[bosch]

Every time a project starts out with, "I will just throw this together on a budget" I find out why that is a bad idea. So here goes, I have a 350 that I wanted to 'freshen up' and put into my Chevelle, until I can get all of the money together to build the 427 that I want to put in it. This 350 ran (until I took it apart) so I assumed the parts were all good enough for a very mild street 350. The plan was bearings, rings, gaskets and maybe some head work. This engine would only be in there for one or two seasons. The car has a 283 in it, so swapping in a 350 should be pretty straightforward.

While cleaning and inspecting the parts I noticed these areas on the crankshaft journals. Are these cracks? Can this crank be expected to live in a 325 - 350 h.p. 350? Will this crank shell out if I really get on it? I am not a machinist and I haven't seen many cracked crankshafts in person so I don't have much to go on here......

Thanks.

 

[jeff swisher]

I had a welded crank in a 350 parts store crank kit .
It had spider web cracks in some journals that my machine shop pointed out to me during mag' test.
He told me it could live or die...It lived many happy miles some at 6500rpm.
Cast 350 crank,,was not ballanced.
I had a 302 ford crank that broke at the #1 rod journal no issues with it at all
never seen more than 5500 rpm..it was balanced and had $1200 worth of machine work done to the long block crank and rods held by arp bolts.
What bothered me about the broken crank was that it was deer season and i had a load of fire wood in the vehicle and a nice field dressed buck..
I was more worried about the deer meat than my engine...HA. Buddy had me in my drive way in less than 1 hour..

Just a crap shoot sometimes.
could be just a surface crack that does not go deep .
maybe this would help.
Ultrasonic shear wave inspections.
They can put an ultrasound probe alongside the crack pushing sound waves at an angle to get an on-screen representation of the crack depth.

or find another crank..

 

[Andy's Auto Repair]

Definately a queston you want to ask your machine shop, not a bunch of keyboard commandos like me.

 

[bosch]

Thanks for the replies. I will try to take it to a machinist and have it checked out but it is actually getting a lot tougher to find a machine shop around here. It seems like all of the shops have shut down. Can't find anyone that has a good reputation and can balance a rotating assembly in my end of the state.

The reason I posted this is because I have heard from other people the same things that Jeff posted. Not all cracks are fatal, not all crack free crankshafts won't break and you can never spend enough money. I was just trying to figure out whether this is fairly common, or if this thing is a guaranteed grenade. If there is any chance I can get away with it I might run it.

I probably won't have a dressed out deer, or elk in the back of my Chevelle, but I also don't really want to have to call a buddy to tow me home if this thing shells out either. That is a bigger deal to me than actually breaking the crank. If the motor blows up, that is what it is. Finding a friend good enough to want to get out of bed late on a Friday night and tow my broke down butt home is the bigger issue.

I tend to agree with Jeff, but let's see if anyone else chimes in.

 

[novaderrik]

it might be easier to find someone that can point you to a good machine shop in your area if we could tell what part of the "big sky state" you live in...

 

[70-SS454]

I would think Bill K could tell you right here...

 

[CoolBlueGlow]

I don't know Bill K, but yes, that's a crack. Clean off the surface with lacquer thinner. Blow it clean and dry. Swab out the oil passage too. Then wipe the surface with any common ultraviolet sensitive dye. Ten wipe off the surface with a clean dry rag. The shine a common UV lamp on it. If you can still see the crack, especially down in the oil passage, it is a crack worth taking seriously. A crack across an oil passage is nothing to take lightly if reliability is important.

350 cranks are dime a dozen...why risk it?

Another idea...

Why not take that 283 and punch it out to 4" and build a 302? Go the road less travelled. The 283 has a forged steel crank. You can wind the piss out of it. big fun cheap and you'll have the only 302 powered Chevelle in a 500 mile radius.

Just a thought

Keith

 

[64play]

bosch, you need a legit 427? (everyone needs a 427)
I too share the Big Sky with you. Shoot me a PM.

 

[Schurkey]

The 283 has a forged steel crank. You can wind the piss out of it.

Cast cranks in some 283s beginning in '64.

 

[bosch]

Thank you Keith and Schurkey. I will definitely get some UV sensitive dye and try to see what I can see. I know that 350 parts are relatively easy to come by. I just wanted to use this because I have all of these parts. Besides, even if this crank isn't useable I will still get some dye and spend some time learning about cracked crankshafts. I wouldn't be into this stuff if there wasn't anything to learn.

I was hoping to do this on the cheap because I have already spent my car parts allowance for the next few months. I recently had a TH400 built, picked up a forged 427 crankshaft and have almost completed a total rebuild of a 12 bolt axle. For now I have to either tinker around with junk I have sitting around here or find something else to do until the cookie jar has something in it again. The wife would prefer that I have something to keep me busy.

I have heard about cracked crankshafts that have been repaired before. I was also wondering if this is something that can be fixed by grinding the crank. I do not plan on having that done to this piece, but just wanted to know. I guess I just wait around till the cookie jar gains some weight or a usable 350 crank shows up on my doorstep.

Not sure if it's bad form to hi-jack a thread I started but we'll see......it is interesting that you bring up the 283. I thought about doing something with the 283 to begin with. After reading enough forums I decided that it just wouldn't pan out. You need heads with small chambers, good flow, decent valve's and I would really like to have accessory holes. This pretty much leaves you with 305HO heads or Vortec's. I already have an Edelbrock Performer RPM intake and standard rocker arms. I don't really want to buy all of that to run Vortec's. I also don't really know that I would have much luck trying to find 305HO heads around here..........so there we are. Also, the 10 bolt that currently resides under the car has 3.08 gears.

Looks like I will have to take on some house projects for the summer........the wife will always let me spend money on those.

 

[chrisstandring]

If it is really cracked then that cast crank would have shortly become a 2-piece crank. A cracked steel crank will run for a while but a cast one won't. Why not see if you can find some spacer bearings so you can put the 283 crank in your 350 block?

 

[CoolBlueGlow]

Re: spacer bearings

No doubt, good idea!

You have the 283 crank - good chance that it is a forged steel piece... Spacer bearings make it fit, reduce your journal speed - win win.

Great idea Chris!

 

[64play]

Instant 302!!

 

[bosch]

Ok fellas, I have to admit that I agree with you. A 302 would be great fun. I have also looked into that. It seems that there are a few hang up's there as well. Apparently the spacer bearing sets are pretty expensive ($209.00 for Clevite's at Jeg's). Also, the 283 rods are not as beefy as the 327 small journal rods. So go for 327 rods if you plan on serious rev's. But the problem is that if you use the 327 rods, with the bigger 4" pistons, the 283 crank will most likely need Mallory metal for balancing. I have been told that's about $50 a plug. So again, the cost begins to skyrocket. Might as well buy some Chiwan crank from the mail order outfits and build a 350.

The whole reason for this 350 was something cheap to tide me over while I save to build the 427 that really belongs in there. Turns out, 427's aren't as common as they used to be. Parts for that pig are starting to become expensive. Another thing, piston selection for a 427 with open chamber heads isn't as good as I once had thought it might be.

I think I recall saying something about the fact that you can never spend enough money........

 

[jeff swisher]

If it was mine i would stick it together and run it.
If it was a buddies or customers then a different crank would be used.
You stated it was running when you took it apart.
and you are building a mild 350.

I gave a buddy 5 bucks in gas (1990's) to bring me a 350 he had
Said it ran..i just needed it for a month or so while i ported my 186's
I had 80 hours each in those heads.
Anyway the 350 ran but ex lobes were gone on a few spots.
WOW that is what a stock 350 feels like with 370 gears...I did not like it ..
BUT>>> i had a working cowl hood and when i would floor it for about 4 seconds going down the highway and then let off the gas she would backfire out of the carter afb and a huge fire ball would shoot out of that cowl hood and cover the windsheild...The screams from the passengers was worth the $5 i paid for it.
I bet that crack ain't no worse than runnin' that wiped out camshaft.
That buddy got one of my 403 and 455 olds and many goodies and heads
when i gave up on the oldsmobiles and went chevy...we traded a lot.
No bargain better than a $5 flame thrower

 

[CoolBlueGlow]

Yeah, welll Jeff makes a good point...tempting to run it-but I still think I would go to the boneyard and dig through the pile of junk cranks and get a better starting point before I would run that cracked crank.

Re: Spacer bearing costs. Yeah, so weld up the main journals on that 283 crank and then have them ground back to standard 350 journal size.

Re: balance. Yeah, forget the rebalance. Take your stock 283 piston and rod assemblies and weigh them. Get an average weight from the eight. Assemble your new 327 rod/piston combos. Weigh them and then hand grind metal off the balance pads on the rod caps to get them as close to the 283 assembly's average weight as possible. If you need more weight off than then balance pads alone can accommodate, take the forging marks off the beams, always grinding WITH the direction of the rod. Grind, then polish, then glass bead the beams. Labor intensive, but low cost.

Re Fireball 350: Yeah, big fun! But, Jeff - you've seen what happens when a crank breaks, right? At like 5800 rpm?

Just not the same effect as blowing a fireball out the tailpipe. And remember, you only get ONE failure experience. Consequently, the odds of having the appropriate passenger in the right seat at the correct moment is much lower.

 

[jeff swisher]

My ford crank broke at less than 2,400 rpm cruising at 50mph
Ford had issues with this in the mid 1980's many cranks broke at the #1 rod journal...I narrowed it down to a ballance hole that was drilled pretty deep into those cranks.
Here is something for you to think about..Small spider cracks from welded cranks do not scare e as much as Hypereutectic pistons.
I have a new set on rods H345np i will never use them..too scared with the way i treat my stuff...

WHY? because i beat a bunch of pistons off the rods with a sledge hammer years ago...the cast ones would bend a little get a crack and about 5-7 whacks i had aluminum and steel separated.
Forged pistons took a few more whacks....
Hyper pistons took 1-2 whacks and shattered most of them..
I got to where i could tell by the flying shrapnel that i just hit a hyper piston.

Some people run them though...I think a crank kit is still cheap from an auto parts store..i could be wrong...
You could have just that one journal ground down to the next size and see what it gets you...

 

[bosch]

Thanks again for the ideas guys. I especially like to hear about hand machine work that can be done. I don't have a lot of experience doing any of that but I do plan to learn. I know that back in the heydays of hot-rodding people were much more self reliant and did great things by hand in their garages. Sure they couldn't optimize an engine the way a good shop can today, but what is the fun of just dropping it off at a shop and writing a check?.....

I was actually going to take a grinder to the heads on this motor. They are 882's, I know, throw them in the river. But I have never ground on heads before and I thought what better heads to learn on right? The valve guides probably have more clearance than they should too. I was thinking about talking one of my co-workers with a drill press into letting me try to do valve guide inserts with his press. Either that or put umbrella seals on them and forget about it.

My dad talks about using his dad's electric drill to port a set of heads for a Pontiac 389 back in the early 70's. He said it took forever and flat wore the drill out. I figure I am at a little bit of an advantage since I have an air compressor and grinder.

I already took a ridge reamer to the block. The cylinders are all in pretty fair shape. I don't have a way to measure the taper (dial bore gauge). But they don't have any deep scratches and measure out at factory diameter (measured using my trusty Harbor Freight dial caliper). The next step is a glaze breaker. I was going to get a flexible hone, the kind that looks like a bunch of grapes. But O'Reilly's rents a 3 stone glaze breaker basically for free. Apparently it doesn't do a very good job compared to a flexible type, but you can't beat the price.

My buddy keeps giving me a hard time about this engine, he say's, 'you just had to take it apart didn't you.' I should have just left it put together and put in a ridiculously oversize cam. Just go out and run it till it breaks. But now that I took it apart I want to try to fix all of these little problems.

Hey Jeff, good thing you weren't running a Holley. It wouldn't have gotten far with those fireballs!

 

[jeff swisher]

Sending a pM

 

[Schurkey]

I already took a ridge reamer to the block. The cylinders are all in pretty fair shape.

There's a really good chance that the ridge reamer ruined any chance of using those cylinders without a rebore.

I don't have a way to measure the taper (dial bore gauge).

Sure you do. Install a ring, push it to the bottom of the cylinder using a flat-top piston or a caliper to assure that it's square in the bore. Measure the gap with feeler gauges. Pull it up to the top of the cylinder--about 3/8 from the deck surface. Again, make sure it's square in the bore. Measure the gap. Compare top gap to bottom gap, divide the difference by 3.1416, and you have the taper. (assumes that taper is bellmouth and even through the cylinder.)

But they don't have any deep scratches and measure out at factory diameter (measured using my trusty Harbor Freight dial caliper).

If they were factory diameter, there wouldn't have been a ridge that needed reaming. The fact that the ridge existed is proof that the cylinders are worn.

Keep in mind that the "ridge" is the original un-worn cylinder wall.