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Ouch! Cam Lobe Damaged


ashyers

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Im guessing this is a Duratec ? I would look into the Crower STG3 cams or the Comp Cams stg 3 , both are great cams , great for racing and good for street , I have a 2.0 Duratec , 11.1 , Stock plastic intake manifold and Focus stock TB making over 200HP to the wheels in a Focus , Would also recommend Adj cam gears and a little dyno time

 

Valve seats , Valve wont cause your worn lobe issue , things that will would be , Valve springs binding , Improper Cam adjustments , Bad Cam grind , Pitting from rust

 

Tom

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papak,

I spoke with Tom C. the other day, he's great! He was able to give me some insight on Crower cams. I also spoke to Shane at Crower who was very helpful.

 

I need to get the engine out inspect things and get it back together so I can spend some time driving the car :).

 

 

 

Tom,

You mention Comp Cams, I haven't been able to find a cam listed for a Duratec motor. Would this be a custom order from them? As far as the cam damage, I'm hoping that I'll be able to to get to the bottom of the issue when I tear down the engine and inspect it.

 

Andy

 

edit: added stuff...

Edited by ashyers
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My apologizes , I said duratec but had Zetec on the Brains , Crower , Burton , Kent or Piper , Crane might have some left hard to say

 

If you cant see the issue for the pitting with the Valve cover off and cam out checking the rest of the engine wouldnt show anything , problem would be in the top where the cam is

 

Tom

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  • 2 weeks later...

We're finally making some progress tearing into the motor (progress, right?!).

 

So far we've found it has Crower rods, Ti retainers, some form of snazzy pistons and what appears to be a wacky cam arrangement. The exhaust cam has a lift of ~.441" so it's darn healthy. The welding on the lobes is visible and I'm reasonably sure that's what failed. The intake cam has a lift of ~.360" and it appears to be stock!

 

The tear down has proved a mixed bag. We've found some nice bits and some evidence of some "band-aid" repairs. They're getting fixed as we go, but it's frustrating to see some of the crappy work someone did in the past. On the other hand I'm working on the car with my Auto Shop students and they get to see first hand a bit of shoddy workmanship and learn from it.

 

As far as cams I have some Crower "Stage 2" cams on the way. I think they will fit the bill well.

 

What's the collective wisdom regarding Ti retainers? I would not have chosen them for a street car, but they're in there and appear to be in good shape.

 

 

Andy

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Stay away from Ti retainers, unless you plan to replace them as a regular maintenance item. They have a shockingly short life span.

 

Randall

 

They do , I have been running them on my street (572 CU IN ) and dirt track engine for more then 20 years , springs changed about a 2 dozen times and no issues , My 720+ Hp Zetec Turbocharged had them on it for 7 years and sold the engine and he ran it another 4 years and sold it to some one else same Crower Tit retainers , I have built thousands of Tir Ret heads through my machine shop over the years and never an issue

 

Alum Ret , short life span

 

Tom

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Tom, curious that your experience is so opposite what was relayed to me by some top tuners over the years.

Perhaps the people I've talked with used Ti retainers made from the wrong alloy. They related sudden failure after mere hundreds of hours.

 

Randall

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I have a friend that own a small parts engineering company in WI, he has made over 35,000 TI retainers for a major manufacture without a single problem. I think it's an internet legend that just gets repeated many times unit it becomes a big problem.

 

Graham

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OK, the motor is nearly completely apart and I need some more help :).

 

How are you guys at identifying pistons? These are fancy bits and I will likely need rings and possibly some spiral locks. They are gray in color and have no identifying marks. They're in OK shape and we plan on running them.

 

EDIT: Found 'em, they are Supertec pistons with a -20cc dish. This yields a CR of ~ 9:1 in the 2.3L. I'm thinking very seriously about replacing them with something that will get me up over 11:1. I have no idea how these ended up in the motor. Anyone need some turbo pistons?!

 

http://www.usa7s.net/vb/attachment.php?attachmentid=14884&stc=1

 

http://www.usa7s.net/vb/attachment.php?attachmentid=14885&stc=1

 

http://www.usa7s.net/vb/attachment.php?attachmentid=14886&stc=1

Skirt.JPG

Side.jpg

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Edited by ashyers
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  • 2 weeks later...

Update:

Things are still moving forward, just a bit slowly. We've totally torn down cleaned and inspected the engine. Parts are taking a bit longer than expected to arrive, but I'm assured they are on the way :). Essentially we're redoing everything. One of my students compared this engine to a Russian nested doll. He said whenever we pull something apart we find something else wrong! Unfortunately he's right. The good news is that there's nothing left to pull apart...

 

I'm hopeful that by next week we can drop off the block and head for some machining and maybe have the motor back in the chassis by February. We'll see! Rebuilding an engine and sorting a car with high school students is not always fast, but it is always interesting!

 

The help I've received from this forum has been great. I really appreciate it.

 

Andy

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The worst part of rebuilding one of these is that the manufacturer never intended for it to be rebuilt. No key ways, etc. Drill out the plugs from the oil journals and tap them for brass plugs. It’s the only way to assure that they are clean.

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