351W - rebuild or replace?
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Elder User
Joined: Jul 2011
Posts: 609
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From: Stockholm, NJ
351W - rebuild or replace?
I recently pulled the 351W out of my '78 (along with just about everything else) and in the process, I broke off a bolt in my crank. The guys over on the Dentside forum suggested I pull the crank, have it polished, install new bearings and seals, and button it back up. But I am leaning towards either a new short block, or a rebuild of this one (my MP435 trans and NP205 transfer case are being rebuilt now). Conan helped with a cam choice a while back when I did a head swap for GT40s, and was just looking for some feedback on my rebuild/replace options.
Are any of the crate short blocks I see on eBay or Summit worth considering? Time isn't really a factor, as I am rebuilding the entire front end, so I have no expectations to drive this truck for months, so if you think I should just tear down my engine and go through it, happy to consider that. I see that there are a number of stroker assemblies avialable. Is that a good option? For reference, this is a 1984 block.
Are any of the crate short blocks I see on eBay or Summit worth considering? Time isn't really a factor, as I am rebuilding the entire front end, so I have no expectations to drive this truck for months, so if you think I should just tear down my engine and go through it, happy to consider that. I see that there are a number of stroker assemblies avialable. Is that a good option? For reference, this is a 1984 block.
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Elder User
Joined: Jul 2011
Posts: 609
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From: Stockholm, NJ
This seems relatively inexpensive for a short block
I already have a cam (with less than 500 miles on it) as well as a complete top end. Do I need forged/hyper pistons or aftermarket rods?
I already have a cam (with less than 500 miles on it) as well as a complete top end. Do I need forged/hyper pistons or aftermarket rods?
FTE Legend
Joined: Jun 2006
Posts: 31,930
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From: Ottawa, Ontario
No.. needless expense on a street motor. Does it have good oil pressure? Burn oil? If it's in good shape just extract that broken bolt and put it back in, if it's a little worn then have it rebuilt locally(do it yourself with help from a machine shop). You could do a slight over bore with new pistons and rings and have the rotating assembly gone through to bring it back to spec and reassemble with new bearings, that's all it will need to be a long term reliable motor. These cheap rebuilds often have mismatched parts and the block may be bored to the limits or even sleaved so it's not at all likely you will get a better motor, but if you personally rebuild yours you know what you got.
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Elder User
Joined: Jul 2011
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From: Stockholm, NJ
Thanks Conan. Truck always held good oil pressure, could definitely use a new main seal as it was leaking a bit. So are you suggesting that I (at a minumum) pull the crank and have a machine shop freshen it up. Do I also have to bring them the block or jsut the crank? Of course, now I have to take the front of the engine apart. Ugh...
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FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
I'm of the opinion that if you are going to do anything internal you do it all, because new bearings on a crank or rods that have not been trued is guaranteeing a failure in the near future, and if you're pulling the whole rotating assembly out you may as well bore it and put new pistons and rings in.
But like i said if there is nothing wrong with the motor.. good compression in all holes, no oil consumption and good oil pressure, then save you $$ and just replace the rear main seal and extract that broken bolt.
But like i said if there is nothing wrong with the motor.. good compression in all holes, no oil consumption and good oil pressure, then save you $$ and just replace the rear main seal and extract that broken bolt.
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Thread Starter
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Elder User
Joined: Jul 2011
Posts: 609
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From: Stockholm, NJ
Thanks Conan
Stupid question. Do I have to remove the crank to replace the main seal? If so, I'm assuming I can just put the main bearings back in exactly where they came out of?
Frank
Stupid question. Do I have to remove the crank to replace the main seal? If so, I'm assuming I can just put the main bearings back in exactly where they came out of?
Frank
Lead Driver
Joined: Aug 2003
Posts: 6,305
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From: Boulder Creek, Ca
If familiar w/ the 78 engine as far as up-keep/history; if so, I tend to go with having the engine rebuilt if there were no issues. Having said that, had to replace 302 engine quickly and purchased a crated long block off ebay from rebuild shop out of the Spokane, Washington, w/ core charge and delivered to door for around $1700, this was over 8 years ago, of course the 7 year, 70K warranty had expired when I had to recently replace the cam and lifters, I of the lifters collapsed, couple hundred bucks later the engine is still running strong.
Not making a recommendation, just suggest do some research, could not find a local shop that would offer any kind of a warranty; although, if they do, suggest check on warranty disclaimers.
Not making a recommendation, just suggest do some research, could not find a local shop that would offer any kind of a warranty; although, if they do, suggest check on warranty disclaimers.
FTE Legend
Joined: Jun 2006
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From: Ottawa, Ontario
IIRC the rear main seal is 2 piece so you have to at least remove the rear cap and loosen the rest, but even of you pull all caps off just make sure they go back in the right order, make sure the rear seal joint is not aligned with the cap joint, and torque all cap bolts in sequence and to the recommended torque.
Cargo Master
Joined: May 2007
Posts: 2,071
Likes: 36
From: British Columbia
Broken bolt removal
There's no need to remove the crankshaft to remove the broken piece of bolt. If you are lucky, you can unscrew it using a small hammer and cold chisel, striking it at a shallow angle near the periphery of the bolt piece.
If that doesn't work, buy a couple left hand drills and drill it out. Drill a half inch deep with a smaller drill, then redrill with a bigger one and it will likely jam itself in and unscrew the piece. By drilling no more than 1/2" you are not likely to go through.
If that doesn't work, buy a couple left hand drills and drill it out. Drill a half inch deep with a smaller drill, then redrill with a bigger one and it will likely jam itself in and unscrew the piece. By drilling no more than 1/2" you are not likely to go through.
Thread Starter
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Elder User
Joined: Jul 2011
Posts: 609
Likes: 1
From: Stockholm, NJ
There's no need to remove the crankshaft to remove the broken piece of bolt. If you are lucky, you can unscrew it using a small hammer and cold chisel, striking it at a shallow angle near the periphery of the bolt piece.
If that doesn't work, buy a couple left hand drills and drill it out. Drill a half inch deep with a smaller drill, then redrill with a bigger one and it will likely jam itself in and unscrew the piece. By drilling no more than 1/2" you are not likely to go through.
If that doesn't work, buy a couple left hand drills and drill it out. Drill a half inch deep with a smaller drill, then redrill with a bigger one and it will likely jam itself in and unscrew the piece. By drilling no more than 1/2" you are not likely to go through.
Cargo Master
Joined: May 2007
Posts: 2,071
Likes: 36
From: British Columbia
Left hand drills
I'm not sure where to get the left hand drills in the US, since I am in Canada.
Up here one would have to go to an industrial supply house that sells to machine shops.
Perhaps one of the mail order places like Harbor Freight or Northern Tool would sell them?
Up here one would have to go to an industrial supply house that sells to machine shops.
Perhaps one of the mail order places like Harbor Freight or Northern Tool would sell them?