Math question tdi + 2 bar =

[..lee..]

tis charge cooled and there was no coolant loss. headgasket didnt blow, engine temp was normal.

haven`t studied the head yet but i think its ok. going to strip and change the valves and guides, not taking any chances this time.

[HarryMann]

is charge cooled and there was no coolant loss. headgasket didnt blow, engine temp was normal.

Right up to the last milliscecond?? For sure...

When Simpson's intercooler split (or pipe blew off) at full chat and probably a similar pressure, it was game over within probably 50 to 100 revs, but his AAZ was probably turning 5 to 6000 rpm (less than one second!)

Similar damage Lee... distorted block etc. Lots of fuel and no air

Your timing didn't slip by any chance?

[syncropaddy]

I still cant get my head around what bent the rods ...... are the valves fecked as well?

[..lee..]

learning to speak spaghetti and stipping the head this weekend. head looks fine. there`s not a mark on the head face, valves all the same colour so i dont know.

ask me one on sport.

[silverbullet]

My money's on duff injector > melted piston > pressurised crankcase > hydraulic'd engine.

Bad luck Lee. There's always petrol if you dig yourself an oilwell and your luck improves!

[footstuck]

Hi mate
Did you feel any power surge (or over willingness to pull) prior to noticing the failure?
Do the skirts indicate it had been running with the rod condition for any length of time?
What where/are the ring gap positions on the failed piston?
They can so easily be clocked during assembley, and worst case, could give a straight flame path.
Maybe as the burn hole became big enough for crank case compression, (early stage) it was able to contain Compresion given the presents of oil flodding, and still cause hydraulic.
Has the rod on the burnt piston suffered marginally less from hydraulicing?

[..lee..]

the burnt piston cyl3 is bent in an s shape quite badly like one other rod, cyl2 i think. the other 2 rods are bent but not as bad as the main 3 and 2. pistons , rods and now we`ve found the block is scrap aswell.

so plan is to get another block bored, uprated pistons from 130hp motor, stock rods new bearings , oil pump. the valves have wear on the stems so head will have new guides and new valves. just hope it holds together this time.

builder is convinced the pistons were sitting low in the bore before it blew. there`s such a big hole in the piston he recons that rod would not have hydroliced. someone on the tdi forum reconed 2 bar was enough to bend the rods on its own so i dont know and i guess ill never know.

van was pulling well, no noticable surge but a second or 2 before it blew i got a bad shudder. it cleared for a couple of seconds and then the shudder came back but this time with lots of smoke.

lee

[syncroandy]

Hope you get a proper VNT ECU and remap for the VB as well ?

[max and caddy]

the upper factory boost limit is 1950 millibars...or 2 bar give or take.

[HarryMann]

Yes, but the factory limit for boost is not independent of the amount and timing of fuelling... boost alone won't do that of course

Van was pulling well, no noticable surge but a second or 2 before it blew I got a bad shudder. It cleared for a couple of seconds and then the shudder came back but this time with lots of smoke.

Awfully difficult to determine chickens or eggs

[max and caddy]

"Yes, but the factory limit for boost is not independent of the amount and timing of fuelling... boost alone won't do that of course "

Come again? wont do what..of course?

[..lee..]

i thought power cut and limp was introduced @ 1.2 bar. whats this 2 bar limit is it the map limit or the safe limit???

new block going down for boreing in the morning so looks like weekend spent rebuilding. not looking forward to a weekend of work i`m absolutely knackered atm.

lee.

[footstuck]

As far as it goes, my understanding is that max boost (spike or SWL)
Will only allow the fuel to burn at a a controlled rate while the 'fuel-in' timing advance, and egt, follow their respective map, or fall within their pre-determined (and researched) Safe limits.
What we all want is MORE. (speaking for me and every one else who puts an engine designed to power a vehicle which weighs 35% less or there abouts, and then opens it up).
Up the fuel beyond, retard or advance the bang beyond, and the results will/ will not be predictable.
If we don't try . . . .


Anorak Not RubberNecker

[HarryMann]

Come again? wont do what..of course?

won't bend rods, hole pistons or break the bottom end

so a charge cooler is not as good as an intercooler because.....

Didn't exactly say not as good, just that in the limit, cannot get air charge temps down as low as an air to air, if freestream ambient air is the medium we are using (and it usually is e.g. packed ice is for dragsters).

Crude reasoning using hypothetical high efficiency for:

a charge cooler;
Freestream ambient air >> water.... say chills it to within 1 degree of ambient
Water >> charge air... say chills charge air to within 1 degree of water temp
.. so that means charge air is 2 degrees above ambient

an air-to-air intercoole;
Freestream ambient air >> charge air.... say chills it to within 1 degree of ambient
... .. so that means charge air is 1 degrees above ambient

Thus air-to-air gives 1 degree cooler inlet air

In practice these temp diffs will often be even greater, which is not to say practial water charge cooler installations are not as good, sometimes they are and in the case of T25s very often so I imagine, and much more practical, being rear engined.

[max and caddy]

i didnt say it would bend the rods! in fact i said its within (almost) the factory specs! then you rolled your eyes and now have dug up my post off the charge cooling thread...have i offended you in some way?

or am i just a being sensitive..?