialy) is not designed for excessivly high speed.
Ever watched a car in a wind tunnel and how, as speed rises, most of the air hits the nose and goes straight over the roof.
At high speeds the TMIC will recieve less and less cooling air and will not be able to control the massive heat soak through the turbo.
leading to obviously higher inlet charge temps,
leading to dettonation and so shearing or even carbonising of that microscopic oil film around the shell bearings of the bigend. There is no oil on the planet that will withstand that sort of abuse.
These engines do not fail in Japan, in the main IMO because they will not go over 112mph and they run on the fuel they were designed to run on, end of story.
Some people know how to treat them and some dont, that isnt a dig at anyone, its just that they have probebly never been told until it hits the fan or they havnt been fortunate enough to see the information available on this board. I mean knock links, additives, gauges, fuel pumps, re-map ect ect.
Just my 2pence worth, im off for a stella or 3.

Turbo_Steve

Can't help but say this:

If you're running an import or running a modified car, why on earth aren't you running gauges?

Knocklink: £150ish
AFR: £50ish
EGT: £100ish
Fuel Pressure £80ish
Oil Pressure £40
Oil Temp £40

That's spending £500 (which to be honest is over the top!) which is £1000 less than that engine rebuild.

The minimum I'd have on any car that isn't standard is a Knocklink and AFR.
As there seems to be some doubt about the fuel pump, it can only be a good investment to fit a Fuel Pressure Gauge.

If you don't want lot's of gauges, put them all in the glovebox, spend a wee bit more and use remote warning lights (e.g. the Defi Setup)

Seems to be sensible to me.