Rod Bearing - SW9 Spit One Out- A Discussion

New 12/03/2004

I have a theory, just a theory.

Engine A in car A goes to Doug or Kirk or Eric for a cam weld. The cam has moved a hair. The welder/mechanic lines things up and all is well.

Engine B has a cam failure and welder/mechanic notes one damaged head, piston & a few valves and replaces the damaged top end stuff.

Engine C in Car C loses a cam at WOT during a 2-3 upshift and takes out the side of the block. That has happened.

Now I wonder how many folks like the owner of Engine B have damaged lower end and don't know it? A rod gets a little bent, a crank a little twisted, a bearing a little crushed. If it is not severe the engine limps on?

Is that a good reason to get 'em welded BEFORE the whole engine is fubar?

Buford

Doesn't seem like this is much of a question to me. Think about the load path thru the engine when the valve impacts the piston. It will have some affect, however small, on the long term life of the engine.

I don't understand 1) why you wouldn't weld and 1A) why you would buy an unwelded SHO. This, in my book, is preventative maintenance and should be done just like changing brake pads and oil filters.

Matt

I think your point is valid, Tim. However, if I understand/remember Larry's situation correctly, the cam sprocket had slipped, but not spun. Wouldn't this mean, in his case, that the bearings would not have been subject to the shock associated with pistons/valves colliding? I can't remember, and couldn't find Eric's video - was there evidence that any of the camshafts had been replaced prior to being purchased for SOWHAT9?

As far as your last question, Yes, it's a good reason to get welded. I think there are other associated, more pressing reasons to get welded. In other words, if the potential for secondary damage to bearings and connecting rods is the criterion one uses to decide whether or not to weld, I think the person's got a screw loose (and it has nothing to do with the connecting rod).

Bottom line for me - if I was looking for a replacement engine, I would have more confidence in an engine that has not experienced failure, than one that has failed and been repaired, just for the potential of "unseen" secondary damage.

Brad Bender

(to Brad)

I'm not too worried about a rear cam failure. If a cam spins in the rear head, the exhaust cam stops. The valves are small and the stems are tiny. They bend, the engine stops and all can be fixed. The impact is not severe enough to cause too much damage to the bottom end. If the valve heads break off, it's a different story, but this happens instantly.

If a cam spins in the front head, the intake cam stops. This presents a bigger problem because the intake valves are larger and when they impact the pistons they bend and can be pushed back into the quench area of the head. The piston can trap the head of the intake valve between it and the bottom of the head. This causes tons of stress in the rods and like someone else said, the powdered metal rods don't bent well.

Doug Lewis
Ford Performance Specialists Inc.
Atlanta Georgia (770) 949-7191

The journal size and crank weight of a V8SHO is about the same as a 283 SB Chevy (over sized). The lower end of the V8SHO with a main web as opposed to main bearing caps is much more ridged than the Chevy.

So when the load path "hits the fan" the lower end has no give and the weakest link is the soft bearing itself.

Some folks have also lost connecting rods. I guess the powered rods neither machine well or have much spring.

My point is if 75% of V8SHO have experienced cam failure, what % of that have a lower end with a greatly shortened lower end life? Folks think they fixed their motor but they have not?

The important point is this, if we go after Ford and Ford says OK, we will shovel you guys a bunch of cams, how much was the cam repair? Problem is JUST a cam repair / upper end repair will not fix some large number of engines or properly compensate a large number of v8SHO owners who will experience premature lower end failure.

Buford
(see Illustration below for reference on Journal Size) - Uncl Lar

There are two parts to this, first part is related to car care.

Second part is legal, what we need to ask from ford to be made whole.

I think a lot of V8 SHO owners have a crippled car with a weak bottom end and may not know it.

Tim

Tim:

If this didn't cause the rod bearing to fail within a few hundred miles after repair:
http://www.venom.org/shofiles/96MG/00_00189.JPG
http://www.venom.org/shofiles/96MG/00_00192.JPG

Then the "dings" on the pistons are not going to hurt the rod bearings or crank assembly. The connecting rod, bearing, wrist pin, and connecting rod cap were all reused on this cylinder and I proceeded to put 10,000 miles on this motor after putting the depicted cylinder back together using only a new piston (and a new head).

There is a reason I didn't reply yesterday to this post..... I guess I stated the reason this time. As much as Ford screwed the pooch on the camshaft drive design, the bottom end and block is more solid than most other motors (let's not talk about the V6 SHO and rod bearings 'kay which has a lower compression ratio to boot).

Respectfully,

Scot Krietemeyer

Impressive, but nasty photos, thanks for sharing.

I am looking for reasons for Larry's' bearing failure. Like I said it's just a theory.

It could be some other folks may not be as lucky, or 10k proves nothing, it is 250k+ I am hoping for with a bottom end like that.
Buford

The bottom end on the V6 engine is as stout as they come. I'd put money on the V6 to last over 200k long before I would the V8 for the simple fact that there are more of them that have done it.

I agree the V8's bottom end is very well done. But the V6 has proven itself in blower configurations, Nitrous, drags, and most importantly longevity. Hell, IIRC the motor was tested to 8 or 10k RPM's by the engineers and deemed 'safe' at those RPM's. I sincerely doubt that the V8 would last at those RPM's.

Having to replace rod bearings at 150k is hardly an indictment of the design. There are far more engines out there that are at that mileage and
more that have never been apart than there are examples that needed bearings. And most of those are on MTX cars that were 'lugged' by folks who don't know how to drive a stick.
Dave Garber

I'm currently looking for the video link myself.
The sprocket had started to come loose. It had, IIRC about 1/8-1/4 play in it. The rest of the cams in the donor looked to be factory original and had secure sprockets. To end the weld splatter theory, the cams were removed from the donor and taken to Eric's shop where they were welded in between bites of his lunch.
Splatter would have had to travel @ 7 miles and I don't think they would have made all the stop lights on Roosevelt Rd.

Uncl Lar

Usually a failure like yours can be traced to one of three things:

1) Poor lubrication. There have been isolated cases of the Duratec oil pump going south and taking engines with 'em. The V8 uses the same design. Now I haven't heard of any in a while, but when Scott Miller was at the Ford dealer, he replaced two or three blown V6 duratec's and one V8 due to oil pump failure while he was there. He had the V8 engine in his basement. That engine only had 13k miles on it!

2) Bad bearing. It's possible the bearing itself simply 'self-destructed'. It's rare, but I've seen that before too.

3) Something plugged up the passageway in the crank journal. This is obviously related to lubrication, but it's not due to the oil pump itself. There have been cases of casting flash breaking loose in the oil passages of the crank journals, preventing oil from reaching the bearing. This is and extremely rare occurrence, and I'm not even sure it would apply to the V8 SHO as I believe it isn't using a 'cast' crank.

If you are planning on re-using this engine, I'd suggest having the oil pump looked at, and using a completely new/different crankshaft.

Dave Garber

Eric completely rebuilt the oil pump when we changed out the engines. All indicators point to the fact that it was not a lube failure. For all intents and purposes the bearing just STB. Details will follow upon autopsy.

Uncl Lar

Another thing to consider is the rod itself. It's also possible that the rod end and/or the rod bolts were at fault. If there was any stretch in the bolts, that would most certainly cause this kind of failure. Or if the rod cap is faulty, either in shape or structural integrity. These you should be able to check when you get them out of the car..

Dave Garber

Did Larry lose a rod bearing or a main bearing?

Buford

Rod Bearing Sheriff #4

Uncl Lar

Actually, I don't think he clarified that in his original post. He said that #4 bearing went 'boom', I just assumed he meant rod number 4?
Dave Garber

Correctomundo Dave
Uncl Lar

Journal Size

The three pictures to the left of the Journal illustration are out of focus however I hope you can see the wear on the bearing and shrapnel in the oil pan. I tried the Macro setting on the Digital Camera - my bad.

Uncl Lar

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