Help! I ran 3 laps at LeMons and killed 3 cylinders!

[cout]

Help! I ran 3 laps at the 24 Hours of LeMons and now I have a 3-cylinder KLZE!

(I've never been on a racetrack before in my life so it's somewhat disappointing that it happened so soon, right as I was getting the feel for the track and the car).

(but *before* that we had a very fast car for a "class 3" -- especially in the rain since our crappy H-rated high-tread tires gripped like a dream on the wet track. LOTS of people were commenting on our speed when our best drivers were on the track).

Here's what I know:

• At first we thought it was an ignition problem. We ran a ratcheting strap across the engine to prevent it from rocking backward into the brake master cylinder (the throttle body fits but when we shift it occasionally rocks back just a bit). The strap was inadvertently run over the front 3 wires and so they had just started to come undone at the boot a little.
• We changed the wires. No effect.
• We didn't get a chance to do the HEI mod, but we did bring an extra disty. The old one was making noise, so it was a good candidate. We changed it out, but it didn't help.
• We took the valve/cam cover off and checked to make sure the cams are spinning properly. They are.
• I'm a crappy racecar driver and my teammates think I missed a shift, causing the timing belt to jump teeth (the KLZE a non-interference motor, right?)
• This guess was bolstered by the fact that there is some damage to both the timing belt cover and the timing belt itself. It's frayed on the outside.
• There are tapping/knocking sounds coming from the engine. With a stethoscope it's hard to identify exactly where.
• We believe we do have spark from the distributor to the plugs.

What could the problem be? Could the timing be wrong in the front but not the back? How do we check?

What things should we check? Is there any hope for this engine?

Also:
[*] The timing belt tensioner pulley is a little bit loose. Not good.
[*] Also we broke the bracket on the accessory tensioner when we did the water pump. We rigged it so it would stay tight but it broke again on the track.
[*] Our plan here is to do some creative tensioning with a C-clamp and a hydrolic jack. Think it will work?

Apologies for not researching this if it's a FAQ. We're a bit stressed/rushed here and we want to get the car running again so we can make laps tomorrow!

(if worse comes to worst, can we safely run it on 3 cylinders?)

Also, apologies for the lack of pictures. I will post some soon when I have time!

[cout]

Also, it's the front 3 cylinders that are the problem, not the back 3 that had the nasty oily broken spark plug wires I mentioned in another thread.

[fowljesse]

OH, man. Sorry to read this. It sounds like you jumped timing. You can find TDC on #1 by lining the crank mark up to TDC, and then putting something (ratched extension) in the #1 cyl spark plug hole, marking the extension at the top of the plug hole, and then turning the crank slightly each direction, to make sure the mark doesn't go any higher than at TDC.

[wytbishop]

When cylinder #4 (front middle) is at TDC compression all of it's cam lobes should be pointed up...all valves closed. So put the crank pulley on the TDC mark and remove the front valve cover. If they're not, turn the engine 360º and they should be. If they're still not that would prove that your front bank timing is off.

[cout]

I wasn't involved in the timing, but when we replaced the belt we used this guide:

http://home.comcast.net/%7Emmunoz70/z/l ... ngbelt.doc" onclick="window.open(this.href);return false;

(very nice guide -- it's so thorough it's almost insulting)

My friends tell me they are positive they set the cam timing correctly, but I definitely want to double check it myself now that we're not under pressure any more.

We spent close to 8 hours trying to diagnose what the problem was, and finally determined that there's zero compression in cylinder #6 (excellent compression in the other 5 though). Not good.

One person suggested that maybe we really were running on 5 cylinders and not 3, but removing any given plug wire from the front bank yielded no difference in engine sound. Could a bent valve keep the front bank from operating at all or is it more likely that we really were running on 5 cylinders?

Given that it was late and we didn't want to risk breaking a valve, we decided to drop out of the race and come back in September. Sort of sad, except we were able to help out our neighbors in their B20A Prelude by loaning our wheels/tires, performing a brake service, and helping them drop some weight (removed trunk and rear windshield). The grin on their team captain's face coming off the track made it all worth it. They let me drive their car out on the track and so I still got some good track time, even if it was in a slower car. In the end we helped them pull up to a 69th place finish with our team right behind in 70th.

We'll take a break for now and start the rebuild in a few weeks. Next time the other teams won't be so lucky, since we plan to be on the track when the checked flag drops!

[wytbishop]

If you have zero compression in one cylinder it's more likely that something catastrophic happened to the piston/rings/cylinder wall. It's hard to bend a valve in one of these engines. It's possible that you burned a valve so badly that it's not sealing at all. How's your mixture? If you're really lean it's pretty easy to cook an intake valve.

[fowljesse]

Yeah. I was thinking burnt valve, since #6 doesn't get as good of oil pressure.

[chillined]

Well, Check your head gasket (Do you have white smoke coming from the exhaust?), and the timing. There's three things to check, Spark, Air, and fuel, so go one by one.