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turd-polish-a-go-go
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Discussion Starter #1 (Edited)
This information should be worthwhile for many of you. After searching the web and the world over, I have found that Samurai enthusiasts know neither Jack nor $hit about 1.3 and 1.6L 8V cylinder head flow, camshafts, or combustion chamber volume. I felt the need to know these things, since I would like to squeeze as much torque as I can out of the little aluminum 1.6 on my engine stand. I choose to stay with the easy 1.6 TBI swap, for weight, simplicity, and cost. I figure with the amount of parasitic drag I’m subjecting my driveline to with reduced gearing throughout, GM alternator, and T/C pump it would be wise to find some “free” ways to get the power back, using a little bit of educated attention to detail during the buildup.

First order of business is combustion chamber volume. Searches led me to nothing but BS and hearsay, and what I ended up with was a list of numbers that looked like a lotto ticket of “true” combustion chamber volumes. We know that the 1.3 and 1.6 are 8.5:1 engines, and the displaced volume varies a bit. It doesn’t take much math to figure that my stock 75mm bore x 90mm stroke block has a total chamber volume of about 53cc. This says nothing about the combustion chamber cast into the head, nor what that means when it comes to machining for increased compression.

There is also this myth about how bolting a 1.3 head on a 1.6 block will increase compression. While this may work with some zero-deck V8’s, it is totally false with the Suzuki. I put a 1.6 head and a 1.3 head side by side on my bench, and measured the combustion chambers, below:

1.6 head:


1.3 head, 1.6 in background:


The two combustion chambers are for all intents and purposes the same: 33cc. Machining variations on my heads varied about .005” end to end.

A note on splitting hairs with significant digits: When aiming for a specific compression ratio, such as my goal of 9.5:1, a few decimals precision is unimportant. The effective behavior of the increased compression ratio depends on too many factors to say a certain number does this-or-that. An aluminum head with good heat control such as polished piston tops and polished combustion chambers should be able to handle 9.5:1 on 89 octane if everything works right, but that's no guarantee. (I do most of my driving around 6000 ft elevation, lowering compression pressure before the burn, and still have the option to run preeemium, should I have the need.)

Next, a note on gasket volume. A factory head gasket has a bore of 77mm, and a typical crush thickness of 1.25mm, yielding 5.82cc in volume. This is important. The Suzuki Swift guys (mainly Europe and Canada) have pushed copper head gaskets into production, allowing you to really toy with that number should you need to. Copper gaskets are available for our engines in a half-dozen thicknesses- to increase compression, or to lower it for boost. This gives us some choice, if we fawk up or want to spend over a hundred dollars on a gasket…

Planimetric combustion chamber profiling was next on my agenda. The combustion chamber is mostly open, with a small flat on the exhaust side. There is a quench area on the rearward side that has a ridge averaging .015” off of the deck face (keeping in mind the machining variations of +/- .005” on my examples). The first ~.015 machined closes this factory-cast "squish space", and changes the volumetric profile of the chamber after that. The first .015” of grind subtracts 1.68cc of combustion chamber volume. Each .010” machined afterwards subtracts 0.90cc. This is the golden egg here, giving you something to go off of when sending your head to the machine shop! Remember to calculate deck volume from your measured deck height, valve reliefs, piston to bore tolerance, and ring height. The factory 1.6 is about 14.18cc deck volume.

Here is a planimetric profile of the combustion chamber, quench volume, and gasket volume, a’la SolidWorks:



I would like to go on to discuss deshrouding the intake valve, intake and exhaust porting, flow rates, and camshaft profiles. I also have info on crankshaft types that were available, and their suitability. So far, I’ve found a *theoretical* gain of ~20 ft-lbs torque for head and cam work alone. More to follow…

-L.B.S. :D
 

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Glad to see that there isn't a difference in volume between the 1.3 and 1.6 head. I put a 1.6 head on my 1.3 Fuely. Did the hybrid TBI, added a properly port matched Calmini header, and a mid range cam. Some said I would lose a bunch of compression and it wouldn't work (Zooky did it so I knew it would). In all, added quite a bit of punch. Very noticable.

Up until recently when my ECU began to act up, now it's a turd burning rich and sputtering. Guess I need new caps. :(

Keep it coming. Great tech!
 

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Did you use the 1.3 timing belt and pulley. Does the 1.3 dist. also work on it? I got a 1.6 head laying around and I run the ZUKS off road MY fi injection so that might be fun to try out.
 

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It doesn’t take much math to figure that my stock 75mm bore x 90mm stroke block has a total chamber volume of about 53cc.
Not too nitpick on your thread, but that would be surface area of a square. The volume of a cylinder with those dimensions is ~397cc's.:)

P.S. Did you know that Google is a calculator? Type in the equation for the volume in the search window "pi*37.5^2*90"
 

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turd-polish-a-go-go
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Discussion Starter #6
Did you use the 1.3 timing belt and pulley. Does the 1.3 dist. also work on it? I got a 1.6 head laying around and I run the ZUKS off road MY fi injection so that might be fun to try out.
the 1.6 distributor housing must be used with a 1.6 cam, regardless of which head it is in. the gears engage a bit differently... also, if you run a 1.3-grind cam (most of what's out there- has fuel pump lobe) you need to run the 1.3 distributor housing.
 

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turd-polish-a-go-go
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Discussion Starter #7
Not too nitpick on your thread, but that would be surface area of a square. The volume of a cylinder with those dimensions is ~397cc's.:)

P.S. Did you know that Google is a calculator? Type in the equation for the volume in the search window "pi*37.5^2*90"
that is an engine dimension, not a formula. :shaking: piston bores are not measured by radius.
 

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that is an engine dimension, not a formula. piston bores are not measured by radius
This is true - bore vs. stroke. I assumed that you took the bore and stroke dimensions to get the 53cc's you mention earlier.

Anyways... back on track. Great research!!!
 

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turd-polish-a-go-go
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Discussion Starter #10
That is good to finally get some numbers. There are many myths of the zukiengines. one example; I believed my 1.6 16v block with 1.3 8v head was an interfearance engine. cause that was what everyone said. But when I tore it down i checked just to be sure. And guess what, no contact :shaking: and that was with as shaved head BTW
i'm planning on doing and interference test after shaving my head about .030 (depends on the deck volume, i plan on performing that measurement on monday afternoon). i've shaved the deck .010 inches without measuring wrist pin height on my new pistons. they came in a rebuild kit to my bore spec, i assumed (there's that word...) they would deck the same, but a sticker on the box from D&J Rock said (cryptically) "deck std 2", and the machine shop , who is a rock dealer, could not find published specs to calc that out. i 'm doing my rod balance and prep myself, and wouldn't pay them to assemble my bottom end just to measure it, and did not take a deck measurement prior to teardown, so they didn't have the info they needed. so i may end up with a less-than-ideal deck height. by shaving the squeeze space out of my head and having a zero deck, i would be a lot closer to the ideal .040 quench space. the quench area is small enough to question whether or not it provides enough turbulence to matter. (i'll ignore the thermal processes of quench space with this engine, the build isn't to be like my pontiac drag motors.) anyway, i think i will have too much deck volume to get any benefit out of quench. the point of this ramble is that i will be doing a valve interference test, and i'll let you guys know how that works out after bringing my valves more than a millimeter closer to the cuts with all that milling. i expect to still have plenty of room, my hypothesis being that the suzuki has a huge amount of deck volume to begin with, it has deeply recessed valves in the combustion chamber (higher than anything else i've worked on) and that the idea of ruining a non-interference engine is hype. my particular pistons will be a variable that will affect my test on other engine builders, but it may be slight. i will do #1 and #4 at the same time, #1 with a clay test at my ~.500 lift, and #4 to measure distance to valve crash at TDC. so we'll see about that.

again, main idea of this thread is to put out information that hasn't been available to those of us who run 8V motors, and to clear up any conflicting info that is out there.

next installment: crankshafts! suzuki used two designs, and what that means to us... with pics, so you can compare your stuff when it's your time to rebuild!
 

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turd-polish-a-go-go
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Discussion Starter #11
ShuDuck- i will look into the flow balance on the 1.6 and 1.3 heads. i have a feeling that the 1.3 is cammed to a more ideal flow balance for its valve sizes (assuming ports are the same as 1.6). the 1.6 has a 89% valve ratio, where the samurai has an 83%. i believe the 1.6 cam has the wrong timing, robbing its efficiency. the 1.3 flow balance and camming may be the reason people are feeling more torque with that head swap. and don't get me started on the aftermarket cam selection...:mad3:
 

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Here are some of the engine specs as supplied by Suzuki and some piston info from ACL

1.3 G13BA
Bore x Stroke 74mm x 75.5mm
Compression Ratio 9.5:1
Cylinder Block Deck Height 186.8mm
Deck Clearance 0.2mm (above)
Cylinder Head Volume 32.2cc
Head Gasket Thickness (compressed) 1.2mm
Minimum Combustion Chamber Volume 38.2cc
Intake Valve O.D. 36mm
Exhaust Valve O.D. 30mm
Connecting Rod Length (between centers) 120mm
Piston Comp Height 28.90mm
Piston Clearance & Position (from Crown) 0.200 @ 45.80

1.6 G16A
Bore x Stroke 75mm x 90mm
Compression Ratio 8.9:1
Cylinder Block Deck Height 213.8mm
Deck Clearance 0.9mm (below)
Cylinder Head Volume 32.2cc
Head Gasket Thickness (compressed) 1.2mm
Minimum Combustion Chamber Volume 50.6cc
Intake Valve O.D. 36.6mm
Exhaust Valve O.D. 32.5mm
Connecting Rod Length (between centers) 139.6mm
Piston Comp Height 28.10mm
Piston Clearance & Position (from Crown) 0.200 @ 48.00
 

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It is very good to finally see some of these numbers come to light.

I run a 16v but have always had suspisions about the chamber volumes on the 8v motors when people said that you could change compression buy swapping the heads.

If you could come up with some chamber volumes for a 16v that would be awesome as I am about to pop my head and try to chase down some compression to the tune of 10:1. If not maybe I'll cc mine and add it to this thread when I pop it.:D
 

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1.6 G16B
Bore x Stroke 75mm x 90mm
Compression Ratio 9.5:1
Cylinder Block Deck Height 213.8mm
Deck Clearance 0.9mm (below)
Cylinder Head Volume 25.5cc
Head Gasket Thickness (compressed) 1.2mm
Minimum Combustion Chamber Volume 46.8cc
Intake Valve O.D. 29.2mm
Exhaust Valve O.D. 25.0mm
Connecting Rod Length (between centers) 139.6mm
Piston Comp Height 28.55mm
Piston Clearance & Position (from Crown) 0.300 @ 53.00
 

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the 1.6 distributor housing must be used with a 1.6 cam, regardless of which head it is in. the gears engage a bit differently... also, if you run a 1.3-grind cam (most of what's out there- has fuel pump lobe) you need to run the 1.3 distributor housing.
I'm getting ready to put a 1.6 head on my 1.3 block. I am going with a Isky Cam, so with that I can use my 1.3 disty? Also do you think I should have the head shaved?

Thanks
 

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turd-polish-a-go-go
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Discussion Starter #16
I'm getting ready to put a 1.6 head on my 1.3 block. I am going with a Isky Cam, so with that I can use my 1.3 disty? Also do you think I should have the head shaved?

Thanks
the isky cam will require you to use your 1.3 distributor housing. personally, i would up compression. there is plenty of room to play, if you are comfortable with tuning your combination to take advantage of it.

melbourne, are those specs for jdm, usa, or holden models? the piston to bore number seems wrong, and the compression numbers don't match the US specs. also, "g16a" is not a set of exact specs, it is a family of engines with some variation in combination. where did you get that data? i'd like to paruse through it.

for 16 valve info, temswift.net is where it's at. those guys have tweaked the sohc/dohc 16v's to the limit. of course, they call the 1.6 a "big block"... the 1300 and 3cyl info crosses over pretty well. check that site out, it's pretty good.
 

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With shaving the head or decking the block to get more compression, would I have to go with an adjustable cam sprocket to get the timing dialed in?? Is their a limit you can go on shaving the head?
 

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turd-polish-a-go-go
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Discussion Starter #18 (Edited)
according to Geofry at Colt Cams in British Coloumbia, the formula for cam timing is -1.5 degrees for every .010 cut. i have not checked the geometry, but decking does retard cam timing. Geofry says he grinds enough advance into his torque cams (meaning intake centerline) that he thinks i should try running my custom grind at the stock timing marks initially, and adjusting with a pulley after driving for a few weeks if i think my powerband is too high.

I will report on tuesday evening on the decking limit without valve crash (method as stated above). i'm doing this my damn self because there is so much garbage information out there (see? already getting conflicting posts: this-is-the-way-it-is-because-i-read-it-somewhere statements) and taking lots of pictures and measurements for your benefit along the way. your mileage may vary, but at least i can cite my references and back them up with photos of the tools and methods used.

edit: oh, and another thing- i can change a spark plug and make up the difference between my measured 33 cc chambers and the 32.2 cc number. as far as i'm concerned, my heads cc to 33 with the plugs in 'em. i've noted the variance in machining, and stand by my math skills and instrument techniques.
 

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I can tell you definitely know more about this then I do so I'll keep reading this topic to get edge-u-ma-cated:laughing:. I was going to try it with out the adjustable cam sprocket and see how it goes. This is one of my winter projects so it may be awhile before I see the results.
 

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melbourne, are those specs for jdm, usa, or holden models? the piston to bore number seems wrong, and the compression numbers don't match the US specs. also, "g16a" is not a set of exact specs, it is a family of engines with some variation in combination. where did you get that data? i'd like to paruse through it.
They are U.S. specs for 1994 models of the Samurai, Tracker and 4dr Sidekick. The specs are in PDF format and about 1.2Mb per file.
 
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