My 348 stopped running on the highway

It was the tensioner bearing that seperated...the inner race seperated from the outer race and flung off...when that let go, no tension...belt still stayed on...

 

here is the link to the thread that has more info on what happened...

http://www.ferrarichat.com/forum/showthread.php?t=104937

 

Hey Al Bundy, did you check out the Ferrari discusion section about a yellow 348 that's been trash? You better go there NOW

 

So are you gonna buy Plugzit's engine? In my opinion that will be the cheapest and fastest way to get your car back on the road.

 

If, key word, tmobileguy’s damage assessment is accurate, why wouldn’t it be faster, and a lot less costly, to buy valves, have the heads freshened, assemble and drive? Costs would be head work, gaskets, new belt, tensioners etc. Just curious.

 

That is where my thinking is going as well...I have run my fingers up down each cylinder wall, and aside from some carbon build up, they are smooth as silk...no scoring at all...

The valve stem are for sure bent, I can bend many of them back with my hand (I'm not implying a fix!)...but NONE are broken...

The dings on the piston heads are very small, they barely made it past the carbon deposits on the piston heads....

I have a line on a set of heads from a wrecked car here in FL....$1500 for both...

What my thoughts are...

Buying the heads and bolting them back on with new head gaskets....Then testing compression, if all cylinders are holding compression then I am assuming I am back in business....YES? NO? THOUGHTS????

Obviously, I am putting on new cam seals, new tension bearings, updating the water pump, new cam belt, and new hoses....

 

Sounds like a good plan if the heads are in useable condition. That is cheaper than buying a bunch of good aftermarket valves and just popping them in your old heads. Then you still have a pair of rebuildable heads you can sell or trade for ?

 

Good plan. What about the metal you discovered in the oil? You should inspect the bottom end while you have it out. If it checks out, be sure to flush out the oil lines, oil cooler, oil reservoir and of course replace the oil filter. Also, blow compressed air through all the passages. You don't want something trapped in there to come back to haunt you.

Personally, I would inspect the main bearings, rod bearings, and cam bearings. That is where you will see the evidence if anything went through the engine. Don't be surprised to see some wear in the direction of travel. But if you see any flaking, pitting, or gouges then you should replace your bearings.

 

I just want to say good luck with this car. I am sure you can work it out.

 

Al, its good to see your back and that you are still trying to get the car up and running.

I cant imagine a better option than nabbing a set of good useable heads for that cost. I dont see how you can go wrong on that deal. And like mentioned, youll still have an extra set of rebuildable heads. Fire that mother up!

 

Got my camera back so I took pics tonight of the bottom of the heads and the top of the pistons as well as 2 .mpgs of me turning the crank and the movement of the pistons...had to turn and hold the camera at the same time so the videography is not the greatest...
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you're a very lucky guy

 

I wonder if there is less "interference" in our 348 engines than we've been led to believe...


When my timing belt slipped all that happened was I that got 16 bent valve-guides and a blown head-gasket.

 

What were you led to believe? Also how did the timing belt problem lead to a blown headgasket?

 

Good question.

 

I am genuinely curious. As far a engine damage from a cam timing issue I have never heard a claim from anyone who showed enough knowledge to pay attention to (the rest I really don't remember because I really don't care what they say) say more than valves will bend and pistons may be damaged. In his pictures and statements that is what I get. A bunch of bent valves and slightly damaged pistons. Am I missing something? Have we been threatened with parts hanging out the sides?

Just wondering.

Ferrari motors especially the 4 and 5 valves have very low lift (don't need much lift with small valves) to do anything very dramatic when you have a piston-valve interface. That and the small diameter stems pretty well insure the valve heads just get pushed out of the way.

As for your head gasket, pretty rare problem on these motors. Can't think of any connection to a timing belt/bent valve problem.

 

Well, you got me on that one. My original theory was that me laying on the intake plenum to remove the cam-belt inspection cover caps caused my head-gasket problem, but I caught so much flack for that theory here that I had to believe that I was in error.

My head gasket was blown at the same time as my cam belt slipped. As to the cause...I don't know. From your words it appears that a slipped cam-belt would be an unusual cause of a blown head-gasket. I had an alternative theory, but that theory was dissed unanimously.

It's a mystery. No big deal, but in relation to this thread I was merely trying to show that I had experienced very little damage from a very similar problem, too.

 

I've never had a problem with a Ferrari, but I had a couple of E-types one slipped a timing chain. it just made a mark on a couple of the pistons and bent a few valves. the work to fix it was more than the cost of the parts.

bad things happen when the valve head gets broken off.....
saw a dino engine that did that. looked like someone took a ball peen hammer to the inside of the cylinder.

 

I would think thats where you get your catastrophic damage. If that valve actually breaks off, then I could imagine some serious stuff going on in there..mainly destroying the cylinder walls...

Do engine designers build interference motors like this on purpose, to make valves bend easily to save damage but to not actually break?

The only thing I can't see is the actually piston breaking....how does it actually break the piston?

 

Looks like it wasn't going to be long before you needed some valve work anyway. From the photo, I see a couple of marginal valve seats.

Also, looks like you're burning oil. Are you going to replace the valve seals on the heads you're getting?

Were those two outer cylinders already clean? Or did you do some cleaning?

 

Did some cleaning myself, going to get them all cleaned up...burning oil, is that from valve seals leaking oil into the combustion chamber?

As far as the valve seals, is this a ferrari weak spot...the new heads only had less then 10k miles, so I was planning on just bolting them in...

 

Here's some items that will break a piston.

1. Sucked valve. Valve retaining clips coming loose (usually weren't installed properly), or extreme rpm's causing the valves to float enough to contact the pistons and allow the clips to come off.

2. Broken ring. Extreme rpm's or overheating are possible causes.

3. Detonation. Preignition caused by incorrect timing, fuel, or overheating.

4. Foreign object sucked in through the intake manifold. (once, I found a bolt imbedded in the top of a piston.)

Never had a piston break because of a broken timing chain or belt. However, I wouldn't say it couldn't happen if the conditions were right, but it would be pretty tough to do.

 

Good, at first I thought you may have been sucking water into those two cylinders.

Valve seals or oil rings.

Don't know if it's a weak spot, but most likely caused by lack of use and age. After all, they ARE 16 years old. I can't remember who posted the statement "You're going to pay for the maintenance whether you drive it or not, so you might as well drive it". I agree whole heartedly.

Anyway, I'd replace the seals, easier now then later.

 

PM me if you are interested in selling your old heads


This is typical damage for belt failure on 348s I have repaired two others with same damage. 30 valves bent each time.

I have also seen the timming belt drive bearing fail. Ferrari upgraded to a better bearing design at some point. Probably early in production.

 

So timing belt failure isn't generally "catastrophic," but something a little less disastrous.

Bent valves. Damage to heads? Pistons still re-useable. Cylinder linings OK. Crank OK. Rods OK.