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Blown motor

77 casa grande

77 casa grande

1/2 ton status
Joined
Dec 23, 2010
Posts
200
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Location
NYC
Well the world did come to an end this morning, at least for my motor anyway. Driving home from a good fishing trip, minding my own business ,truck running fine, all of a sudden BOOM! WTF? Probably a rod or wrist pin, whaterver it is, it ain't good.
Already on line looking at new motors. By the time I'm finished with all the "might as wells" on a rebuild I can buy a crate motor for half the price.
I have (or had) a 400ci and I'm looking at the 350ci 260hp 350lbtq from Jegs. The 400 was only rated 175hp 300lb tq. I should be able to swap everything except the flexplate and balancer. Is there anything else I need to look for?
 
Since you have to replace both the harmonic balancer and flexplate anyways you might want to get an engine with a 1 piece rear main seal as they are less prone to oil leaks both from the rear seal and from the better 1 piece pan gasket. The only thing you'll have to deal with then is the intake bolt angles on the 4 center bolts that are a different angle than the 1986-earlier engines. You can elongate the holes and the grind the manifold to square the bolt head properly OR you can buy a carbed intake to fit those heads.
 
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I'm trying to do this as for as little as possible, so I'd like to swap over as many parts as I can. A new motor was not in my plans, in fact I was close to finished ,the last two items I needed were shocks and a twin stick shifter to replace the pos one on there now. The 400 was running great, it gave no indication that anything was about to let go. Not a knock, a ping, a tick, nothing. Thats whats got me so pi**ed.
The one piece seal motor, though tempting requires more time and money than I can justify. The truck is not a dd and the crate motor puts out about the same hp &tq.
 
Sorry to hear it,I will look around for you.

"Driving home from a good fishing trip,"

On a lighter note where EXACTLY where you fishing,ya know,since you wont be there for a while......................................:D
regards Scott
 
77 casa grande said:
I'm trying to do this as for as little as possible, so I'd like to swap over as many parts as I can. A new motor was not in my plans, in fact I was close to finished ,the last two items I needed were shocks and a twin stick shifter to replace the pos one on there now. The 400 was running great, it gave no indication that anything was about to let go. Not a knock, a ping, a tick, nothing. Thats whats got me so pi**ed.
The one piece seal motor, though tempting requires more time and money than I can justify. The truck is not a dd and the crate motor puts out about the same hp &tq.
Click to expand...

So how does it require more time and money. :dunno: You already have to buy a new harmonic balancer and flaxplate anyhow. The intake manifold can be reworked like I said without buying a new one.
 
The vortex motor is about $500 more but I will research it further. Not being closed minded, just have no experience with the vortex
 
It doesn't have to be a Vortec engine, although that is better. Just a 1987 and newer style that uses a one piece rear main seal, and center bolt valve covers. Those are all roller engines as well, although not all are equipped with a roller cam. You are much better off to get Vortec heads and a roller cam for only $500 though.

Martin
 
Any idea what let go? Will it turn over or is it locked up?
I'm wondering if the block is good for a core.
 
The motor still turns over in fact it still runs. Don't know exactly what went but my guess is a broken rod or wrist pin. Won't know how much damage is done untill its opened up. I'm betting its toast. The motor has at least 125K miles on it. Speedo wasn't working when I got it.
 
Just went through pretty much the same dilemna. GM crate motors only have warranty when used in the correct application. So no warranty if you buy their later model crate and stick it in your 76. If you decide to go with a later model engine, your probably better off finding one at a junkyard.

Least expensive, least risk, and easiest swap would be the 350/260.
 
Ok, since you did not say what the symptoms were that make you think the engine went "BOOM" and no one has asked yet i'll take the liberty to ask, why do you think it went "BOOM"? Does the engine now make knocking noises, ticking noise perhaps?
 
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Sorry about that. Should have done that from the beginning.
Sounds like the rod is slapping around in the #2 cylinder not blowing any oil, but can see small puffs of black smoke from the right side exhuast like its running x-rich
 
Pull the No. 2 sparkplug and see if its mashed flat. Wrist pin or whole top half of the piston could have come loose. Usually hits the plug when it does.

Had a piston separate at the wrist pin on a 350 one time. Pulled that head, and the top half of the piston just lifted right out.

On that one engine, it would have been salvageable. I would not have wanted to put in a new piston and rod and then taken it out to the track, but I suspect it would have given a few tens of thousands of miles more service as a DD.

Certainly long enough to make other arraignments.
 
Going to look at it today. I've had that "work" thing that keeps getting in my way. The truck is parked out on the street so I don't want to tear it apart just yet, it will be easier to drive it into position rather than push.
I've deceided to go with the 350/260hp. I know, 2pc main seal and all that, but I choose it for the following reasons:
1, Like Chalet 2506 pointed out, the warranty might be voided if not used in its inteneded application
2, With the exception of the flexplate and balancer, all my parts are a direct bolt-up including the intake which I just purchaced less than 3 months ago(no disrespect to you 4x4High just stating my reason. I do appreciate your input)
3, 2pc main seal. As I stated before this truck is not a daily driver. We all on this website tailior our trucks to our requirements. This truck is driven less than 5K miles a year, 90% highway the rest is flat sand beaches. I'm not rock climbing or mud bogging and don't need to beef up my rig, bone stock has been working fine for me. Fuel economy and dependablity are my two big requirements. A 2pc seal should conservatively last 80k mi. By the time I put on that many miles, I'll be in diapers.
4, Cost, 260hp/350tq delivered for $1625, I think is a great value.
Will continue to post as this progresses.
 
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You wont be disappointed. I have the same engine in mine and it runs well. As good or near as good as newer vehicles. Starts up like a champ, idles nice and has good power all around.
 
Recieved my new motor today and went strait to wrenching. So far so good, no forseeable problems. Will swing motor out first thing in morning. Had to stop working tonite (wifes birthday:doah:)
 
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