250 project

[bigblue91]

bought a 250 as a project for when the weather gets better. been rebuilding a 305 in automotive during my 1st semester in school so i have a little basic knowledge on rebuilding.
the maverick the 250 was pulled from read 68,000 miles and the interior showed almost no use so I believe the miles.
the engine ran fine a few years ago when it was pulled, the owner said. i have a few questions though?
what should i expect internally to be replacing in this 250 with the miles it has? should the cam, lifters,valves,rocker arms, etc be fine?
i want to try and get by without any machining or taking the engine to a shop,
if i get a hone and ridge reamer and use them do i just get stock piston rings as a replacement or do i need oversized?

im going to pull the carb off here soon? is there any websites i could type in information and find a rebuild kit for the carb for a 75' maverick 250? its the original carburetor, im assuming as everything else on it is unaltered.

i plan to keep the build stock and don't want a race engine but is there anything you guys recommend do during a rebuild to help boost performance? it came with the duraspark ignition system and i want to rebuild and reuse the 1 barrel carburetor.

also any tips for a a first time carb rebuild, i plan to do that first?

any advice/tips would be appreciated.

thanks
bigblue

 

[Bayrunner]

Big blue, If the motor had only 68K miles on it. And you are sure of this. You also are not going to put any HP parts, as I understand; why rebuild it? At most, pull the head, look at the cylinder walls, then you will know if it only has 68K on it. It costs you a head gasket only.

Just my thought!

 

[bigblue91]

im figuring if and when i put it in a car. i would rather have a fresh engine then an engine with 68,000 miles on it that could have been rebuilt.

 

[JackFish]

If you've never used a ridge reamer be aware that it's very easy to put the cylinder out-of-round.
At 68k it may not be necessary anyways. That's hardly broken in.

If you do pull the head it might be necessary to have it shaved to compensate for the thicker head gasket that you'll have to use for a replacement.

 

[JackFish]

It costs you a head gasket only.

Just my thought!

Plus shaving the head because a thin steel gasket is no longer available.

 

[wallaka]

68k shouldn't need a ridge reamer, just a hone. If the engine is pulled anyhow, might as well freshen up the bottom end. Either buy a rebuild kit or piece it together on ebay like I did--much cheaper that way. I rebuilt the motor for less than $250. New rings, new gaskets and rod and crank bearings. Cam bearings were fine, but I had spun a rod bearing and the crank bearings were worn. Got the crank turned .10/.10 under and bought bearings to match, and honed the cylinders. Disassembled and cleaned the lifters. I cleaned the top end good, but nothing needed replacing.

It's a good idea to mill the head while you're at it to bring the compression up a bit. That and a 3-angle valve job and a backcut on the valves can be done for $200 or so as well, maybe cheaper. I don't know if you're going to put a cam in or not, but the motor is begging for a mild cam, something like a Clay Smith 264/264 will net you a little power and economy to boot. Classic Inlines has a kit with the cam, bearings, lifters and a timing chain set for $250.

 

[bigblue91]

I don't know if you're going to put a cam in or not, but the motor is begging for a mild cam, something like a Clay Smith 264/264 will net you a little power and economy to boot. Classic Inlines has a kit with the cam, bearings, lifters and a timing chain set for $250.

that sounds like a good deal and idea, thanks


jackfish
about the gasket and shaving the head, what exactly will i have to do, why don't they make the old style thin gasket anymore?

i would like to get by without ridge reaming since that would be new to me. I'm no expert on rebuilds though, if I replace my piston rings and all i did was hone the walls do i oversize .020 or .030, go stock or what?

also if and when is the ridge reamer necessary, is there a particular ridging to look for or is any ridge visible mean i need to use one?

thanks for the tips guys

 

[69.5Mav]

im going to pull the carb off here soon? Is there any websites I could type in information and find a rebuild kit

Big Blue

For about 4 to 5 times the cost of a rebuild kit you could buy a Holley/Weber 5200 and an adapter (around $125) form Langdon’s stovebolt. It's a much better carb and a two progressive barrel so it will improve your economy, drivability as well as give you an extra 5 HP with the adapter. I f you are planning to remove the head you could have it direct mounted and pick up 25 HP instead.

The carb on your mav engine is 35 years old at best. You can buy the Holley/Weber 5200 brand new from Langdon but you might have to wait for it. I have two of these on my 170 I6 mavericks and they both worked right out of the box.

 

[bigblue91]

im going to pull the carb off here soon? Is there any websites I could type in information and find a rebuild kit

Big Blue

For about 4 to 5 times the cost of a rebuild kit you could buy a Holley/Weber 5200 and an adapter (around $125) form Langdon’s stovebolt. It's a much better carb and a two progressive barrel so it will improve your economy, drivability as well as give you an extra 5 HP with the adapter. I f you are planning to remove the head you could have it direct mounted and pick up 25 HP instead.

The carb on your mav engine is 35 years old at best. You can buy the Holley/Weber 5200 brand new from Langdon but you might have to wait for it. I have two of these on my 170 I6 mavericks and they both worked right out of the box.

do you have a link for that carb/adapter. im interested in that idea.

i don't like to waste things though so i probably will still rebuild the carb that came with it, I'm needing one soon for my 77 Mav, bought a cheap 1 barrel from autozone for it 2 years ago and has never ran right. I may rebuild the original off the 250 and put it on the 77'

 

[jahearne]

I agree with everyone else. At 68k that motor still has plenty of life in it if the oil has been changed a few times. Pull the head to inspect the cylinder walls, no ridge or score marks, you're good to go and I probably wouldn't pull the pistons especially if the inside of the valve cover is fairly clean. I've seen low mileage engines with tons of gunk caked on the inside of valve cover and have to wonder if the oil was ever changed at all. Run your finger nail up the side of the cylinder wall and if it catches you need a ridge reamer and if you need ridge reamer you may need to machine the walls to accept new pistons. Your finger nail can catch on built up carbon, so make sure it's cleaned off. But at 68k, I seriously doubt any ridge at all. I use a wire wheel on drill to clean the carbon off the tops of pistons and combustion chamber. Cover the lifters so dirt don't get inside the block. Clean out between the cylinder wall, piston and first ring real well. Rotate the motor as the piston goes down it will leave dirt behind clean up with WD-40 and good rags. Ambitious? pull a main cap, how do the bearings look? Any gouges? If one looks good, I'm sure they all are. Do not mix them up. Be absolutely sure to replace main/rod caps exactly the same way they were removed. They will have marks on them to identify their orientation. Identify those before you disassemble. While you're at it replace rod bolts with ARP bolts from Classicinlines. Replace the timing chain & gears, oil pump and rear main seal as good insurance at minimum replace the timing chain. Actually, purchase 1969 timing set because the later years are for smogged motors. If you don't need a ridge reamer and still feel the need to replace the rings use a cylinder hone soaking it good with WD-40 as you work it up and down the cylinder wall a couple times. Careful when using a brand new cylinder hone as they can have a pretty good bite when new. Replace the rings with a new set of standard rings. If the motor was previously rebuilt, which I doubt, the pistons will be stamped with .10 or .30, etc. then you'll need rings to match. Be absolutely sure that the ring grooves in the pistons are real clean. What else... if everything looks okay this far, I'm sure the cam & bearings, lifters and rockers are fine. Pull the lifters and look for scuffs and cupping. Be sure to keep them in order as each lifter has broken-in to it's corresponding cam lobe. Clean the rockers real well; there's a small oil hole. A good cam to go with is a dual pattern 264/274 from Classicinlines as well; it helps out the exhaust side of things. Replace the cam, replace the lifters; never use old lifters on a new cam! Lap the valves if you don't take it in for a professional valve job. Replace the valve guide seals; they will come with engine gasket kit, give them to your machinist if you go that route - three angle and back cut is real nice especially with that cam and a header. Of course if you don't take it to a machinist you'll lose compression like everyone else said. Direct mount 2bbl is a great upgrade and definitely worth thinking about if the head is going to a machine shop. Oh, and a port divider.

At most this motor should need is a general overhaul, timing set, oil pump, rings, gaskets and valve job. If oil changed regularly, can get away with timing set, gaskets and valve job and be done with it saving your money for ARP rod bolts, 3 angle and a cam maybe a 2bbl, header & exhuast, too. The 264/274 cam and 3angle valve job will work great in a stock 1 bbl motor, but I probably wouldn't do a direct mount 2bbl without a header and exhaust system, which can add to up $$ real fast. Not saying you can't but most performance upgrades work well as a package and stock exhaust sufficates a performance engine even a mild one.

Well, I've said enough. Have fun,

 

[bigblue91]

good information to take in consideration and the exact info i needed.

 

[69.5Mav]

do you have a link for that carb/adapter.

Main Stite (Home Page)

http://www.stoveboltengineco.com/

Carb $75

http://www.stoveboltengineco.com/acartp ... ductid=178

Adapter $15

http://www.stoveboltengineco.com/acartp ... ductid=174

Air Cleaner $30

http://www.stoveboltengineco.com/acartp ... ductid=175

Total $120 + shipping + misc.


I would;
dirrect mount the carb
three angle valve job with a back cut on the valves
shave the head to get the compression ratio to 9-9.5 to 1
put in a dual pattern cam 264/274
replace oil pump timing chain rear main seal and arp rod bolts rod bearings and maybe the main bearings
get a free flowing exhaust with a flowmaster hush power 2

I would not;
get a header unless I was racing it
replace the rings/pistons unless they needed it

 

[bigblue91]

:thanks:

 

[jahearne]

Check out what David, coauthor of Falcon Performance Hanbook, (have you got your's yet?) has to say about pistons in a 250, which we should seriously consider even for a mild performance 250: viewtopic.php?f=1&t=60043

I'm in the process of installing a 250 and AOD in my Ranchero and can't leave anything alone yet stock even though I too have a low mileage motor.

2bbl adapters from Classicinlines. http://classicinlines.com/products.asp?cat=46

 

[CZLN6]

Howdy Big Blue:

Wow! You've got lots of good advice. I was wondering whether this car has an auto or manual trans? The stock OEM carb should be a Carter RBS one barrel. It is a very good, easy to rebuild, and very low profile carb. It was used exclusively on the 250s because of hood clearance. Anything else you use with a 250 in a Maverick will create hood clearance issues.

About the only thing I seen at 68k is a worn eccentric on the cam that actuates the fuel pump. Symptoms are it acts like it is running out of gas when it gets hot. You will change the fuel pump thinking that's what it is, and sometimes it is, but if a new fuel pump doesn't fix it, it's likely the eccentric on the cam that has gone flat, or at least, flatter. Fixing it requires a new cam or installing a pressure switched electric fuel pump. Pulling the head will give you a good insight into the condition of the engine. So long as the head is off and you'll have to invest in a valve job gasket set, doing a performance valve job is a good investment for a daily driver Maverick 250.

I had a '72 with a C4. My kid's drove it through high school. They lived through several fender-bender accidents/character-building opportunities in it. We called it Myrtle- after an old Norske aunt. Like her, it wasn't too pretty, but it was hell for stout. When we went to look at it my daughter flipped her hair and declared it ugly. That convince me that it was perfect. When her clique was going somewhere, Myrtle was never the 1st choice of cool cars to ride in, but it was, sometimes, the only choice. We still talk about it and now my kids are thinking about a "Myrtle" for their kids to learn in. Enjoy!

Adios, David

 

[bigblue91]

heck i would of drove myrtle, lol. no this motor isn't destined for anything really. I might put it in my maverick when her 6 needs a rebuild but i don't think it will be anytime soon.
i just want a good motor for when i plan a swap or find an old body that i can throw a good motor in.
ive read the maverick forum tech articles and have heard about the hood clearance problems when the offy triple carb and 2 barrel carbs (which is why i never put it on my mavericks engine) are used so i was really just wanting to rebuild the original carb.

yea there's been great information which I needed. to answer your tranny question i dont know what the original mav had or what I plan to put it in (though my mav is a 3 speed automatic)

ive been hoping to find a fairly cheap 2 door mav to fix up, the 4 door isn't my (or anyones) taste really but i couldn't pass at the price and condition of it. hopefully i can find an old 2 door one day and put this 250 i plan to rebuild in it.

bigblue

 

[early ford fan]

Howdy Big Blue:

Wow! You've got lots of good advice. I was wondering whether this car has an auto or manual trans? The stock OEM carb should be a Carter RBS one barrel. It is a very good, easy to rebuild, and very low profile carb. It was used exclusively on the 250s because of hood clearance. Anything else you use with a 250 in a Maverick will create hood clearance issues.

i also have a 250 from a 75 maverick.it came with a carter yp.so thats not stock?

 

[CZLN6]

Howdy:

EFF- I'm not familiar with a Carter YP. Do you mean a YF? The RBS was used on all 250s from 1970 until somewhere in the mid 70s. It was replaced by a Carter YF during the 1975 production year. YFs were used on 250 until 1979, for sure, and then replaced by a version of the Holley #1946. So a '75 250 could have had a Carter RBS or a YF. I believe that the YF from a 250 was rated at 193 CFM compared to 215 for the RBS. Personally, I prefer the RBS because of a few more CFM, a lower profile, and a very simple carb to work on.

Adios, David

 

[bigblue91]

how will i know the difference, any #'s or something to spot?

 

[chad]

how will i know the difference, any #'s or something to spot?

Yes, look on the pass side (write down the info...I know it's cold out, I just did it for my carb rebuild). Look on the driver's side, write that down too. Do a google search w/the info. I got a 'exploded view' of my 40 yr old carb!!!
Have fun, let us know...(ask THEM the q's - I new to this).