TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > AMC V8 Engine Repair and Modifications
  New Posts New Posts RSS Feed - 68 390 heading for the dyno soon
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

68 390 heading for the dyno soon

 Post Reply Post Reply Page  123>
Author
Message
 Rating: Topic Rating: 1 Votes, Average 5.00  Topic Search Topic Search  Topic Options Topic Options
jcisworthy View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jul/23/2009
Location: North Carolina
Status: Offline
Points: 2805
Post Options Post Options   Thanks (1) Thanks(1)   Quote jcisworthy Quote  Post ReplyReply Direct Link To This Post Topic: 68 390 heading for the dyno soon
    Posted: May/15/2018 at 4:20pm
Should have this 68 390 on the dyno hopefully Friday. Made a stock appearing deep oil pan using an AMC stock pan and the bottom from a stock SBC oil pan with a Canton internal pickup. 
Specializing in dyno services, engine building, and cylinder head porting

rbjracing.com
Phone Number 518-915-3203
Back to Top
6PakBee View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar
Charter Member

Joined: Jul/01/2007
Location: North Dakota
Status: Offline
Points: 5454
Post Options Post Options   Thanks (0) Thanks(0)   Quote 6PakBee Quote  Post ReplyReply Direct Link To This Post Posted: May/15/2018 at 8:06pm
Wow, that is nice work on that pan. Thumbs Up
Roger Gazur
1969 'B' Scheme SC/Rambler
1970 RWB 4-spd Machine
1970 Sonic Silver auto AMX

All project cars.

Forum Cockroach
Back to Top
SONOFAMX View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Aug/08/2007
Location: Indiana
Status: Offline
Points: 226
Post Options Post Options   Thanks (0) Thanks(0)   Quote SONOFAMX Quote  Post ReplyReply Direct Link To This Post Posted: May/15/2018 at 8:50pm
Very nice John
Did you mean GMC?
Back to Top
mmaher94087 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Apr/01/2008
Location: Arizona
Status: Offline
Points: 1676
Post Options Post Options   Thanks (0) Thanks(0)   Quote mmaher94087 Quote  Post ReplyReply Direct Link To This Post Posted: May/15/2018 at 9:31pm
Placing the cork on the front of the pan ought to make life easier. Nice welding job!
Mike
Back to Top
Ram Air Rick View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar

Joined: Jul/04/2007
Location: United States
Status: Offline
Points: 2667
Post Options Post Options   Thanks (0) Thanks(0)   Quote Ram Air Rick Quote  Post ReplyReply Direct Link To This Post Posted: May/16/2018 at 5:22am
What a stealthy cool look on the oil pan !

Nice mill ! 

Well done !

Please post dyno results when done !

Rich C.
Back to Top
jcisworthy View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jul/23/2009
Location: North Carolina
Status: Offline
Points: 2805
Post Options Post Options   Thanks (0) Thanks(0)   Quote jcisworthy Quote  Post ReplyReply Direct Link To This Post Posted: May/22/2018 at 4:19am
Little delay of game. After a couple heat cycles one head leaked water. 

Doing another set of heads. This is the second head this happened to in the same sopt so I started looking at them along with an untouched casting. 

I found that this little spot is a thin spot on in the castings. There is a parting line there inside and out. If there was not a parting line inside the water jacked in this spot the thickness would be more than enough. 

 Bringing my bowl cut in .050" less will leave .080 or so thickness there. There is a minimum of .130" all around the hole. Hole is about .100" in diameter. 

Engine made 444 HP and 452 TQ after cam break in and no tuning on a 5500 rpm pull. I think there was water in the hole at that point. Went to start it again and it was hydro locked. I expected about 50 more ft lbs of TQ and 450-475 hp. 

For a small cam this engine made very good power and when it is fixed it will make more. 

Cam is a Bullet custom ground on .904 lobes, 214/226 @ .050, .544/.576 lift with 1.7 rockers, 114 LSA in at 110

9.0 compression, heads flow 250-255 through an Edelbrock R4B intake at the lift of the cam and 275-280 through the heads at the lift. 

401 Wiseco 27cc dish pistons and Molnar 5.858" rods. Pistons are .050 out of hole with Felpro .045 compressed gaskets

This is the first time I had a ported iron head leak on or off the dyno. Unfortunate but such is life sometimes.



 
Specializing in dyno services, engine building, and cylinder head porting

rbjracing.com
Phone Number 518-915-3203
Back to Top
jpnjim View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Nov/25/2007
Location: New England
Status: Offline
Points: 2752
Post Options Post Options   Thanks (0) Thanks(0)   Quote jpnjim Quote  Post ReplyReply Direct Link To This Post Posted: May/22/2018 at 2:36pm
Very interesting build John!

Sorry the water port bit you, but you'll never know what the limitations are if you don't push the boundaries. Smile

Small cam 9:1 build with an R4b is right up my alley,
you might end up with the mildest idling 500/500, 87 octane AMC on the planet! Clap

I had a couple questions,
why the wide 114lsa?
were you trying for smooth idle & low octane capable?

I guess the R4b is for it's stout mid range,
did you find many places to improve it?
If you were able to flow it, how did it look on the bench?

edit,
I reread your post, looks like the R4b ate 25 cfms of your flow work,
not bad for a dual plane designed in the 1960's,
did you do anything to the intake besides port match it?
Are you running the divider as delivered? (notch cut out between the rear two barrels).


My build is similar in some ways

both my lobes are similar to your exhaust at 
228 @.050"  .564 lift (904 grind)
but I went with a 108LSA to get the early intake closing/increased cylinder pressure.

I'll most likely also use an R4b, for the low end, but also to help tame the overlap/idle quality.

What's the application for this engine?
Would be great in almost anything (from Trail Jeep to tow vehicle to a Street Strip Rebel Machine).
Actually has tire burning Rebel Machine written all over it!

Thank you for taking the time to post up real builds with real numbers here!
Even the untuned 444/452 is very impressive for a 9:1 build with a 214/226 cam!
Nice work.


Edited by jpnjim - May/22/2018 at 2:45pm
71 P-code 4spd Javelin/AMX
some Jeeps and some Fords
Back to Top
jcisworthy View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jul/23/2009
Location: North Carolina
Status: Offline
Points: 2805
Post Options Post Options   Thanks (0) Thanks(0)   Quote jcisworthy Quote  Post ReplyReply Direct Link To This Post Posted: May/22/2018 at 4:52pm
Thanks Jim, this is going in a 68 Ambassador 390 car.

The R4B and air gap hurt these heads 25-30 CFM after .500 or so. Torker hurts them about 15. 

The intake is the customers so that is why I used. I do like them though and I am not opposed to it for this build. I extended the divider slot and port matched it. 

When I have a small cam in a decent size CID engine I set the cam up like this. The CID gets the low end and the cam install plus heads get the mid and upper.

I went with an LS 1.7 ratio pro comp T&D rocker shaft copy for this engine also. The engine had valve float at 5700 or so but I think it was the geometry. I set it up according to T&D instructions with a supplied tab but I was not excited with the way it engaged the valve, or it was not the way I would have set it up anyway. I think that is what caused the float because I have 360# open pressure on a 8mm stem relatively light valve, 1.270" od PAC racing spring and light retainer. I cant see this engine floating until something north of 7K rpm's. 

It will be set up the way I set up all my engines when it goes back to the dyno. This will be about  a 6K rpm engine.  
Specializing in dyno services, engine building, and cylinder head porting

rbjracing.com
Phone Number 518-915-3203
Back to Top
jcisworthy View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jul/23/2009
Location: North Carolina
Status: Offline
Points: 2805
Post Options Post Options   Thanks (0) Thanks(0)   Quote jcisworthy Quote  Post ReplyReply Direct Link To This Post Posted: May/22/2018 at 4:55pm
Dyno pull 


Specializing in dyno services, engine building, and cylinder head porting

rbjracing.com
Phone Number 518-915-3203
Back to Top
jpnjim View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Nov/25/2007
Location: New England
Status: Offline
Points: 2752
Post Options Post Options   Thanks (0) Thanks(0)   Quote jpnjim Quote  Post ReplyReply Direct Link To This Post Posted: May/22/2018 at 6:27pm
Thanks for the informative response and for putting the dyno sheet up!

Wiseco pistons, Molnar rods, LS valvetrain, nicely worked over dogleg heads and what I'm guessing is a very smooth cam that makes 400+ lb/ft everywhere in an Ambo = sweet sleeper that will surprise a lot of unsuspecting people LOL



 
71 P-code 4spd Javelin/AMX
some Jeeps and some Fords
Back to Top
 Post Reply Post Reply Page  123>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.094 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or