Login Register

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
G16A Main Bearing Caps
I have 3 G16A blocks, 2 are cracked, 1 looks like I can rebuild it. Problem is that the main bearing caps do not look good on that one. They have many little hair-line cracks in them.

Question: Is it advisable to use a good looking bearing cap from one of my bad blocks if it is the same size letter?

For example, if the bad one is #5, size "C" and one of my bad blocks has a size "C", but it is cap #4 then is it advisable to replace the #5 cap with the better looking #4 cap from the cracked block?

Does that make sense? The letters represent size ranges for the bore diameter. So, I am wondering if anyone else has tried this and how it worked. I am concerned that even though the Cap size letter matches the block it might still be a little out of round and effect my bearing to crankshaft journal clearance.

Thanks in advance for any advice you can spare.
1995 Suzuki Sidekick JX 4WD 4-door hardtop, G16 1.6L 16 valve L4 SOHC, 4-spd Auto Trans (Asin AW Model 03-72 LE), Non-ABS, Assembled in Ingersoil, Ontario. Currently in Tok, AK.
those are all bored in place, so must be re-ALIGNED bored on a machine shop.

in fact just like day one in the factory, over sized caps(smaller I.D.) it is bored to perfection.
know that the ID of bearing shells are based on that perfect boring, the shells are crushed and then fit. (very tricky this, and never ignored,)

just like cams are, (in a head or in a block)

i needed block and had took at like 5, and only one was good but crank a wreck)
G16s good enough for cores, is not easy to find. not now.
that is why spinning (wrecked) a main bearing is bad, unlike rods, that are simply swapped ,wrecked for good bores
I bet suzuki does not sell blank main caps. to begin anew, and the block side, is not replaceable.
so they'd have to spray liquid metal to that , super expensive that. done say on antique cars,
finding a good block is not easy.
I do not know if some bearing companies sell bearing for oversized main block bores, G16.
It sure possible but I never seen them for G16. (they'd have thicker shells to do that)

usually the shop would have the catalog LIST of shells in hand then the machines shop align bores to the size in the book.
then buys them.
and new ground main crank journal sizes.. matched up too.. only that way works,
you'd have to see every makers catalog of bearing shells, main.
a big job. searching.
Thanks for the quick reply.
As I read it, you advise that using the main bearing caps (shells) from a different block is a bad idea.
I wish I had easy access to a machine shop, but I don't (nearest 200 miles).
I think I will just use the caps that I have with the block even though I don't really like the way they look.

Another question: How much do you think having the cylinder head off of the block actually effects the roundness of the cylinders? I am planning to use a fixed hone to hone the cylinders to fit size 2 pistons. All 4 cylinders on the block are bored to size 1 pistons. My concern is that the cylinders are currently out of round about .0005" or a little more (haven't done careful measuring yet). From previous comments I wonder if I hone them to round without using a head plate like machine shops (I don't have) then will that actually cause the cylinders to become out of round when I bolt the head back on?
1995 Suzuki Sidekick JX 4WD 4-door hardtop, G16 1.6L 16 valve L4 SOHC, 4-spd Auto Trans (Asin AW Model 03-72 LE), Non-ABS, Assembled in Ingersoil, Ontario. Currently in Tok, AK.
Also, as I am shopping around I am finding that there are "standard" main bearings for the g16a. Not three different standards or color codes, just one standard size available. So far, I have not even found the dimensions of the "standard" bearings. There should be three standard sizes, right?
Where do you buy main bearings?
1995 Suzuki Sidekick JX 4WD 4-door hardtop, G16 1.6L 16 valve L4 SOHC, 4-spd Auto Trans (Asin AW Model 03-72 LE), Non-ABS, Assembled in Ingersoil, Ontario. Currently in Tok, AK.
I can answer that, no blind person, can , this text box.
we use 2 tools here, (not counting all surfaces check for warpage , metal checks and pressure checks that all machine shops for engines do.
the bores are checked first for out of alignment, with special tools all shops have
then with bore gage, for excess sized main bores
took me 10hours labor to do that on one block all tools in hand.
Ok, you should get great book , called engine builders say at , Barnes & Noble.
it covers all stuff, not possible type here
but here, put in the wrong bearing caps, and sizes matching crank journal sizes.
with assembly lube
set main bearing cap torque,staged, all caps staged in parallel.
then if you cant turn it by hand ,now you know way.

roundness, is also in that book,
when you tighten the 4 head bolts say on one cylinder the bores distort.
there are youtube videos and 3d simulations there showing this effect.
and heat, factor. (bores change size and shape from cold to hot.

the rings can only hide a small about of out or round, ok? tiny. Try bending and old ring, see, it don't bend (oops cracked), but can do vertical taper easy
There are 3 ways
2:junk yard jerry rigs.
3;Totally wrong, the endless story.
not saying what is right wrong only facts,. I have 4 books of that type, all together wow. full coverage.

one way is to use shims washer on custom sized (length short) mm, for all head bolts (not stock too long)
and torque them to spec, the washers will help spread the forces. and hopefully work. while boring or honing.

out of round is very bad thing mostly
as is warpage

the see how bearing shells really work, most folks have no clue.
links, see crush here.

see hydrodynamic lubrication

the inside bearing surface is not round

the shells are not simply round inside, and if you know this, measuring with pastigauge works.
one guy didn belive me so we torgue a bearing in the main, and with the bore gauge turned it in this shell, see that needle change, it is real.

one more
torque and heat distortion is covered in all classes and books on engine building

the best engines are last honed hot and pre-torqued,
for sure racing, 1 more HP can win a race
and now, the word green (CO2 rules) means , no bypass gasses, from out of round cylinders.
Also the rings can seat in, if out of round tell how that can happen?
food for though.....hope it Sings like a bird.
my building a G16 page covers this, with proof from the factor at suzuki. then historical.
no, standard means stock base sized, (with sub sized color codes0
then large sizes,(ground cranks,) they grind it until its perfectly round, and stop at the first over size.
there are 2 bearngs classes.

Historical way:
real suzuki bearings from suzuki, and very old subsizes. (pistons and rods bearings too)_
why because they are very crudely gang ground all mains at 1 time.
Picture in your mind, 4 grinding wheels, and all 4 are not same size, (close but not close to equal or right)
the parts are measured by a team ,to measure all parts and color code then for later, (gee it does work) but wow ,what crude.
My guess is the balance the crank latter with the 4 odd sized pistons.
enter sub size color codes.'

now 25 years later, those engines are not made. ( FAR AWAY IS SOUTH AMERICA OR?)
and are only landing in a very modern machine shopS unlike above above but humans with very great skills and tooling (crank grinder polisher)
the old cranks (no more new, or if like $2000 cost sure) the old crank has 8 places to be wrong, not counting end play, and wobble is reject.
what do they do, the measure in at least 16 places and for wobble. 90degrees apart.
if it fails, it is useless crank (hot liquid metal spray is NOT worth this car)
the mAN then says out load, this crank can be ground the next over sized bearing then does so and is 100% perfect and polished and radius ground.
Using non suzuki parts, if you hand those suzuki parts now he'd pull his hair out.


They even may magneflux it first. for cracks no human can see until now.

same story engine bored,
Then 25 years later, the shop bores it super perfection, and now magic color coded sub sizes as seen on top deck side ,1,2,2,1 codes.
those old codes are useless now, you have new non suzuki made pistons now. (cam ground oval new precision made pistons)

in fact those top made pistons have a data sheet with the kit, how to precision bore and hone those old cylinders.
the bore man bore to the data sheet, exactly
after all has no idea at all the thermal dynamic heat effects on this new secret alloy piston. (lots exist some are very strong)
he knows all about, heating the block and torque plate for sure on RICE motors or thin wall USA v6/8 SMOG engines (trash)
some might say, sorry due that the RACE option the Premium option.

I've no idea at all what is in your engine before or after or in your kit.
not at all.
nor all those measurements,

what I did on one is buy a new 100% reground crank to perfect under sizes on all journals and EQUAL
on others ive got super huge crank grinding shop in town, 1/3 cost of above.
if the crank is not straight or the line bores are off the oil pumping dynamics fail inside the bearing,per link above.
That is why its best to do it right, but if not car is good from grandma's trip to church 1 day weak, never near 6000 rpm

cheers and good luck..
and mixing factory parts with modern is no good. (sure grind cranks x8 sure bore hone block) but use new parts.
see engine also with one new piston
and one new rod journal ground an fit to new shells.
fun to see,but do?

(01-30-2019, 09:29 AM)Nunapitchuk Wrote: Also, as I am shopping around I am finding that there are "standard" main bearings for the g16a. Not three different standards or color codes, just one standard size available. So far, I have not even found the dimensions of the "standard" bearings. There should be three standard sizes, right?
Where do you buy main bearings?
Wow, such long responses. I appreciate the time you spent on them. And have to say you have an interesting writing style.
Lots of good info, I will have to reread a couple of times.
I still have questions if you have energy to write a little more. First let me give you a better description of my situation:

Machine shop not an option, very rural. I have good quality micrometer and bore gauge (Fowler). I have nice heated workshop. I have fixed hone with 3 grades of grinding stones, but no boring machine. I have moderate metal fabrication skills and tools (no lathe). I have '93 service manual and '94/'95 supplementary manual. Attempting to rebuild an engine for a second '95 Sidekick (I have completed one already -- see my face book page, "Suzuki Sidekick Restoration Project" for more on that project).

I disassembled my spare engine from a '95 sidekick (16V, G16A block) and found that it was cracked between cylinder 1 and cylinder 2 through the main bearing mounting surface all the way to the piston sleeves on both sides. That block is trash.

I have one other g16a block. No info about it, but I suspect that it came from a '93 model, already disassembled, part of an extra parts car that was included in the purchase of another parts car (I have a collection of 4 including the one I rebuilt already). Inspection of this spare block indicates that it is not great, but no cracks, and top surface within specs, some taper and out of round in cylinders (still to be carefully measured). It has marks and scratches in the main bearing bores making me think that the main bearings may have turned. I do not have the bearings or the crankshaft that came out of this block.

The crankshaft from the cracked block appears to be in excellent condition. All main journals measure 2.0470" with maximum out of round of 0.0001". Well within the manual specs. The main bearing caps concern me because they have tiny cracks. None go all the way through and all short. Looking at them yesterday, I am thinking I could probably go ahead and use them. No other choice. I tried cap from other block and measurements were all out of wack. I torqued one original slightly cracked cap down (#5) and measured the bore at 2.2077 vertical and 2.2074 near horizontal (0.0003 narrower across than it is up/down). Looking at the manual, those measurements appear to be usable. So I need a main bearing with outside diameter of 2.2077, inside diameter of 2.0486. Shopping now to see if I can find them before I do any more work on the block.

So now that you know all about my engine;
1. Where do you buy main bearings when you need them?
2. Rock Auto has main bearings listed as "standard" set. Same at LowRange. Neither of them list the dimensions of the bearings. Do you know what they mean by "standard size"? I have written messages asking them, but no response yet.
3. You mentioned using shims/washer with head bolts as an alternative to the head plate for honing the piston cylinders. Do you have an example/illustration of doing that. It might be something I can do that would be better than honing without anything on the top surface of the block.

PS. I am a hobbyist. I do this just for fun. I like to do a good job, but sometimes have to settle for OK. And money is an issue according to my wife. Smile.
1995 Suzuki Sidekick JX 4WD 4-door hardtop, G16 1.6L 16 valve L4 SOHC, 4-spd Auto Trans (Asin AW Model 03-72 LE), Non-ABS, Assembled in Ingersoil, Ontario. Currently in Tok, AK.
engine building is one of the longest topic there is, besides custom eCU tuning

standard means ( at the factory ) this is the standard grind, (as varies by the wear in the factory grinding wheels,AND COLOR CODED TO MATCH ERROR)
this is why they have sub sizes, no other reason just that.
When you buy new bearings, from not Suzuki you get 3 sizes only, and for a new ground crank,
you can not use say brand new bearing from USA, on old , never ground suzuki crank. see why?
that means only this old crank fits only those just removed bearings,but if lost only suzuki sells them. ok?>
standard .010, 0.02. 0.03
in case seller and grinder are using imperal inches. so my guess is standard is the color code for suzuki for loose standard.
tell me how to grind any used crank to standard so is really bogus.
the main bearing max is .0016" clearance, top to bottom not sides of journal.
ever heard of federal mogul or trw. ?

see suzuki 5 colored bearing main here, (part id 40 )
note some sizes are not discontiuned for ever.
with this 1 fact you learn why all cranks must be ground and using USA bearing best, 0.010' may work, a mike proves this is minutes

in a real shop in the USA they get say ground to perfection NO ERRORS, to the next major size. (smaller journal)
the engine serial number G16xnnnn x is the year, on all USA engine blocks using same letter codes used for VIN year)
main bearings may have turned. (well using that MIKE, tells you in 5 minutes if it was ground or not,the spec page in your FSM is clear on that.
main cracks are no good ever. would be kicked to curb., but you have no choice lacking , doing aligned board new main bore mounts..... so is now off table.

there are in fact bearing makers in the USA, that sold bearing since, 1920's famous makers.
then those ebay crap, called DNJ (joking, defiantly NOT japanese) and vast others no named or using other odd names.
that is the problem now,
the top brands are all very good. bearings mains or rods. mains is topic now.
the are precision made to fit ONLY stock main bores,and have stock set preloads, if loose will spin and leak oil, all bad bad bad.
The crush if first, at full torque , and like this the bearing is now at spec ID , inside diameter and fits the new ground crank perfectly
when using and old crank and old bearing , measure the crank journals in 8 places, 9degr. apart
then with 4 bearing loaded and torqued with 4 used bearing shells from the old but looks good crank
I then use the bore guage tool to see if all 4 bearings are at spec, 8 places. that is 16 measurements
then the 4 plasitgage check now, to prove the above was not done right.
In a schlock shop (amateurs) the just to the the Plasticgage and pry
in the super bad shop just turn crank by hand (no pistons/rods)
if spins with 1 hand the bad guy says hey this is good.

its lots of labor and cost here.
why skip a step, blows my mind. but is common, we do 20 checks on the crank
21; for crank wobble
22; for line bore way off.
23: end play,
24: and lots of checks for cracks, those are super bad. (A SHOP MAGNEFLUX THE Crank after all why grind a cracked crank
those cracks are,from bad ROD seizing and the huge forces to the crank,
or from engine ping from H3LL (detonation) EGR DEAD.

federal Mogul

3 sizes, std, .1mm and .2mm

suzuki is here, and some are out of stock. 5 sizes.


those are very good bearings, not from some lame china cloners.

Forum Jump:

Users browsing this thread: 1 Guest(s)