I am building my first engine and would like to build a 347 stroker. The engine is out of my 89 f150 4x4. Upon teardown, I found that it has already been bored .030" over and the mains and rods are .010 under. The cylinders show very little wear except for one decent sized scratch. The main and rod bearings all show quite a bit of wear, which leads me to believe something got in the oil or it was assembled badly. Is it possible to bore it to .040 or .060 and stroke it without running into overheating or durability issues?

Thanks

 

Yes, espescially .040. It will have a tendency to run a tad hotter,and it will depend a lot on what kind of compression ratio you wind up with. Did it run cool before?

 

Your gonna find that many of the stroker kits aren't offered with pistons that are over .030. Your going to be very limited in what compression you want to run.

 

How many miles are on the enigne? I always say this... find a reputable machine shop to work with. If the motor has under 100k miles on it you might only need a hone job on the cylinders, depends on how bad the scratch is.

Try Coast High Performance or Summit Racing. I think they offer kits that are .030 over for strokers. I know for a fact if you have 5.4 rods and stroker crank you can get pistons from KB that are .030 over, and I am sure speed pro has them too.

Since you are trashing the crank the main wear should not be a problem.
You can always sleeve the block, but that will cost money. You may be able to get another block from a u pick it u pull it place for far less than a sleeve job, but one cylinder is not usually that bad.

You will also have to cut notched in all the cylinder walls to clear the rotating assembly, which you might want to leave to the machine shop.

 

I have done some more searching and found a kit by eagle specialty products with pistons and rings for a 4.040" bore from summit. The engine has around 180,000 miles on it and has always ran plenty cool. I do not think I will be able to get away with a hone job, as the scratch is fairly deep. Do you think there will be any problems if I go with a .040 overbore?

Thanks for your suggestions so far.

 

While I was away I found two on Ebay ; T&l Engine and Go fast stuff both offer .040's for their kits but be aware that you will be looking at high CR (depending on heads) with these pistons.

 

.040 to .060 you will be fine..... all these people telling you it going to run hot..... why?

 

Is there any advantage to only going to .040, or should I just punch it out to .060?

 

only go as much as you need to....

 

Well, I tried honing it today with little success, so it looks like i'll be boring it .040 over.

 

get it to a machine shop and have them measure it, clean it, install cam bearing, bore it if need be, and install the new pistons on the rods....

 

On all the thin wall casting Ford bocks you should only bore the minimum to clean up the bore. I would have the machine shop sonic test to make sure there was no "core shift" in the original casting which can cause problems with areas in the bore that are too thin. -- Chuck

 

i bet you will find that you will have to go 060....010 isn't much and barely more than a hone.

 

I went ahead and ran a couple of figures for compression ratio, and as long as you stay above 60cc heads, and are at .040, your compression shouldn't be that bad, but it will be around 10:1.

 

I agree with Chuck. You gotta get a good machine shop on board to tell you what you should do. I personally hate building up stock blocks punched out more than .30 over and putting any kind of money into them like stroker cranks, aftermarket rods or fancy heads. You chances of failure due to a cracked bore got up a lot with each .010. You are not working with a siamese bore race block that is made for that sort of thing.

Stroker kits cost a 1K. Machine shop work is ususally another 1K, without the additional work to notch the bottoms of the bores for the stroker.

I'd do the notching myself, not everybody building a stoker does.

A new block is like five hindred bux or less. Is is really worth risking a failure due to a cracked bore?

Something like that happens you could walk away with a damaged piston and rod, or worse the whole bottom end is a total.

Worse some Chebby guy pulling a U-turn to laugh at you once the smoke clears and the other motorists realize the loud boom wasn't an IED!