boring out the block?

[barroom hero]

most likley my engine is gonna need to be rebuilt. when i bought it i was told it was rebuilt ~10k-20k miles ago. took the valve cover off, and found twigs . my dad thinks it was stored outside with the cover off, and he's gonna have is friend thats a mechanic come check it out. if i do have to get the engine rebuilt, will boring the cylnders larger (ive seen pistons in up to .060 over) result in extra power, or just more fuel burnt? thanks for all the help, this is my first car.

 

[Lazy JW]

I don't like the idea of finding twigs inside my engines I would tear the engine down and do a very thorough measurement of everything, such as cylinders, crankshaft, etc. IF it was properly "rebuilt" and IF it was only driven 10-20K then it shouldn't need rebored. You won't notice any significant increase in power or fuel consumption on an otherwise stock engine that was bored .060" over.
Joe

 

[CZLN6]

Howdy Barroom Hero:

Boring, as part of a complete block rebuild, is to make a true sealing surface for the new pistons and rings. True means straight. As an engine wears the cylinders tend to wear in a barrel shape. The process of boring and honing to create a good seal will give an engine it's best performance both in power and economy.

You didn't say what year you are working with, but .060" overbore is the maximum for these engine. Even if you could find larger oversize pistons, at .060" the cylinder walls are getting thin to the point that they are losing their structural integrity and prone to distortion from tightening parts in place, heat cycles and engine pressures. With these engines it is best to overbore only enough to true the cylinder walls. The increase in displacement, by itself, is not enough to notice.

As I said before boring and rebuilding, usually gives more power and economy when compared to a worn-out engine, due to improved seal and efficiency. In your case, where the engine only has 10 - 20k on it, and you suspect that the engine was stored outside with the valve cover off, you may be looking at a situation were you are dealing more with surface rust and dirt accumulation. Depending on the quality of the rebuild and damage from the environment, you may be able to get a good engine with just a good cleanup. Cross your fingers and say a prayer.

Let us know what yur find and enjoy the journey.

Adios, David

 

[barroom hero]

thanks for the help guys. im not sure if the engine has been bored out or not. id like to start dissassembling the engine as soon as i can, so i can get my car running finally , ive had it since august, and with school this has been my first chance to do some real work with the car. what would you guys suggest as a good manual or some sort of guide for rebuilding the engine? i want to do everything right.
thanks for all the help.

 

[CZLN6]

Howdy Back:

Start by posting what year engine and vehicle you are working with. Trans type helps too. Then decide what you're goals for this engine are, both for short and long term.

Start by getting a shop manual for your year and vehicle. Read through all the posts here relating to rebuilds. Then click on the website on my signature for info on the "Falcon Six Performance Handbook".

Adios, David

 

[barroom hero]

thanks for all the help guys. im working on a 67 mustang coupe, and the engine is a 1966? 200 block (the tag under the coil reads 200 66 5, 33-S, and the block is stamped C6DE), and as of now i have a 3 speed tranny, i beleive the 3.03, not sure how to check on that. the engine and tranny are both out of the car.

right now my goal is to get the car on the road, and then im trying to decide if i want to keep the 6 or sell it for soemthign with an 8. to get the performance i want out of my car, i just dont have the money or knowledge to hop up the 6 past basic upgrades . again, thanks for the help.

brian

 

[addo]

Being that you're young, and keen to get the car on the road, it's time to ground a few big ideas. The aim here is to get it running sooner, for less.

UNLESS some basic inspections can reveal that the motor actually needs a rebuild, leave it be. Twigs in the rocker area will eventually "wash" into the oil pan and rot away. No problem. Look for fine metallic glint in the oil, if none, you're OK. Don't even take the head off if you can turn the motor by hand (pop the spark plugs and soak the cylinders with thin oil at least overnight, first). Test the compressions with a gauge; see if you can get close to 100 pounds each. Even substantial anomalies often "bed in" once an engine is running again.

Before the motor goes in, do check the waterpump (99¢ gasket) and replace the thermostat. Check your tranny by pulling the top cover and looking at the gears and oil. Replace the oil and buy/cut a new top gasket. Make sure the engine is not weeping excess oil onto the back of the flywheel. Bolt up the driveline and check the clutch actuation.

All basic stuff, but if you take it this far you've gained practical knowledge that will hold true for a lot of situations. Now it's time to wrestle with the engine and gearbox as you install the driveline (it's easier pre-assembled, for the novice). Do your adjustments, check carb and spark, and it's a goer.

Beats looking at an engineless car and a pile of half-built parts, and wondering when you'll have time to finish it.

Regards, Adam.

 

[CZLN6]

Howdy Back Barroom Hero and All:

The trans is an easy Identify with the engine and trans out of the car. If it's a 3.03", it will have 9 bolts holding the top cover. that's the one you would like. If it's a non-synchro 1st gear, 2.77" it will have 4 bolts holding the cover.

Addo's advice makes good sense. Kinda like a "Bird in the hand".

Doin a good running six is not as expensive as you might think when compared to swapping in a bent 8. Do you're homework before you decide.

Adios, David

 

[barroom hero]

hey guys, merry christmas to those who celebrate it.
David, i checked the tranny, and it is the 3.03", so thats good to know. as of now, i'm not even thinking about if i want to keep the 6 or go with an 8, i just wanna get the car running .
Adam, thanks for the help, i just have one follow up question, when you say to check the compression with a gauge, how do i go about doing this?
thanks for all the help guys.

 

[addo]

Compression gauges can be bought or borrowed. The best type are the ones with a variety of screw-thread adapters on the end of a flexy hose connected to the gauge. One of these adapters will fit your spark plug thread, and there'll be an o-ring type seal as you wind it in.

Get the gauge threaded in tight (hand tight!) and remove all other spark plugs. Now turn the engine over. Junkyards hook up a starter, flywheel and bell, but you can just grab the balancer and turn it clockwise as fast as safely possible. Maybe see if you can turn it with a socket and breaker bar on the balancer. Watch the pressure rise; the gauges have a one-way valve. The gauge will "pump up" over a number of turns to a plateau. That's your pressure reading. Write it down somewhere safe and repeat for the other five.

If all are showing compression (they will even run on 80 pounds happily enough ) then do the install and get it started. Test the compression after running at a variety of motor speeds for half an hour, while the engine is still hot (this is suited to teamwork). You'll likely find they've all jumped some. After a few weeks, repeat this. At that stage, you're at the effective "peak" of its abilities and can safely diagnose any issues. But before this, minor corrosion to bores or valve stems can cause misreading of symptoms.

Regards, Adam.

 

[XFlow_Fairlane]

I just got a 200 that was unknown of condition and after pulling the head I found clean cross hatching and .030" pistons from a very recent rebuild. I am going to get it decked (78 block) to bump it up to 9:1 and a cam then back together it goes and into my car with a t5 behind it.

nick