machining

[88ranger5.0]

does anyone have an idea about the cost of machining my block.. im looking to bore and maybe have the crank turned.. just a ball park for what it might cost. trying to get the final answers before the build takes off.. im looking at .030 or maybe .040 overbore. i have some really nice flat tops that are .040 over..

 

[Psychopete]

Give your machine shop a call.

 

[88ranger5.0]

i havent found one in my area yet, i live in a pretty remote part of the state... i just figured id ask so id have a ball park idea..

 

[85_Ranger4x4]

I was told about $150 for each operation, prices will vary wildly though. You can't have it done until you find somebody anyway, price it before you commit.

 

[88ranger5.0]

I was hoping to do both for under 500.. thanks man now I have to find a shop

 

[Gotta_gofast]

The engine shop I use will charge $500 to acid clean, magnaflux (check for cracks and fractures) engine blueprinting (bring every dimension within true specs), line bore/hone main journal/caps, install new cam bearings, bore cylinders, and clean out/remove casting flaws in oil passages and water jackets, and install freeze plugs and other odd and ends. I really like Tom and Brenda as they do not give you a generic "job". You need to have your pistons and rings before they bore/hone the cylinders because every piston varies in size. My Wisecos were within 0.002" but some of the cheaper brands they say have seen much worse (Keith Black hypers differed 0.007" on one small block) so they will adjust each bore accordingly.

It costs me $225 to have my rotating assembly cleaned, magged, micropolish the journals and balance everything.

Some shops are run by real idiots! Make sure you find a reputable shop. The first time I walked in to Tom and Brenda's place I witnessed a Chevrolet based 540ci with two turbos screaming on an engine dyno. It made 2800hp on alcohol and I later learned it found its way into a 2wd pulling truck!

 

[88ranger5.0]

ive already got my pistons and rings. they are .040 oversized and my block is strong.. so i will def do my homework... i can do my own freeze plugs and such thats no biggie but turning my crank and boreing/honing would be great.. Thanks alot for the info. its been hard to even find a shop within 50 miles of me so far.. gotta keep looking

 

[Gotta_gofast]

Is this for a performance build or just a street build?

At minimum have the shop mag out your stuff so you know you're working with a solid sound piece of iron. (should be no more than $50). Most shops will automatically have the block cleaned if they have to machine it.

You will be surprised how much quieter and how much smoother your engine is if you have the rotating assembly balanced! If you plan on spinning more than 5500rpm on stock crank/rods you should have this on your shopping list!

Good luck finding a shop!

 

[88ranger5.0]

its a moderate strip build. only looking for around 350-400 hp.. i will ask what they do for what prices... my truck is just gonna be a strict bracket racer... will the overbore and flat tops help with compression?

 

[Gotta_gofast]

Hard to say, "flat top" pistons is a general word. You will need distance from the deck to the piston top at TDC, valve relief volume, compressed gasket thickness and cylinder head volume. Take the total combustion chamber size (stroke times bore plus bore times compressed gasket thickness plus combustion chamber volume plus valve relief volume) and divide said number by (bore times piston-to-deck clearance plus bore times compressed gasket thickness plus combustion chamber size plus valve relief volume)


PDC=piston to deck clearance
CCV=combustion chamber volume
CGT=compressed gasket thickness
VRV=valve relief volume

(bore X stroke) + (CGT X bore) + CCV + VRV
(PDC X bore) + (CGT X bore) + CCV + VRV

In otherwords, a low compression flat top piston on a 64cc combustion chamber can see a compression ratio less than 9:1. A higher compression flat top piston under a smaller (58cc) combustion chamber might yield higher than 11:1.

For what you plan on doing, you really should have the block blueprinted and have everything balanced. I have seen production 5.0L blocks split (they split in the lifter valley) at 450hp. Quality ARP hardware and attention to detail will be valuable assets!

 

[88ranger5.0]

its a stock 92 roller block from a crown vic. im not sure what the clearences will be yet but i will def have this done.. thanks for all the info. its really hard for me to figure out the diff between dish and flat tops, ive been scouring the web and the lingo is just too hard for me to understand... i guess im a little thick headed.... haha

 

[Gotta_gofast]

A flat top piston is just that, a flat top.

A dished piston has a recessed "dish" within the piston. If you have a 5cc dish piston, it is simply stating that if you took a flat top piston and removed 5cc volume worth of aluminum, you would see a 5cc dished piston. This type of piston will lower compression ratio, and usually has a slight advantage in less detonation because of the way it compresses the air/fuel mixture. Similar to squish bands on a 2 stroke head. It forces gases to the center of the cylinder.

"Domed" pistons are opposite of dished pistons. If I have a 2cc "dome", I have added 2cc volume worth of aluminum to the top of the piston (to take up space in the cylinder) to increase compression. If using a larger cylinder head combustion chamber, this is an economical way to "take up space" and increase CR.

A cast piston, hypereutectic piston, and forged piston will also expand at different rates. Since we want our tolerances in our engine to be "just right" at operating temp. An aluminum piston will expand more than the iron cylinder it sits in. How much depends on the material and density. What type of pistons are you running? I can explain to you what tolerances you should expect to see with piston to bore clearances and how much ring gap you need to run a safe engine.

If you are really interested in engine operation from simple math calculations like static and dynamic compression ratios all the way to air flow theories and camshaft profiles, I suggest picking up some engine books by reputable authors. Its really easy to get addicted!

dished example
http://www.summitracing.com/parts/TFS-51404010-401/?rtype=10

domed example
http://www.summitracing.com/parts/SRP-150070-1/?rtype=10

 

[88ranger5.0]

thanks, i will be looking into some good reading material..

 

[85_Ranger4x4]

If you are going to reuse the stock heads check the piston to valve clearances too.

I highly recommend different heads than the E6's that should have came on that engine if you are going through the work of rebuilding it.

I checked into rebuilding a 302, my gawd it adds up quick...

 

[88ranger5.0]

im gonna check on some gt heads off an explorer.. heard good things. im gonna do alot more research before i start this. i might not even use these pistons i might look for new .030 oversized instead.. there is alot of great info on here. i am doing the rebuild with my cousin in his garage.. slow and steady