Port and polishing my heads while motor is out. Other questions on engine

terry8750
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Joined: April 1st, 2011, 12:55 pm

March 17th, 2016, 2:41 pm #1

so i had to pull my power unit for the pilot bearing in my trans.and i have decided to get a new friction disc and timken throwout bearing and timken pilot bearing.i decided it was time to refresh my heads with new seals and headgasket set from felpro and port and polish my head.
now i have a couple questions.
1. is there anything particularly that i need to worry about removing to much material in the runners.my idea was to bore out the exhaust runners a bit and just polish the intake runners knife edge the port serperators and polish the combustion chamber and take .030 out of the deck
2.should i ball hone the engine block and put new rings in or no? im not seeing to much wear in the motor i did happen to notice some vertical scratches that i can slightly feel.maybe where the ring edge rides ?
3.anything else anyone would reccommend.
and no im not finished yet the first exhaust port is only been rough cut with a burr bit and isnt even finished yet


























Last edited by terry8750 on March 17th, 2016, 2:51 pm, edited 1 time in total.
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terry8750
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Joined: April 1st, 2011, 12:55 pm

March 17th, 2016, 2:49 pm #2

oh and another question i had was g16b intake manifold will it fit? are the runners larger ? i noticed that if enlarged my intake ports its not gonna do me much good without larger intake runners and the g13b runners are the same size as the ports on the head.
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snowfish
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Joined: February 23rd, 2009, 8:14 pm

March 17th, 2016, 3:26 pm #3

Couple thoughts............... :hmm

Since you're down that far, why not do rings? Of course measure to insure bore & taper are within tolerances. ^o)
Good idea to mic the rods & mains too. Could grind .010 under if necessary. :gamerz
The intake & exhaust manifold gasket is a good guide as to how much material to remove. This is port matching.

Sounds like your getting a valve job with new valves? :news That's good. :thumb

I can't help with the G13B runner question. :shake I haven't personally been down that road Yet. ;)

Upon re-assembly, insure that your parts & work area are as close to surgically clean as possible. Looking forward to further updates. :cheers

............I'll be back in a bit........



IC3
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terry8750
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Joined: April 1st, 2011, 12:55 pm

March 17th, 2016, 3:30 pm #4

as far as the valves go im just gonna lap the valve seats the valves are in excellent shape.head is gonna be hot tanked
im currently working on a honda d16 stainelss steel header modifying it to fit the metro.
most every thing is in awesome shape considering the 200k miles on it.hell the combustion cambers didnt really have much carbon on them either

Last edited by terry8750 on March 17th, 2016, 3:32 pm, edited 1 time in total.
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t3ragtop
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Joined: May 2nd, 2010, 10:48 pm

March 17th, 2016, 11:35 pm #5

you want to be very careful and very conservative if you want to whittle on that g13bb head.

on the intake manifold you don't want to increase the diameters of the port runners. just clean up any casting imperfections. since the g13bb uses injectors mounted into pockets at the ends of the runners it's okay to do a light polish on them. the trick that really improves flow isn't all that easy as it requires cutting the plenum in half and fitting machined velocity stacks at the inlets to the runners.

in the ports you have to be extremely conservative in opening them up. if you enlarge them very much it actually reduces velocity. that slows down airflow to the point where the cylinders don't completely fill in the short time that the intake valves are open. remember that air molecules have mass and it takes a certain amount of energy and time to get those air molecules moving. velocity is more important than volume in this case.

on the exhaust side you can open the port a bit more but gas velocity is also important here. the area around the valve guides/ valve stems is sort of sensitive as well so you don't want to carve much off the valve guide seat bosses.

i have seen a lot of guys do a gasket match and manifold port match thinking that they were going to improve flow to a large degree. one thing that you want to be aware of is that the design engineers left a step from the exhaust port to the manifold. that serves to block exhaust gas from traveling back up the pipe and into the port where it's reverse flow affects the exiting gas. that's known as reversion and that step i described becomes an engineered anti-reversion feature.

don't go too deep. there are some areas where the coolant passages can be uncovered which ruins the head. ;)

and lastly, the sohc 15v head isn't all that super for flow anyway. if you read fainya's thread where he fitted a dohc 16v head to the g13bb block and added a cam angle sensor to the end of the cam where the twincam distributor sits, you will see that without porting the head at all he increased the flow by a larger factor. the g13bb still operates on it's fancier control set with distributorless ignition but runs a lot better. he drove that car from texas to northern ohio for last year's geopalooza and it was a righteous piece of work. ;)
Reformed Elitist Prick!
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Ephemeral Glade
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Joined: May 22nd, 2009, 6:37 am

March 18th, 2016, 12:35 am #6

Man, I love when T3Ragtop posts stuff!
Simulit Shadow Field Rep.
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terry8750
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Joined: April 1st, 2011, 12:55 pm

March 18th, 2016, 3:07 am #7

t3ragtop wrote:you want to be very careful and very conservative if you want to whittle on that g13bb head.

on the intake manifold you don't want to increase the diameters of the port runners. just clean up any casting imperfections. since the g13bb uses injectors mounted into pockets at the ends of the runners it's okay to do a light polish on them. the trick that really improves flow isn't all that easy as it requires cutting the plenum in half and fitting machined velocity stacks at the inlets to the runners.

in the ports you have to be extremely conservative in opening them up. if you enlarge them very much it actually reduces velocity. that slows down airflow to the point where the cylinders don't completely fill in the short time that the intake valves are open. remember that air molecules have mass and it takes a certain amount of energy and time to get those air molecules moving. velocity is more important than volume in this case.

on the exhaust side you can open the port a bit more but gas velocity is also important here. the area around the valve guides/ valve stems is sort of sensitive as well so you don't want to carve much off the valve guide seat bosses.

i have seen a lot of guys do a gasket match and manifold port match thinking that they were going to improve flow to a large degree. one thing that you want to be aware of is that the design engineers left a step from the exhaust port to the manifold. that serves to block exhaust gas from traveling back up the pipe and into the port where it's reverse flow affects the exiting gas. that's known as reversion and that step i described becomes an engineered anti-reversion feature.

don't go too deep. there are some areas where the coolant passages can be uncovered which ruins the head. ;)

and lastly, the sohc 15v head isn't all that super for flow anyway. if you read fainya's thread where he fitted a dohc 16v head to the g13bb block and added a cam angle sensor to the end of the cam where the twincam distributor sits, you will see that without porting the head at all he increased the flow by a larger factor. the g13bb still operates on it's fancier control set with distributorless ignition but runs a lot better. he drove that car from texas to northern ohio for last year's geopalooza and it was a righteous piece of work. ;)
thats exactly what i wanted to hear thank t3.im just trying to get as much out of the stock setup as i can and as many miles as possible.once this motor dies im going j23 hell or high water.ive been looking and i can a complete wrecked suzuki aerio for around 600 to 1000 dollars with the 2.3 in it.
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terry8750
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Joined: April 1st, 2011, 12:55 pm

March 18th, 2016, 3:29 am #8

snowfish wrote:Couple thoughts............... :hmm

Since you're down that far, why not do rings? Of course measure to insure bore & taper are within tolerances. ^o)
Good idea to mic the rods & mains too. Could grind .010 under if necessary. :gamerz
The intake & exhaust manifold gasket is a good guide as to how much material to remove. This is port matching.

Sounds like your getting a valve job with new valves? :news That's good. :thumb

I can't help with the G13B runner question. :shake I haven't personally been down that road Yet. ;)

Upon re-assembly, insure that your parts & work area are as close to surgically clean as possible. Looking forward to further updates. :cheers
i got some bore readings so here you go
these are the best tools i had and i know there is room for discrepancy as these are not the most accurate forms of measuring bore taper



all measurements are in mm
lx= measurement taken length wise of the block
xx= cross axis of long ways
1= 1/2 inch down from deck hieght
2= middle of the sleeve
3=right above the piston at very bottom of stroke
cylinder #1
lx
1...73.95
2...73.98
3...73.95

xx
1...73.98
2...73.98
3...74.00

cylinder #2
lx

1...73.98
2...73.94
3...74.02

xx

1...74.00
2...74.00
3...73.95

cylinder #3
lx

1...74.00
2...73.98
3...73.90

xx

1...74.03
2...73.98
3...73.97

cylinder #4
lx

1...73.94
2...73.97
3...74.00

xx

1...74.00
2...73.95
3...73.98
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terry8750
Elite Member
Joined: April 1st, 2011, 12:55 pm

March 18th, 2016, 4:09 am #9

those measurements are within guidelines for cylinder bore dia. limit 74.15mm(2.9196in.)
and tapper and out of round limit. 0.10 mm (0.0039 in.)
im really impressed with the measure ment ive gotten and how everything looks as hard as i drive it and with 200k miles on it i was expecting alot worse.
goes to show you if your change your oil and keep the carbon build up down everything wears nice and even
im still gonna pull the pistons and at least clean the carbon out of the ring lands and check for wear down low and give it a quick ball hone .
all though im not sure if i wanna mess with a good thing.its got so much compression if i put my hand over the bore it will damn near suck the skin off my hand
Last edited by terry8750 on March 18th, 2016, 4:16 am, edited 3 times in total.
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rjsdotorg
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Joined: May 21st, 2012, 3:40 am

March 18th, 2016, 5:06 am #10

A lot of people put 1" copper tubes or other restrictors in the intake to increase velocity.
One moto race builder puts a hump of Bondo-glass just before the valve stem to increase velocity and decrease reversion.
94 base AT converted to MT
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