That sounds like the best plan for sure. Thanks for the input. Sounds like crank & rods need to be checked out first with a good bore gauge before doing anything with bearings. The block can go too to check for out of round and taper, and cam bearings. Cylinders look OK to me but I'm not trying to be cheap where it counts most.

Being my first time going through an engine on my own, I really do appreciate the input of those with experience. I'll get some opinions on a good shop around here, and try to get it in next week.

 

Pulled the cam last night. Saw this: Must Read....PSA for Windsor Roller block guys - Ford Mustang Forums : Corral.net Mustang Forum about cracked roller blocks. So I shot brake clean on the block above the cam bearings. Sure as **** my block has the cracks on journal #2 & #4. Cam bearing look pretty good, some wear but it's even and doesn't look like it picked up any crud.

Anyone bothered to look at their roller 5.8L's for these cracks and see them? Or heard of a failure due to this? I understand the concern is the crack bleeds oil pressure from the cam bearings and it spins the bearing. It just seems far fetched to actually occur in a relatively low output build, and I've never come across someone having a failure from this issue. I'm a bit disappointed, and to do it again I'd have just bought a non-roller block & run link-bar lifters. Oh well.

 

Jim really knows his stuff. This is basically a specialty shop that only builds Ford Stroker motors. And as far as how they may have developed > Ford Mustang Forums : Corral.net Mustang Forum - View Single Post - Must Read....PSA for Windsor Roller block guys

 

I understand that guy does it right. He built a reputation and successful business on building the best. Of course he won't risk it, and no honest business person would.

In regards to that post you linked to: what other vehicles did 5.8L roller blocks exist in, other than vans, buses, trucks? I'm unaware of a different donor vehicle.

I wonder how many blocks are cracked, and running fine over 200k miles? There isn't an epidemic of spun cam bearings in roller 5.8L trucks, is there?

As for environment, a guy in that forum said his cracked 5.8L is out of the proverbial granny driven truck. So who knows. I wouldn't be surprised if this was a production issue, but with no drivability issues Ford either didn't worry about it or they didn't know.

So, anyone ever actually hear of or see a cam bearing spun in one of these cracked roller blocks?

 

I'm not aware of any other vehicles either. Jim had the fleet vehicle theory earlier in the thread but then someone later said the bores in question seemed correspond where the bolts were for the spider retainer. Someone did say they thought it may be a casting issue.

I think the only thing to count on is it being a roller block. No other correlations seem to be showing themselves.

 

Yea the cracks are only on the two bores with the spider retainer bolts. The bolt holes are drilled through the block, into the bore, and tapped all the way too. Filling the tapped holes with brake clean, I can see the solvent weep out the crack when looking down the cam bores (bearings still installed).


For those unfamiliar, these are the tapped spider hold down holes in a 94-96 roller 5.8L block. They are directly atop the #2 and #4 cam bores.


Looking down the cam bores, you can see the place were brake clean is slower to dry out. It's on the two bores with the spider hold down bolt holes. Can just see the #4, while the #2 is easily seen here.


During production, I could see tapping those holes with too high of feed rate stressing the casting..Drilling likely wouldn't do it but a tap acts as a wedge to some degree. Maybe it was when the cutter was getting dull or coolant/cutting oil wasn't flowing sufficiently, and that's why it seems 2 or 3 in 10 crack. I know when I used to work in a machine shop, the cutters didn't last forever. The last couple parts before a cutter was indexed or changed were usually still OK (or they were scrapped) but not dead on like the rest, they were pushing the tolerances. Dull cutter may have exerted more "wedging" force in the hole yet still cut decent threads. The block may have been cracked then, or cracked shortly after it was put in service. I suppose it doesn't matter. I have another roller block at my parents, but that's some 850 miles away and it may be cracked too.

 

That's a good point about when they were being machined, especially tapped. Another thing that Jim mentioned was if they weren't cracked when taken apart for the first rebuild, they more than likely weren't going to crack. Maybe that could possibly mean they were cracked all along.

But as far as symptoms this would cause, I don't know. And Jim didn't mention either. I think he only uses Dart blocks now when he's doing a from scratch build.

Another platform I didn't think of earlier was the Bronco. They came with some. My dad has a '96 with one.

 

"what other vehicles did 5.8L roller blocks exist in, other than vans, buses, trucks?"

1995 Mustang Cobra R. Kind of rare though.

It seems unlikely that making the threaded hole for the spider causes the crack, isn't it only 1/4" thread?

Maybe it formed when the block cooled after casting and developed stresses.

 

It is 1/4" 20 pitch.

 

Machine shop is polishing the crank and inspecting the block. Older man working there said the crank looks pretty good. He tentatively said I should run 0.001" undersize main bearings with standard rod bearings, but will recheck after polishing. He agreed with me that a hone & re-ring should be just fine as the cylinders look good (I didn't measure any out-of-round or taper with my snap gauges & caliper--though I understand those aren't the ideal measuring tools) and the rings weren't stuck. He even loaned me a Go-No-Go gauge to check the ring lands. I should hear back today about the block, it was boiling over the weekend & they'll magnaflux it today. Neither of the guys that run the shop had seen this sort of cracking on a 351w roller before.

 

Two guys checked with magnaflux and couldn't see anything. Cam bearings went in with normal force, and the old ones hadn't moved one bit. So, I'm going with this block. Chalk it up to a science experiment. If she splits in half or spins cam bearings, I'll be sure to report back, but I seriously doubt that will happen.

 

Scored a set of GT40P heads on ebay last week, fresh out of the shop, for about half what the shops on there sell them at. My machine shop would have charged me more to go through my E7's so I'm happy. They came in today. Measured the combustion chambers at 59cc's. Bolted the Chinese SS headers to them, installed Autolite 104 plugs. Plug #7 is the only one that a stock 351w plug wire won't easily fit. It has 3/8" clearance on the plug itself but not enough room for a boot. Going to try a short plug there.



Plug #7.




Driver's side bank.




Passenger side bank. Plenty of room.

So I'm happy that at least I won't have to modify for plug fitment too much. Starter clearance is yet to be known but I'll post about it when I get there.

The bottom end is nearly together but one Clevite bearing had a manufacturing defect so I'm waiting on a replacement. In the mean time I've started on the lower intake port work.

 

Sorry to revive an old thread, but it wouldn’t let me send a message. Have you had any issues with the cracks? How many miles on your rebuild? I’m about to find out if my ‘95 351w is cracked too…hopefully not but I’m expecting the worst.

 

I had my 94 core block checked and it I got a good bill of health. Rough bored to .030.

 

As I understand it, these particular cracks are acceptable in a non-racing application.