Vortec 350 Build - Page 2 - 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
  #16 (permalink)  
Old 04-20-2012, 12:57 PM
Silver Surfer's Avatar
More machine than man
 

Last journal entry: bwaahhaahahaaahhaa
Last photo:
Join Date: Jul 2005
Location: Kansas City, MO
Age: 37
Posts: 810
Wiki Edits: 0

Thanks: 92
Thanked 62 Times in 52 Posts
Assuming you will keep the OEM 4.000" bore. Here are the numbers I come up with

bore: 4.000"
stroke: 3.48"
Head vol: 68cc
Piston dish: 10cc
Squish band*: .050"
CR: 9.12:1

* Squish band = deck clearance (which is about .025" using 1.560" compression height pistons) + head gasket compressed thickness.

Here are the pistons: http://www.summitracing.com/parts/SLP-H423ACP/
These are a manageable $15.95 a piece.
Keep in mind these are 1.540" compression height. OEM is 1.560" and these numbers are going to factor into your deck height especially since you are not decking.

Another option would be these
http://www.summitracing.com/parts/SLP-WH423NP/
at $20.99 a piece. And they are a compression height of 1.550"

Looks like Summit offers pistons with a compression height of 1.562", but these get into the $40 range. So if you are going to be a stickler about squish and cost and stuff you might be cheaper to get the block decked and throw reduced compression height pistons, assuming YOU do the tear down and assembly of the block. A machine shop will charge you extra for that labor.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #17 (permalink)  
Old 04-20-2012, 01:24 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
IIRC, SP 423 pistons are a 4 valve relief, round dish piston. If that's the case, even w/an ideal quench distance, the quench is compromised by the round dish.

The 1.54" CH rebuilder specials w/a minimal 0.005" cut to the decks (for shim gaskets to seal), still will have a quench of ~0.055" (~9.020" deck height + 0.020 shorter piston compression height + 0.015 HG thickness). Or you can go ahead and cut the deck 0.020"- at more cost for the machine shop labor, plus less strength to the decks- to get a 0.040" quench figure.

Or bite the bullet and buy pistons that have an inverted dome and a CH of 1.56". Give the decks a skim for steel shim HG seal (keeping as much deck thickness as possible), and get a better quench from the D-shaped dish along w/a tight, 0.040" quench distance.
Reply With Quote Quick reply to this message
  #18 (permalink)  
Old 04-20-2012, 01:29 PM
Silver Surfer's Avatar
More machine than man
 

Last journal entry: bwaahhaahahaaahhaa
Last photo:
Join Date: Jul 2005
Location: Kansas City, MO
Age: 37
Posts: 810
Wiki Edits: 0

Thanks: 92
Thanked 62 Times in 52 Posts
But I think the OP should stay away from the shim gasket unless:
1) the block is decked and the heads are milled to ensure flatness
2) the machine shop checks for warpage on both and gives the okey dokey for flatness
Reply With Quote Quick reply to this message
  #19 (permalink)  
Old 04-20-2012, 01:40 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
That's why block decking to ensure HG seal was accounted for in the figures I supplied. Flatness, while a requirement, is only half the equation- the surface finish is also important if using shim head gaskets. Coated shim gaskets are a little more forgiving but will still seal best w/the correct finish.

Had I also been discussing CR in that post (it was about quench, primarily), I would have said that milling the heads, while not affecting the quench, WILL slightly raise the CR. But I wasn't, so I didn't. Have to draw the line somewhere, lest the post turn into a freaking book. Like this one is fixing to do.
Reply With Quote Quick reply to this message
  #20 (permalink)  
Old 04-20-2012, 01:56 PM
rollie715's Avatar
Registered User
 
Last photo:
Join Date: Jan 2008
Location: Bellingham, Wa
Posts: 32
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thanks again,

The last few posts have been the most helpful so far. I started this new thread because a previous thread ended up with lots of book chapters between differing views.

At this point, my next step is to tear down my motor and see what I have to work with. Then I will get back to the detailed specs needed.

The piston combinations and recent comments on cam overlap and dynamic compression has been encouraging.

I will add updates as I know more.

By the way, I'm planning un using a carb and not the fuel injection or computer.
Reply With Quote Quick reply to this message
  #21 (permalink)  
Old 04-20-2012, 02:20 PM
Silver Surfer's Avatar
More machine than man
 

Last journal entry: bwaahhaahahaaahhaa
Last photo:
Join Date: Jul 2005
Location: Kansas City, MO
Age: 37
Posts: 810
Wiki Edits: 0

Thanks: 92
Thanked 62 Times in 52 Posts
Quote:
Originally Posted by cobalt327
That's why block decking to ensure HG seal was accounted for in the figures I supplied. Flatness, while a requirement, is only half the equation- the surface finish is also important if using shim head gaskets. Coated shim gaskets are a little more forgiving but will still seal best w/the correct finish.

Had I also been discussing CR in that post (it was about quench, primarily), I would have said that milling the heads, while not affecting the quench, WILL slightly raise the CR. But I wasn't, so I didn't. Have to draw the line somewhere, lest the post turn into a freaking book. Like this one is fixing to do.
My bad, I misread your post
Reply With Quote Quick reply to this message
  #22 (permalink)  
Old 04-20-2012, 02:23 PM
Silver Surfer's Avatar
More machine than man
 

Last journal entry: bwaahhaahahaaahhaa
Last photo:
Join Date: Jul 2005
Location: Kansas City, MO
Age: 37
Posts: 810
Wiki Edits: 0

Thanks: 92
Thanked 62 Times in 52 Posts
Quote:
Originally Posted by rollie715
Thanks again,

The last few posts have been the most helpful so far. I started this new thread because a previous thread ended up with lots of book chapters between differing views.

At this point, my next step is to tear down my motor and see what I have to work with. Then I will get back to the detailed specs needed.

The piston combinations and recent comments on cam overlap and dynamic compression has been encouraging.

I will add updates as I know more.

By the way, I'm planning un using a carb and not the fuel injection or computer.
What are your horsepower goals, street manner goals (low end, high end power, torque, loping idle)? That will narrow down your cam selection, and that will determine your compression ratio. Then tear down and inspect your engine, then machine work, then parts selection to get your compression ratio and squish.
Reply With Quote Quick reply to this message
  #23 (permalink)  
Old 04-20-2012, 03:25 PM
rollie715's Avatar
Registered User
 
Last photo:
Join Date: Jan 2008
Location: Bellingham, Wa
Posts: 32
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Silver Surfer
What are your horsepower goals, street manner goals (low end, high end power, torque, loping idle)? That will narrow down your cam selection, and that will determine your compression ratio. Then tear down and inspect your engine, then machine work, then parts selection to get your compression ratio and squish.
Very good question.
Originally before I did any research I threw out a ballpark goal of 300hp, 400torque, slight lopey idle, 15mpg in 3500lb Camaro.
700r4 tranny, with appropriate rear end ratio.
Daily driver, Street use only, Good low end torque, Strong launch from a standing start, Spin tires when desired, good street manners for normal driving. No desire to wind it up to high rpm.

Initial feedback suggested a fuel injected engine, but since then I'm leaning back to using a carb. At this point I'm thinking of an L31 or 350HO as a base, but with slight improvements, which would put me in the mid 300's for power and 380-420torque.

On the subject of piston top design for good quench. Realizing that I will probably need some kind of dish, it seems the best design is the D shape where the flat top matches up with the flat portion of the head for maximum quench area. Here's the two styles suggested above available from Summit for a good price. Neither one is a tru D shaped dish.

SLP-H423ACP60


SLP-WH423NP

Last edited by rollie715; 04-20-2012 at 03:30 PM.
Reply With Quote Quick reply to this message
  #24 (permalink)  
Old 04-20-2012, 04:16 PM
Silver Surfer's Avatar
More machine than man
 

Last journal entry: bwaahhaahahaaahhaa
Last photo:
Join Date: Jul 2005
Location: Kansas City, MO
Age: 37
Posts: 810
Wiki Edits: 0

Thanks: 92
Thanked 62 Times in 52 Posts
For quench in order of best to worst piston design:
flat top no valve relief
flat top 2 valve reliefs
flat top 4 valve reliefs
D-Dish
Dish and dome (not sure which is better than the other)

Why are you stuck on the d-dish? I would do everything I could with manipulating deck clearance, piston compression height and head gasket thickness so I could stick with flat tops.
Reply With Quote Quick reply to this message
  #25 (permalink)  
Old 04-20-2012, 04:30 PM
rollie715's Avatar
Registered User
 
Last photo:
Join Date: Jan 2008
Location: Bellingham, Wa
Posts: 32
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Silver Surfer
Why are you stuck on the d-dish?.
Not stuck, just trying to learn this new myself. I just keep modifying what I think I know as I learn more.

Thank you
Reply With Quote Quick reply to this message
  #26 (permalink)  
Old 04-20-2012, 10:22 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by rollie715
Not stuck, just trying to learn this new myself. I just keep modifying what I think I know as I learn more.

Thank you
The Vortec head has an excellent combustion chamber shape, you do not want to alter that, but there are ways to add volume to it w/o disrupting the chamber's function.

So if you want to use a FT, research reworking the combustion chambers to gain volume and see if it's something you think you can handle. You'll need grinding tools, and eye protection, and a good amount of spare time. It can be done w/nothing more specialized than a Dremel, sanding rolls and bits, a pair of goggles and a way to measure the chamber volume accurately as you work. You'll never want to do it twice, it's a dirty time consuming job. But it is an option, although getting 12cc more volume w/o running into problems might be impractical if not impossible.

BTW, the second piston above isn't a SBC piston. Post #17 describers the SP 423 pistons- round, 4 valve relief.

I believe you ought to build this engine right. That may well mean spending more than a ten spot on a piston. If you want cheap, then so be it.
Reply With Quote Quick reply to this message
  #27 (permalink)  
Old 04-20-2012, 11:50 PM
rollie715's Avatar
Registered User
 
Last photo:
Join Date: Jan 2008
Location: Bellingham, Wa
Posts: 32
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by cobalt327
BTW, the second piston above isn't a SBC piston. Post #17 describers the SP 423 pistons- round, 4 valve relief. .
I think the Summit site was showing the wrong picture. Upon googling the part number I found this picture which might be a more correct photo: Quench area looks much better in my opinion.

ZWH423NP


This picture was found at this link, but doesn't match the 4 valve relief description either:
http://autoplicity.com/products/4118...c_pistons.aspx

I'm wondering with a 10cc dish, if this picture could be right with the valve reliefs taking up most of the volume. The picture shows a flat top in the quench area, but only 2 valve reliefs.

Last edited by rollie715; 04-21-2012 at 12:00 AM.
Reply With Quote Quick reply to this message
  #28 (permalink)  
Old 04-21-2012, 12:18 AM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by rollie715
I think the Summit site was showing the wrong picture. Upon googling the part number I found this picture which might be a more correct photo: Quench area looks much better in my opinion.

ZWH423NP


This picture was found at this link, but doesn't match the 4 valve relief description either:
http://autoplicity.com/products/4118...c_pistons.aspx

I'm wondering with a 10cc dish, if this picture could be right with the valve reliefs taking up most of the volume. The picture shows a flat top in the quench area, but only 2 valve reliefs.
A two valve relief SBC FT piston generally won't be over ~5cc.
Reply With Quote Quick reply to this message
  #29 (permalink)  
Old 04-21-2012, 10:16 PM
rollie715's Avatar
Registered User
 
Last photo:
Join Date: Jan 2008
Location: Bellingham, Wa
Posts: 32
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I hope you don't mind if I just keep adding more to this thread. As the name implies, I hope to document my research and build of my Vortec 350.

Just in case you you haven't been following all of my thread, I have a 350TBI out of an 89 1500 pickup, that I plan to rebuild and turn into a carburated Vortec engine. Today I started stripping it down. I believe this motor was originally a flat tappet design, but was built on a block that could easily be converted to roller tappets. Here's a couple pics of the area where a spider and lifter guides(I'm not exactly sure what they are called) would be. It looks to me like the guide area is already machined, but the spider mounting risers need to be drilled and tapped, a job which I should be able to do easily. Can someone familiar with the machined guide area, confirm that my block is machined ready for the roller lifter guides?



Here's a closeup of the machined guide area.


The next question, is where would be an easy and cheap place to buy a spider and guides?

I'm also guessing that judging by how deep the existing lifters sit down inside their holes, that a new set of roller lifters will stick up higher into the guides and require a different set of shorter push rods.

Last edited by rollie715; 04-21-2012 at 10:22 PM.
Reply With Quote Quick reply to this message
  #30 (permalink)  
Old 04-22-2012, 03:51 AM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
eBay usually has vendors selling the spiders and dog bones. You'll also need a cam retainer plate to match your block, it's held on w/button head screws for clearance. There were two different widths of cam retainers so get the right one to match your block. If your block isn't drilled for the retainer, either retainer will work.

Push rods are about 7.2" long for the hydro roller, FT cams used a push rod about 7.8" long. The exact length will be decided after you mock up the engine using the cam, heads, valves, head gaskets, rockers, rocker studs, etc. you intend to run.

HERE is one of many threads on valve train geometry.

HERE is a list of valve train points to check.
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:
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
350 Vortec TPI Build: Need some help/advice/suggestions 90CamaroRS Engine 8 08-26-2011 10:43 PM
What Cam is best for stock L31 Vortec 350 heads? 327 Build Colder2012 Engine 7 06-13-2011 07:22 PM
350 csfi vortec build questions Valkyrie5.7 Engine 12 04-21-2011 11:44 PM
96-00 350 Vortec Build grandprix601 Engine 8 02-17-2010 08:12 AM
1999 Surburban Vortec 350 need build help RICHat22 Engine 3 02-08-2009 05:28 PM


All times are GMT -6. The time now is 12:23 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.