Broke my race engine

Racer Chris · Post by **Racer Chris** » Mon Jun 24, 2002 8:37 am

Dropped a valve, moments after going 135mph at Pocono, Saturday.

I'll tell more after I remove the head.

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Chris F.

www.tangerineracing.com

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Mon Jun 24, 2002 9:53 am

Been there, last time was at 6K, destroyed it all.......Blew the seat clear up the intake into the carb.

Now you get a chance to use those nickies:-)

johnhora · Post by **johnhora** » Mon Jun 24, 2002 5:51 pm

Sorry to hear that Chris....blew mine last year pulling one of those damn massive hills at Watkins Glen....a rod thru the top of the engine case.

John

Zeke · Post by **Zeke** » Mon Jun 24, 2002 8:24 pm

Me sorry too, Chris. I know you've done a lot of work to your car last winter and in the spring (spring, that was just a couple of days ago, huh) in anticipation of going out this summer

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Milt 914 2.0 Race Car (under construction)

Racer Chris · Post by **Racer Chris** » Tue Jun 25, 2002 4:13 am

I've learned to take this sort of thing in stride. It's all part of learning. I consider occurances like this to be signs. And I might have seen it coming. When we were heading out, the tow vehicle acted up (transmission) before we even reached the highway. So we went home and transfered all the real important stuff to the Dakota and left a bit later. Actually, towing with the Dodge was much more comfortable. It just meant I didn't have a lot of tools or supplies.

One of the things I had modified for this season was the carbs. I didn't have an opportunity to run the engine on a dyno, so I knew I would have to re-jet to get a good mixture. It was definitely too lean, and maybe in the short time I ran it I caused the damage from overheating.

Last night I pulled the exhaust pipe to see inside, and don't see a valve head. The stem is a little bent, and the port is all chewed up from the seat out to where the opening is bigger than the valve. My question is: how does the valve head get past the seat? Someone told me he had this happen on his 911, and he found the valve head in his Supertrapp. I haven't found mine yet.

I still consider myself lucky. I have never blown up, or been stranded on the track, with a trail of oil behind. I always find the damage while in the pits. This time I lost power to one cylinder while in the infield part of the track. Thinking it was a clogged jet, I did one more lap at somewhat reduced speed, before returning to the pits. There were no bad noises coming from the engine, only a sour exhaust note. I could see the exhaust going cold on my EGT gauge, but never imagined it was because of a missing valve head. The spark plug told the story though. The ground electrode was bent to one side and the center electrode was slightly bent, with the insulation broken off.

It must be time to build the bigger and better motor. Meanwhile I'll see if I can use one of my less powerful engines for a few races.

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Chris F.

www.tangerineracing.com

maf 914 · Post by **maf 914** » Tue Jun 25, 2002 10:18 am

I have never lost a valve, so this is just a guess, but I suppose when the valve head breaks away from the stem it rattles around the combustion chamber as the piston hammers it. After a few edge-on hits it probably curls or folds which allows it to pass through the seat past the valve guide and out the exhaust or intake port. Altogether a pretty violent end for the valve.

Mike

ray greenwood · Post by **ray greenwood** » Tue Jun 25, 2002 2:07 pm

Are you sure yet that the valve is not stuck in the top of the piston? I have one like that on my "trophy shelf". I lost a valve head once too. It came all the way out the exhaust...and blew a hole in a 3 day old Ernst muffler. There went an extra $200 Bucks...insult on top of injury. Never found the valve head obviously. Ray

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue Jun 25, 2002 6:26 pm

Chris, It might be in the sump if it shot through the piston.....

I have had them shoot by the seat too, I lost one at damn near idle in a 2.0 and it ended up in the heaterbox...

Racer Chris · Post by **Racer Chris** » Wed Jun 26, 2002 5:13 am

I removed the engine from the car last night, and pulled the valve cover. Sure enough, the outer valve spring is broken.

I haven't found the valve head yet. I assume it was ejected because of the damage to the exhaust port. I may remove the head tonight. I also have to work on a back-up engine right away. I already entered the Lime Rock regional on the Fourth of July.

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Chris F.

www.tangerineracing.com

Racer Chris · Post by **Racer Chris** » Thu Jun 27, 2002 7:31 pm

I pulled the cylinder head tonight. You can see pictures of the damage at the links below:

http://www.tangerineracing.com/DroppedValve.JPG
http://www.tangerineracing.com/BadPiston.JPG
http://www.tangerineracing.com/CombustionChamber.JPG

No wonder I can't find the valve head. There's one bit of the seat left, embedded in the cylinder head. Incredible that I didn't hear a thing, considering the violence that took place inside, at 6000rpm.

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Chris F.
www.tangerineracing.com

[This message has been edited by Racer Chris (edited 06-27-2002).]

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Fri Jun 28, 2002 6:23 am

SWEET!!

Thats really sweet, but my last one was better...LOL

I'll send you a pic.

Racer Chris · Post by **Racer Chris** » Thu Jul 04, 2002 6:11 pm

Well, I did it again! LOL!

This time at least I got to finish the race. The same valve in the backup engine went just as I was starting the last lap at Lime Rock today. I was leading my friend, Smarty, by about one or two seconds for most of the race, after passing him on lap 3. He nearly ran into the back of my car as I slowed suddenly. I was able to limp around the track to the pit lane and across the finish line. No one else passed me, so I scored a second place.

Looks like I'll be building two engines this summer. Shad, I need those Nickies, asap!

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Chris F.

www.tangerineracing.com

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Fri Jul 05, 2002 9:23 pm

Hmmmn...

Thats weird, what valves are you using??

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Jake Raby
Raby's Aircooled Technology
www.aircooledtechnology.com

Racer Chris · Post by **Racer Chris** » Sat Jul 06, 2002 4:36 am

The two engines are built completely differently, so there's no direct relationship between the two failures. The backup engine was built using parts I had hanging around (the heads aren't even ported), and the primary engine has custom built heads with everything else to match.

I pulled the backup engine last night, and removed the valve cover. The scenario is a bit different this time. The aluminum retainer on the intake valve is broken right at the step for the spring. I bet the head came off this valve and got under the exhaust valve, because the exhaust rocker arm is broken too. The springs survived, but the broken rocker caused the retainer to come off the exhaust valve.

I abused this engine for the better part of two seasons already. The heavy duty valve springs were good for only about 6400rpm, which is right where I was shifting. Actually the valves would start to float at the end of No Name Straight, before I braked slightly for the uphill turn. Then going down the hill into the diving turn I was shifting just before the valves floated.

I have a bigger camshaft for this engine, a set of Carillo rods, and hopefully a set of Nickies, with pistons, on the way soon. Now I need to rebuild the heads to make some good power.

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Chris F.

www.tangerineracing.com

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Sat Jul 06, 2002 10:17 am

Chris, Give the Marnell valves a try, I'm still waiting to break one of them.....

The retainers can cause big problems....I have an idea for you to try, email me or call me.

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Jake Raby
Raby's Aircooled Technology
www.aircooledtechnology.com