BMW Show Post Mortem Results In (Pics as well)

[Paul@1320]

Here at 1320autos we like to share the good with you, but we feel when there’s some bad it’s only right we share those facts with you as well.

So the first two runs on Sunday were without nitrous, due to the fuse on our nitrous relay blowing and not activating the nitrous and fuel solenoid.

Once that was fixed it was a case of going on a run and hoping the new experimental driveshaft would hold up.

I launched with too few revs as I was worried about the shaft snapping, hence the poor 60ft of 2.3, but once the nitrous kicked in it pulled like a train. Even going into the strong headwind the 60ft-1000ft showed we had nearly gained a 1/10th over our previous best.

At 11.4 secs into the run the engine nosed over. As soon as I felt it I lifted my foot off the throttle and switched off the engine by this point there was water coming up the windscreen as the bottom hose had blown off.

What’s scary is that with all the above it still ran a 12.36@107 (fastest BMW of the day, I wonder how many BMW mags print that)

So was I gutted?? Yes and No; drag Racing especially heads up nitrous racing is accompanied by a real strange mentality, that is: you have to blow it up to learn how to improve it and move forward with the main aim of going faster.

Do I know why it happened? Yes and no. We just have to rebuild it and subject it to the same abuse with a few alterations, otherwise how can we advise a customer on a combo of parts if they wish to go this route.

Good news: all 4 pistons don’t look as if they’ve done a day’s work.

Unfortunately a lot of people will blame the nitrous, when in fact the air fuel.were in the 11/10-1 range for most of the run.

Enjoy the pics

[supercoopers]

Yowsa, that's gotta hurt

Thanks for sharing the details with us though and that is a good time despite the engine damage!

Good to know that the JE pistons are pretty strong then eh?

From the look of it is it possibly due to detonation? Too much ignition advance or too hot in-cylinder temps?

Cheers,

Henry

[Paul@1320]

It'll hurt the wallet thats for sure

We haven't pulled the pistons out as yet so hopefully the top ring land clearances are still there.

There was no sign off any detonation,the igniton usually retards to about 10deg with the nitrous.

As for the temps who knows though when you look at the colour of No4exhaust they look like they were hotter but that cylinder was okay

The cylinder pressures would of been very high

May have to stick on a real dyno next

[MINIMANIAUK]

Looks like the gasket has failed and been failing for some time,just too much load on it, solid copper one next I would say and sealing rings,and tighter bolt torque

[MINIMANIAUK]

not suprised the pressure popped the hose off!! the worrying thing is what times you will get with a pukka gasket? and what times you got with it as is
no4 was the only cylinder burning properly 1/2/3 would have been igniting randomly with reduced pressure - however tight you pulled down no4 end just do the same to the others

[AndyH_MCS]

WOW! Thats a fair bit of damage! Is there much damage on the block? Tom was saying on the leakdown it indicated a headgasket failure but would have been suprised if it was as its a multi layered jobbie.

Hope you get it all sorted and come back bigger and better

Andy

[Paul@1320]

Yes it looks that way Andy that it was a head gasket failure rather than the amount of nitrous we were throwing down it.

We was going to make the BMW show the last one of the year but it now looks like we might have to book in for the Fireworks meet just to see if that 11.5 & 120+ is in there and to see if we have found a cure for the headgasket

[Lucky Dave]

It was interesting to see how loose my old head was when I removed it a while back!

I dont think there is any bmw spec for re tightening over a period?

[JAMIE1131]

That defo looks like detonation damage to me, I've seen a lot of engines that have let go having heard them knock and the damage to the cylinder head was very similar. It only takes one or two cycles to cause a lot of damage.

[Paul@1320]

Quote: Originally Posted by JAMIE1131 (original)

That defo looks like detonation damage to me, I've seen a lot of engines that have let go having heard them knock and the damage to the cylinder head was very similar. It only takes one or two cycles to cause a lot of damage.

Thanks for comments Jamie, obivously you are a very luky man to be paid to witness and learn the stuff that you do.

I'm personally going for headgasket failure as I was told not to use this make, but at least I know myself now and can pass this advise onto our customers.

We'll start repairing the head next week and have it all back togeather for the fireworks meeting and see if it holds togeather.

I might try and get the old data logger we have lying around fitted so we can measure the egt's on all 4 cylinders.

Wouldn't be nice to be able measure the cylinder pressures

[JAMIE1131]

Quote: Originally Posted by 1320autos (original)

Thanks for comments Jamie, obivously you are a very luky man to be paid to witness and learn the stuff that you do.

I'm personally going for headgasket failure as I was told not to use this make, but at least I know myself now and can pass this advise onto our customers.

We'll start repairing the head next week and have it all back togeather for the fireworks meeting and see if it holds togeather.

I might try and get the old data logger we have lying around fitted so we can measure the egt's on all 4 cylinders.

Wouldn't be nice to be able measure the cylinder pressures

Get some Kistler sensors fitted to the head, there only £1500 each!!

[BRMCooper]

Paul whens the Fireworks meeting? i take it-it's around the 5th i may come up and watch ya run!