Block Test Dye kits?

p_b82 · 01-04-10, 12:15 PM

Any-one know anything about them, or whether they are worth it etc?

Also any-one know if it can be got easily from a motorfactor?

I could go round and ask but i dont have time today.....

Basically i am asking because i have had a repeat coolant explosion but we are still not sure of the cause.

When driving the car normally, quick blast of throttle up to motorway outside lane speeds she is fine, holds her collant and gernally is a nice place to be...

however if i use full throttle from 3500rpm in 4th up to 4500 in 5th she overheats after about 1minute...

the way the car is clamped together is using ARP headstuds - these have a low deflection rate they can't be stretching, but the head itself may be warping slightly under this load and breaching the HG....

It could also possibly be the localised heat resulting from full throttle is overhwelming the coolant system that was never designed to cope with the sorts of heat being generated now...

It could be the back pressure of the turbo on the exhuast side combined with the high boost (25PSI) in the intake side pushing the pressures up and lifting the head...

So many unknowns and i think the only way to find out where we stand is to have the head taken off again and looking to see what is what.

If there has been no compromise, we know it is coolant system in general and there is something we can do about it.... if it has lifted the head, then the only option is to reduce the tune of the car. Most likely via boost and fuelling.

Grr

stamford · 01-04-10, 12:32 PM

I must admit to not knowing of a block test dye kit, I do know about crack testing using a special dye and UV light. I did this many moons ago when I used to work in a foundry. Only problem is this partucluar method required a cleaning tank to take the dye and then washed off allowing it to settle in any hairline cracks, the UV highlighted this if found. Quite how this would work if the fault was internal and not visable is another matter.

I get the feeling that you hit the nail on the head and the current design cannot take the pressures generated and finds the weakest exit point. I think you are going to have trouble pinpointing the cause without spending alot of time and money monitoring the engine and finding any hotspots in the operating range you see it happening.

Jay-ZS+ · 01-04-10, 12:32 PM

Sorry to hear your still having issues, hope you manage to track down a solution

p_b82 · 01-04-10, 12:45 PM

Thanks Mick...

here is a link to one i found on fleabay - not really much help as with easter i would not arrive with me until next week.

http://cgi.ebay.co.uk/BT500-TEST-TOO...item2a00e63235

I think that should probably be good enough as you plug it into the coolant system - but i dont think it is designed to bse used while 'in use' as i can't see anyway to stop that just being blown off the end of a coolant hose!

Theonly real way i think to reallly ID the problem is to have the engine out and on a dyno - would be quick a reliable to ID at what point it all goes tits up... however i dont want the expense of that....

Seems that detuning is likely to be the only option - the question will be, how much tho

stamford · 01-04-10, 12:55 PM

That's your normal 'sniff' type tester where it changes colour if gasses found in the coolant. I thought you meant a dye penetrant type tester if looking for mechanical breakdown in the metals, my apologies.

Jay-ZS+ · 01-04-10, 12:55 PM

That looks like the kit that was used when mine was tested, what happens when you take the expansion cap off after it has all cooled right down? I could hear a 'woosh' of gas and the level would rish then drop make down. Not sure if this was the gasses coming out

p_b82 · 01-04-10, 01:02 PM

Ah ok.... matt thought he might have known one that goes into the coolant and changes the whole thing - he doesn't recon the snif test on my engine would be worth it.. as it wont happen until thrashed...

not sure about the coolant but yesterday there was no pressure and the level did not move at all... so there is no latent pressure being stored in the system....

It also doesn't pressurise after a few hard revs from cold - which is the normal tell tale failure of the L-series when the HG goes...

I am thinking that i will probably end up cutting the fueling back from about 3800rpm onwards.. probably to drop the torque beneath 200lbsft.....

I am thinking it is the much shrter time period of the high rpm causing the pressure to remain high, and not being able to drop inbetween each stroke that is part of the problem.

A few people on .org are probably going to look into reducing the compression again, but really in my mind there are far too many unknowns with that route... it will need a large amount of remapping to achieve it, fuel economy will drop, and there is nothing to say the same problem will not occur as soon as you crank up the fuelling to compensate for it...

Steves Cleenz · 01-04-10, 03:03 PM

have you tried running the car with out a thermostat in ? reason i say that is probally from the power its running the water flow might just be slow enough for the temp to rise that little causing it to over heat

just an idea

p_b82 · 01-04-10, 03:44 PM

I hadn't no... but i guess it is worth a thought - tricky thing is that while the car is cold we dont really want the water flow through it, as it will take even longer to warm up..

If only there was a way to find out what was going on without taking it all apart!

dogsbe · 01-04-10, 07:44 PM

On the dervs, the block tests are not very conclusive. I know on mine, I ran a number of block tests and kept getting a negative. However, there was clear evidence of head lifting around cylinder 4. To my knowledge, early days of HGF on a derv is unlikely to show.

By all means, do one if handy. If you get a positive, then you have problems. If you get a negative, you cant rule out hgf.