Split Block ????

flatchat(Chris) · 10-15-04, 08:56 PM

While cruising along the freeway to the Gold Coast the other night--passed a flatbed towy with a friends cobra on board and I know that It's just had a stoker motor fitted (347?) so I'm guessing the maiden voyage didn't go so well.
Sure enough the block had completely split in half length ways.
Any experiences with this type of failure out there???
I'm thinking that the year 2004 and Ford engines have jinxed our corner of the world.
Gotta keep smiling though [img]/ubbthreads/images/graemlins/cool.gif[/img]

Lynn · 10-15-04, 09:51 PM

Flatchat,

When they go, that is usually how they do it.

I bet it looks just like this (btw, caption read- cam swap the easy way!):

flatchat(Chris) · 10-16-04, 03:37 AM

Thanks Lynn, your picture completely describes my ramblings.
Incredible Huh!
[img]/ubbthreads/images/graemlins/cool.gif[/img]

Keith Hardy · 10-17-04, 02:33 PM

Caramba! Never seen nowt like that although had a 289 HiPo once which had the block skirt inadvertently holed a few times by errant rods making their escape. Just blobbed on some weld and carried on racing!!!Should one suspect a small manufacturing defect in the casting process perhaps? Or too much horsepower?

Lynn · 10-17-04, 06:54 PM

Keith,

The later model small blocks have gotten incredibly thin and light in the webbing areas. Usually they work fine, but every once-in-a-while the moon and stars align and pow they pop in half. Obviously, it usually happens with high performance engines, but most times it isn't necessarily an outrageous engine. I am sure there were flaws in the crystaline structure of the cast iron that allowed the crack to start and then propigate, but, to my knowledge, it isn't something you can predict or check for beyond looking for existing cracks. Don't know if Ford or anyone has studied this type of failure, but on a couple of occasions there had been a recent event that may or may not have been a contributing factor. With the one I recall, the guy had noticed an erratic oil pressure a week or so earlier. He changed his oil filter and cut it open with nothing found. Fresh oil was put in and everything seemed fine up to the moment it let go. Suprisingly, I believe the engine pictured here actually continued to run for a short time being held together, so to speak, by peripheral parts.

But, the motor I am building now started with an R302 block. :-) Better safe than sorry.

Regards,
Lynn

Pete. · 10-17-04, 07:16 PM

Looks like a minor electrical problem to me.........

Caused by the camshaft destroying the distributor. [img]/ubbthreads/images/graemlins/grin.gif[/img]

Craig White · 10-17-04, 10:54 PM

Attached images below of that stroker motor Flatchat is talking about.

Had 450km's on it, 3 days old.

This is owners description of how it happened:
"On motorway...Changing lanes , in 4th., a bit of acceleration, and KLUNK"

All new components used in build were saved from any damage. Cobra didn't suffer any damage and most of all no one was injured.

He had used his existing block for 347 stroker. Block is 302 roller. Block was not magnafluxed for cracks during rebuild.

Craig White · 10-17-04, 10:57 PM

Another photo...

I have a few more, but these 2 are the most interesting.

Also, thanks FLATCHAT for ride on Saturday. Really made my weekend. [img]/ubbthreads/images/graemlins/smile.gif[/img]

Lynn · 10-18-04, 01:52 AM

CraigW,

The cracks running down the webs from the main stud hole are pretty typical. It did get me to thinking though; was the guy running main STUDS? If the studs are bottomed out when they are installed, they can put a huge amount of stress on the webs as the engine heats up and things start expanding.

I am glad to hear that nothing untoward happened to anyone or the car. It is great that he can salvage most (if not all) of his new parts. In order of preference, suggest he look at the Dart Iron Eagle (4 bolt all mains), Dart Sportsman (4 bolt 2-4, 2 bolt 1 & 5) and the Ford Racing R302 (4 bolt 2-4, 2 bolt 1 & 5). The Dart's webs are beefier than Fords. The cylinders are truer as well; this means you can go to 4.185" bore without ultrasound with the Dart blocks. The max on the R302 is 4.125 I believe. Dart has true priority oiling for the mains and a number of other really nice features. If you or he would like more info on the Dart blocks, let me know. I have info on the 8.2", 8.7", 9.2" and 9.5" deck height blocks. You can also order with 4.000 or 4.125 rough bore. (They will hone to these numbers, but they do have to be honed. While not finished blocks, they are said to be more finished than the R302.)

Lynn

Regards,
Lynn
Regards,
Lynn

Tim Kay · 10-18-04, 04:11 AM

Lynn,

If the Dart block is available in a 9.5" deck is it the same as the Ford W351 which are the siamese bore 454 cu. in.?

If so then the intake manifold will be different than a standard 302 and won't there be a height conflict for a GT40?

The reason I ask is because I would sure like to consider that motor PI Motorsports is advertising as the "Hammer". If they wedged it into a CAV, it must be doable. I haven't seen the specs yet on the "Hammer" but I assume it's a tall deck 351w.

Lynn · 10-18-04, 10:48 AM

Tim,

I believe you are absolutely correct in your assumption that it is a 427 Windsor based on the high deck SVO block. The Ford SVO blocks compete a bit better against the Dart than the R302 does against the Dart 302 based blocks.

Edit: RE above: My bad, I confused the PI Motorsports reference with the post I put up the other day on the Roush 402IR. They are very similar. Check out the Roush thread if you haven't already, its another option though. GottaLovit!

Many kits allow for a 351 to be installed, or so they claim. What they don't tell you is that it may take the worlds largest shoe horn to get it in there :-) Some chassis just wont accept the engine and have it fit under the rear deck. Robert has done some amazing things with the RF considering it uses a right-way-up Audi transaxle and it is usually the transaxle used that limits the motor used when it comes down to it. He may have used a different gearbox in some of his Hot Rod 40s. I don't recall the exact combos he used, just the fact that he has put an example of nearly every Ford V8 there is in a RF at one point or another. Amazing guy, that Robert!

I am glad that you asked a question though because I forgot to include the fact the various Dart blocks are also available in Iron or Aluminum!

Regards,
Lynn

Gary Gibbs · 10-18-04, 06:47 PM

The standard deck height of a 351W is 9.5". For those new to the site. You can look at my website for pictures of the Dart 427W (4.125x4) that fits in the CAV with a 2" carb spacer and Race Demon carb with room for an aircleaner!

Tim Kay · 10-18-04, 09:52 PM

Gary,

In viewing your Dart 427 it appears to be similar to the 427 installed in the CAV currently n ebay.

I am most interested in purchasing this motor, any suggestion or special concerns when considering this motor.

Gary Gibbs · 10-18-04, 10:23 PM

Not really. I think you could be happy with this combination. It is a beast. Easy to drive, but lots of torque and power. A second gear pull (up to 95 mph) and it feels like it is going to spin the tires all of the way up. However, it just sticks and goes though. First gear will shread the tires at full throttle.

flatchat(Chris) · 10-18-04, 10:57 PM

So aah, will the block split???? [img]/ubbthreads/images/graemlins/tongue.gif[/img]

Gary Gibbs · 10-18-04, 11:41 PM

Dart claims their blocks are good for 2000 HP. Looking at the block I can believe them. It is very well built. Thick webbing, and 4 bolt mains on each cap, etc. You can also now get Aluminium and save 100 lbs.

ijvpet · 10-19-04, 05:59 PM

Gary,

You have to post a video. It sounds outstanding.

**patbarry** · 10-19-04, 10:04 PM

I am very weak on engine design, but would a siamese block be any stronger? How would they compare on the street versus a conventional engine as far as cooling?

Finally, would it correct to say the blocks began to crack up top or down below? If they start up top, how would a four bolt main help stop that?

Lynn · 10-19-04, 10:23 PM

Pat,

Virtually all of the blocks that have been suggested, including the FMS blocks, are siamese bore blocks. I have never heard a word about overheating peculiar to the siamese race blocks. Although, I asked the exact same question when I first began to research them.

To the best of my knowledge the blocks begin to crack in the webbing walls of the mains. 4 bolt main blocks, almost by definition, have thicker webbing than standard 2 bolt main blocks, but as you have no doubt noticed, there is variation in the thickness between the different race blocks. Also, the 4 bolt main caps hold the crank tighter and prevent any distortion from even starting in a side to side direction which is to say a spreading of the webs(presumably how the whole failure mode gets started given that the blocks crack length wise: 90º to the spread.) They do the job that main girdles try to emulate on 2 bolt blocks. I have never seen a post mortem report on one of these to the high engineering standards of our friends on CSI :-), so I am, admittedly, speculating somewhat at this point.

Regards,
Lynn

killroy · 10-19-04, 10:26 PM

A siamese block has cylinders that are joined at the sides.