Help...!!!

[Excaliber]

I agree with the machine shop, any material left over from the failure will be taken care of by the filter. OF COURSE how could advice such as 'tear it all the way down and inspect\replace EVERYTHING' be wrong? That kind of advice is a sure bet and one a lawyer would certainly go with!

Cost\Benefit analysis:
Go with the machine shop, put in a roller, change the oil and filter and get on with your life.

There is no 'good ole oil' like we have used for 35 years around anymore. Oil HAS fundamentally changed, it is NOT your 'daddys oil' anymore. No need to go synthetic (can if you want) the key is the missing ingredients, like ZDDP. Thats why it is IMPERATIVE you use an oil additive that DOES contain a healthy dose of it to make up for todays INFERIOR oils.

I reject the argument there has been a 'bad batch' of cams out there. The recent cam failures, I'm convinced, ARE 'oil related' for the most part, and in conjunction with improper breakin procedures.

[ffindling]

Originally Posted by Eliems

Machine shop is saying, "Put the roller cam in without removing the engine, the metal filings will have been caught in the oil filtre."

They said if I insist on sending the engine out for inspection of the bearings, they will charge me if the bearings are OK.

I am pretty sure the mechanics can remove the oil pan and inspect the bearings without pulling the engine and I have asked them to do this.

Feedback please.

If the camshaft failures were caused by oil starvation, installing a roller setup will do little good, just might take longer to fail. Of course, you can pull the pan and inspect the main and rod bearings, but even if they are in good shape, that may not be indicative of oiling issues with the valve train. Something is causing those failures and unless that cause is isolated and fixed, throwing new parts into the engine is likely to yield the same results.
Camshafts rarely fail as long as they are properly lubricated and manufacturer-recomended break-in proceedure is exactly followed.
Have you sent the failed camshaft/lifter assemblies back to the manufacturer?
They can generally determine if the failure was caused by a defect in manufacture or by some external issue such as oiling. If they determine the
failure was caused by a manufacturing defect, they usually make good on it
and replace it. Of course, if it failed due to oil starvation, they would be
less inclined to replace it. Most cam grinders stand behind their products
and when they fail, they are as anxious as you to find out why it did fail.
Oiling issues with 385's have never been a big problem, but like any other
engine build, the ducks have to be in a row. There are plenty of them out
there running flat tappet cams with pretty high seat pressures, so the 385
design is intrinsically capable of running such setups, but like any other
engine build, good block prep is absolutely essential!

....Fred

[Eliems]

Here is the cam the machine shop has ordered ...

http://store.summitracing.com/partde...5&autoview=sku

what do you think?

I am not looking for anything wild, I want reliability and torque, low rpm performance.

Thanks, Greg.

[CarsByCarl]

Originally Posted by Eliems

Here is the cam the machine shop has ordered ...

http://store.summitracing.com/partde...5&autoview=sku

what do you think?

I am not looking for anything wild, I want reliability and torque, low rpm performance.

Thanks, Greg.

The cam seems smallish, but for "reliability and torque, low rpm performance" it should serve you well.

As for the cause of the flat lobes....if the main and rod bearings look acceptable, and the cam journals/bearings don't show any oiling issues, you're probably good to go.

[ByronRACE]

So you want a smooth idle like a production car in a Cobra?

You'll have more bottom-end grunt than the tires can connect regardless. Personally, I'd go with more duration, a more agressive idle lope, and shift the power band up 500-1500rpm so you can get some power out of it.

216/224 at .050 is a tiny cam. Sleepy really. I bet the power peaks by 4800rpm. Yes it'll have a smoother idle. Yes, it'll make explosive low-end torque in a narrower band. But, it'll all be over well before the rpm capabilities of the engine have even been explored.

I'd be looking for something more along the lines of a 230/240 at .050 and would recommend running various cam choices through a simulator before you decide.

My little 435" has a 242/256 at .050 and should peak by 6300 in a NA application. With 25 more cubic inches, I bet it would peak around 6K...which is closer to what I'd shoot for if you want to get power out of it.

[Eliems]

So they pulled the pan to check the bearings on the crank (at my insistance after assuring me the metals from the 4 lobes would be contained in the oil filter) and sure enough all the bearings are toast!

Back to the machine shop (under warrantee) for a complete rebuild! This is two months now since my Cobra was in my garage.

On the bright side I should get a better motor and no worries about the metal sludge. The machine shop can install the roller cam and no break-in!

Patience!

[Excaliber]

Man you must have really ground them down to have that much bad stuff in the motor!

I toasted ONE lobe, shut down the motor immediatly and was surprised to find very little (if any) bad stuff in the motor. I decided to rebuild anyway for other reasons. You made a good call having it torn down. Hyd roller, all though pricey, IS a good call. The split pattern grind will serve you well.

I went with 292 flat tappet myself. Idles at around 1100-1200 (nice and lumpy) and pulls good from 2000. It's streetable, and yet aggressive.

[ByronRACE]

I'm glad you went ahead and fixed it the right way. The folks that say "the metal will go into the filter" just don't want to face the grim reality that there's a lot of work (and money) ahead to fix it the right way.

The ostrich approach to automotive repair isn't recommended; it just ends up costing you in the end. You would have ended up spinning a bearing, potentially destroying the crank, or worse... Glad you avoided that.

Byron

[Excaliber]

You have to do a cost\benefit analysis based on the damage. Armed with a 'warranty' the choice is easier to make than if it was 'out of pocket'. Of course it's ALWAYS a safe bet to do a total tear down, but thats not always the most practical approach. It can be a tough call in many cases. In this case it sounds like FOUR lobes were ground to a powder, thats extensive metal floating around!