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questions on my 283 chevy build

11K views 29 replies 12 participants last post by  BigEd36 
#1 ·
hey every one. im about to start re building a 283 i got for my rat rod, it already has a summit 1102 cam and 416 heads which will be getting a valve job and maintaining the standard valves, but the block needs a bore. i brought a bunch of spares and with it came a mint set of +0.40 pop up dome 10.5 to 1 pistons. as this is my first engine build i was just curious if these pistons would cause issues with my final compression ratio and if they will clear the valves with the .421/.444 lift on the cam?

im still a bit of a novice so any and all advice is much appreciated
 
#2 ·
The 416 (14014416) heads have 1.84" I valves and 1.50" E valves with 58cc combustion chambers. They were used on 1980-1986 287 and 305 engines.

You will not have piston to valve interference with that camshaft, those heads and pop-up pistons. With a 283 + .040" os bore, you will not have problems with pump gas with the initial timing set at 10 degrees BTDC, in a light weight vehicle. If you move the initial advance up to 12 degrees for more performance, you may have detonation problems on 97 octane gasoline, especially if the engine temperature is above 200 degrees. Flat top Pistons would be a better choice.
 
#7 ·
I don't know how you calculate initial timing advance but I cannot get an engine to start with more than 16 degrees initial timing advance, no matter what compression ratio and I use a Snap On dial back timing light. We still have 97 octane no-lead gasoline available at the pump in Texas. It is commonly called "premium" gasoline. It is good for 10.3:1 static compression ratio or 8.7:1 dynamic compression ratio. However, 97 octane premium pump gas is nearly useless for high performance engines because it is no-lead and you will pound out the exhaust valve seats if the valve spring seat pressure is more that 120 lb.

According to the early GM shop manuals, when you could still buy Gulf Crest 105 octane at the pump, the factory recommended only 6 degrees BTDC initial timing advance on new cars with as little as 9.5:1 compression ratio. That was because the factory did not know what grade of gasoline the car owner was going to use. That was part of the factory's "CMA" drive line warranty program.
 
#4 ·
I have the same set up but with flat top pistons. make sure you have the right piston pin height or the pistons will sit .040 down in the bore. Don't ask me how I know. Double check your bearing clearances. I got only 15 lbs hot oil pressure at idle. triple check cam bearing as that is where my problem is. Mine is a blast to drive as it has some power and it likes to rev.
 
#6 · (Edited)
To know for sure if your combo of parts will work, you need to know exactly what you have.The 416 heads need the chambers cc'd to verify the volume.They are advertised at 58cc, but, they can vary being as small as 52cc.Especially if they've been decked a few times.Your pistons 10.5:1 rating is based on given set of specs.Yours could be more, could be less.Same with piston to valve clearance.You will need to check this during the mock up phase.Lots of things can cause variances, such as, how much the heads may been decked.How the cam is installed & timed.So, you need the actual volume of your heads, amont of dome on pistons, piston to deck hgt @ TDC,& your chosen headgasket compressed thickness.With this info, you can determine your SCR.Then you need your cam's specs, mainly the intake valve closing point to determine the DCR (dynamic compression ratio), or, the actual running compression of the engine considering cam timing.Offhand, i'd say you will have problems.
 
#9 ·
cheers for the advice. the heads and the block have never had any machine work done so the deck height is fully stock, how would i go about getting the heads cc'd? could i not incorporate a thicker head gasket if the piston to valve tolerances are slightly out?

i also was reading on another forum about a guy who had used 12-1 pistons in a 283 with a cam that had about .555 intake lift
 
#10 ·
hey vinnie

Im hoping to be at least 350-380hp but would like to take it as far as i can with out compromising reliability or my bank account hahaha. Most of the work and engine was already built and in a hot rod but it developed a bad smoking problem out the left side only 12,000miles after having the new cam, lifters push rods and rockers, i picked it up cheap after it had sat a few years in his shed and striped it as soon as i got home and figured it would have been due to extremely worn bores after 3 rebuilds and retaining the factory bore size plus a couple deep scours. So its getting a full rebuild from the crank up to the valves. Up top ive got a 350cfm holley with vac seconds sitting on a edelbrock bowtie 2 victor Jr intake manifold, Im also contemplating putting a 327 crank to stroke it out but thats depending on the verdict of this thread :D
 
#11 ·
valve lift has nothing to do with using too much compression. The 49 cc heads I mentioned will work with flat tops.With cast iron heads on a 283 I would look for 9 3/4:1 compression.

when you build a performance engine you need to do some math,starting with desired hp you want/need?
The math starts with head flow required to make said hp and then you do more math to determine at what rpm this hp will occur

budget will need to be figured into the equation also.

lets start out building a 325 hp 283 punched out to 292,,,
so the engine needs to put out 1.1 ish hp per cubic inch,
so a 6400 rpm peak power would easily eclipse this goal.

Your heads must flow a little over 200 cfm on a 3.935 bore.
most head flow charts rate the head flow with a 4.06 bore so you will need heads that flow 235 plus cfm
Many cheap options come up,but most have too large of combustion chambers.
to cheap fast cc a head,seal a junk C.D. (compact disc) over the combustion chamber and measure how much fluid it takes to fill combustion chamber.
use flat top pistons,deck height of .037-.043 including compressed thickness of head gasket.
I would use a small SOLID lifter cam that has pressurized lubricating of the cam/lifter area.
PLEASE, do not use a hydraulic flat tappet cam.
I would use a performer rpm intake
a modified 650 double pumper Holley
1 5/8 inch long tube headers Balance the engine
use good valve train ie; roller rockers and stud girdle,

what is the weight of your car?
How will it be driven?
I would choose a transmission and rear to match the small engine and higher rpm power potential.

sorry my post would have been a little wilder if I saw your question.. 327 crank,060 over bored 283 b;ock nets 316
 
#14 ·
ok so i think my hp goals may have been a little ambisious given my budget, but after taking in every ones advice ive decided im going to buy some flat top +40 pistons, apparently my blocks max safe bore is +60 so id like to keep that in reserve. also should i go with chromoly rings for this build?

Ive brought a set of 1.90" inlet valves which i will have fitted to the 416 heads (which i have yet to cc) along with a good port job and all new valve and seat cuts.

I think i will stick with the 650cfm holley for now, and the edelbrock bowtie 2 victor jr intake as it is rated at 3500-8000rpm.

i am currently undecided as to what kind of cam i want to run, i like the idea of a solid lifter cam. but im not shure it will be needed for my application (a light weight rat rod) when it comes to cams my knowledge is rather limited so if some one wants to sell the idea to me im still open to it.

and as for roller rockers i was thinking of just getting a set of 1.50's and if a stud girdle is going to be nessasary up to the 280-300hp mark.

also if any one knows of any links to compression calculators could they send them my way? or any links that can aid me in getting my head arround the math involved in engine building.

cheers guys
 
#15 ·
Link to every calculator you could ever need : Wallace Racing - Automotive Calculators

If that mint set of .040" "Pop-up" pistons have a solid dome and not a hollow dome(easy to see from the underside what they are), any basic machinist with a mill or a lathe can turn them into flat-tops, I've done it numerous times to tailor a compression ratio to the engines needs. Cutting domes off has been done for countless years.

No such thing as "chromoly" rings.....there are standard moly rings, plasma moly rings, and chromed rings. There are also plain cast for basic rebuilds and stockers good to 400 hp or so, and exotic tool steel, stainless, etc high high hp race rings.
Standard moly is good for anything under 500-550 hp, plasma moly for above that ...chrome rings are almost strictly for use in dirty, dusty environments and take a rather long time to break-in. Chrome rings are not much in use anymore except industrial and large equipment applications.

The 650 Carb is a good size, but you will likely find the Bowtie Vic Jr to be too big, it is intended for 350 cube and larger engines turning 3500-8000, by comparison this would be a 4500-9000 rpm intake on a 283...a Performer RPM or similar will likely be your best performance intake.

1.5 ratio roller rockers on 7/16" studs should be fine without a stud girdle for about any cam in the range you are likely to be using.
 
#16 ·
Well,well, Dome Pistons! They create more compression but they don't quench the combustion as well as a partial dish or flat top piston. Also , they Could cause interference with the heads depending on set up( but not because of the cam lift( that's a small performance cam). Remember, that's a short stroke engine,also,it won't be Very torquey ,certainly not without a Low rear gear,at least 411:1.They are great engines and can turn some high RPMS set up correctly. Good luck, just some things to Consider.handy7rick Also, I'd highly recommend ,Flat top Pistons (4 eyebrows ) with Power Pack 283 heads. Very good for low end torque and Can turn high RPMS . I used them on a 350 with dish Pistons and a Crane Fireball cam (similar in size to your lifts) and it turned 7200 rpm many many times.
 
#17 ·
Back in the day,the Power Pack heads were a great choice for a lil 283.However,with todays modern heads,they are seriously outdated.For a restoration,they would work,but,by the time you put in hardened seats & rebuild a set,you could have a much better head that will provide lots more power with a lot less cam.The ports & valves are way to small to make any serious power with.
 
#18 ·
Ok so its been almost a year since i started this thread and ive had some what of a major change in direction for this motor hahaha.

One of my mates here dose a lot of messing around with serious turbo applications of all kinds and has convinced me into force feeding my little 283. Ive read alot of good feed back about people running boost on them with good results. im not planning to be running more than 8-10psi though it and have already had a turbo built to suit the engine which should have me seeing the boost come in at around 3000-4000rpm to keep it street-able. Ill be hunting for a cam to suit also.

But my main question is relating to my options for my head and piston combo to acheive between 8.5:1-9:1 compression.

i already have two sets of heads and would like to use one of the two as alloy heads are not in my budget at the moment.

The 416 heads (56cc 1.84"I 1.5"E) and also a set of 487 heads (75cc 1.94"I 1.5"E) ive done some work on a compression calculator and using the 416's with +30 flat tops and a 0.41 head gasket i will have 8.95:1 CR and with the 487's with the +40 domes and a .015 head gasket will give me 8.58:1

any ideas or theory's on what is going to provide me with the most reliable performing combo? i know some one has already mentioned that flat tops are the way to go but since deciding to boost this motor i would like to hear some more opinions

thanks
 
#19 ·
Since we never found out before...are the domed pistons you have Forged?? Or just Cast??

If you were choosing between forged domes or cast flat-tops, I'd say use the forged dome/487 head combination.....or if the domes are solid have the dome machined off and use the 416 head.

The major focus here with the turbo is to use Forged pistons to avoid a piston explosion. Cast or Hypereutectic are not ideal in a boosted application. Domed or flat is a very secondary consideration that is easily worked around in your case.

A turbo 283 ought to be a lot of fun, and get really reasonable fuel mileage to boot.
 
#20 ·
Yea unfortunatly the pistons i already have are only cast hence why ive been trying to decide what combo will work best since im going to have to get new forged pistons any way.

I read in an old manual that if you had the option between useing higher comp heads or larger valve heads that the higher comps are a better choice. I cant remember the reasoning behind this however. I just want to make shure im spending the money on what is going to be the most ideal for my application
 
#21 ·
Your head question/concern is less daunting considering you're going to use a turbo because the turbo will overcome some or most of a head's efficiency issues. It sounds lke you're on a budget and you plan to use one of the sets you already have. This coupled with the idea that you're going to buy a new set of forged pistons would tell me that either set will be just fine depending on the condition of the heads because you can change your SCR depending on head choice with a different piston volume depending on which set of heads you choose. Come up with a combination that yields 8.5-9:1 SCR. There is always alot of talk about quench distance being between .035"-.045" ideally. This is similar to head efficiency in that the turbo will overcome most any quench issue when in boost, but not when out of boost.
The most demanding part to select in this build will be the cam.

My attitude towards a streetable turbo build is this, use the best heads you can afford, get your quench closest to optimal as you can afford to build a solid street driver and then let the turbo do the work for all of the top end goals. Pick a cam that makes decent idle vacuum and idles smoothly (wide LSA and mild duration leading to very little overlap.) This will make for a very driveable motor. If you can get your 283 to make 250-275hp NA, then your 10 psi will push well past 350hp making a reliable build for pump gas.

If you're only concerend about 1/4 mile times or dyno numbers, then a different approach is needed.

I throw this statement out whenever I hear of someone putting together their first turbo build - boost is addictive and it's hard to resist the urge to turn it up. Keep in mind your original goals and the limits of your parts (I have to remind myself often:thumbup:)

Good luck - Jim
 
#22 ·
cheers Jim that helps alot. from that and the info Ive gathered from the rest of my research i think im going to go with the 416's with flat tops an the .015 gasket which will put my quench at 0.35 anyway.

ill still be spending a bit of money on the 416s putting in new stainless valves with a fresh grind and seat job and new springs, the pump gas we have here in New Zealand is unleaded 98 octane, so im told that the exhaust springs should be kept under 120lbs seat pressure to prevent them pounding out the seats? any suggestions what springs would be ideal for my application?
 
#23 ·
You're using a FT or a roller? But I would not recommend a set of springs until I was 100% positive what the cam specs are. And I have to admit that a new set of valves and springs with machine work puts those of on this side of the pond into using aftermarket heads. Are you going to get them machinined for rocker studs or at least get the press in studs pinned?

If memory suits me, those do have hardeneed seats in them already?
 
#24 ·
Also, don't let me mislead you into thinking that I have the expertise of others here with long block knowledge - I'm a novice, as well, that has been messing with a turbo'ed SBC for a couple of years and presently can tell you alot of thing not to do LOL :)

Eric, Tech, Vinnie, Joker, Chuck, Engine Czar, etc. can give you ALOT better hard part recommendations than me.

Best of luck - Jim
 
#26 · (Edited)
Main thing about the small bore motors is that you have to keep the valve head sizes small (1.90"/1.50" for instance) to prevent shrouding the valves against the cylinder walls. Bigger valves do not necessarily make a faster motor.

Every motor builder should know everything there is to know about his motor, including the exact combustion chamber volume and the intake and exhaust port volumes. Unless you have owned the heads since they were produced, you have no idea what previous owners did to them. They need to be cc'd and they also need to be checked to see if anyone has cut the (head to manifold) angle. The interface between the heads and intake is one of the least checked things in motor building, but one of the most important, along with squish/quench. If the ports on the intake aren't square to the ports on the heads, there will be a gap, either at the top of the ports or at the bottom of the ports. If the gap is on the top of the port, it can be found by spraying ether or other combustible substance around the area with the motor running. If the motor speeds up, there's your vacuum leak.

On the other hand, you will never find a gap on the bottom side with a combustible substance because you can't get to it from the top of the motor. If the gap is on the bottom, it will confound the air/fuel mixture just like a gap on the top of the port, but on the bottom, we have still another player in the mix, the motor can pull oily crankcase vapors into the cylinders on the intake stroke which will result in fouled and oily spark plugs. This will begin all sorts of scenarios in your mind, including thinking maybe bad rings or bad valve guides or excessive valve to guide clearance or a myriad of other possibilities. So, take some time and make absolutely certain that the intake to head junction at the top and bottom of the ports is flat and parallel and able to seal up.

You made a statement earlier about using a thicker head gasket to lower static compression ratio. That is a very bad idea. It has been found that using a thicker gasket and lowering the SCR that way can lead to worse deonation than it you had left the thin gasket in place. Squish/Quench is king as far as controlling detonation, although it isn't quite as critical with a blown motor because the blower helps to homogenize the mixture just as squish/quench does. You should know this and keep it written down somewhere.....
Static compression ratio is a function of 5 different values, cylinder volume, combustion chamber volume, piston deck height (measurement from the crown of the piston to the block deck with the piston at top dead center), piston crown configuration and head gasket bore and thickness.

Cylinder volume, combustion chamber volume and piston crown configuration should be used to determine static compression ratio.
Gasket bore/thickness and piston deck height are used to determine squish/quench.

Every engine build should begin with measuring the block deck height, then choosing a crank/rod/piston "stack" that will fit into that block deck height, then cutting the block deck heights to the desired piston deck height.

BLOCK DECK HEIGHT: The measurement from the centerline of the main bearing bore to the block deck surface where the heads bolt on. Measure all four corners of the block. Factory blueprint for this measurement is ~9.025" (nine inches and twenty five thousandths of an inch). You can do this at home with a 12" dial caliper by adding 1/2 the main bearing bore to the measurement taken with the caliper.


PISTON DECK HEIGHT: The measurement from the crown of the piston (the flat part of the crown that is just above the top compression ring and NOT including any pop-up or dome) to the block deck where the heads bolt on. Factory blueprint for this measurement is ~0.025" (twenty five thousandths of an inch).

SQUISH/QUENCH: The measurement from the piston crown to the block decks where the heads bolt on and including the head gasket thickness. Most hot rodders will shoot for somewhere between 0.035" (thirty five thousandths of an inch) and 0.045" (forty five thousandths of an inch). As the piston approaches top dead center, the air/fuel mixture above the piston will be trapped between the crown of the piston, where there is a flat mesa, and the bottom of the cylinder head, where there is another flat mesa. As the piston comes up, it compresses and "squishes" that slug of mixture across the cylinder to the combustion chamber area of the head. This very high speed mass of mixture breaks up droplets of mixture and homogenizes the fuel/air slug go that all of the mixure can burn properly. This prevents detonation and makes more power. Squish/quench is the sum of the piston compression height and the head gasket thickness. If, for instance, the piston crown was exactly even with the block deck (called zero deck) and the gasket thickness was 0.041", then the squish/quench would be 0.041".

COMPRESSION HEIGHT: The measurement from the centerline of the wrist pin to the crown of the piston, not counting any pop-up or dome. Design measurement for a 350 motor is 1.560" (one inch and five hundred and sixty thousandths of an inch). Some manufacturers will shorten the compression height to make concession for the machine shop cutting the block decks to get a fresh surface for the head gasket to seal to. This shorter piston kills squish/quench and is to be avoided by us hot rodders. Use a 1.560" or taller piston in a 350 and a 1.025" or taller piston in a 383 build when using a 6.000" connecting rod. A 283 with a 5.7" rod and 3.000" stroke crank would use a piston compression height of 1.800".

STACK: The sum of the crankshaft RADIUS, the rod length and the piston compression height. The smart way to build a motor is to first measure the block deck height, then choose a stack of parts that will fit onto that space, then cut the excess off the block decks to reach a ZERO DECK so that you could then reach a pre-determined SQUISH/QUENCH with a certain thickness head gasket. For instance, if the block deck height was 9.015" and the stack of parts to be used was 9.000" and the build included using iron heads, then you could use a 0.020" thick steel shim head gasket and generate a squish/quench of 0.035". However, if you were going to use aluminum heads with this combo, you wouldn't want to use a steel shim gasket because of the possibility of "fretting" the heads. You would want to use a thicker composition gasket that would asborb some of the twisting and turning of the aluminum due to the different growth and shrink characteristics of the aluminum heads against the cast iron block. The thicker gasket would act as a cushion against cracking the heads. What you would want to do in that case is to cut the block decks to ZERO DECK HEIGHT and use a 0.035" to 0.045" thickness head gasket to set the squish/quench.

Here is what you want to use to CC volumes....
https://www.summitracing.com/parts/sum-911581/overview/

Use Isopropyl Alcohol from the grocery or drug store and color it with food coloring from the grocery store so you can see the alcohol in the burette.

Maybe this will help you to understand some of the subtleties of engine building and how to do it right.

I have no idea how I got two videos of the same thing on here.....

.
 
#28 ·
I developed a habit, a long time ago, of buying nice tools. Eric is correct, you could probably come close to replicating the results with another system, but I just like nice stuff. I have outlined on this and other forums several times, how a fellow could do some measuring for other hot rodders and recoup the cost of the equipment. $35 for cc-ing V8 heads, $25 for a V6, $20 for an inline six or four.
 
#29 ·
A very good video but it fails to tell what you do when you find differences between chambers and what tolerances are acceptable. If you need to equalize your chambers you will need to know where it is best to grind and where the limits are.
If you use your head gasket to draw a circle around your chambers that will tell you where the line is not to cross but you want to start by removing any shrouding of the intake and exhaust valves. Polishing the chambers is not necessary but it will eliminate sharp edges that are prone to detonation. There are some "imperfections" in chambers that exist for a reason so learn as much as you can before you start grinding away.
 
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