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351w crankshaft help

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    Posted: November-27-2018 at 1:09pm
My ccw (reverse rotation) cast stroker 351w is eating its main bearings in 5 hours (less than 3000 rpm).

anyone switched cast cranks on a 351w ccw engine? Any special mods I'm missing (directional polishing/oiling mods)?

Any help is appreciated.   My machine shop and I are scratching our heads. No apparent causes.
Craig
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ps...ca engine appears fine at this point
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SNobsessed Quote  Post ReplyReply Direct Link To This Post Posted: November-27-2018 at 1:21pm
Oil foaming?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gt40KS Quote  Post ReplyReply Direct Link To This Post Posted: November-27-2018 at 4:36pm
Oil contamination? Perhaps an oil analysis could point out potential causes.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote zwoobah Quote  Post ReplyReply Direct Link To This Post Posted: November-27-2018 at 4:38pm
Have you checked the crank for straightness? Use plastigauge for bearing clearance?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: November-27-2018 at 7:28pm
crank is off 1 thousand on #2.

never used enough for foaming

anyone using straight car cranks on ccw?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gary S Quote  Post ReplyReply Direct Link To This Post Posted: November-27-2018 at 8:08pm
I am on a 302. I told my machine shop what I was doing,they took it from there. Don't recall what they did or if they even told me- it was almost 30 years ago. The crank is a 1974 ish. I know that doesn't help much other than it can be done.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tryathlete Quote  Post ReplyReply Direct Link To This Post Posted: November-27-2018 at 9:09pm
Originally posted by zwoobah zwoobah wrote:

Have you checked the crank for straightness? Use plastigauge for bearing clearance?


Zwoobah—right on.

Are you pre-oiling crank during assembly? Plastigage is critical to get the right clearances. Is the crank and bearing set matched (if crank turned down—bearings have to be matched to what was removed)? I assume you know all this.

Just an odd thought—if you’re getting detonation and I mean severe—the load can cause the main bearings to distort and turn blocking oil feed holes and then things go south quickly. Doubtful that’s the cause here but just mentioning it. Saw this failure once on an aircraft recip when bad gas was used.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tryathlete Quote  Post ReplyReply Direct Link To This Post Posted: November-27-2018 at 9:11pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gary S Quote  Post ReplyReply Direct Link To This Post Posted: November-27-2018 at 10:20pm
Interesting part about grinding and polishing a crank Pete.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tryathlete Quote  Post ReplyReply Direct Link To This Post Posted: November-27-2018 at 11:10pm
I agree Gary. Microscopic fuzz is an interesting concept. Grinding opposite direction to engine rotation and polishing in the same direction......
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: November-27-2018 at 11:30pm
the polishing certainly maybe the issue here.

dunno. But could it do this in so little time and use?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tryathlete Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 6:08am
I think there’s a much bigger issue causing failure. What do the crank journals look like? What image in the link best represents the failure?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 6:20am
One thing I can't help noticing here is that you're speaking car talk on a boat forum.

You seem to be referring to a CCW engine as reverse rotation. It probably makes sense to you and your machine shop but might cause some confusion here

If you're looking at it the way the marine industry does (from the rear looking forward) then a reverse rotation engine is CW or Right Hand rotating and a normal automotive engine is CCW or Left Hand rotating in the marine world

Are these crankshafts you're using the older 2 piece rear main seal type or the newer 1 piece rear main seal crankshafts? Where did the stroker crankshafts come from? Have you talked to the manufactured?

SNobsessed mentioned foaming and you said it hasn't run long enough. Foaming that he's referring to is the oil being aerated by the crankshaft as it spins due to sump level being too high and losing it's lubrication qualities.

Is it real hungry and eating all the main bearings or just one or some of the bearings?

Are the rod bearings OK?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tryathlete Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 10:39am
Can we see some photos of the crank main journals after the 5 hour teardown?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 11:03am
rod bearings are ok. the mains are down to copper. the rods and cams show some sign of perhaps debris from the other bearings, or result of running low (4psi) oil pressure after the mains were toast.

I'm having difficulty getting ahold of the crank manufacturer. I bought these stroker kits during a dark period for Coast High Performance during 2016. Although at time of purchase I was told it was a cast Scat, it looks like it may be a Star Galaxy Inc (SGI) which may be under at this point.

I'm having trouble posting a pic here of the bearings.

What I'm trying to find out is if other sbf guys are using auto cranks in a reverse rotation application. If they are, did they repolish the journals in an opposite fashion? Did they do anything special to the oil passages in the crank?
.
On the internet, everyone has an opinion. Since the machine shop and the crank shop haven't found any glaring deficiencies, Im reaching out here to see if. by installing a new crank without modifying it, did we overlook something that everyone else does. I figure many of you on this site are running sbf, and many may be reverse rotation, and I'm looking for first hand input.

youtube video shows bearings in random order. 1 main bearing shell is missing (loaned to friend for inspection). it was as bad as the worst in pic.

https://youtu.be/LOQcDlLTo9E
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 11:35am
https://youtu.be/LOQcDlLTo9E

bearings randomly placed
1 main shell missing, but as bad as worst.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 12:17pm
https://youtu.be/LOQcDlLTo9E
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 1:37pm
PCM does list different part numbers for their RH and LH crankshafts for 302 and 351 engines.

Even the later ones with no wick lines/helix lines and a 1 piece seal had different part numbers.

I always thought it had to do with the chamfering of the oil holes in the crank and that a normal rotation crank could have the chamfers cut right so it could go both ways.and depending on the seal, you had to deal with wick lines on the older 2 piece setup, and with the 1 piece you just needed the right seal

I would take none of my chamfering talk as gospel though without some verification
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TRBenj Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 1:41pm
I’m running a 1-piece 331 stroker kit backwards... so no issues with the oiling, generally speaking. I do not know for certain f it was polished in reverse (though I am always clear to specify this on my RH cranks when having them ground/polished). No way is the lack of polishing going to wipe your bearings after 5 hours though. What were your bearing clearances set to? What weight oil?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 2:03pm
10w30

I think 2 thousandth...maybe slightly more.
3 inch journal... maybe should be closer to 3 thousandth

thank you...what I was looking for.

Do you know if they repolished crank before installing?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 2:10pm
Originally posted by 428CobraJet 428CobraJet wrote:

10w30

I think 2 thousandth...maybe slightly more.
3 inch journal... maybe should be closer to 3 thousandth

thank you...what I was looking for.

Do you know if they repolished crank before installing?


Probably the same oil and same clearances as the normal rotation engine that doesn't seem to have a problem?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TRBenj Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 2:17pm
Better get confirmation... ideally the person setting the clearances also confirmed the block measured up ok and also sourced the correct bearings (to match the crank). And whoever did the assembly checked the clearances in place.

.0020 sounds very tight. Should have been approaching .0030.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 2:56pm
keno...yes

trb...block ckd ok. I think we will line bore b4 assembly to make perfect. and polish crank backwards. Since, at this point, we cant find anything glaring.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Duane in Indy Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 3:11pm
Originally posted by 428CobraJet 428CobraJet wrote:

trb...block ckd ok. I think we will line bore b4 assembly to make perfect. and polish crank backwards.


Never heard of boring just one main, we always align bore and hone all of the mains. We had a bar ground .001 undersize and would put the mains brgs in and torque the caps and then rotate the bar and verify that the block was still good. The bar was longer than the over all length of the crank. Our blocks would move around a lot.
If your block is good, and your clearances are good then I would start looking for oiling issues.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 3:32pm
the crankshaft is off 1 thousand on #2 journal.

if we line bore...yes all of them. and straighten crank and polish and cut directionally
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Duane in Indy Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 3:47pm
Originally posted by 428CobraJet 428CobraJet wrote:

the crankshaft is off 1 thousand on #2 journal.


A production crank w/i .001? You should be happy as can be!!!   How did they check it?? Most shops don't have the tooling to check any closer than that.
Like I said, I would be looking harder at the block than worrying about a thou. on the crank.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 4:18pm
he put the crank on a saddle on each end and measured the distance from a baseline.

if the engine is set up with 2 thousandths clearance total... well I'm no expert
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tryathlete Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 4:55pm
While you’re still apart, might as well balance those components before assembly
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 5:43pm
they have been. At time of purchase.

Hopefully that wont change in the machining.
thank you..
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tryathlete Quote  Post ReplyReply Direct Link To This Post Posted: November-28-2018 at 5:58pm
Originally posted by 428CobraJet 428CobraJet wrote:

they have been. At time of purchase.

Hopefully that wont change in the machining.
thank you..


Sure hope not!
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