Feelin' Cranky

Because the crank in my pickup is trashed . And from the looks of the camshaft this isn't the first time my son has run it low/out of oil (a
long and sordid tale) . This is my '86 GMC Sierra 1500 , 305 H motor and a 700R4 trans with 2.73:1 rear axle . I'll be taking parts to a shop for stuff I can't do , bore .030 over , check the heads out and a/n . And the crank ... the rod journal for #1 measures 2.071" , spec is 2.0988 - 2.0998 . It might clean up at .040 under , I don't know . Have to see what the guy at the machine shop says . Which brings me to a question - what about welding up a journal and regrinding ? I had one very bad experience with a welded-up journal back in the early 80's , a $700 rebuild went 35 miles before it ate the rod bearings . I ain't going down that road again .
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305 cranks are far from rare. I's NEVER go 40 under, and the only way I'd weld a crank is if there was no other option. Gotta be a "lawn ornament" somewhere within a few miles of you with a crank that will clean up ar 5 under or better, and you know you have a keeper. If you want a real stout engine put in a forged 350 crank and run a fluid-damper (the 350 is balanced a bit different from a 305 because 305 pistons are lighter) Newer cranks will fit your 86 as 86 is the first year for one piece rear main seals.
Better yet get the rotating assembly ballanced to use the forged 350 crank with NO issues.
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On 12/4/2021 9:20 PM, Clare Snyder wrote:

I'd love to go "all the way" with this motor and do the balanced/blueprinted thing ... but this is a budget build . I'm pretty sure the shop that's doing the machine work can supply another crank - I too am leery of anything more than a .020 under grind . I just want a truck that isn't always trying to decide what gear it wants to be in . The terrain up here is pretty hilly , and those 2.73's just ain't gonna cut it . I'd have been happy just to get my truck back intact and install the new 3.42 gears . But since the boy finally managed to blow up the motor , I'm going to build this one right and have some fun with it . I plan to stick with the stock 9:1 C/R , but it's getting a new cam (Elgin E-922-P) with some small/long tube headers and a new intake manifold . A friend says he has an Edelbrock that will fit , probably a Torker . Depends on what the carb bolt pattern is , I plan to keep the stock Rochester Q-jet . If his won't fit my carb (and he doesn't have one to fit) I'll put an Edelbrock Performer on it . Either one will be a good fit with the cam/header combo I gave selected . This motor has the 601 heads , which are supposed to flow better than the 116 (?) heads . As of right now I'm not planning on doing any port work , but I got all winter , and who knows ... We ain't rich , but I can afford to do whatever I want within reason . If the original trans is still at my house in Memphis , it's going to be rebuilt and installed . I can recoup part of the cost from selling the unit that's in there now . I don't plan on leaving the kids any cash ...
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On Sat, 4 Dec 2021 22:45:06 -0600
<snip>

Those 700R4 trannies weren't all that strong. While your at it replace it with a 350 turbo and you'll loose the overdrive and shouldn't need the steeper rear gear change.
You build up that motor and it's very likely to take out the 700R4 in short order anyway...
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wrote:

Losing the overdrive doesn't help low and second gear. Putting in 3.42 or 3.55 gears gives more "pooch" at the bottom end - overdrive returns some highway "comfort" to the setup. A well built 700R4 will stand up to anything a healthy 305 will hand it if the gears are right.
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On 12/5/2021 3:43 PM, Clare Snyder wrote:

I was going to say pretty much the same thing ... Thanks Clare .
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On Mon, 6 Dec 2021 14:00:22 -0600

The early ones had problems. When I was getting mine (1982 K10) fixed... hmm around 1986 the transmission shop was making good money on them. They called'em 60,000/1600's or something like that. 60,000 miles and $1600 to repair. I also found 350 and 400 turbo kits to outright replace them and I considered this but the 6.2 diesel made that difficult. The 700R4 used a throttle cable for shift point control and the turbos used vacuum. It only weighs a pound or more than a TH350 and yet it has another complete gear set. At the time the TH350 was well known for taking a crap load of abuse and the 700R4 was getting tore up in Astro Vans at 60k miles with V6's. I drove it for over 40 years but I was pretty careful with how I treated the transmission after learning more about them...
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On 12/4/2021 8:20 PM, Clare Snyder wrote:

I tend to agree. I've rebuilt a couple V8 engines (mostly Fords) and if you are in that deep a decent crank just isn't that much compared to the cost of your time to pull the engine and flip it over again.
The big question is, "Was it just run low on oil, or was it overheated too?" I've seen an overheated engine get rebuilt (not by me) and it didn't last long.
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"Bob La Londe" wrote in message
The big question is, "Was it just run low on oil, or was it overheated too?"
-------------------
How can you tell?
I've completely torn down and rebuilt old motorcycle engines but never gone beyond a top end job on a car, so this is interesting.
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On 12/5/2021 10:33 AM, Jim Wilkins wrote:

Well when somebody rolls in with a blown radiator hose or a blown freeze plug, its not steaming anymore, and the engine seizes up when they try to restart it that's a dead give-a-way. If you just have the engine on hand I wouldn't know how to tell.
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On 12/5/2021 3:48 PM, Bob La Londe wrote:



A severely overheated motor will show signs of "cooking" on the caked on grease - extreme cases the deposits will actually be scorched .
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On 12/5/2021 9:35 AM, Bob La Londe wrote:









It shows no signs of overheating , but this isn't the first time he's run it low . Inspection of the camshaft shows several lobes with degraded edges on the opening side ramps . As far as I'm going with this motor , it wouldn't really matter . New post coming momentarily .
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