351W HO Project
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Senior User
Joined: Dec 2004
Posts: 171
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From: Va. Beach, VA
351W HO Project
Hi all… I’m a new member, just discovered this site a few days ago and I think it’s great. I’ve been reading the archives the past few days and have learned a lot. I’m about ready to embark on a project and would like some advice from the group on what’s my best way to proceed.
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I have a 1985 full size Bronco with the 351W HO motor in it. The truck has been sitting for 4 years untouched. I need to do something with this truck as it’s getting to be an eyesore in the backyard. I’m thinking of pulling the motor and either rebuilding it or putting in another motor so I can use this truck as a tow vehicle for my boat. The motor has about 200,000 miles on it and before the motor started giving me trouble it ran perfectly, no smoke, no knocking noise and great oil pressure. I had the carb rebuilt about 6 months before all the problems.
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It’s been awhile but I’ll try to describe the series of events that caused me to lay the truck up. The first trouble I started having was that the engine would backfire once in awhile as I was cranking it over, it didn’t do this all the time. Once the motor started it ran fine. One day while I was trying to start the motor it backfired and caused some damage, not only did it destroy the starter but it broke a few teeth off the flywheel. Like a dummy I just put in a new starter and went with it. This worked fine until the starter would hit the deadspot in the flywheel. I’d have to crank the motor past the dead spot with a socket on the balancer and it would start fine. After tearing up many starters this way I decided to replace the flywheel. This solved most of the problem but the motor still occasionally backfired while trying to start it.
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A few days after replacing the flywheel I did something really stupid. The motor had a valve cover oil leak so I decided to fix it. I pulled the valve cover and noticed quite a bit of sludge buildup. Being a dummy I decided to knock all this sludge off the head with a big screwdriver. This worked fine in cleaning off the head however I neglected to cover up the oil passage at the back of the head. I put everything back together and started up the motor, no oil leak anymore so I decided to give it a drive. Everything ran fine until about 15 minutes later when I noticed my oil pressure drop to near zero and the motor started clanking. I pulled off the road and cut the motor off. A visual inspection of the motor didn’t yield any results so I let everything sit for 15 minutes or so and started it back up. The oil pressure came back up to normal and the clanking stopped. I proceeded to drive the truck home with no problems but just as I was pulling in the driveway the oil pressure dropped to zero and the motor started clanking again. I cut it off and let it sit for a while before starting it back up. Again after sitting the oil pressure came up to normal and the clanking went away. I let it sit idling for an hour with no problems but when I got in the truck and revved the motor a few times the oil pressure again went to zero. I cut the motor off and it hasn’t been started since.
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After talking with many mechanics about my problems they all agreed that sludge had fallen into the motor and was clogging up the oil pickup screen. No problem, I’ll drop the oil pan and clean out the sludge. Wrong… after many attempts I realized the oil pan wouldn’t come out of this truck easily. It seems the front axle and 4wd stuff blocks any attempt at removal. It looks like the only way to remove the oil pan is either engine removal or front axle/suspension removal.
This is where I stopped working on this truck and stored it away. I guess the first thing I need to do on this project is to pull the motor and see what needs to be done. Sorry for the long post, I hope I didn’t put any of you to sleep. I wanted to describe all that I could remember about what happened before I jumped into this project. I’m sure that along the way I’ll be running into problems that will require the help of this board. From what I’ve seen on this board so far I feel that with your help I’ll be able to tackle this project without too many headaches. I’m sure you guys will be hearing from me regularly over the next few months.
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Here’s my first few questions…. Where’s the best place on the motor to hook up the chains from the motor lifter? How much of the top end should I remove from the motor before pulling it? Anyone want to take a stab at why my motor was backfiring while I was trying to start it?
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Rob
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com
fficeffice" /><o></o>I have a 1985 full size Bronco with the 351W HO motor in it. The truck has been sitting for 4 years untouched. I need to do something with this truck as it’s getting to be an eyesore in the backyard. I’m thinking of pulling the motor and either rebuilding it or putting in another motor so I can use this truck as a tow vehicle for my boat. The motor has about 200,000 miles on it and before the motor started giving me trouble it ran perfectly, no smoke, no knocking noise and great oil pressure. I had the carb rebuilt about 6 months before all the problems.
<o
></o>It’s been awhile but I’ll try to describe the series of events that caused me to lay the truck up. The first trouble I started having was that the engine would backfire once in awhile as I was cranking it over, it didn’t do this all the time. Once the motor started it ran fine. One day while I was trying to start the motor it backfired and caused some damage, not only did it destroy the starter but it broke a few teeth off the flywheel. Like a dummy I just put in a new starter and went with it. This worked fine until the starter would hit the deadspot in the flywheel. I’d have to crank the motor past the dead spot with a socket on the balancer and it would start fine. After tearing up many starters this way I decided to replace the flywheel. This solved most of the problem but the motor still occasionally backfired while trying to start it.
<o
></o>A few days after replacing the flywheel I did something really stupid. The motor had a valve cover oil leak so I decided to fix it. I pulled the valve cover and noticed quite a bit of sludge buildup. Being a dummy I decided to knock all this sludge off the head with a big screwdriver. This worked fine in cleaning off the head however I neglected to cover up the oil passage at the back of the head. I put everything back together and started up the motor, no oil leak anymore so I decided to give it a drive. Everything ran fine until about 15 minutes later when I noticed my oil pressure drop to near zero and the motor started clanking. I pulled off the road and cut the motor off. A visual inspection of the motor didn’t yield any results so I let everything sit for 15 minutes or so and started it back up. The oil pressure came back up to normal and the clanking stopped. I proceeded to drive the truck home with no problems but just as I was pulling in the driveway the oil pressure dropped to zero and the motor started clanking again. I cut it off and let it sit for a while before starting it back up. Again after sitting the oil pressure came up to normal and the clanking went away. I let it sit idling for an hour with no problems but when I got in the truck and revved the motor a few times the oil pressure again went to zero. I cut the motor off and it hasn’t been started since.
<o
></o>After talking with many mechanics about my problems they all agreed that sludge had fallen into the motor and was clogging up the oil pickup screen. No problem, I’ll drop the oil pan and clean out the sludge. Wrong… after many attempts I realized the oil pan wouldn’t come out of this truck easily. It seems the front axle and 4wd stuff blocks any attempt at removal. It looks like the only way to remove the oil pan is either engine removal or front axle/suspension removal.
This is where I stopped working on this truck and stored it away. I guess the first thing I need to do on this project is to pull the motor and see what needs to be done. Sorry for the long post, I hope I didn’t put any of you to sleep. I wanted to describe all that I could remember about what happened before I jumped into this project. I’m sure that along the way I’ll be running into problems that will require the help of this board. From what I’ve seen on this board so far I feel that with your help I’ll be able to tackle this project without too many headaches. I’m sure you guys will be hearing from me regularly over the next few months.
<o
></o>Here’s my first few questions…. Where’s the best place on the motor to hook up the chains from the motor lifter? How much of the top end should I remove from the motor before pulling it? Anyone want to take a stab at why my motor was backfiring while I was trying to start it?
<o
></o>Rob
Postmaster
Joined: Jun 2001
Posts: 4,496
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To pull the engine, I usually hook a chain to the front accessory bolt and the back tranny bellhousing bolt...you could also buy a plate that bolts to the intake to pull it....I wouldn't remove anything to pull it. If you do use the bolt method be sure the chain is close to the block, otherwise you'll be fixing a broken bolt.
Backfiring = improper timing, choke not properly adjusted, air (vacuum) leak.
If it ran before the carb rebuild then my guess, someone did something wrong either rebuilding the carb or upon reinstallation.
The low oil psi probably is associated with a clogged oil pickup screen, since your dropping material into the engine was followed by this condition.
You have to unbolt the engine and tranny, then raise the engine slightly, to get the oil pan off/unbolt pickup tube.
FWIW, if you get the urge to go with an aftermarket intake and carb, you may wanna reconsider. I noticed nothing changing my intake to a performer and going with a 600 cfm edelbrock. I recently found data that supports my experience, aparently the edelbrock performer intake has a simillar design as the stock unit...so if you were stuck with one of the HO engines with a cast intake then the only benefit would be weight but is that really a concern in a heavy truck??
Good luck
Backfiring = improper timing, choke not properly adjusted, air (vacuum) leak.
If it ran before the carb rebuild then my guess, someone did something wrong either rebuilding the carb or upon reinstallation.
The low oil psi probably is associated with a clogged oil pickup screen, since your dropping material into the engine was followed by this condition.
You have to unbolt the engine and tranny, then raise the engine slightly, to get the oil pan off/unbolt pickup tube.
FWIW, if you get the urge to go with an aftermarket intake and carb, you may wanna reconsider. I noticed nothing changing my intake to a performer and going with a 600 cfm edelbrock. I recently found data that supports my experience, aparently the edelbrock performer intake has a simillar design as the stock unit...so if you were stuck with one of the HO engines with a cast intake then the only benefit would be weight but is that really a concern in a heavy truck??
Good luck
Last edited by jwtaylor; Dec 28, 2004 at 10:40 AM.
Thread Starter
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Senior User
Joined: Dec 2004
Posts: 171
Likes: 0
From: Va. Beach, VA
Thanks for the reply. I ‘m really not planning to make any changes from stock to the motor. I drove this truck for 10 years everyday and it always had plenty of power for what I needed. I had the carb rebuilt at a Ford dealer so I’m assuming they did it right. It’s been so long that I really can’t remember why the carb needed to be rebuilt. I’ll probably rebuild it again since it’s been sitting so long.
I’ve never rebuilt a motor on my own. Years ago I had a 69 convertible Mustang that I pulled/reinstalled the motor but a friend rebuilt the motor for me. Yesterday I ordered the book by Tom Monroe “How to rebuild small block Ford engines”. I’m hoping that it’s a decent book that will help guide me through this process. If anyone has read this book did you find anything that he says to do that you didn’t agree with?
I’ve never rebuilt a motor on my own. Years ago I had a 69 convertible Mustang that I pulled/reinstalled the motor but a friend rebuilt the motor for me. Yesterday I ordered the book by Tom Monroe “How to rebuild small block Ford engines”. I’m hoping that it’s a decent book that will help guide me through this process. If anyone has read this book did you find anything that he says to do that you didn’t agree with?
