ford 300 rebuild questions
#1
ford 300 rebuild questions
i just picked up a rebuilt 300 for 75 bucks. the motor was never ran and sat outside. i was told the block was brand new. are the rod and main bolts reusable? im looking to spin this motor to 6500 rpm. im trying to avoid spending a ton of money on machine work. there was some rust on the cylinder walls, will i be able to just hone it out? it isnt really heavy rust. will the stock main bolts be able to handle about 3-400 hp?
#2
#4
What harte and Fordman said.
I have used stock main bolts for that level of build. I have also experienced broken main caps on a couple of engines. To get to that level of performance spending a ton of money on machine work is mandatory, as is obtaining a slew of custom and aftermarket parts.
Just curious, what are your plans for the engine / vehicle?
I have used stock main bolts for that level of build. I have also experienced broken main caps on a couple of engines. To get to that level of performance spending a ton of money on machine work is mandatory, as is obtaining a slew of custom and aftermarket parts.
Just curious, what are your plans for the engine / vehicle?
#5
my plan is to use it in my truck just to do something different than a v8. i am also going to be experimenting with casting my own heads for it so i want strong bottom end so i dont have to worry about it blowing apart. one more queestion, if i switch to arp rod bolts how far out of round do they need to be before honing the big end is required.
#6
Here is one of the first steps in building a reliable high rpm short block.
If you are going to run 6000+ rpm it will be very important to lighten the piston and use the stronger 1965-1968 rods that do not have the oil spit hole in the big end as shown on the left.
The 1965-1968 240 rod (Forging number C5AE found on the lower rod beam) is 6.80" long versus the 300 rod at 6.21".
If you use the 240 rod on the 300 crank you can reduce the piston and pin weight at least 30%
The stock piston and pin on the right weigh a total of 819 grams.
The Autotec piston and pin on the left made for the 240 rod weighs 574 grams.
The early rods use a .912" diameter pin while the later rods use the .975" pin
The rod beams have the forging lines ground off the sides and are polished and shot peened.
Then they are resized for the same center to center length while being fitted with ARP bolts.
The centers on this set of six from different engines had a .004" difference in center to center length.
Are you looking at casting a high port "U" head like the stock configuration or a crossflow head?
If you are going to run 6000+ rpm it will be very important to lighten the piston and use the stronger 1965-1968 rods that do not have the oil spit hole in the big end as shown on the left.
The 1965-1968 240 rod (Forging number C5AE found on the lower rod beam) is 6.80" long versus the 300 rod at 6.21".
If you use the 240 rod on the 300 crank you can reduce the piston and pin weight at least 30%
The stock piston and pin on the right weigh a total of 819 grams.
The Autotec piston and pin on the left made for the 240 rod weighs 574 grams.
The early rods use a .912" diameter pin while the later rods use the .975" pin
The rod beams have the forging lines ground off the sides and are polished and shot peened.
Then they are resized for the same center to center length while being fitted with ARP bolts.
The centers on this set of six from different engines had a .004" difference in center to center length.
Are you looking at casting a high port "U" head like the stock configuration or a crossflow head?
#7
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#8
There have been examples of 5500 rpm for short periods of time with stock 300 parts.
It is recommended using Hypereutectic replacement pistons rather than the standard cast pistons.
The standard cast pistons have a tendency to break the bottom of the skirt off into the oil pan.
In order to make power at 5500 rpm requires a fully ported, big valve head.
What are your plans for the stock head?
What year is this engine?
It is recommended using Hypereutectic replacement pistons rather than the standard cast pistons.
The standard cast pistons have a tendency to break the bottom of the skirt off into the oil pan.
In order to make power at 5500 rpm requires a fully ported, big valve head.
What are your plans for the stock head?
What year is this engine?
#9
#11
1.) Standard cast pistons are not reliable for any build and are at risk for broken skirts as previously mentioned. Use Hypereutectic cast pistons.
2.) It is always a good practice to replace used connecting rod bolts. Resize the rods with ARP bolts.
Then I would be confident with 5000 rpm shift points.
When you go to a crossflow head that flows better than 300 cfm, peak power will be above 6000 rpm using a good street/strip cam profile.
You will need a different bottom end to handle it. The 240 connecting rod and custom forged 4032 alloy piston combination as previously mentioned is the most economical combination.
Also consider that the crossflow head and cam combination will need a higher compression ratio and depending on your design may also require valve reliefs in the piston meaning that you will need a different piston anyway.
#13
Still good.
But I would gently scrape them around the scratches to eliminate any proud-standing metal with a razor knife.
Those look like the old style copper/babbit bearings. Did you get them online? Most all newer bearings are aluminum surfaced.
Copper / lead babbit is better for dirt imbedability and aluminum holds up better to higher loading.
Don't little little quality issues like that annoy you? It sure does me.
But I would gently scrape them around the scratches to eliminate any proud-standing metal with a razor knife.
Those look like the old style copper/babbit bearings. Did you get them online? Most all newer bearings are aluminum surfaced.
Copper / lead babbit is better for dirt imbedability and aluminum holds up better to higher loading.
Don't little little quality issues like that annoy you? It sure does me.