Engine & transmission -HELP! - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 04-26-2004, 02:27 AM
59vette's Avatar
Member
 
Last photo:
Join Date: Oct 2003
Location: UK
Posts: 78
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Engine & transmission -HELP!

Fellow hotrodders, please help me a bit with this

To make a long story short, I tore my engine apart and rebuilt it because of different issues.

It has the following specs:
283 +.30
11:1 pistons
462 heads, 1.94/1.5 valves
SSI cam, 304 adv, 230 0.050", .453 lift for both valves, installed straight up
torker 1 intake
2" ram horns
575 vac. sec.speed demon
Pertronix ignitor 2 ignition and coil with MSD wires.

Gear box: TH400
JEGS 10" converter (2700-3K adv stall, stalls by : ~2000 by ear measurement...) Didn't measure rpm with the timing light (my rev counter is broken...) (stupid me... )

Problem 1: only 8-10" vavuum at idle (~900 rpm), = low vacuum for the modulator = high transmission pressure = gearbox slams into gear.
Converter did help a bit, but not very much.

How can I fix this?
Is there a T/V cable modification that will work with the 400, in order to lower the pressure at idle?
Will a dual plane intake create more vacuum/ enough for the gearbox to work?
I already have an adj. modulator adjusted all the way out.
Is there a cheap trick to modify the modulator?

Problem 2: Engine idles fine, but sometimes when put into reverse or drive, it will idle for a few secs, before rpm drops and it dies.... but not every time...
it did NOT have this problem before the rebuild...

Problem 3: High rpm pinging/knock
Plugs are hot ones, AC Delco R45's
Timing is set at 35 at 3000rpm, static+ mechanical.
I expect that this one will be solved by changing the plugs to R43's, along with a fine tune of max mech. adv. at 3000 rpm.

Problem 4: Driveshaft yoke leak at gearbox
When engine is idling, car stationary the driveshaft yoke leaks badly, but then engine is stopped it does not leak

Now before the rebuild I had the #1 problem, #2 and #3 are new.
I did have an unidentified gearbox leak before, so it could be the yoke, but I for sure know that the rear and front seals were leaking and maybe also the pan, but all those are now exhanged...

Any help appreciated!


/Bjarne

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 04-26-2004, 08:10 AM
BOBCRMAN@aol.com's Avatar
Member
 
Last photo:
Join Date: May 2002
Location: Holly, michigan
Posts: 8,108
Wiki Edits: 0

Thanks: 24
Thanked 262 Times in 246 Posts
problem no. 1: 230 @ .050 cam= low manifold vacuum.
cure: milder cam
no. 2: also cam related
cure: you could possibly drill the primary throttle plates
no.3: colder plugs
n0.4 possibly the wrong yoke.
cure: if yoke has vent hole in the center, try replacing
the o-ring on the trans output shaft. If no o-ring
on shaft try welding up vent hole in yoke
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 04-26-2004, 08:20 AM
galaxieguy3's Avatar
Member
 
Last photo:
Join Date: Sep 2003
Location: Gouverneur, NY
Age: 47
Posts: 170
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
problems 1 & 2 & 3
Am I reading this right?
304* advertised duration cam in a 283 and you are asking why vacuum at idle is low?
You are probably lucky that it even idles at 900 rpm in neutral, much less in gear.
I dont believe a dual plane manifold will help your vacuum situation, it also wouldnt do you any favors as far as performance is concerned. According to cam specs I am looking at, the power band for a cam that size in a small block doesnt even start until about 4300 rpm +or-. Most dual plane manifold rpm ranges are from idle to 5500 or 1500 to 6500 +or-.
Not sure on cable mods, not really familiar with that trans.


problem 4
Check to see if you have excess movement at the driveshaft yoke or output shaft on the trans. Check the yoke for wear at the sealing area.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 04-26-2004, 02:12 PM
59vette's Avatar
Member
 
Last photo:
Join Date: Oct 2003
Location: UK
Posts: 78
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
BOBCRMAN, galaxieguy3 , Thanks for your input

I know that I would have a low manifold vacuum, this is not a surprise, but everyone already thinks that my vacuum is too low, and I cant figure out why.
Heck, I even tore the engine apart and I still have this da***d problem.

cam change is not an option atm, with 11:1 I will need a cam with some overlap later intake closing, to make it run on normal octane ratings.

Not happy about drilling the throttleplates, don't wanna spoil a brand new carb.

Now everyone tells me that I should have more vacuum but I don't, and it p***** me off that I cant figure out why.
Atm I spend all my time reading all info I can about carbs, manifolds, cam and vacuum, to see if I can find out something.

Transmission:
There is no o-ring on the shaft, gonna weld up the yoke then...

Still looking for good ideas
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 04-26-2004, 03:11 PM
Grumpy
 
Last photo:
Join Date: Dec 2002
Location: D.C.
Posts: 1,447
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Okay...

1. the cam has too much duration = low vacuum.

2. Maybe vacuum issue, dont expect an engine with a cam like that to idle.

3. If your running 11:1 you will have to use race gas, no real way around it. Try smoothing the chambers, and using different plugs, but will have to use race gas.

4. I would guess a seal problem, did you mean where the driveshaft goes in to the tranny?

Anyways get a smaller cam and lower the compression, almost no way around it unless you want to always use race gas. This is NOT a street car setup, I can tell you that right now. You also should NOT have more vacuum with that cam and setup, sorry. Maybe get a vacuum resiviour
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 04-26-2004, 03:31 PM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,654
Wiki Edits: 0

Thanks: 15
Thanked 58 Times in 55 Posts
With your combo you don`t have a lot of cubic inches and you`ve got a big cam, what you have is a high revver combo, the cam would be somewhat more tame in more cubic inches, but is considered wild for a 283. First thing I would have did was got rid of the torker intake, it`s making the problem worse idle wise, I would go with a dual plane intake to get back some low end torque, it would probably give it enough back to idle half way decent and it would also help vacuum being it has less plenum area, it would also aide in tuning wise. I`ve always heard about the original Torkers, there great high revver intakes, but not worth anything down low, the torker II was a improvement because the runners are longer and narrower, so it goes to show the torker isn`t really needed on a street machine, this was why Edelbrock replaced the Torker with the Torker II. How about advancing the cam 4 degree`s at the timing chain, and going with a dual plane intake and see how it runs? advancing the cam would lower the power band by about 200 rpm, and the dual plane intake would help low end power and the car would likely idle without shutting off. also by doing these 2 mods the car will still have plenty of high end power so there`s no worry there, but if this is a street machine, then I don`t see the need for high revver stuff in a street car, engines don`t see over 3000 rpm on the street, it`s torque that moves the car around, not horsepower, and anything you do to aide in low end torque will help the problems your dealing with, as a last band aid resort, you could use rhoads lifters, they bleed down at lower rpms, making the engine "see" less duration, therefore they`ll increase vacuum at low rpm, as rpms increase the oil demand overcomes the lifters ability to bleed it off in time and the cam is restored to full lift.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 06:34 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.