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Oyvind Ryeng
03-21-2004, 03:32 PM
I *have* searched, using all the possible keywords, but: nothing.
Yes, I know you loose some of that oh' so precious low-down-torque /w short stroke.

Anyway, the A20 engine with it's enormously long stroke; will it not rip the pins out of the pistons @ 8000RPM? Possible to change crank? Machine old crank to shorter stroke?

shepherd79
03-21-2004, 03:47 PM
talk to sean. he can help you with that.
i wouldn't rev the stock motor past 6500 rpm.

Hash_man_Se_i
03-21-2004, 04:55 PM
I was also wondering along the same lines as this. Like if you get those higher compression pistons, and maybe some other things like bigger injectors, and higher flow fuel pump, i would only imagine that the A20 could hold up to higher revs, and produce more power?

shepherd79
03-21-2004, 05:15 PM
the problem with higher revs you will need wild cam to get the benefits of higher revs.
the stock cam is not designed for high revs.
if you get cold cams wild stage, it will produce more power at higher end.

A20A1
03-21-2004, 07:38 PM
Wasn't someone going to put the A18 crank in?
As for the high revs everything was fine for me till the motor detonated... which caused the crank bearring to split and well that as you say was that.

Oyvind Ryeng
03-21-2004, 09:34 PM
A18 crank? Sounds interesting, but isn't the A20 just an overbored A18?

Cams are a problem, yes. The original ones are made to give lots of low-end torque, but they are ineffective at higher RPM's. Of course, if you get like 280-duration cams with 10-11mm-ish lift, you would loose some low-end torque. But what difference does low-end torque make when it pulls like HELL towards redline? :D

The problem with high revs is not the fuel- or ignition system; that is easily taken care of. The problem lies with the high possibility of mechanical failiure in the pistons/pins/rods/crank because of the excessive piston speed. Naturally, a crank with shorter stroke would not move the pistons/rods as *fast* as a crank with longer stroke *at the same RPM* - less stress is put on the crank /w shorter stroke. One more thing; the weight of the moving parts: think of the following: hold a 2-pound object in your hand, jerk it up/down 8000 times a minute, and notice how tired your arm gets. Then do the same without the object in hand; you don't get as tired. Think of the poor crank that has to move the pistons up/down thousands of times a minute; try to imagine how strong it has to be...

Cyric_accord
03-21-2004, 09:37 PM
How about building a Stroker kit for the A20? increasing the stroke to slow down engine speed and make a higher Tq.

A20A1
03-21-2004, 09:40 PM
How about building a Stroker kit for the A20? increasing the stroke to slow down engine speed and make a higher Tq.

Then it would just be sad to drive it around... as is it has good drivability.

Hey how did you know I had a 280 duration cam. :D

Oyvind Ryeng
03-21-2004, 10:05 PM
Well, a 280-cam is usually a good choice in most engines that want more top-end without loosing all low-end TQ. How is your idle, A20A1? Sometimes a long-duration-cam gives rough/nervous idle. What lift is it? Who made it? Regrinded?

EDIT: More ontopic, a long-stroke crank would be the opposite of what I want. I don't want ANY driveability; I want to break traction with both wheels in 3rd gear @ over 4000 RPM (when the boost is at it highest, and the evil cam starts to get into its working range).

Cyric_accord
03-21-2004, 10:17 PM
Then it would just be sad to drive it around... as is it has good drivability.

Hey how did you know I had a 280 duration cam. :D


Ok, just checking... looking at all possibililties.... :dunno:

A20A1
03-21-2004, 10:27 PM
Idle is a bit rough due to the drop in vacuum, I had to rig up an extra vacuum holding tube to help raise the vacuum signal to the advance diaphragm on the distributor.
Normalyy I'm good at about 800 to 1000 rpm but after the motors warm I can get it to idle down at 500 rpm, even in gear (AUTO)... pretty nifty... I give all the credit to my accel coil and BOSH +4's.

The cam was a regrind... done by Colt cams in Canada. I'm in Hawaii BTW
It's a 4,000 rpm to 7,500 rpm powerband.
I forget what the lift was, I have the card somewhere...

I'm currently working on adapting a 4bbl carb as my second project for my high reving A20. I already built a 4-1 header... as you can see in my sig pic. I also upped the oil pressure by adding a spacer in the valve behind the oil filter.

I think my first motor might have detonated cause, over heating due to the water pump spinning too fast... and possible the plugs I was using weren't the correct heat range... the plugs ceramic was blow apart... but the electrode itself wasn't damaged so I can rule out it getting smashed by a piston. I've also been running with the stock fuel pump... baaaaad idea. But when I get the money I'll get a good pump.

I don't care for drivability either... but my exhaust noise attracts cops from miles around. :(

Oyvind Ryeng
03-21-2004, 10:40 PM
A20A1: Nice project! Was the water temperature high when you killed the last engine? I was under the impression that a waterpump @ high revs would move more water = cool better?

Maybe you are leaning out @ WOT & high RPMs? What jetting are do you have? And what carb? Standard?

diegoaccord
03-21-2004, 11:17 PM
Why are people so scared to go above 6500?

It'll take atleast 8500 STOCK. I do it all the time. With the stock set up, It ain't moving after 6500, but it'll rev with or with out load on the engine. I'll do 8500 in 1st, and about 8000 in second.

I refuse to rev past 7000 on 3rd, 4th, or 5th, since it takes a bit to get through them.

But, shit, just get the head to make the power @ 8000+ R/MIN, cause as it is we're already physically capable of atleast 8500, even though it is an A20.

A20A1
03-21-2004, 11:32 PM
A20A1: Nice project! Was the water temperature high when you killed the last engine? I was under the impression that a waterpump @ high revs would move more water = cool better?

Maybe you are leaning out @ WOT & high RPMs? What jetting are do you have? And what carb? Standard?

If the pump spins too fast, cavitation in the coolant may lead to a lack of coolant flow through the engine. My water temp guage was hooked up to the radiator not to the thermostat housing at the time... so it wouldn't really matter what the temp was on the guage. not that I could remember.

I had the 32/36 Weber... and it was jetted rich. Thought my O2 sensor could have been bad, fouled.

Oyvind Ryeng
03-22-2004, 12:01 AM
It'll take atleast 8500 STOCK.

But, shit, just get the head to make the power @ 8000+ R/MIN, cause as it is we're already physically capable of atleast 8500, even though it is an A20.
What!? I could never imagined that it could withstand 8500 stock! Well, I guess it's a Honda, after all. <3

You got any problems with big end- or Rodbearings? Excessive wear?

A20A1
03-22-2004, 12:18 AM
LOL I had an 86, the acelerator cable or linkage got stuck, so I tossed it into neutral to slow down, but went a bit too slow so I ended up in the middle of the intersection so I threw it back into gear which made the most kick ass burnout from a neutral drop @ 8,500 - 9,000 rpm... sadly the motor was toast. :D
Oil messes everywhere...
I took some parts from her and got it towed.

diegoaccord
03-22-2004, 12:19 AM
Nope. This is my 2nd carbed 3G 89 DX 5sp 4dr. They both got abused. The first one had 159K on it.

In the first car, over time, I think valves got burned, because one time after hitting about 7800 the engine's note had changed, and you could hear valve slap. The 8000 R/MIN led to increased oil usage, and eventually the loss of oil pressure one day on the interstate. But, the bottom end held up. No spun bearings, no welding the rings to the bores, or anything. the head WAS the problem.

This 3G has alot less miles, and I use synthetic oil, and going past that '8' mark hasn't been one problem, not in 4000 miles of 8500 EVERYDAY.

I'm getting a digi cam for this spring's/summer's race action. I'll make sure that I take video of me spinning an A20 to 8500.

diegoaccord
03-22-2004, 12:27 AM
An 86? Neutral drop?

I see in your sig, you have 2 89's, and an 86. I know atleast the 89 that was in your 7500 video was auto, and apparently that 86 is. Please don't tell me that other 89 is auto too. What about the Rolla? Man in this town finding a 3G auto is a rarity. You might have more auto 3G's in your yard than there are in all of Cincinnati.

A20A1
03-22-2004, 12:42 AM
Sadly it was auto too... I have some parts left over from the 5-speed swap I was doing... I just need the trans.
The rollas a slushie too.

A20A1
03-22-2004, 12:48 AM
Ok, just checking... looking at all possibililties.... :dunno:

Personal preferance really... not to say you couldn't do it... but who knows how much travel is possible before the piston drops right out of the cylinder... :dunno:

Oyvind Ryeng
03-22-2004, 12:56 AM
...Or into the valves. I am still shocked, actually, that a stock A20 will handle 8500 on a daily basis. No need for a short-stroke crank, or titanium conrods, or ultralight pistons, obviously.

EDIT: What about the valvetrain? No modifications needed?

A20A1
03-22-2004, 01:14 AM
I've had burnt valves on one of my heads... and leaky valve guides/seals. But that head was on it's way out anyways. The valve guides and seals on my new head are giving out... I can see oil building up along the stems... nothing major though.

If I had the money I would go with all the piston, connecting rod, and bearring upgrades I could... reguardless of what the stock bottom end could handle. Balance the bottom end too.

Oyvind Ryeng
03-22-2004, 01:34 AM
I've had burnt valves on one of my heads... and leaky valve guides/seals. But that head was on it's way out anyways. The valve guides and seals on my new head are giving out... I can see oil building up along the stems... nothing major though.

If I had the money I would go with all the piston, connecting rod, and bearring upgrades I could... reguardless of what the stock bottom end could handle. Balance the bottom end too.
Yeah, reinforcements are always good to invest in. A little sad the day the fuelmanagement system decides to give to little fuel to your turbomachine, thereby burning holes in your precious Diamond-pistons. The more you invest in the motor, the bigger the fall if anything fails; sad but true.

A20A1: So why don't you overhaul your top? It can't be sooo hard to do yourself?

Oyvind Ryeng
03-23-2004, 12:05 PM
The Accords also came with the A16 (carburetted) engine, and the main difference between the cranks seems to be:

Connecting rods big end bore: A20=45mm, A16=42mm

Other than that (and the stroke) the A16's crank seems to be a perfect replica of the A20's.

A16A1 bore*stroke: 80mm*79,5mm
A20A4 bore*stroke: 82,7mm*91mm

This means that on the A20 spinning @ 8000 RPM the pistons avarage speed is a devestateing 4773 ft/minute!

The A16 crank throws the piston @ a reasonable 4133 ft/min!

As far as I can think, the compression ratio with the A16-crank and conrods should be lower than with the A20's - perfect for turbo!

Now, where do I get a hold of a Honda A16 crank /w conrods...?

eightyfivelude
03-23-2004, 03:37 PM
am i lost here.... why the hell would you want to put a crank with a shorter stroke in... do you have any idea how much power you would lose. Not to mention the piston wouldn't travel far enough up the cylinder. I could not see that being to any benefit what soever... less stroke = less power.

Matt

Oyvind Ryeng
03-24-2004, 06:05 AM
True, Matt. But imagine a crank with two metres stroke spinning at 8000 RPM. The average piston speed would then be an insane 104933 ft/minute! Needless to say, the crank/conrod/piston would have experienced mechanical failiure LONG before the 8000 RPM.

On the other hand, a crank with only 2 inches of stroke would have to spin at an unbelievable 1259196 RPM TO PUT THE SAME STRESS TO THE MOVING PARTS (excluding bearings) as the 2-metre stroke crank!

You see my point? A crank with shorter stroke puts less stress on *everything*.

od2681
03-24-2004, 08:20 AM
wahts the point of revin high if it makes max hp at lower rpms than 8000 or somethin

Oyvind Ryeng
03-24-2004, 09:31 AM
The point? There is none, except for scaring the shit out of the B16-boys when the A20 revs 10.000 RPM, and sounds like a Formula Atlantic Toyota AE86). Plus, I want a totally hysterical engine character (power EXPLODES somewhere after 5000 RPM) that is expensive to drive (and build!)...

eightyfivelude
03-24-2004, 10:50 AM
I totally see where you are coming from with the whole less stress higher revving thing. You could just go to paeco and buy titanium rods and pistons, get a aftermarket crank. Buy the 5LB aluminum flywheel from ACT, loose all accesories minus the alternator, rebuild the tranny cause there is no way in hell a stock one will spin up to 10,000rpm. Get ARP rod bolts and get them to make you up a set of head studs and main studs. Get the head built with bigger titanium valves. Upgrade the springs and keepers. Put a bit of money into bigger injectors and a nice computer control system. Then you can have a motor that runs like 12 second quarters, rev's up to 10,000rpm and is naturally aspirated. You wouldn't lose any power due to the shortened stroke...

That is what I would do rather than dink around with little things. DO it right the first time and go big or go home :)

Matt

Low Tek
03-25-2004, 10:20 PM
I think my first motor might have detonated cause, over heating due to the water pump spinning too fast...

so how do we slow it down then? I will have a high rev motor soon

Oyvind Ryeng
03-25-2004, 10:37 PM
DO it right the first time and go big or go home
The cost of going all-out /w half the engine in titanium, the rest super-custom-built-one-of-a-kind-won't-find-anything-similar-in-100-years just to be able to (safely) spin it to 10,000 RPM would really be high. I would guess approx. $10,000 building *just* the engine. The A20 was really never ment to rev this high (just look at the relative weight & complexity of the valvetrain and the rediculessly long stroke), therefore one might as well get a B16-swap if one wants to rev high. That little lump of steel and aluminium is Japanese engeneering at it's finest. I'd guess the B16 would take 10K RPM stock without valve-float or ripping itself to pieces.

The way I see it, using $10,000 to get "the last couple of thousands of RPM" out of the A20 is just wrong. Better get a turbo - the best and cheapest way to get alot of power from the A20.

However, the thought of having a 10K RPM all motor A20 just brings foam around my mouth. $10,000 worth of foam.

Oyvind Ryeng
03-25-2004, 10:39 PM
so how do we slow it down then? I will have a high rev motor soon
Underdrive pullies. They are available for our cars; "search and ye shalt find"

eightyfivelude
03-26-2004, 02:55 AM
obviously there is gonna be some huge shelling out of cash fo a motor like that. But to get any honda motor to run into the 12 and 11 or less N/A is gonna cost a shit load of money. There is a 2nd gen prelude in montreal running a et-2 or A20/A18 hybrid in the 11 second range... and there is no way in hell he spent close to $10000. There is no need for highrevs, torque and power should be made under 7000 in a realistic car


Matt

Low Tek
03-26-2004, 03:38 AM
nice... glad to know that will be an easy fix

Low Tek
03-26-2004, 03:42 AM
10k rpm - that just sounds to scary to me.. mine is goin to 8 and thats it, but it will have more push to it too.. and I am not even close to $10,000

Oyvind Ryeng
03-27-2004, 01:30 PM
Well, building a highpowered N/A-engine is always costly, unless the engine you build is like 700 cui... Not to mention you usally have to get to the "right" side of 5000 RPM to make some power, if you have to run some aggressive cams.

evans 86prelude
03-28-2004, 08:17 PM
if u wanna rev get a civic

Oyvind Ryeng
03-28-2004, 09:00 PM
A Civic is not an Accord...

evans 86prelude
03-29-2004, 05:14 PM
really?.. well if u plan to rev u better get a good bottom end i had my bt1 to 8000 and passed i thought oh thats cool then it one day it died and thought what was i doing reving the balls off it... and for some reason right when i got the car it had no rev limiter and later it did and it limited at 6800 but it was too late because the motor was ready to blow and it did. computer messed up i guess

urd_86hb
04-06-2004, 01:37 PM
OK, so am I understanding this correctly? A STOCK 86 Accord fuel injected will spin to 8500 rpms w/o blowing up? Also, why would you want to rev that high? On mine, the power is from appx. 3700 rpms to 5800 rpms. I have tried taking it to redline (6300) when racing, and it feels faster when I shift at 5800. The power feels like it falls off after that. So if it falls off after 6000 or so, why go to 8000? Isnt the power just going to fall off even more? Also, does the 86 lx-i motor have a rev limiter?

'A20A3'
04-06-2004, 02:25 PM
A cam grind is what changes the "falling off" of the power at higher RPM's. The stock cam is designed to give results exactly like you describe. Power in the 3700 to 5800 range. The A20 feels alot more torquey that other Honda's I've driven. I plan on investing in the full engine package Sean is offering on Accordcentral.com, but I plan on modifying the head as well. I plan to have a redline of somewhere between 7000 and 7500, having a powerband from 4000 to somewhere around 7200. I want to keep the torque that the A20 has, just increase it.

I don't know maybe it's just me, but there's something about 8K/min that reminds me of a bee flying around my head. Kind of annoying. :ugh: