What is the cause of this?

Hello

I have a TD camaro with a TFX hemi with AJPE stage 2 fuel heads, msd 44 promag, SSI standard helix 14/71, powerglide car.

My engine puked itself this weekend.

I only got one test run and then on the burnout of the second run my engine was dead.

The rod on #1 cyl. is mostly gone and the rod on #2 is wasted too. Crank has deep marks after the all the debris. I found the bearing pieces from both rods they are of course mangled but they have not spun and are not showing copper. Also i found 2 complete rod bolts in the pan banged up ofcourse but othervise looked ok, Is that normal to find complete rodbolts like that? The valvehead in the pan was sitting on top of piston #2, Both pistons have made contact with the head, The block is dented but not windowed.
The engine was on a mech. throttle stop on the burnout and on the test run we had it mechanically limted to 3/4 full throttle.

I am cuirous to know what starter all this? Rods too old? loose bolts? bad bolts? ???

The engine is not new but it is a fresh rebuild, build from fuel parts

Pictures:

 

Next question is how much oil did you have in it? The bearings I see in the pan are preety scorched. 1 and 2 are the first to get tore up when you run it out of oil. Eight quarts only gets you to 700 feet You hurt it on the first lap and finished it off on the Burnout. That assumption takes for granted all the rods are /were torqued correctly.

 

it is the back side of the bearing that you are seeing in the picture.

I havn't taken the rest of the pistons out of the block yet, we just packed it up I'll tear it down and take some more pictures.

We used a normal clip on throttlestop that is clipped on the throttle cable oppesite the k valve. On the brunout. during the run we used a small spacer on the cable.

Here is a picture from the burnout with the throttlestop:

http://spotted.stiften.dk/gallerier/dragrace-paa-mosten-race-way#506194

When an engine like this detonates, wouldn't the bearings be squashed or pancaked?

the oil was changed before after the first run. and we had it started on the stands in the pits before the second burnout. on all startups we first make sure the is oil pressure before starting the engine is started with a normal 48 volt aircraft style starter.

The throttle stop fell off in right at the end of the brunout that killed the engine, just before it quit, quite odd i actuarly noticed this myself. Here is a video of the burnout:

we run 16 - 17 liters of oil

http://www.youtube.com/watch?v=eZ3N...DvjVQa1PpcFOKtX2TZGrlYka9iKeCbf-HkvDAsPYgBQw=

 

Oil pressure

What sort of oil pressure and type of oil do you run

 

if the back of the bearing is black, it was detonation. i have several rods and cranks from doing burn outs with too much timing.

 

I agree with Mike, three quarter throttle does not work good on a K valve, the motor is still getting almost full air, but the fuel is restricted, leading to detonation. Might have shattered the rod.

 

Also, how much timing were you running with that 44 amp mag. Depending on compresson and boost, it shouldnt ever be more than 28 degrees, I have run as little as 23 with a screw blower

 

When was the last time the pan was taken off...????
better yet How often does it come off,..????


VM

 

kaboom

hard to judge from the video, but what rpm was the engine turning on the burnout? sounds to me like it was very high, maybe a bit too high. doing a burnout with a stout blown motor its easy to get carried away.

 

We run 70 wt nitro oil.

It always made alot of pressure on all startups and, just checking the pressure before startup with the starter it always made 80 + psi with the engine running it is over 100 psi.

Engine was build this winter by a friend of mine that i also bought it from that runs and owns several TFD in Europe.
It has been started twice before on stands before this weekend. Then again on stands before the first run, on the first run, then again after on stands before the brunout, and lastly on the burnout that killed it. We where planing to check bearings after the second run i quess we should have done it before the second run .. :-/

Timing was set at 30 on the first run, on the last run we backed it down to 27, 23 sounds really low to me are you sure about that? If it is indeed correct we must have been pounding the engine with 30 and 27.

I will get pictures of the ground straps today also

I am gonna tear it down today and take some more pictures

@ Mike

regarding the k valve it is a alcohol specific one with the little notch. Reading your posts, you are saying restricting the engine with the k valve is a no no. And is basicly the cause of all this mess ? Instead we should have been limiting the the engine via timing correct?

I believe we ran it rather fat this weekend

I know it is not a good measure, but the engine went thru about 120 liters of alcohol this weekend doing the warmup on stands, getting the idle set right, doing the first run and then the last burnout.


It has a 125 main pill in it now, I did all the math on the system following the books from Spud, according to those the engine should be running with a 180 main pill. We stated the day with a 132 in it and changed it during the warmup, engine sounded good on the stands after we got the blades and the k valve adjusted.
The engine has 6 nozzles in the hat, 4 in the back of the blower and then 8 in the runners. I can't remember the size of the nozzles in my head i will check my book for this. The pump is a new 1200 endele. setup is a copy paste form other setups like mine that my TF friend also build. These engines run very nicely and have been for several seasons. But obviously something is off in my setup.

Static compression is 9.8:1 if i remember correctly. Cam is a standard fuel cam. We turn the blower 46% od

All in all I am hearing most of you are saying we killed it with detonation, from either restricting the engine the wrong way or too much timing or a combination of both. And my original thought of bad rods, rod bolts, loose rod bolts etc is just plain wrong.

Sorry for the long posts.

 

fresh rebuild "from fuel parts"....... does this mean rods and pistons were used from a fuel car? if so how many runs were on them? I don't think the timing was an issue because your running low compression for an alky motor. Could simply be that the rods were already past their life expectancy from their time on nitro.

 

Not trying to divert the thread but I saw this video of you on Youtube when I looked at the one you posted and it really captured my interest. What single lane dragstrip is this? I thought from the pictures I saw it was Mosten but that has two lanes, right?

Tom

http://www.youtube.com/watch?v=ZZHr-zEUbEY&feature=relmfu

 

The rods where new pistons used but with low runs don't remember how many will have to ask

Yes "Mosten" is indeed a single lane dragstip, when it is used for dragracing. We dont have any permanent tracks in Denmark. So when we race the road is blocked off, prepped with the usual trakbite golddust and so on. and then we race against the clock.

The video you linked is with me and my car it was with my old 555 chevy also blown on alcohol, that clip was taken when the engine chevy broke a piston rod due to an ingnition coming lose.

 

@ Mike

Yes the order in which you described it is how it went.

After the first test run we changed the oil, started it on the stands in the pits. We did not check bearings between the test run and the brunout that killed it. The car felt really strong on the test run, i had to lift as it started spining. brunout was fine on the test run.

The plugs looked normal after the test run, but i am by no means an expert on reading plugs, so we just reused them they are autolite plugs

We didn't pre heat the oil

I really doubt it is an oil issue, all the bearing look fine except for some debris from the rods, no bearing is showing any sign of having spun. Oil pressure was fine all day and on all startups, before any startup we spin the engine over with the starter to make sure there is oil pressure.

Also we only race 1/8 mile.

I have just taken it apart i toke some more pictures here is a link to the album: http://s249.photobucket.com/albums/gg208/sunelarsen/hemi/

it contains pictures of the plugs, bearings, front snout (which it split). and of the first crank throw.

Thank you all for taking the time to comment on this

 

I dont know much about autolite plug but it looks to me you had two different plugs in it, the porcelain looks different. Just something I noticed.

 

I have just taken it apart i toke some more pictures here is a link to the album: http://s249.photobucket.com/albums/g...nelarsen/hemi/

Picture #18 Plugs look burnt, particularly the one on the left.