improving flow for the 3FE’s top end

[RockDoc]

https://forum.ih8mud.com/60-series-wagons/222189-extreme-valve-body-just-installed.html

If you don't have a aux ATF cooler, consider adding one. There are a few threads in the FAQ I believe on flushing and such.

 

[ntsqd]

[hijack]

snip....
ntsqd,
Are you a machinist or gear head?

Yes.
I worked as a conventional machinist/fabricator (rarely did direct engine machining unless modifying for 4 bolt mains etc.) in an engine machine shop that focused on racing and unusual application engines during my undergrad days. I designed and built most of their dyno hardware (except the load cell itself), built a couple Drag cars, fork lift parts, etc.
[/hijack]

 

[RockDoc]

Called the machinist today, haven't had a chance to look over things yet..... I'll call tomorrow again if they don't call first.

Pulled out the MAF camshaft to give it a look over, and this is what I found

2 lobes are wiped, several are sad looking and so are the journals... so it looks like I'll be looking into the regrind options for the cam I pulled out of the 2F. Oh well, got this cam for free, and the solid timing gear will still be put to use. It was pulled from a MAF HiPo engine that died an early death due to a botched oiling system, so I guess I'm not surprised.

A ways back I mentioned the different exhaust valve stem length and corresponding difference in rocker arm geometry between the 2F and 3FE, here are a few pics to illustrate the rocker arm portion of that story.
First a comparison from above. Plan view geometry looks the same.

The 2F rocker tips are even between the intake and exhaust.

On the 3FE, the rocker arm tip is slightly higher for the exhaust (longer valve stem) than for the intake.

You can see that the 2F (*'83-earlier 2F per Jim*) has beefier adjusters on the push-rod end of the rockers.

 

[ntsqd]

ZDDP?

 

[lehiguy]

Why the 2f cam and not the 3F? You are planning on resurfacing the lifters I presume. Are you going to mill the head? 8:1 is not really a recepie for power...

 

[ntsqd]

You can still find someone to resurface lifters?

 

[FJ40Jim]

You can see that '83-earlier 2F has beefier adjusters on the push-rod end of the rockers.

Fixed it for ya.

 

[RockDoc]

ZDDP?

May have been an influence, but my understanding is that the rebuild of the block it came out of left a botched oiling system which killed the bottom end bearings. I'm betting oil-starvation more than weak add-pack, but it makes a good example of what can happen if oiling needs for the cam aren't taken care of.

Why the 2f cam and not the 3F? You are planning on resurfacing the lifters I presume. Are you going to mill the head? 8:1 is not really a recepie for power...

This is going on a 2FE. The 2F cam is loose and, to my eyes, in good shape. I have a spare 3FE I'll be tearing apart for all the peripheral stuff I'll need to bolt up to the 2FE. This, however, is sitting complete right now, so I have no idea of the condition of it's cam. I may still have to tear into it to grab 2 more good lifters to send though, as a couple from the 2F have a touch of pitting.

The plan has been to shave the head to give a chamber of 73cc (stock 3FE is 77cc by my measure) to give a DCR of ~7.4 with a 260* cam. I'll need to decide what cam I'm going with pretty soon so I can revise the instructions for the shop if needed (head is in, but they haven't started on it yet). If for some reason I decide to run a stock cam, the dynamic compression with stock 3FE chambers is already going to be relatively high for a deep-breathing 2F.

 

[RockDoc]

Just realized I mess up the intake closure angle for the stock 2F (should be 53* rather than 43*), so my math in here is wrong. I'll redo it and post up.....

Some geometry fun from early this morning.

I've been playing around with the dynamic compression ratio, which is the idea that a true measure of the compression in the engine takes in the timing of intake valve closure. If the cam timing is changed (i.e. longer duration), you change the effective compression ratio (i.e. drop), and that's why engines that use long duration can run higher static compression ratios. This is detailed in Dalton's book, and is used to help decide a safe compression ratio to run with an "upped" cam. By keeping the dynamic compression in line with what is seen with the stock chamber volume and cam timing, you stay in a safe zone despite monkeying with both of these parameters.

So looking at the Fs, here are three diagrams that I used to figure out the swept volume of each configuration from the point of intake valve closure on the compression stroke. All is done to scale, with the 3FE having a stroke of 95 mm and a center to center connecting rod length of 148 mm, and the 2F having a stroke of 101.6 mm and a rod length of 190.5 mm. Intake valve closure is 48* ABDC for the 3FE, 43* ABDC for the stock 2F, and 59* ABDC for the Delta regrind posted up by Dave-T in the first camshaft link in post 1.
View attachment 320457

So, from the effective sweep for each configuration, the following has been put together. I've assumed that the late 2F (2F with world market 3F head) has a stock compression ratio of 8.3:1 (posted by Jim elsewhere). You might notice I am calculating for the 2FE now.

Piston area 69.4 cm2

Stock 3FE comp: 8.1:1
Squish vol: 92.84
Swept vol: 659.17
Total vol: 752.01
Stock head CC vol: ~77

Stock effective sweep: 83.5mm
Effective swept vol: 579.2 cc
Dynamic compression: 7.24:1

Stock late 2F comp: 8.3:1
Squish vol: 96.53
Swept vol: 705.1
Total vol: 801.63

Stock effective sweep: 91.1mm
Effective swept vol: 632.2 cc
Dynamic compression: 7.55:1

2FE with Delta cam (59* ABDC intake close)
effective sweep: 82.1
effective swept vol: 569.8

for effective compression of 7.55, squish vol: 87.0 cc
CC vol: 71.2 cc
static compression: 9.1:1

So it looks like with a longer duration cam, 9.1:1 should be pretty safe on the 2FE. If someone can let me know what is a safe static compression to run with the stock cam, I can push the numbers a bit further (although static compression of 9.1:1 sounds pretty high already).

Oh yah, I also have 5 of the intake ports all done up like shown for #5 in pics above. So when I have a chance, I'll run them all with the flow bench and compare them to #2 (the un-modified standard).

 

[RockDoc]

Fixed (I think)


Jim, if you are watching....
You mentioned you have a 2F running a DCR of 7.8 and it needs better than regular gas... and that the stock value (which I posted as 7.55) was close to the limit for regular..... Given that I've revised the stock value to 7.14, (7.24 for the 3FE), do you feel that 7.24 is close to the limit, or would 7.4 be safe on a desmogged motor?

Edit, I just realized that I wrote down the wrong intake closure angle for the 2F here, and calculated wrong. Corrections in red where needed



Some geometry fun from early this morning.

I've been playing around with the dynamic compression ratio, which is the idea that a true measure of the compression in the engine takes in the timing of intake valve closure. If the cam timing is changed (i.e. longer duration), you change the effective compression ratio (i.e. drop), and that's why engines that use long duration can run higher static compression ratios. This is detailed in Dalton's book, and is used to help decide a safe compression ratio to run with an "upped" cam. By keeping the dynamic compression in line with what is seen with the stock chamber volume and cam timing, you stay in a safe zone despite monkeying with both of these parameters.

So looking at the Fs, here are three diagrams that I used to figure out the swept volume of each configuration from the point of intake valve closure on the compression stroke. All is done to scale, with the 3FE having a stroke of 95 mm and a center to center connecting rod length of 148 mm, and the 2F having a stroke of 101.6 mm and a rod length of 190.5 mm. Intake valve closure is 48* ABDC for the 3FE, 43*(53*) ABDC for the stock 2F, and 59* ABDC for the Delta regrind posted up by Dave-T in the first camshaft link in post 1.
View attachment 401093

So, from the effective sweep for each configuration, the following has been put together. I've assumed that the late 2F (2F with world market 3F head) has a stock compression ratio of 8.3:1 (posted by Jim elsewhere). You might notice I am calculating for the 2FE now.

Piston area 69.4 cm2

Stock 3FE comp: 8.1:1
Squish vol: 92.84
Swept vol: 659.17
Total vol: 752.01
Stock head CC vol: ~77

Stock effective sweep: 83.5mm
Effective swept vol: 579.2 cc
Dynamic compression: 7.24:1

Stock late 2F comp: 8.3:1
Squish vol: 96.53
Swept vol: 705.1
Total vol: 801.63

Stock effective sweep: [STRIKE]91.1mm[/STRIKE] (85.4mm)
Effective swept vol: [STRIKE]632.2 cc[/STRIKE] (592.7cc)
Dynamic compression: [STRIKE]7.55:1[/STRIKE] (7.14:1)

2FE with Delta cam (59* ABDC intake close)
effective sweep: 82.1
effective swept vol: 569.8

for effective compression of [STRIKE]7.55, squish vol: 87.0 cc[/STRIKE]
for dynamic compression of 7.14, squish vol: 92.8 cc, 77 cc chamber volume, 8.6:1 static compression
for dynamic compression of 7.24, squish vol: 91.3 cc, 75.5 cc chamber volume, 8.7:1 static compression
[STRIKE]CC vol: 71.2 cc
static compression: 9.1:1[/STRIKE]

So it looks like with a longer duration cam, [STRIKE]9.1:1[/STRIKE] 8.6:1 should be pretty safe on the 2FE. If someone can let me know what is a safe static compression to run with the stock cam, I can push the numbers a bit further (although static compression of [STRIKE]9.1:1[/STRIKE] 8.6:1 sounds pretty high already).

Oh yah, I also have 5 of the intake ports all done up like shown for #5 in pics above. So when I have a chance, I'll run them all with the flow bench and compare them to #2 (the un-modified standard).

A 2FE with a stock 2F cam and no head shave will yield a DCR of 7.38....
As I posted somewhere earlier, I was planning on a DCR of 7.4 with a 260 cam and a chamber volume of approximately 73cc......which I think is still the plan, but with a Delta KC 859 regrind rather than the MAF.....

 

[Clonestocker]

RockDoc,
Do you think there is some kind of deficiency in the combustion camber design or fuel delivery that creats the need for higher octane fuel? The static compression is so low. I think my 3FE has a slight part throttle detonation problem because of dirty injectors(poor spray pattern?). It passed smog with flying colors but. What mods are done to the advance curve on these motors? Usually you throw more advance sooner but that would make the need for better fuel even worse. I don't know if the head on my cruiser has ever been off but the mileage is about 275,000. Could some of the issues be carbon related? Need some opinion. Has anyone ever had the cam grind on a cam doctor to determine all of the timing events? Maybe a cam regrind by someone that understands how cam events work (positive or negative) could throw a spin on this subject. thx matt

 

[RockDoc]

I'm no expert by any means, but my first thought would be carbon. Carbon will boost the compression ratio by taking up volume in the chamber, and will also reduce the transfer of heat away from the chamber (leaving a hot surface to promote pre-ignition). I have the impression that the 3FE is bad for carbon build-up, at least in the intake. Does your rig get out for long hard workout very often? An Italian tune up may be in order (steep windy roads that lead to lots of full throttle running) or running some water through the intake to steam it off. My truck always feels really strong after a multi hour run on the highway. Second, IIRC, iron heads are a little more susceptable to detonation, as they are less efficient in removing/evening heat at the chamber surface (but if you are carboned up, that's not going to be a big part of the equation). Are your O2 sensors good? Throwing any codes? Perhaps you have mixture issues.

Part of the story for the low static compression is the valve timing. The earlier the intake valve closes (i.e. stock timing) the higher the dynamic compression/compression pressure for a given static compression ratio. By changing the cam to a longer duration/later closing spec (like a 260* cam) you can bump the static compression without bumping the dynamic compression/compression. It's the dynamic compression/compression pressure that's going to dictate what octane you need to run (from my understanding). That's where all the calculations above (that I botched the first time) come in. You can bump the static compression, and as long as you are altering the cam timing such that the dynamic compression doesn't exceed the stock value, you can be reasonably sure it will still run on the same grade gas.

When considering the above, keep in mind that this is my first experience delving into the guts of an engine, so I honestly don't have a good feel for how these engines compare to more modern designs in terms of cam timing and dynamic compression and such....

 

[RockDoc]

A couple questions:
1) Anybody have any good tips for removing the timing gear from the camshaft without a press? Is striking the nose of the cam through a socket kosher?
2) Is there a functional difference between a 2F lifter and a 3FE lifter (different part number on toyodiy)? Two of my 2F lifters have slight pitting... was thinking I would pull a couple out of my spare 3FE... or can Delta deal with some pitting?

 

[Clonestocker]

As far as I have always been told, using and old cam is fine but you should always replace the lifters. Lifters are ground with a slight crown so they rotate. Any used lifter because of wear is dished. Are new lifters not available? I know someone that has a lifter grinder but don't know what he might charge to resurface them. matt

 

[Cruiserdrew]

Pretty sure you can get them resurfaced. Try a camshaft grinder. If that fails, I think I have some spares, but they should probably be resurfaced, so....

 

[ntsqd]

I've always given them the Navy Flotation Test. Have yet to have one float.

 

[RockDoc]

I've always given them the Navy Flotation Test. Have yet to have one float.

 

[ntsqd]

That said, are 2F/3F/3FE lifters rare and/or spendy? I could see a re-facing argument if they are essentially unavailable for whatever reason.

 

[RockDoc]

List at $35 a piece on toyodiy. IIRC, others have had their cam ground and lifters resurfaced for ~$150. IIRC, I seen it posted that the stock lifters have no crown to them anyway.....

 

[ntsqd]

The crown wouldn't be very easy to see by eye. They have to be rocked on a micro-flat to tell if they have a crown or not. At least all of those that I've worked with in the past were like that.