1986 Bronco XLT street build...

[Emelio]

Hello Gentlemen,
Trying to decide what to do next on my Bronco project; your advice would be greatly appreciated. A while ago I performed a "leak down test on the 351W, 5.8L engine that my Bronco came with and cyl.7 and 8 looked weak showing about 44% leak. I did an oil change and installed a new filter and yesterday I run a "cold" compression test on all the cylinders; the results were as follows:
Cyl 1...158 psi
Cyl.2 ...165
Cyl,3....125
Cyl.4....170
Cyl.5.....170
Cyl.6...135
Cyl.7..130
Cyl.8...41
Three cylinders being less than 75% of the strongest ,number #8 being the weakest...
What bothers me was the fact that spark plug on # 8 was rusty ;the guy who sold the truck had it parked for the last 12 years. When I drained the oil, first it came out about 1qt of water then the oil.
At this point most likely I need the engine rebuild. Does someone have recommendations as to the quality parts (intake, exhaust headers, pistons, timing chain... etc)I must change , what should I keep and what should I get rid of in order to make this truck for street configuration?
I know that I ask many questions but I really need guidance to get the job correctly done ...

Thank you!

Vic

 

[Tiha]

If you are not looking for huge horse power and just a nice daily driver what about a used engine?

Or a factory reman?

Gotta say I did a SBC a couple years ago and the parts quality seems horrible compared to 20 years ago. I am not sure who I would recommend, hopefully someone else has some good input.

 

[Emelio]

If you are not looking for huge horse power and just a nice daily driver what about a used engine?

Or a factory reman?

Gotta say I did a SBC a couple years ago and the parts quality seems horrible compared to 20 years ago. I am not sure who I would recommend, hopefully someone else has some good input.

Thanks Tiha,
No need of huge horse power, just a nice daily driver having parts that will keep the engine running for a long time. Whoever started looking into this truck before has removed some smog components, the EGR valve, etc . and messed with the electrical circuits. I fixed the electrical though and now everything works as supposed to. I do not need the smog components back . The carburetor was stock but in bad shape so I bought an Edelbrock 1906 AVS2 carb to replace it. Also I got a new Weiand 8023 WND Stealth intake, water pump, fuel pump distributor etc. Mostly interested to know about the internals for the rebuilt since, as you say , parts are not as they used to be 20 years ago... Hard to find 351W blocks around ;the engine currently installed in my truck has .040 overbore cylinders, but I'll look around hopefully finding a stock one . It seems like this project will be taking longer than I thought but I'm not in a rush to complete it in a certain time window...
Thanks again.

Vic

 

[Tiha]

There was another thread about purchasing reman engines.

If yours is already 40 over I would worry about being able to bore it far enough to fix the cylinders. But then you never know what you got until you get the heads off and measure.

A local machine shop can help you a lot with parts too. I am very disappointed in my local shops, they think everyone wants a race motor.

 

[Emelio]

There was another thread about purchasing reman engines.

If yours is already 40 over I would worry about being able to bore it far enough to fix the cylinders. But then you never know what you got until you get the heads off and measure.

A local machine shop can help you a lot with parts too. I am very disappointed in my local shops, they think everyone wants a race motor.

Thanks for additional info Tiha, I'll check for the thread and also locally with machine shops; they're a few of them around where I live..

Best,

Vic

 

[goodO1boydws]

Hello Gentlemen,
Trying to decide what to do next on my Bronco project; your advice would be greatly appreciated. A while ago I performed a "leak down test on the 351W, 5.8L engine that my Bronco came with and cyl.7 and 8 looked weak showing about 44% leak. I did an oil change and installed a new filter and yesterday I run a "cold" compression test on all the cylinders; the results were as follows:
Cyl 1...158 psi
Cyl.2 ...165
Cyl,3....125
Cyl.4....170
Cyl.5.....170
Cyl.6...135
Cyl.7..130
Cyl.8...41
Three cylinders being less than 75% of the strongest ,number #8 being the weakest...
What bothers me was the fact that spark plug on # 8 was rusty ;the guy who sold the truck had it parked for the last 12 years. When I drained the oil, first it came out about 1qt of water then the oil.
At this point most likely I need the engine rebuild. Does someone have recommendations as to the quality parts (intake, exhaust headers, pistons, timing chain... etc)I must change , what should I keep and what should I get rid of in order to make this truck for street configuration?
I know that I ask many questions but I really need guidance to get the job correctly done ...

Thank you!

Vic

From those comp and leak down numbers my guess is that you have at least 2 valves either just sticky and/or not sealing well (3 & 8) and may have a head gasket leak directly between 6 & 7-or those 2 cylinders also have poorly-sealing and/or sticky valves that coincidentally are sealing similarly poorly.

(2 adjacent cylinders that have significantly low and identical readings is typical of a head gasket leak between them.)

If ALL the problems are in the heads with valves simply not sealing well because the engine has been sitting too long, the engine may not need a lot of work to get it running reasonably.

Especially if you''re able to do it yourself, just taking the heads off and dissembling the parts, cleaning them up, inspecting them to determine if they have significant wear or rust OR NOT, then hand lapping the valves and installing new seals might possibly be enough. (Mini-miracles do happen.)

On the other hand, if the coolant is non-existant (or totally exhausted) there can be a LOT of rust to the machined head gasket surfaces of the block and heads, and having much rust THERE tends to require remachining because it can create roughness with spaces big enough that air or liquid may be able to flow.

If a head gasket leak is between a water jacket and a cylinder, coolant would leak into that cylinder and eventually end up in the oil pan by passing through the ring clearances. If the coolant gets high enough in a cylinder, in some cases it can reach and rust a spark plug before it drains into the crankcase.

You may have/have had BOTH condensation AND a coolant leak.

Having a lot of WATER in the crankcase of a vehicle that's been sitting that long is to be expected-from condensation, and it almost always comes out CLEAR and first from an oily pan and continues for a while before you start to see any oil coming out, because the oil floats on it. You MAY be able to SEE or SMELL if its ONLY that or if there's antifreeze (rusty or not) mixed in with the condensate-if there's still a reasonably strong % of coolant mix in the radiator or reservoir to compare.

CONSCIENTIOUS farmers with tractors and other equipment that sometimes sat for months outside used to partly unscrew the engine oil pan drain plug, (and the transmission, and the rear end, and the hydraulics reservoir too if any of those had low enough drain plugs) and let the water drain out until oil just began to drip, as a matter of routine, before tightening the plugs and starting the engines.

 

[Emelio]

Thank you for the posted info. Indeed it's a good suggestion to open and inspect engine internals before setting for a reman engine . Last year I drained the coolant, was not left too much of it not even two gallons , mostly came from the engine block. It was discolored and not notice any traces of oil in it or coolant in the drained oil. I must pull the engine and inspect.
Did not know about the farmer's trick. Every day I learn something new...
Thanks again!

 

[Emelio]

Just pulled a F4TE 5.8L engine from a '95 F-250 at the local junk yard just in case I need to swap the existing engine...I plan to have it rebuilt. It took me 5 hours to pull it out but the price was right and it was also fun, less handling the engine hoist by myself...

 

[goodO1boydws]

Just pulled a F4TE 5.8L engine from a '95 F-250 at the local junk yard for $230 just in case I need to swap the existing engine...I plan to have it rebuilt. It took me 5 hours but the price was right and it was fun, less handling the engine hoist by myself...

I know the F4TE is a roller rocker engine, but I don't remember you saying-what year is your Bronc?

 

[Emelio]

I know the F4TE is a roller rocker engine, but I don't remember you saying-what year is your Bronc?

it's an '86 XLT...I plan to use the '95 engine block...Most likely the cylinders' bore which are .040 on the '86 engine, will need to be .060 overbore and I do not want to push it that far even if for street drive it is ok I think...

 

[Jimbo26]

Hello Gentlemen,
Trying to decide what to do next on my Bronco project; your advice would be greatly appreciated. A while ago I performed a "leak down test on the 351W, 5.8L engine that my Bronco came with and cyl.7 and 8 looked weak showing about 44% leak. I did an oil change and installed a new filter and yesterday I run a "cold" compression test on all the cylinders; the results were as follows:
Cyl 1...158 psi
Cyl.2 ...165
Cyl,3....125
Cyl.4....170
Cyl.5.....170
Cyl.6...135
Cyl.7..130
Cyl.8...41
.......

This is beginning to sound somewhat familiar