Welcome to the next installment of the

Topic of the Week

Let's talk about engine rebuilding.

Some of us have the time, energy and know-how to do this, some of us don't, and some of us want to learn how (so we can decide it's money well spent on the next one :flipoff2: )

So, beyond dismantling the whole damn thing, and putting it back together, lets talk about what needs to get done. Head porting, cam choice, rockers, cams, pistons, machine work (necessary or just cheap insurance), etc.

this should be good, I for one don't have the machinery or tools needed to do the "extra" things needed besides assembly/disassembly (and barely enough for that). The porting/polishing and reshaping of my combustion chambers was just a tad bit out of my league:rolleyes: so I paid somebody else to do that.

I know that you can buy porting/polishing bits at NAPA, but where do you get insructions on just how much you should polish?

Can you balance a rod at home in your garage?

What kind of tools are needed to rebuild an engine that the "average guy" wouldn't have in his garage?

The one trick I know about doing your own head is opening up the ports so they breathe better. You can get the grinding cones from Eastwood. Take your exhaust / intake gasket and put it on your head. Then take your die grinder with the grinding cone on it and open up the port to match your gasket. You want everything to be smooth so as not to restrict flow. All you are doing is opening up your ports a little. Not that big of a deal but it does help and it is cheap.

A head mod that will yield more of a gain than fooling around with ports is CC'ing the combustion chamber.
I usually dressed up the high flow areas of the ports, matched the gaskets, did a 3 angle valve grind and called it good. Without a flow bench, gains are minimal, you can even loose flow.
CC'ing the chambers is where the big gains are. With some time and patience, you're better off doing this at home.
Just get yourself a small piece of 1/2, 3/4 or 1" plexiglass, a marked burette, and some automatic transmission fluid and put the die grinder to better use. :D

Don't go wild on the "bumpstick"
Most small-block V-8's do well if you keep the duration at about 280*, with 284* as a reasonable maximum.
Keep lift between .460 and .510.
When you go crazy on the cam, your bottom end goes straight down the toilet.

Nothing beats blue printing the block and balancing the assembly.
Not too many "do it yourself" tricks here.
You'll be MILES ahead if you take this to a respectable machine shop. There will be plenty to do after the machine work is done.

Looks like this thread needs a bit of direction...

Probably none of us are going to do our own machine work. But we need to be able to talk intelligently to the guys at the machine shop.

What are the basic machining processes, and what do they do?
What are some of the steps that some may consider optional, while others consider them critical?
What's plastiguage and how do you use it?
What do you need to do to build an engine for propane vs gas?
Designing a build for high rpm vs low end grunt?

The one trick I know about doing your own head is opening up the ports so they breathe better..... intake gasket and put it on your head......open up the port to match your gasket. You want everything to be smooth so as not to restrict flow. . [/QUOTE]

Do you want the intake ports smooth? Doesn't that affect fuel atomization? Don't hi-torque motors work better with longer smaller intake ports?

I've got a vortec 5.7 I want to go thru this fall and am looking for some pointers on where to spend the money, roller rockers?, flat top pistons?, head work?....but I would still like to get 20 mpg when not "on it" and in overdrive.

the single most important aspect in my mind is the machine work.
I have some very recent prices from NAPA on machine work required in a well-used engine:
tank cleaning:$50
cylinder boring:$25/cyl
cam bearings: $38
pins pressed in pistions:$6/ea.
crank machining: $140

gets expesnive quickly.

a few things that I claim to know about, but might not:
appropriate cam lobe size is a funciton of engine displacment. a cam that barely idles in a stock 350 might sound stock in a stroker 415.

offroad and anybody looking for torque want long runners and a lot of plenum volume in the intake. port velocity is everything.

comrpression is a meaure of combustion efficiency more than power. a higher compression ratio will deliver a little more power than an otherwise identical motor with a lower compression ratio, but will be more efficieint and deliver better milage.

Sorry MO, I don't have answers to the thigns you suggested. And I have never built a motor myself. But I have a couple of tips.

If you buy new rods and psitons, get a full floating version. Then you don't have to have the pins pressed in the pistons. They are not that much more, if any. I bought mine off of Ebay, brand new for dirt cheap.

Get your whole rotating assembly balanced. It will run a bit smoother, and be capable of higher RPM's. It doesn't cost too much, as far as I remember.

Port match your intake to your heads. This will insure there is now interfering with the flow from the intake to the head. You can do this yourself at home with some grinding wheels nad a die grinder.

Use quality ARP bolts. Cheap insurance if you ask me.

A cast crank, good rods, and hypereutectic pistons combination can go a long way. The rods are teh first place to put your money. Most people don't need forged parts. But they are nice if you have extra money to play with.

JMO

Steve

No one has mentioned "Magnafluxing" yet.

It would be a pisser to find out too late your block or your heads were cracked.

Machine shops do this first to see if you are wasteing your money on the valve grinding etc.

Don't know how it works but somehow it makes any cracks show up.

Layman's plastigage info:

Read the package...but basically it is used to measure very small tolerances on bearings. It comes in different sizes of measure.

You lay out a strip on the crank, for example, using the size that fits your FSM tolerances. You bolt the cap to torque (with the bearing on) and remove the cap. The plastiguage will stick to one suface, probably the cap. It squishes to a certain width that you measure with the guage from the package. This measure should be in the tolerance range in the fsm.

For longer lasting oil pressure you want to be on the lower end of the tolerance. For example: If the tolerance is 5-20 x 1/10,000ths you want to be in that range but you will have better oil pressure at 7 than at 17. As the bearing wears it will proceed up the tolerance scale so if you start at 7/10,000ths a zero miles you will be much higher at 150k miles down the road and your oil pressure will drop in proportion (in theory).

Overly simplistic but you should get the general idea.

Oh yeah...if you are not in the tolerances you have to go to a "10, 20, 30 over/under" bearing.

On cylinder boreing and honeing :
Have the pistons you are going to use beforehand. Have the machine shop bore each cylinder for for a spicific piston, some shops do this anyway some don`t, and there will be slight differences between pistons.
Have them Bore useing a torque plate because when you bolt the head on the block the cylinders will change shape and the torqe plate simulates haveing the head bolted on.
This will add up to a better ring to cylinder wall fit which will make the engine more efficent and wear better.
Just my 2cents

Magnafluxing uses iron powder and an electro-mangnet to find cracks in metal objects. Basically you dust an area with the iron powder, then apply a magnetic field with the magnet. The magnet will pull away all of the dust. If there is a crack present, the iron will stick in the crack. The crack will show up as a black line.
Note that this only works with ferrous materials(iron based).
For aluminum blocks and heads, dye penetrants can be used.
A dye is applied with an aersol can, then wiped clean. The dye will "penetrate" into cracks. When the suface is wiped clean, the dye will show any crack with a bright line.

If you see the factory hash marks on the cylinder walls no need to get it honed.

Sometimes you get luckly.

Building a motor envolves quite a bit of thinking about what you want out of it when you are done and what you are willing to spend. If saving $$ is what you are after or near stock power then just buy a junkyard motor or go to Pep Boys and get a motor there. If you have some extra $$ to spend and are a little particular about what you want then build a motor is allot of work but really rewarding in the long run because you speced the parts and maybe even put the whole thing together so you have some real pride in it.
Here are a few things that I feel are important:
On heads you need to unshroud the valves so do some but not much work in the boal area, match the gaskets on the intake/exhaust, and knock off any casting marks in the runners but don't go to town or you will suffer low end. On the exhaust side you can get after it some if you like. Summit sells a porting kit for $30-40 or so and a drill is all you need.
On compression there are tons of things to think about. Carb or EFI, cast iron or aluminum heads, elevation it is opperated at, and tires size and gear ratio. Worse case would be a carb/cast iron head motor with 3.07 gears and 40" tires at sea level. With this combo I bet 8.5 would ping. Or EFI with aluminum heads, small tires with 4.88's at 8000 ft and I would bet you could run near 11 to 1.
What cam? To me all this talk about low end power to trail rig is crap. But thats just me because at 120-1 crawl ratio a Briggs 5hp lawn mower motor would get you down the trail. So what I build for is for 1500-6000 power not 0-5000. Now if you run mud or sand or tow then it really comes down to gearing once again to determine what RPM's you are running at and shoot for adding power where you need it.
Have the motor balanced for sure.
Be sure they do use a torque plate when boreing as stated earlyer.

I cant say enough for complete engine balancing. It is more beneficial in a high rpm motor, but will improve performance and make any motor run smoother. I always have blocks and heads boiled and magnafluxed. Usually have them decked and line honed. You can do a pretty good job of blueprinting with the method stated above using some plasti gage. The main thing is be very anal with your tolerances and take your time, double check everything before you assemble. Do everything you can think of to improve the internal workings of the motor while you are building it, cause you dont want to open it up again. Things like a high volume oil pump, quailty rings, having the oil ports on the crank champhered(sp?), etc, will all ensure you have a healthy long lasting engine.
Just my .02.

-Jeremy

If you see the factory hash marks on the cylinder walls no need to get it honed.

thats not totally true you should always hone a engine if it has any miles on it to get rid of any glazing on the walls you would still be able to see the hash marks but the rings would not seat as well with the cyl. glazed

I am currently rebuilding an engine(the block is at the shop now) and can help a little with the pricing. I am taking a few short cuts for money but not major ones. The engine is a 2.8 V6 (I know not a good place to start but I don't have the money for anything else and couldn't find a used 3.4). I was going to have it honed and ridge reamed but b/c of the wear that would have taken it to .006" over and that would be a little too sloppy. The gentleman at the machine shop was very helpful and I was able to learn a few things. I personally would go to a machine shop over NAPA or someplace like that b/c I feel they would be better and possibly lower priced ( and in my case the guys at the counter are the ones who do the work)

Boring .030" over 15/cyl =$90
"Baking" the block=$50 this cleans out all the oil passages and also included replacing the expansion plugs.
Installing new camshaft bearings=$80
Grind valves and seats =$120 for both heads
Complete engine kit ~ $450 this was a deal through the machine shop. The parts are not performance but are quality parts and it was cheaper than anywhere else I saw. It includes: pistons, rings, camshaft, camshaft bearings, lifters, oil pump, crankshaft, crankshaft & conn rod bearings, all gaskets and seals, expansion plugs.

The crankshaft added about a 100. I was not originally going to replace it but it was scored too deep. I also noted that what he is charging for a new crankshaft is more than what someone else on this thread quoted for polishing the crank. I should have had him polish the heads and block but that would have been an additional $200.

Tim

Always price shop machine work. By me I have an incredible machine shop. Only two guys work there, but all they do are race motors. But there prices are double what it is for me to get it done from a "Napa" store. And the guy doing the work at the Napa store does all the engine work for the big time street racers (real motors, not the import crap)around here.

So do double check prices. Be careful of the "whole in the wall" place that gives yo ua bad feeling.

JMO

Steve

when assembling engines, I prefer to know the exact clearances on the rod & main bearings. I know most people (and a lot of machine shops) rely on plastigauge, but I feel it is not anywhere near precise enough for my engines. I will only use a dial bore gauge with a measurement accuracy of .0001 . If you are paying money to have an engine blueprinted, make damn sure the engine builder is not using plastigauge, if they are, you are getting ripped off. the whole point of blueprinting an engine is for exact tolerances. Think about it, when using plastigauge you are measuring a squished peice of wax with the wrapper it came in. If you are happy with good enough when building your engine, honestly you will probably be alright, but for gods sake don't pay for it.

Here's a few things I learned the hard way.

When honing an engine don't get carried away. I was putting rings in my 302 and thought the object was to remove the scoring on the side of the cylinder. It's not, you just want to go long enough to see hash marks. This made my engine have some pretty bad piston slap until one finally broke . (they probably wouldn't have lasted as long as they did if they weren't forged pistons)

Be careful when installing the pistons. I chipped one of the skirts on a piston when it went down too far and hit the crank.

If the engine doesn't seem balanced, especially after a swap, find the source of imbalance or have it balanced. I made this mistake on my Mustang when I swapped the auto tranny out for a stick. The flywheel, while correct for that year engine, was not perfectly balanced for my engine. It didn't seem too bad, so I ran it. It kept getting worse and worse until about a year later, I decided it was time to do something about it. By then it had broken the harmonic balancer and screwed up the crank.

Always double check the machine shop's work. After getting said motor rebalanced with a new crank, I was ready to go back together. Just for grins, I decided to plastigage the rod and main bearing clearances. Found out that my crank which was marked .010 - .010 under was actually .010 - .020 under. Would have been bad if I had put it back together that way. As it turned out, they cheerfully restamped my crank and exchanged the bearings.

Above all, do it right the first time. I've had my Mustang's engine apart 4 times trying to just fix what was wrong with it. (Mostly because I was poor and it was my only transportation so I wanted to be done quickly) Finally I went through it completely and didn't scrimp on anything that needed attention. Haven't touched it since.

Like surgery, cleanliness is next to Godliness when engine building ...

http://www.monsterslayer.com/jeep/images/EngineAssembPrep.JPG

A couple of things I do:

Clean the flashing off of the rods, heads, eng valley, etc. This reduces the stress lines and allows oil to fow back to the pan easier.
Put small pieces of screen in the oilreturn holes in the heads. If you lose a piece of the eng in the heads, this will stop the laeger pieces from getting into the lower end.
Clean up the ports, both intake & exhaust, but don't polish them. At low RPM's, the air needs a little turbulence to keep the feul mixture from falling out.
Backyard balancing of pistons, rods, pins is fairly easy. Just get a scale, wiegh each component, and match them together so they all wiegh as close to the same a possible.
Run a tap down all the bolt holes, it cleans them up and if you have a bad hole, it's easier to fix.
Mild cams will allow the engine to last longer. Engine wear, assuming proper maintenance is performed, is directly proportionate to the amount of fuel used. More HP & torque = more & quicker wear.

Having built several engines over the years, I have yet to have an engine problem due to using plastigage for the clearances. Although using a dial indicater is more accurate, I have yet to build an engine that sees over 6000.
For engine running under 400 HP, you can get away with a 2-bolt block.
Line boring, crankshaft line boring, torque plates when doing the boring & honing, all add up to a longer life for the engine.

Most stuff is covered well so here's a couple of assembly and teardown tips.
1: only remove pistons at top or bottom dead center. Otherwise the rod may catch the bottom of the bore.
2: use a ridge reamer if the bore's badly ridged. NEVER EVER EVER use a punch on any part of a rod to drive a piston out. Use a hammer handle.
3: resize your rods! especially if you put new bolts in, you HAVE to resize them.
4: don't be cheap and assume you can install cam bearings yourself. You can't, unless you have the $$$ tool. (tried it, oops) Be very careful and guide the cam all the way in, don't nick the bearings.
5: set the thrust on the crank. Don't just bolt it down. You'll need to give the rear of the crank a good whack with soft-faced deadblow when all the caps are torqued around 10 ft/lbs. If you drive a manual and don't do this, you WILL wear one side of the bearing more than the other.
6: No matter what the machine shop says, get a rifle brush and clean the crank oil passages. Hell, get a long one and do the block too.
7: some piston/ ring packages go in tighter than others. When driving the piston down the bore I like to leave the upper rod shell off until it gets close to the crank. It sucks to have the shell fall out on the floor. Use 3/8 hose over the rod bolts, or be extremely careful. It's amazing how bad a rod bolt will fawk up a journal if you're not careful.
8: Don't use cheapo stock replacement VatoZone type pistons. They have a low compression height on the assumption the heads have been milled, and will kill your compression. Try to run a .010" to zero deck height if you're playing with a good motor, you can run more compression ratio, or at least get more timing out of it.
9: lifters. Don't mess with them. They are cheap, about 2 bucks apiece for most engines. Used lifters on a used cam, or new one, can go :nuke: in a hurry.

Like the book? :flipoff2:

As said before, if you are paying for a engine to be rebuilt then Plastiguage is OUT. Dial bores or nothing.

There is also having the piston holes bored from either the Deck side or the Crank side. Having it down from the crank side is better and the price will definetly reflect.

Balancing and blueprinting is worth the time. If for nothing else that getting the extra life out of the engine. I like to ensure that my entire piston assembly (piston, pins, rods and bearings) are all within a gram. Spend the time making sure it is all right the first time.

USE the assembly lube. I don't know how many jackass's I have seen that use motoroil and think it is fine, its not.

Keep the cam mild and match it to the intake/exhaust system. What I mean is that there is no need for a cam that is able to accomidate 350 cfm and having a intake trying to stuff in 900 cfm while the exhaust will only move 100cfm. Get them as close to possible. I have found that most people over carb thier engine BIGTIME. do the math and get the correct carb, intake, cam, valves, headers, exhaust the first time. You will be suprised at the small ass carb that makes your engine scream and last forever.

CC'ing your heads is worth it as well.

Good motors take a long time to build. These guys who start a project and are done at the end of the weekend are either very good or very novice. My old man can do it, but he raced NHRA for 10 years. I certainly cannot do it and therefore don't even take the risk trying.

AlaskaZJ said: "There is also having the piston holes bored from either the Deck side or the Crank side. Having it down from the crank side is better and the price will definetly reflect. "

What is that? I have never heard of that option before. Since you can't get a boring bar to feed through the bottom of the block (crank journals in the way) that sounds suspect to me.

Another area I look at heavily-The OIL System, deburr the lifter valley I.E. SBC,Pontiac.What you don't want is all of the oil to be pumped up top and laying in the valve covers when you are on it hard in the mud(been there, done that) open those return holes up. Crank scrapers,windage tray,a deeper pan (I run a 10 QT Moroso) good high volume pump and pickup, I even put baffles in the pan to help keep the oil in place for up and downhill action. Don't forget to check out specific engine brand sites for the "latest tricks":D

Originally posted by Slagburn
AlaskaZJ said: "There is also having the piston holes bored from either the Deck side or the Crank side. Having it down from the crank side is better and the price will definetly reflect. "

What is that? I have never heard of that option before. Since you can't get a boring bar to feed through the bottom of the block (crank journals in the way) that sounds suspect to me.

i was confused when i read that but thought about it and i THINK this is what it means
crank side means the block so decking the block as oppose to decking the head. i dunno just makes sense to me, this is all VERY GOOD info cuz im in the process of rebuilding my 4.3 and dont want to fawk anything up and im too broke to have it done for me.:D

I rebuilt my first motor back in 05, it was a 304. I took my block in to a local engine shop and asked for it to be cleaned and magnafluxed. When I received it, it looked fantastic, really looked great.

What I didn't realize was that I turned the block into them will all the oil galley plugs installed. I also didn't notice that when I received the block, the oil galley plugs were not replaced.

After many, many hours of troule-shooting no oil pressure I learned that the oil galley plugs were not installed at the top of the block. I think it's called the oil valley? I apologize for that.

Point is, if you see a threaded hole in your block... it probably means that something screws into it.

Lou

Can we start breaking down the processes that are being talked about? CC'ing, balancing the motor, blueprinting... This coming from somebody that knows none about the entire rebuilding process and doesnt want to get ripped off...