Broken Crank

[Mr.Spool]

I purchased it recently and only put a few hundred miles on it. Probably hurt from before. I added the ecu-GN, E85, Husek trans. Also found part of a head gasket in the oil pan when I replaced the timing chain and rope seals.

Sounds like it had the life

 

[xlr8ngn]

I have seen many cranks broken as yours is. All of them were externally balanced.
Some were traced to cheap harmonic balancers, some from loose balancer bolts and SEVERAL were the early design SCAT LS stroker cranks that needed 3 or 4 slugs of mallory metal in each end counterweight to achieve "proper" balance. Scat has finally changed all of the counterweights on the LS cranks, so they will internally balance like everybody elses units.
My new build uses a Scat crank that can be internally balanced, but I had to remove a TON of weight to achieve zero balance prolly because of the Wiseco pistons lighter weight. A lot of the weight savings is from a more normal weight piston pin. I believe anyone building an engine with stock replacement pistons buy a lighter set of pins, as stock ones are waaaay heavier than aftermarket ones. A better alternative is lighter aftermarket pistons anyway.
If you bring a Scat crank in to be zero balanced, expect to pay extra for the time for all of the weight that needs to be removed. I think its worth it in improved performance. Also, dont forget to balance the cast iron pulley spacer deal too, mine was way off, even tho it was factory balanced. It does hang way in front of the balancer, putting more load on the front of the crank.
P.S. I also zero balanced my stock flexplate and balancer rather than buying aftermarket, as mine is a "street car."
TIMINATOR

The car wasn't ran in years and when I bought it and got it running, there has been a vibration I couldn't put my finger on right at 2k rpm. I replaced the poly trans mount with a rubber one and it was significantly better, but that vibration was still there and very noticeable to me. IDK if the vibration was a crack propagating or something else, it definitely was always there. The new assembly will be internally balanced for sure. I like your practice of using stock parts to keep the profile down.

 

[xlr8ngn]

Sounds like it had the life

I sent it to the grave with 25 psi, hope to salvage the bones. At least I fixed my vibration, lol.

 

[xlr8ngn]

"The rods were still on the journals but it did "grow" a little in length pushing the front crank snout forward. The crank locked up tight between the back of the #1 main cap and the thrust bearing".
When you are doing the suggestions already made, look very close at the entire ft bulkhead of the block. The hit with the crank side loading the cap bolts could wreak havoc with the threads.

Thanks, taking the block to the machine shop to mag and see if the line bore won't be too excessive. Not sure how easy that call will be without more or less doing the job. Not sure if the bulkhead could be pushed forward also, not sure how to check. Lots of uncertainty, but would like to salvage if possible. I'll inspect the holes and measure the bolt movement side to side and front to back versus the other ones? I have a dial indicator to measure the movement.

 

[SCOOBY DOO]

Thanks, taking the block to the machine shop to mag and see if the line bore won't be too excessive. Not sure how easy that call will be without more or less doing the job. Not sure if the bulkhead could be pushed forward also, not sure how to check. Lots of uncertainty, but would like to salvage if possible. I'll inspect the holes and measure the bolt movement side to side and front to back versus the other ones? I have a dial indicator to measure the movement.

When I was apprenticing in Toronto we had the contract for Blackwwod Hodge which was a large diesel rebuilder. I saw some seriously fucked up diesel blocks saved. Yours should be a walk in the park. I saved a ton of twisted diesel rods with the Robbie boring bar.

 

[Chuck Leeper]

My 109 from Ruggles, not only cracked the crank, but spit the side of the block out on the track @ Reynolds.
Faulty boost controller put an end to it.

 

[xlr8ngn]

My 109 from Ruggles, not only cracked the crank, but spit the side of the block out on the track @ Reynolds.
Faulty boost controller put an end to it.

I guess I'm lucky now that these blocks are $$. I'm in Woodstock GA, who is a good machinist in our area for Buicks?

 

[Chuck Leeper]

I guess I'm lucky now that these blocks are $$. I'm in Woodstock GA, who is a good machinist in our area for Buicks?

Sorry I can't help.
Garry Grimes, Twister Engines in Alpharetta, has done several for me.
The last one, some 5 yrs ago, was his last Buick.
Someone has bought all of his Buick parts.
I'm not sure what he's done with his Buick tooling.

 

[GNONYX]

Many years ago when factory was only given 12,000 warranty, my 1976 Chevy monte Carlo had 13,500 mile when the engine die on the 60 mph highway. Dealers found the crank shaft split in two and claimed it couldn't do anything since the warranty has expired, so I pulled the engine and replaced with 350 4 bolt main.
Anything internal components really sucks and costly, especially with everything being so expensive; the only thing cheap is DIY labor.

 

[TurboTGuy]

Richard Clark is around 6 hours away, up in Burlington, NC.

 

[hensleyt]

I hurt a 109 with KR. the front two caps needed replaced. Naturally It needed 3 of the 4 replaced ,block was maged and given a clean bill of health. so I spent money on caps line bore and hone decked and .010 bore. new rotating assembly the first set of main bearings lasted 30 min.
I won't lie it was on the tight side but was in spec. Second set same 30 min. So back to the machine shop to re line hone .0005 and re mag, again clean billow health. And the third set could not get past the 30 run-in time. I trashed the block bought a short block from AZ GN and I have 10K miles no problem. I blamed myself for the first set thinking I had missed something but not time #2 and 3. Two different engine builders could not say why but there not Buick builders. (I was in Hawaii at the time) I have my own theory.
MY point? Get someone that machines Buicks. I have built 10 maybe 12 engines 3 were 3.8 and one of those kicked my butt all the rest have been good.

 

[Chuck Leeper]

Along the crank/line bore topic.....
When Jim Ruggles did my 109, he told me that a common line hone process was a bit "iffy".
He explained that the v sicks block is so short, that there's a possibility that the hone bar could wobble and oversize the end bores.
He, and the Sunnen rep, came up with a work around.
Don't know if this problem is prevalent with the newer machines.
AIRC, one of his shop guys used to frequent the board....Steve?
Would be nice if he would get into some of these threads.

 

[SCOOBY DOO]

We used an elongated dial indicator and checked the bores at 12, 3, 6 and 9 o'clock on the outside, inside and outside of the bores. You have to be way beyond anal when checking measurements.

 

[hensleyt]

I have never blamed the line hone. all was good and round in all position , back was a few tenths larger. cap being a little softer. don't know
Crank always turned very nice. I believe it was the inspection of the block not knowing what to look for. I believe as it came up to temp something was moving or when I pulled the heads down something moved. Rod bearing damage was just trash from the mains.
Again the only lesson to get from my mistake is get the machine work done buy a good Buick shop. It sounds like your block was under some stress.

 

[SCOOBY DOO]

I have never blamed the line hone. all was good and round in all position , back was a few tenths larger. cap being a little softer. don't know
Crank always turned very nice. I believe it was the inspection of the block not knowing what to look for. I believe as it came up to temp something was moving or when I pulled the heads down something moved. Rod bearing damage was just trash from the mains.
Again the only lesson to get from my mistake is get the machine work done buy a good Buick shop. It sounds like your block was under some stress.

Question. Did the new main caps have the 45 degree chamfer.

 

[hensleyt]

Yes Scooby Im almost sure it did.like 99.9%. I did not toss it, these 109 are getting a little hard to find. and I will probably take it to Zimmerman racing in Phoenix know that I'm on the mainland,Again a good Buick builder.
My point to. OP get the machine work done by a reputable Buick shop.

 

[TurboTGuy]

Mike Zimmerman knows his way around a Buick V6 engine, no doubt.

 

[xlr8ngn]

Nice ring orientation. Came from the factory this way as far as I know.

 

[TIMINATOR]

Rings rotate on the piston in normal operation. That's why when doing a leakdown test, if u have a low cylinder, start it up, wing it a few times and recheck before getting excited....
TIMINATOR

 

[xlr8ngn]

Rings rotate on the piston in normal operation. That's why when doing a leakdown test, if u have a low cylinder, start it up, wing it a few times and recheck before getting excited....
TIMINATOR

I've never seen oil rings consistently in or near aligned like this before.