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304 on the dyno

Printed From: TheAMCForum.com
Category: The Garage
Forum Name: AMC V8 Engine Repair and Modifications
Forum Description: AMC-made V8 engine mechanical, ignition and fuel from basic repair to high-perf modifications
URL: http://theamcforum.com/forum/forum_posts.asp?TID=98091
Printed Date: Apr/18/2019 at 11:37am


Topic: 304 on the dyno
Posted By: jcisworthy
Subject: 304 on the dyno
Date Posted: Jan/11/2019 at 1:46pm
304 build on the dyno. 

3.800 bore, 3.44 stroke, 312 CID, 9.72 compression, ported iron heads with 1.84/1.5 valves, LS 1.7 ratio mini shaft rockers, Molnar rods, Racetec pistons, 5cc flat top two valve reliefs, .040 quench with 3.810 bore, .040 thick Cometic MLS gaskets, air gap intake, factory appearing deep oil pan, Doug's 1 7/8 headers, Quick fuel brawler 600 CFM mechanical secondary carb, billet MSD type ignition

Best pull, 381.8 TQ @ 3600, 363.3 HP @ 5500







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Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203



Replies:
Posted By: jcisworthy
Date Posted: Jan/11/2019 at 1:49pm
More pictures, 




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Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203


Posted By: 1982AMCConcord
Date Posted: Jan/11/2019 at 1:51pm
Wow! Now that is more than respectable!!!!!!!!!!! Good work!!!!!!!!!!!!!!!!!!!!!! This 304 would be a lot of fun!!!!!!!!!!!!! 


Posted By: jcisworthy
Date Posted: Jan/11/2019 at 2:01pm
Dyno video links

https://www.youtube.com/watch?v=r3Ve6TdIOVc&feature=youtu.be" rel="nofollow - https://www.youtube.com/watch?v=r3Ve6TdIOVc&feature=youtu.be

https://www.youtube.com/watch?v=iz2ws6ElVUk&feature=youtu.be" rel="nofollow - https://www.youtube.com/watch?v=iz2ws6ElVUk&feature=youtu.be


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Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203


Posted By: JolleyGreenSST
Date Posted: Jan/11/2019 at 2:14pm
Great job! My only questions are for such a low rpm range why the need for Molnar rods? And why again did the dyno run end at 5500rpm? 

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"God is good all the time and all the time God is good!"


Posted By: shootist
Date Posted: Jan/11/2019 at 2:20pm
Now that is pretty impressive numbers for a little ole 304 AMC motor. 

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Posted By: jcisworthy
Date Posted: Jan/11/2019 at 2:23pm
Originally posted by JolleyGreenSST JolleyGreenSST wrote:

Great job! My only questions are for such a low rpm range why the need for Molnar rods? And why again did the dyno run end at 5500rpm? 

I use Molnar rods in everything. For a little extra money it does not make sense not to. 

It was starting to nose over so that is where he pulled it to. 

It will pull strong to 6K no problem


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Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203


Posted By: EVF_Sportabout
Date Posted: Jan/11/2019 at 4:35pm
What I can't get over is how high and flat that torque curve is it hits 350 @ about 2900 and just stays up there all the way through.  We had one pull where it hit 381.8 @ 3600 RPM.  Its going to be a fun driving Sportabout yes its going in a wagon!


Posted By: jpnjim
Date Posted: Jan/11/2019 at 5:54pm
Sweet parts combination!
 That Air Gap was born to sit on a set of ported 304 heads like that,

 it sounds amazing on the dyno and ought to RIP in a Hornet Wagon!

Nicely done John Clap



edit,
couple questions,
did you leave the intake divider intact on this build?
did you happen try a pull with an open carb spacer?

That 600 Double pumper is probably the perfect match for this engine,
 just curious if it left any power on the table at the very top (especially if the full divider is intact).





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71 Javelin AMX P-code Go pac 360/4spd/3.91's
was Green/green now T/A red w/blk leather

88,89&98 Jeeps


Posted By: Buzzman72
Date Posted: Jan/11/2019 at 6:26pm
After seeing these numbers, can we all stop telling newbies with a 304 to use it for a boat anchor and get a 360 instead?

Some of us love seeing what can be done with small cubic inch naturally aspirated engines.


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Buzzman72...void where prohibited, your mileage may vary, objects in mirror may be closer than they appear, and alcohol may intensify any side effects.


Posted By: purple72Gremlin
Date Posted: Jan/11/2019 at 6:37pm
Awesome.  And I have a 304 in a 79 AMX....Which I am keeping in the car.


Posted By: 72gremx401
Date Posted: Jan/11/2019 at 6:40pm
And probably get decent MPG .while cruzin .


Posted By: jcisworthy
Date Posted: Jan/11/2019 at 6:43pm
[QUOTE=jpnjim]
Sweet parts combination!
 That Air Gap was born to sit on a set of ported 304 heads like that,

 it sounds amazing on the dyno and ought to RIP in a Hornet Wagon!

Nicely done John Clap



edit,
couple questions,
did you leave the intake divider intact on this build?
did you happen try a pull with an open carb spacer?

That 600 Double pumper is probably the perfect match for this engine,
 just curious if it left any power on the table at the very top (especially if the full divider is intact).


Milled a notch in the air gap. Did not try a spacer. Quick fuel mechanical 600 brawler carb was very good out of the box. 






-------------
Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203


Posted By: Sonic Silver
Date Posted: Jan/11/2019 at 6:50pm
I believe you called it on this one John. On the "304 Ported Heads" thread Dec. 15, you said "I am hoping for 350-375 horsepower with this combination." Looks like you made it.


Posted By: jcisworthy
Date Posted: Jan/11/2019 at 7:14pm
Factory appearing oil pan I have been making for these engines holds 8 qts with an FL1A oil filter and Canton internal pickup 



 






-------------
Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203


Posted By: 232jav3sp
Date Posted: Jan/11/2019 at 8:04pm
Oh, how I want!!!!!! Well done, sir! 


Posted By: dbltrbl
Date Posted: Jan/12/2019 at 1:47am
Originally posted by EVF_Sportabout EVF_Sportabout wrote:

What I can't get over is how high and flat that torque curve is it hits 350 @ about 2900 and just stays up there all the way through.  We had one pull where it hit 381.8 @ 3600 RPM.  Its going to be a fun driving Sportabout yes its going in a wagon!

Are you planning to use headers or freeflows?


Posted By: jcisworthy
Date Posted: Jan/12/2019 at 6:41am
He is going to use shorty headers

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Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203


Posted By: mixed up
Date Posted: Jan/12/2019 at 7:41am
those are impressive numbers  thats right there with any chevy small block in a lot of cases how much did it cost to make the combination it always the factor is why people build a 360 or go chevy

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69 amx 290 auto
65 220 290 4spd
80 ford fairmont


Posted By: Trader
Date Posted: Jan/12/2019 at 7:54am
Well done.
I have a question on the 107 degree, my though's are going to 109 degrees would flatten the torque curve a little but put more HP on the table at a higher RPM. That little stroke engine should rev out to 8000 RPM with ease and not hurt bottom end much at all.
You have been in the 0.52x" lift on most of your builds so it looks like you found the sweet spot for a cast head AMC.
How are you picking your separation angles? Results are excellent!!! 


Posted By: jcisworthy
Date Posted: Jan/12/2019 at 8:31am
That little cam is not an 8K cam by any means. I expected the power band to be where it is. 

In the car 6K is no problem but 8K is way out of its power band. This engine can rev will past 6K but why, it will not be making any power there so it does not make sense.

I chose the separation angles based on the small cubes. I wanted to help it on the low end and meet the customers needs which is a very user friendly street engine for his wife in the Hornet wagon. 

This engine meets those needs very well


-------------
Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203


Posted By: pfordamx
Date Posted: Jan/12/2019 at 9:17am
did you test a bigger carb just out of curiosity? with the small engine and low rpm it probably didn't use all of the 600 but i'm just curious. and i'm also curious about the headers i would think a set of 1 5/8s would've provided a better torque curve and maybe more power. i know we went from a set of 1 5/8s hedmans to 1 7/8s supercomps many years ago. on 390 with the big summit cam lol and a torquer and it actually lost a little in the 1/4 mile. we dont have easy dyno access here in oklahoma. 


Posted By: jcisworthy
Date Posted: Jan/12/2019 at 10:32am
I did not test any other carbs. Looking at the vacuum through the pull the engine likes the carb size. 

.5-1" of vacuum through the pull is a good carb size

I was told by David Vizard that 1 5/8 headers would probably pick up the torque by 20-25 and a touch on HP

I do not have a set of 1 5/8 headers ready for O2 sensors so I went with the 1 7/8 again


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Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203


Posted By: Boris Badanov
Date Posted: Jan/12/2019 at 11:35am
A dream project is a 4" stroke crank in a 3.875 bore 304.

Very NICE build.

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Gremlin Dreams


Posted By: Jmerican
Date Posted: Jan/12/2019 at 12:09pm
Dang I woulda sent you some small tube Jeep headers. Nice job. I knew it would be there, power wise. 




Posted By: Trader
Date Posted: Jan/12/2019 at 12:50pm
Going to have to mini tub that grocery getter!



Posted By: DaemonForce
Date Posted: Jan/12/2019 at 3:17pm
This has me wondering if I should rebuild my iron 304 or go looking for an aluminum 401 block and destroke that like I've been curious about for years. The 304 is a torque monster and while I don't have any numbers to reflect that, it's spooky on the street. Your 304's numbers reflect those power jumps fairly close and I don't know how I feel about that.


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1971 Javelin SST
American 304 2v | FMX | AM20-3.31

1983 American Limited
Jeep 4(.7)L S-MPFI | 1982 NWC T-5M (4.03/.76) | Dana30IFS/35-2.72


Posted By: WesternRed
Date Posted: Jan/12/2019 at 4:48pm
Nice build, would be interesting to see what it would do with a bigger cam to support more RPM and how much HP it could make up there. Bucket loads or torque is perfect for the street though.

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I've finally given up drinking for good...........now I only drink for evil.


Posted By: jcisworthy
Date Posted: Jan/12/2019 at 6:51pm
Thanks,
With a larger cam and 1 5/8 headers, I would be surprised if it didn't make 400 or more torque and HP. 

A cam and valve spring change could turn this engine into a 7K or more rpm engine no problem. There is plenty of piston to valve clearance where a pretty aggressive cam can be used and the engine has the parts and mods to that rpm without issues

More compression with a bigger cam would be better though


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Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203


Posted By: 232jav3sp
Date Posted: Jan/12/2019 at 7:54pm
Originally posted by jcisworthy jcisworthy wrote:

Thanks,
With a larger cam and 1 5/8 headers, I would be surprised if it didn't make 400 or more torque and HP. 

A cam and valve spring change could turn this engine into a 7K or more rpm engine no problem. There is plenty of piston to valve clearance where a pretty aggressive cam can be used and the engine has the parts and mods to that rpm without issues

More compression with a bigger cam would be better though


I can dig that.

So... When are you going to build a 232/258?? Lol


Posted By: Trader
Date Posted: Jan/12/2019 at 8:03pm
Yes, but your building for the customer, that I understand.
So as of today, the 304 is now the hot 360 and the 360 is the bolt on upgrade 401.
I find it exceptional that you have shared the details of your builds with the few AMC followers left.
I thank You.



Posted By: Mopar_guy
Date Posted: Jan/12/2019 at 8:34pm
Originally posted by 232jav3sp 232jav3sp wrote:

I can dig that.

So... When are you going to build a 232/258?? Lol


When you pay him to build one! LOL I'm sure he would be happy to do so but he doesn't work for free. Wink


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" http://theamcforum.com/forum/hemilina_topic95889.html" rel="nofollow - Hemilina " My 1973, 5.7 Hemi powered Javelin


Posted By: jcisworthy
Date Posted: Jan/13/2019 at 7:34am
An engine like this does not come easy, it takes a lot of knowledge, time, money, good parts and precision work. The engines I build are blueprinted, with a lot induction work, attention to every detail, and an emphasis on making great power within the parameters given. 

I was told by a multi winning Engine Masters competitor that a good measure of an engine is the rpm range where the torque is within 10% of the peak torque. He said if it carries for 2K that is a good engine. 
This engine is within 10% from 2800 rpm's to the end of the pull which is excellent. This is a good little street engine. 


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Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203


Posted By: ADAM12MATADOR
Date Posted: Jan/13/2019 at 9:50am
Nice build. I actually have a Popular Hot Rodding Engine Challenge 401 that i need freshened up.


Posted By: EVF_Sportabout
Date Posted: Feb/04/2019 at 1:40am
I just want to thank John for all of his effort on this build. The dyno results speak for themselves.  He truly is THE AMC engine specialist!  He listened to me and used those conversations to build an engine based on what I needed it to do.  The cylinder head work and intake porting and experience custom grinding CAMs were indeed the magic sauce that made this little 304 special! He is a great honest guy that can really make red white and blue power! 


Posted By: Sonic Silver
Date Posted: Feb/04/2019 at 9:05am
Originally posted by EVF_Sportabout EVF_Sportabout wrote:

I just want to thank John for all of his effort on this build. The dyno results speak for themselves.  He truly is THE AMC engine specialist!  He listened to me and used those conversations to build an engine based on what I needed it to do.  The cylinder head work and intake porting and experience custom grinding CAMs were indeed the magic sauce that made this little 304 special! He is a great honest guy that can really make red white and blue power! 
I agree with everything you said about John. We are lucky to have someone with his attention to detail and willingness to please his customers.


Posted By: jcisworthy
Date Posted: Feb/04/2019 at 9:14am
Very kind words, thank you 

I am not going to lie, there is a customer or two where the communication was lacking and things did not go as well. 

Probably not a good thing to say about myself but I would be lying if I said things always work out perfectly. 

One thing I can say is, in every case a top notch product was delivered in the end. 


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Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203


Posted By: Greyhounds_AMX
Date Posted: Mar/06/2019 at 2:22pm
John, how much is a custom hydraulic flat tappet cam from Bullet? Just as a reference point for everyone.

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1968 AMX 390 / T5


Posted By: jcisworthy
Date Posted: Mar/06/2019 at 3:51pm
203 plus shipping for a typical American V8 iron flat tappet cam 

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Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203


Posted By: Trader
Date Posted: Mar/06/2019 at 4:45pm
I cannot get an off the shelf cam for that price!
Just out of curiosity John, I plugged the 304 build into my obscure formulas;
I get your build for a 4200 RPM center, and this produces a maximum torque (cylinder pressure) at 22 degrees ATDC.
By no means knocking your work, I wish I had the knowledge, experience and TOOLS!
Your intake open and close match closely to my calculations for best cylinder charge.
My calculations bring me to reducing the duration of the exhaust by 4 degrees, showing it would pick up 4 ftlbs of torque and 6 to 8 HP. This is of course on paper and not the real world.
Would very much like to see how you came up with your custom grind!

 Are you calculating by peak cylinder pressure and fall off pressure number?
Am I also correct in that this is for an automatic transmission with a higher then stock stall converter?
   


Posted By: jcisworthy
Date Posted: Mar/06/2019 at 5:58pm
This is an automatic 700R4 trans 354 gear, 26" tire and a mild converter application. 

With this cam I called Bullet to order and told him what I had for lobes and LSA, ICL then he recommended a slight change and I told him to go for it so he did. 

Typically, I order a cam with the lobes I want from the Bullet master lobe list. I choose LSA and ICL based on the customers desire for the engine then adjust compression for cylinder pressure. 

So far it has been working out well. 

Of course cylinder heads and intake play a large part also. 


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Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203


Posted By: Trader
Date Posted: Mar/06/2019 at 8:21pm
Thanks
And rightly so, you cannot look at a single aspect but the entire combination of engine components, transmission, gearing, application, customers plans,  etc.
Likely people being the hardest part of the equation!
By the math I'm using:
Just for your interest, take it or leave it, from 2000 to 4500 RPM a 304 has the highest torque at 22° and a 401 at 24°.
The drop off power curve puts the exhaust open at 70° BBDC on a 304 and 68° BBDC on a 401 assuming your using the 111° separation angle and 107° ILC.
These numbers seem very static unless there is a drastic change. A torker intake vs a dual plain being a big one.  The torker likes lots more overlap by the numbers I'm using.
Look forward to your next build!


Posted By: Sonic Silver
Date Posted: Mar/06/2019 at 9:02pm
Originally posted by Trader Trader wrote:

Thanks
And rightly so, you cannot look at a single aspect but the entire combination of engine components, transmission, gearing, application, customers plans,  etc.
Likely people being the hardest part of the equation!
By the math I'm using:
Just for your interest, take it or leave it, from 2000 to 4500 RPM a 304 has the highest torque at 22° and a 401 at 24°.
The drop off power curve puts the exhaust open at 70° BBDC on a 304 and 68° BBDC on a 401 assuming your using the 111° separation angle and 107° ILC.
These numbers seem very static unless there is a drastic change. A torker intake vs a dual plain being a big one.  The torker likes lots more overlap by the numbers I'm using.
Look forward to your next build!
I'm trying to understand this, but I need some help. When you say "the drop off power curve puts the exhaust open at 70* BBDC", etc., what does that mean if the exhaust opens before that or after that? Also, what do you mean by the 22 or 24 degree number for max torque between 2,000 and 4,500 rpm?

   What is the number for a 360 engine, if the 304 is 70 BBDC and the 401 is 68 BBDC? If the exhaust valve opens before this, do you lose some cylinder pressure and torque? If it opens too late, what happens, detonation? Thanks.


Posted By: Trader
Date Posted: Mar/07/2019 at 5:42am
I will explain best I can as I don't have the excel knowledge to graph this.
The intake closing, cylinder diameter, stroke and cylinder velocity all contribute to charging the cylinder. There is a peak period for the intake to close to obtain the highest gas charge.
The timing and detonation of the charge at a set RPM will dictate the crankshaft angle with the most power to the crankshaft. This is a lot more like a spike then a curve compared to a valve opening curve.
As the spike starts down the cylinder pressure is dropping but there is a point that pressure vs calculated torque fall off very quickly.
Everything seems to be a compromise. In a perfect world, a low RPM engine will use all the available power. The higher up the RPM you set the goals.  Typically 3000 RPM to use 80% to 85% of the available power. This can be calculated to the exhaust valve opening point. This in turn sets your degrees of duration, overlap ...
So now you have numbers for intake open, close, exhaust open, close.
Type of valve train drive will dictate how aggressive you can make these points and also how much lift.
Then you can take your valve sizes, lift, head flow, intake flow, exhaust flow and calculate the charge and pressure to get a torque/HP number.

And no I have not calculated a 360 as it takes still over an hour to come up with one engine combination.
  
 


Posted By: austinsamx74
Date Posted: Mar/16/2019 at 8:55am
Did you use early 304 heads too get your compression or custom piston .Thanks just curious


Posted By: jcisworthy
Date Posted: Mar/16/2019 at 1:00pm
086 castings with a custom 5cc piston set at zero deck

3.8" bore with Cometic 3.810 bore .040 compressed MLS gaskets


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Specializing in engine building and cylinder head porting

https://www.rbjracing.com
Phone Number 518-915-3203



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