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Ouch! Cam Lobe Damaged


ashyers

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Looks like I get to deal with cam repair and replacement! I was aware of the noisy valvetrain when I purchased the car and here's the reason:

http://www.usa7s.net/vb/attachment.php?attachmentid=14783&stc=1

http://www.usa7s.net/vb/attachment.php?attachmentid=14784&stc=1

The cam is a Web Camshaft grind and they were able to look up the specs from '03 when the engine was built. It was repaired once in '05. Here we go, down the rat hole! I'm hoping to have it in the mail to them this week for evaluation, repair, and suggestions on how stop this. I don't have the exact cam specs handy, but .400" lift and 244deg were mentioned during our phone conversation.

 

I wanted a project...

 

Andy

CaterhamEx5.jpg

CaterhamEx5a.jpg

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As a person who knows all about camshafts melting down on dynos recently :ack: :banghead:, you have to ask why it happened before you repair/replace.

 

Why only one lobe and why that rather unusual damage? What did it hit?

 

Since it is the second time it received damage does it make sense to drop in a brand new replacement? You can replicate original specs to avoid needing a retune and have peace of mind to know it is not weakened and potentially happen again.

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Only one cam lobe, the rest are perfect. I some ways the damage looks like flaking, but in some ways impact damage. Do you know if it was a billet cam or was it welded up? I would try and find an independent opinion before you send it back to the manufacture. Do you have a local engine builder/ race shop. Show it to them and see what there is opinion is, use that and the manufacture opinion to come up with a cause.

 

Graham

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Mike,

You're right, the big question is what caused it. These cams are welded and reground and there were signs of wear on a few other lobes, both intake and exhaust. The one in the photo is the worst example. The valve clearance was .016" so there was some material removed :).

 

As far as the cause Web suggested the possibility of incorrect spring rate or interference. There were also signs that the car sat a bit because some of the lobes showed signs of corrosion on the heels of the lobes. This could tie into the cold blooded nature of the engine's current cooling arrangement. Diagnosis is going to be tough without history on the engine...

 

Any suggestions for a good valve spring compressor that will allow me to remove the springs while the head is on the engine?

 

Andy

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Any suggestions for a good valve spring compressor that will allow me to remove the springs while the head is on the engine?

 

Compressed air into the sparkplug hole will hold the valves closed while changing springs or seals--if you have good valve seats.

 

What kind of oil were you running?

 

 

Randall

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Graham and Randall,

Thanks for the responses.

 

Graham, I think you were typing the same time I was! There's some further info in my post.

 

Randall, as far as oil I believe the PO was running 5w-40 Motul. Do you have a recommendation for a valve spring compressor that works well on the Duratec?

 

Andy

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Motul oil is as good as it gets, so that is not the issue. I think you just need to pull the head and get it checked out a set, head, springs and cams. I think it will be a false economy to do anything else. Someone might have cut the spring seats, the valve seats might be the problem, and you would never know. Another option is to just get a new head, get it build by a reputable shop and swap it over, that would be my plan of attach.

 

Graham

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I’m thinking your going to find the problem is deeper into the engine than your camshafts. I’d pull the head off and get a better idea of why just one lobe is banged up.Something with that cylinder chamber is bent, stuck, what ever you would like to call it. I would also clean out the oil pan and maybe even replace the oil pump. Aren’t these cars fun. Best of luck Sir..

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Randall, as far as oil I believe the PO was running 5w-40 Motul. Do you have a recommendation for a valve spring compressor that works well on the Duratec?

 

With Motul, I wonder where the other lobe wear you mention came from. I vote for a complete tear down. Something major isn't right. Sorry, I don't have Duratec experience, so I can't recommend a spring compressor.

 

 

Randall

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Minor update:

Did a compression test today to get some more insight:

Max was 205psi, Min was 190psi

 

I haven't had the chance to do a leakdown test or cut open the oil filter to see what's been caught. Maybe tomorrow. If I get really inspired I may pull the motor and put it on a stand so I can have a look...

 

Andy

 

Andy

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Yesterday I pulled the dry sump filter screens, cleaned the tank, and opened up the oil filter. The screens were clean and the tank had a minute amount of tiny metal particles on the floor. The pick up is about 3/4" off the floor of the tank so any chunks would tend to collect there. The filter looked OK. As far as the cam, I dropped by a friend's shop who builds mostly high end sprint car and drag motors. I saw my first 900cid NA Hemi with a 1+" lift cam. You could put a tennis ball down the intake ports! The general consensus (guess?!?!) is that the welding on the cam failed to adhere to the base metal.

 

As I was monkeying around with the oil system I found a few things that bugged me about the wiring and cooling system, and decided to pluck the motor. As I said earlier, down the rat hole...

 

While preparing to pull the motor I've yanked out about 10' of 5/8" heater hose, gained access to the ECU, and if I can steal some time during the holiday I'll finish the job.

 

When I opened up the ECU I also found some this:

http://www.usa7s.net/vb/attachment.php?attachmentid=14793&stc=1

 

Anyone want to try and decipher the engine description. It's "car-chelogy" :).

 

and this:

http://www.usa7s.net/vb/attachment.php?attachmentid=14794&stc=1

 

I guess this is the orig connector for the factory ECU? There's was some splicing done to fit the MBE unit that I'm going to clean up.

 

I'm pretty happy that the ECU was not "locked" and I've also obtained the PIN to open up the Master level and really cause problems! This will be helpful it I replace the cams with a different grind and that's looking like a good option at this point. I'm not sure I want to go down the road of welded cams further.

 

Does anyone have cam advice? The map info above gives an idea of the current setup (7250 Limiter, 11.5:1CR) and even with a flatted cam (.400" lift, 244deg dur.) it's pretty healthy. It would be nice to obtain them on this side of the pond.

 

Andy

 

edit: fixed images

ECU Description.jpg

Connector.JPG

Edited by ashyers
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THe second image is because you attached the images on the forum. If you just embed an image hosted on a third party site then those second images will not show up. Ignore it for now.

 

 

I have heard of Crower frequently but never used them.

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If you order from Crane, make sure that they understand the the cams are for a track car. Otherwise, they will adjust the grind to add 4 degrees of advance (?) for emissions. I had to adjust this out with adjustable sprockets. Pain in the ass.

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papak,

What grind are you using?

 

How's the performance? I don't intend to push this motor over 7250 and will be driving it on the street with an occasional auto-X.

 

You mentioned Crane is in San Diego, is it possible you have Crane and Crower confused? Crower is in San Diego and Crane is in Mississippi.

 

Thanks,

 

Andy

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I have the Stage 1 cams. Whenever I do rebuild the motor, I will use the Stage 2 cams. They are listed for boosted applications but Tom Carlin (Birkin distributor) said that they work well with a normally aspirated Duratec with stock rods and pistons. I use a rev limit of 7000 rpm.

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