Crossroads?
#1
09-23-2018, 08:15 AM
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Crossroads?
At a crossroads in what to do with the engine in my truck (1986 F-150 351W HO 4WD). The engine and transmission to my knowledge is all original and has around 140k on it. Currently I have a pretty good leak coming from the front main/front crank seal, whatever you want to call it behind the harmonic balancer. Plus I have a couple of sticky lifters that won’t come loose no what I have tried. Also I have a coolant leak that I just cannot find where it’s coming from.
Knowing that to replace the front seal the timing chain cover will need to come out so I might as well replace the chain with a double non roller and change sprockets as well. While I’m in there, would it be worth putting a different cam and having the valves reworked as well?
Or go full crazy and rebuild the entire engine just for the fact of the unknown life of the engine? I have a set of FloTek 180cc aluminum heads, rockers, Hedman ceramic coated shorty headers just setting in the garage wanting to be used......but all things cost time and money.
Knowing that to replace the front seal the timing chain cover will need to come out so I might as well replace the chain with a double non roller and change sprockets as well. While I’m in there, would it be worth putting a different cam and having the valves reworked as well?
Or go full crazy and rebuild the entire engine just for the fact of the unknown life of the engine? I have a set of FloTek 180cc aluminum heads, rockers, Hedman ceramic coated shorty headers just setting in the garage wanting to be used......but all things cost time and money.
#2
09-23-2018, 12:35 PM
It's up to you. If it sits in the driveway all week and just used for hauling off the trash on the weekends, probably not worth messing with it, use it as is. I can put up with minor leaks, but if it's a puddle, I would repair it. I would not replace the camshaft, not worth it and a lot of work. If all the lifters do is make a ticking noise, and it runs ok otherwise, I would leave them alone also.
If you have big plans for this truck, then by all means pull it and go through the whole thing.
If you have big plans for this truck, then by all means pull it and go through the whole thing.
#3
09-23-2018, 01:40 PM
Franklin hit it on the head.
If you do go for pulling the motor you may want to look into 3 different ways to go to get a 'new" motor.
1 is to get prices to rebuild yours. First is who is going to turn the screws you or the machine shop putting it back together? Some shops will not warranty to motor if they will not put it together.
Look at new pistons, cam & lifter, timing chain & gears, gaskets, bearings. They would need to bore the block for the new pistons, re-size the rods and turn the crank.
I would use your new heads, what you have for rockers & push rods as you may not be able to use your old ones?
That is just to name a few and it adds up fast.
The next would be looking in to a short block that has been machine work done and rebuilt.
Short block is less heads, intake, oil pan, timing cover, valve covers and a few other things you reuse from your motor.
Being less heads you would use your new heads but you would also need rockers & push rods that you may not be able to use from your motor.
The last is a long block. Again it is a rebuilt motor with most of the parts on it, heads, rockers & push rods, oil pan & timing cover, valve covers.
Now you may need to swap oil pans & pump pick up because front & rear sumps. May also need your intake & valve covers but for the most part it is a rebuilt motor.
As you can guess the short block is cheaper than the long block and the long block maybe (most of the time it is) cheaper than rebuilding your motor.
So price out all 3 to see what works best for you.
Dave ----
If you do go for pulling the motor you may want to look into 3 different ways to go to get a 'new" motor.
1 is to get prices to rebuild yours. First is who is going to turn the screws you or the machine shop putting it back together? Some shops will not warranty to motor if they will not put it together.
Look at new pistons, cam & lifter, timing chain & gears, gaskets, bearings. They would need to bore the block for the new pistons, re-size the rods and turn the crank.
I would use your new heads, what you have for rockers & push rods as you may not be able to use your old ones?
That is just to name a few and it adds up fast.
The next would be looking in to a short block that has been machine work done and rebuilt.
Short block is less heads, intake, oil pan, timing cover, valve covers and a few other things you reuse from your motor.
Being less heads you would use your new heads but you would also need rockers & push rods that you may not be able to use from your motor.
The last is a long block. Again it is a rebuilt motor with most of the parts on it, heads, rockers & push rods, oil pan & timing cover, valve covers.
Now you may need to swap oil pans & pump pick up because front & rear sumps. May also need your intake & valve covers but for the most part it is a rebuilt motor.
As you can guess the short block is cheaper than the long block and the long block maybe (most of the time it is) cheaper than rebuilding your motor.
So price out all 3 to see what works best for you.
Dave ----
#4
09-23-2018, 02:59 PM
The engine and transmission to my knowledge is all original and has around 140k on it. Currently I have a pretty good leak coming from the front main/front crank seal, whatever you want to call it behind the harmonic balancer. Plus I have a couple of sticky lifters that won’t come loose no what I have tried. Also I have a coolant leak that I just cannot find where it’s coming from.
140k? Ha, that's just getting broken in!
My '84 351W has about 220k on it and is still going strong. Most of those miles the truck is working hard, too, so it isn't like I'm that little old lady from Pasadena.
As previously mentioned, it all boils down to what you want to do and how much you want to spend getting there.
The timing cover seal is an easy repair. Expect a little grief with the water pump bolts if they've been on there a while, but that's about it. Also expect to find a groove worn where the seal rides on the damper, but you can get a repair sleeve for that, no big deal.
Lifters? Not sure what to suggest there.
Coolant leak? Have you used a pressure tester on the cooling system? Many times a leak is very small and evaporates on a warm engine before you can see it. I've found many leaks with a pressure tester on a cold engine that I couldn't find when warm.
#5
09-23-2018, 03:40 PM
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All very good recommendations, thanks for your replies. Yes this is a truck I do plan on keeping for a long time, and most of the time it is a daily driver between it and the Bronco. I guess I just need to crush some numbers, and come up a good plan if rebuilding is worth it at this time, or just make some repairs (fix leaks) and just keep on rolling. I do know for a fact that the transmission is on its last leg. The 2-3 gear (C6) change is getting worst and now flares up every time it changes no matter how much throttle is being applied. So maybe I should turn more time and attention to the transmission first before it completely decides to crap the bed.
#6
09-23-2018, 04:43 PM
Fleet Mechanic
Do the transmission as well while the engine is out. Yep, it all turns into time and money, but a drivetrain teardown is not something you want to do twice.
#7
09-23-2018, 07:21 PM
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Those shiny new parts deserve a fresh short block. It really does not make sense to put them on a well used engine, even if there may be some miles left in it. Rebuilding your engine is fine, just choose your parts wisely as they must all work together.
Do the transmission as well while the engine is out. Yep, it all turns into time and money, but a drivetrain teardown is not something you want to do twice.
Do the transmission as well while the engine is out. Yep, it all turns into time and money, but a drivetrain teardown is not something you want to do twice.
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