Machine work for engine efficiency

[frankendat]

The goals of my engine build are maximum efficiency and torque. I am willing to lose some performance, especially top end in pursuit of these goals. My question today is benefit vs cost for a 5 angle valve job. The current plan for the head is to smooth the inside, gasket match the ports and polish areas where exhaust flows. The equipment and skill to perform a valve job I seem to be lacking. If there is a way to accurately set the correct valve angle in reference to the seat, then I have experience lapping parts and would attempt to match the new valves with the new seats. (I am thinking patience and some lapping/grinding compound will suffice)

Advice is welcomed, thank you

[datzenmike]

I would love to see dyno results of 3 or more valve seat angle jobs. On paper there is extra flow at extremely small lifts so it looks impressive but the valve does not spend very much time at those small lifts. If any gains I would expect it just above idle where the valve is moving slower. If any gains it's only valuable to extreme racing where 1 or 2 hp is added to twenty other small gains.

[frankendat]

27 minutes ago, datzenmike said:

I would love to see dyno results of 3 or more valve seat angle jobs. On paper there is extra flow at extremely small lifts so it looks impressive but the valve does not spend very much time at those small lifts. If any gains I would expect it just above idle where the valve is moving slower. If any gains it's only valuable to extreme racing where 1 or 2 hp is added to twenty other small gains.

That was my thinking as well. Aside from smoothing edges and gasket matching can you think of anything else (purchased at a machine shop or home done) that is of benefit to do to the head while it is off?

My list thus far--

replace valves/outer springs/valve guides/valve keepers and seals

reuse inner springs

ceramic coat valves

smooth edges/gasket match

soak head and clean out all oil and coolant passages

install new valve seats

hand lap valves (I will need guidance here)

heat cycle head to remove oil in metal (I had trouble with this when coating my Z24 head)

ceramic coat head

Have machine shop block/level and true head

Reassemble

 

Thoughts?

[bananahamuck]

I don't know about numbers at all  but when i pull off a good valve job it is very noticeable .

 

  You can tell when you're cutting if it's going good or if you are just getting done. Never done it professionally i just have my own older Sioux machine and  seat tooling and been doing it for 30 years for myself and family.

 

 In the late 80s  I picked mine up with all the tooling from friends brother that ran auto shop in Seattle , because the older machines can't  grab the newer smaller valves in 3-4 valve style heads , so he was upgrading . And 98% of inserts the seat cutters ride on ,that i have, wont go into that kind of head either. 

 

i have never ported other than playing around with diegrinder on junk head

 

 

anyways.

 

 

 

 

 

 

..

Edited April 19 by bananahamuck

[datzenmike]

If it needs a valve job it will always be a noticeable improvement.

 

You can chuck the valve in a drill and spin it against sand paper to round the edge on the cylinder side of the face. This is usually a sharp edge and air hates passing by a sharp edge. Thing flared air horns or trumpets on side drafts. The edge on the seat where air enters the combustion chamber should also be rounded but care must be taken to not mar the seat. This is the goal of the 5 angle valve job to round the otherwise sharp edge off and smooth the flow.

 

But all this will maybe gain you something at high RPMs and big CFM numbers. If building for economy, efficiency and torque the stock valve job is probably 'good enough'.  

 

 

[frankendat]

5 hours ago, datzenmike said:

If it needs a valve job it will always be a noticeable improvement.

 

You can chuck the valve in a drill and spin it against sand paper to round the edge on the cylinder side of the face. This is usually a sharp edge and air hates passing by a sharp edge. Thing flared air horns or trumpets on side drafts. The edge on the seat where air enters the combustion chamber should also be rounded but care must be taken to not mar the seat. This is the goal of the 5 angle valve job to round the otherwise sharp edge off and smooth the flow.

 

But all this will maybe gain you something at high RPMs and big CFM numbers. If building for economy, efficiency and torque the stock valve job is probably 'good enough'.  

 

 

 

I don't have a drill that spins true enough, but I could put the valve in my lathe.

Where/how is lapping used? I have lapped gun parts to the 10 thousandth and currently have a set of Z24 intake and exhaust valves that move in their brass guides like they are gliding on glass. _(I will complete the same process with the KA24E valve/guides). I am confused regarding the exact position needed for the valve relative the seat. I have calipers and micrometers. if I know exactly where the valve needs to be I can put it there.

[frankendat]

9 hours ago, bananahamuck said:

i have never ported other than playing around with diegrinder on junk head

 

junkyard head and pawn shop air powered grinder, that sums up the breath of my experience as well (unless you count gasket matching as "porting")

[datzenmike]

I think you can. It involves the same work, tools and results. It improves breathing at higher revs, it's permanent, it never goes out of tune, and I enjoyed doing it.

[datzenmike]

9 hours ago, frankendat said:

 

I don't have a drill that spins true enough, but I could put the valve in my lathe.

Where/how is lapping used? I have lapped gun parts to the 10 thousandth and currently have a set of Z24 intake and exhaust valves that move in their brass guides like they are gliding on glass. _(I will complete the same process with the KA24E valve/guides). I am confused regarding the exact position needed for the valve relative the seat. I have calipers and micrometers. if I know exactly where the valve needs to be I can put it there.

 

Don't touch the valve/valve guides. You can't polish or lap them. They are perfect when the head was built and time will only wear them looser.

 

The used valve/seat will self center as it closes.  There's no real need to replace valves and almost always they can be re-faced and then lapped against the old or a new seat for a good seal.

[frankendat]

3 hours ago, datzenmike said:

 

Don't touch the valve/valve guides. You can't polish or lap them. They are perfect when the head was built and time will only wear them looser.

 

The used valve/seat will self center as it closes.  There's no real need to replace valves and almost always they can be re-faced and then lapped against the old or a new seat for a good seal.

Au Contraire, Mon Frere,

I ceramic coated each new valve stem with a thin friction reducing substrate. Then, I took each new valve and new brass valve guide and burnished the two together, until the two moved without resistance. The valves and guides will be kept and installed in sets going forward. 

 

My confusion is how to determine the how the new valve and new valve seat can/should be lapped together

[frankendat]

13 hours ago, datzenmike said:

I think you can. It involves the same work, tools and results. It improves breathing at higher revs, it's permanent, it never goes out of tune, and I enjoyed doing it.

How is "porting and polishing" different from smoothing the casting ridges in the head and gasket matching? When working on the Z24 head I used this as a guide http://www.kangamotorsports.com/blog/2016/11/datsun-cylinder-head-cleaning and planned on doing it again for the KA24E head.

[datzenmike]

 

8 minutes ago, frankendat said:

Au Contraire, Mon Frere,

I ceramic coated each new valve stem with a thin friction reducing substrate. Then, I took each new valve and new brass valve guide and burnished the two together, until the two moved without resistance. The valves and guides will be kept and installed in sets going forward. 

 

My confusion is how to determine the how the new valve and new valve seat can/should be lapped together

 

New is different than what I said.

 

New valve and new seat should be very close. All that's needed is to lap them. I use an electric drill to spin them.

 

Ceramic coatings you bake on in an oven is a good idea on the combustion chamber side of both valves. You might as well do the piston tops and the combustion chamber itself.

 

2 minutes ago, frankendat said:

How is "porting and polishing" different from smoothing the casting ridges in the head and gasket matching? When working on the Z24 head I used this as a guide http://www.kangamotorsports.com/blog/2016/11/datsun-cylinder-head-cleaning and planned on doing it again for the KA24E head.

 

I don't see any real difference in smoothing casting flash and 'porting and polishing'.

[frankendat]

12 minutes ago, datzenmike said:

New valve and new seat should be very close. All that's needed is to lap them. I use an electric drill to spin them.

Yes, that is my understanding as well, but I can't find any information on the correct way to perform it. Engines are precise machines there must be data and suggestions how to accomplish. 

 

13 minutes ago, datzenmike said:

Ceramic coatings you bake on in an oven is a good idea on the combustion chamber side of both valves. You might as well do the piston tops and the combustion chamber itself.

I am on it :)

 

13 minutes ago, datzenmike said:

I don't see any real difference in smoothing casting flash and 'porting and polishing'.

Awesome! I found the link in my last post (about a 240) an excellent reference. It is that type of guide/information I seek for lapping new valves in new seats, but I would settle for the proper angles/fitment and how to achieve it.

 

Yesterday, I pulled the windows out of the D21 I am scrapping and true to form, I damaged the first one. After that learning experience the rest went smooth and fast, but there is what I don't know, that I don't know. After lapping the first valve it may become clear, even easy, but I really want to avoid trashing a valve or a seat, which is why I am seeking the information with such persistence. 

 

[datzenmike]

Z24 Valve seats...

 

Intake 

45⁰

Then cut a 60⁰ on the combustion chamber side down into the 45⁰ cut till the valve contact surface is 2mm wide.

 

Exhaust

cut the seat at 45⁰ till the widest part is 37.5mm diameter.

second cut is below the valve contact surface at 15 degrees to smooth the flow into the port.

 

New valves will need nothing done to them and will fit the prepared seats. A little valve grinding compound and some lapping to remove any irregularities.

[frankendat]

3 hours ago, datzenmike said:

Z24 Valve seats...

 

Intake 

45⁰

Then cut a 60⁰ on the combustion chamber side down into the 45⁰ cut till the valve contact surface is 2mm wide.

 

Exhaust

cut the seat at 45⁰ till the widest part is 37.5mm diameter.

second cut is below the valve contact surface at 15 degrees to smooth the flow into the port.

 

New valves will need nothing done to them and will fit the prepared seats. A little valve grinding compound and some lapping to remove any irregularities.

Excellent! Is there any way you would share this information on the KA24E? (or point me to the place where I can find it?)

[datzenmike]

FSM factory service manual for '89-'90 S13 240sx and 90-'97 D21 had KA24E engines. None of this fits the Z24.

[frankendat]

1 hour ago, datzenmike said:

FSM factory service manual for '89-'90 S13 240sx and 90-'97 D21 had KA24E engines. None of this fits the Z24.

I am working on a KA24E. I only mentioned the Z24 because I have some Z24 parts and was trying to save money. I have yet to acquire a FSM that includes the KA24E. Could I talk you into providing the valve seat lapping information? If not, no worries, I need to get a 90 D21 engine FSM.

 

In other news, I gave up trying to find valve keeper options, bit the bullet and ordered a new set from Nissan.

 

Thank you for your continued guidance.

[datzenmike]

You'll need the FSM for valve and seat information.

[Stoffregen Motorsports]

19 hours ago, datzenmike said:

Z24 Valve seats...

 

Intake 

45⁰

Then cut a 60⁰ on the combustion chamber side down into the 45⁰ cut till the valve contact surface is 2mm wide.

 

Exhaust

cut the seat at 45⁰ till the widest part is 37.5mm diameter.

second cut is below the valve contact surface at 15 degrees to smooth the flow into the port.

 

New valves will need nothing done to them and will fit the prepared seats. A little valve grinding compound and some lapping to remove any irregularities.

Sometimes it's beneficial to grind the valve out of the box. They can have a ridge that impedes flow. A three angle valve job is not only what you do to the seats, but the valve as well.

 

[Stoffregen Motorsports]

Compare that valve to this valve and you can see the obvious gains in flow.

 

[frankendat]

17 hours ago, datzenmike said:

You'll need the FSM for valve and seat information.

I acquired an FSM from a 1994 D21 with a KA24E (I thought the KA ended in 93?) Anyway, downloaded all 1,112 pages and what do you know the valve information IS in there! I downloaded and purchased all the manuals for my 1984 when I bought the truck, don't know why I didn't do the same when I purchased the parts truck. 

Many questions have been answered and a few new questions present.

 

Since the FSM is for a 94 it talks of an ABS brake system, but I have seen no ABS system on the 1990. Is there one and I missed it?

 

Any other discrepancies come to mind between a 90 D21 w/KA24E and a 94 D21 w/KA24E?

 

A final note on valve installation, I am having difficultly envisioning the interplay between the valve and the seat and it is likely misunderstanding of one aspect. In my mind the valve and seat interact on an angle and the valve would require fitting to this angle, BUT the more I look at it, the valve and seat appear to be at the same angle. The valve and seat are lapped together the same as if they were directly in line with one another (because they are directly in line with one another) The "angle" I have been worrying about does not exist. In fact, I could take some grinding/polishing compound, align the valve and seat vertically, in a drill press or a mill and match them together perfectly before installation.

 

Did I just figure it out or have I gone off the rails?

[frankendat]

5 hours ago, Stoffregen Motorsports said:

Sometimes it's beneficial to grind the valve out of the box. They can have a ridge that impedes flow. A three angle valve job is not only what you do to the seats, but the valve as well.

 

My valve came with a slight undercut, do they require additional work?

[datzenmike]

The KA24E was only 2 years '89-'90 in the S13 240sx car. The D21 truck was '90 -'96 when the KA24DE took over. heads should be the same.

 

The pistons used for the first 3 months in the S13 240sx were domed for 9 compression, later reduced to a 2.8cc dish.

The S13 rods were fitted with bushings and pins were fully floating to reduce friction

[frankendat]

34 minutes ago, datzenmike said:

The KA24E was only 2 years '89-'90 in the S13 240sx car. The D21 truck was '90 -'96 when the KA24DE took over. heads should be the same.

 

The pistons used for the first 3 months in the S13 240sx were domed for 9 compression, later reduced to a 2.8cc dish.

The S13 rods were fitted with bushings and pins were fully floating to reduce friction

How was my valve/valve seat understanding?

 

[datzenmike]

Good. Both are 45⁰ so when together it seals tight.

 

Stoffregen

: Has anyone dyno-ed a before/after 3 or 5 valve angle job and posted the numbers? Most of the flow bench gains are at very low lifts and almost no time is spent there on a running engine. At just 4,000 RPMs the intake is opening 33 times a second.