A unique BBC application - 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 10-21-2009, 10:51 PM
techinspector1's Avatar
Senior Curmudgeon
 
Last wiki edit: DynoSim combinations Last photo:
Join Date: Oct 2005
Location: Hemet, California, USA
Age: 72
Posts: 12,975
Wiki Edits: 326

Thanks: 765
Thanked 1,023 Times in 855 Posts
Don't know squat about props, etc, but I do know that if I had rectangular port heads, I wouldn't trade down for oval port heads. I'd keep addin' cubic inches until the rectangles THOUGHT they were ovals.

If you'd like, I can put the basics into my DynoSim software and play around with different carbs, manifolds, headers, c.r., cam timing, etc and post the results of changes. Not that the software will be definitive, it won't. But it's fairly useful at comparing changes of parts.

If you want me to do this for you, the first thing I will need is a complete set of flow figures on the heads that you feel are real world from 0.100" valve lift through 0.700" valve lift. I can probably look 'em up on Stan Weiss or Purple Sage, but I'd rather get 'em from you so that you feel confident with 'em.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #17 (permalink)  
Old 10-22-2009, 12:59 PM
airboat's Avatar
Registered User
 
Last photo:
Join Date: Mar 2006
Location: Canada
Posts: 286
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts


I have a 19' Eliminator inboard with a 454 and I just pulled it out last weekend for more power. If it has 330 HP short block it will have cast flat tops with no dish. Mine are like new but IMO a little tight for a boat and cast and not enough compression. Mine has 360 for heads and I think I will stay with them adding CC polish, porting and a Performer and double pumper. I like the fact that I can pull my kids on a double tube or a wake boarder at 1500 and go around corners without touching the throttle. Just like a tractor.

speed is tough because the hull is really a semi-displacement type of hull, holeshot is fantastic, I have rear facing seats at the front and have almost lost people. 0-50 in a little over 2 seconds? Can't do WFO pulling skiers up.

A roller cam would be nice but mine is getting a Comp 270s because that is what I have sitting on the shelf and probably Keith Black Hypers for just over 9/1. Tight piston/deck clearance (.028-.040) and total seal rings.

You have me worried though. I don't think mine is reverse rotation so i'll have to spin up the starter now to check for sure but if it is I'll just change the starter and shifter linkage for the velvet drive!

Carb on mine is listed as a 715cfm but like i say going to double pumper, I just don't like vacuum secondarys on a boat.

I have the aluminum logs that Glen L sells
Attached Thumbnails
Click image for larger version

Name:	P8120397 (Medium).JPG
Views:	1214
Size:	62.1 KB
ID:	41415  

Last edited by airboat; 10-22-2009 at 01:20 PM.
Reply With Quote Quick reply to this message
  #18 (permalink)  
Old 10-22-2009, 02:49 PM
OLNOLAN's Avatar
Registered User
 
Last photo:
Join Date: Apr 2009
Location: Louisiana
Posts: 1,048
Wiki Edits: 0

Thanks: 399
Thanked 102 Times in 84 Posts
Hey Trb

Hey Man, you ever thought about putting a blower on it? I'll bet a Weiand 177 would wake her up. I'm gonna attempt to post some peeks of my stuff.

My arsenal-rectangle port 502

406 sbc in the Eliminator

Mercruiser Alpha 1

ok lets see if my pics work. olnolan
Reply With Quote Quick reply to this message
  #19 (permalink)  
Old 10-22-2009, 03:19 PM
airboat's Avatar
Registered User
 
Last photo:
Join Date: Mar 2006
Location: Canada
Posts: 286
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
An easy bolt on would be a set of these edelbrock heads.

PERFORMER HIGH-COMPRESSION 454-O

100cc semi-open chamber heads feature a 1-1/2 rolled over (angle milled) design that improves intake port alignment and provides a smaller combustion chamber without shrouding the valves
9.2:1 compression with flat-top pistons for an outstanding high performance street head
8.8:1 compression ratio when used on 1987-up TBI-equipped 7.4L dished piston motors
Produced over 450 ft/lbs. torque when combined with our Multi-Point EFI System


PERFORMER HIGH-COMPRESSION 454-O
Chamber Size Intake Port Size Valve Sizes (in/ex) Bare (single) Complete (single)
100cc 290cc 2.19"/1.88" #60489 #60499
Note: See the Cylinder Heads Chart for specs. Mark IV rocker arms and valvetrain parts required.
Reply With Quote Quick reply to this message
  #20 (permalink)  
Old 10-22-2009, 07:02 PM
airboat's Avatar
Registered User
 
Last photo:
Join Date: Mar 2006
Location: Canada
Posts: 286
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Actually If I were you I would tear it down when it's out. Mine started, idled and ran great. Oil pressure and everything looked great however found evidence that the crankcase got filled up with water once. rust line on a counterweight, rear upper main shell had a strange coloration. I'm glad I pulled it apart.

My bore's look like a torque plate hone will clean them up and get me the clearance I want. A constant load engine like in a boat should be set up a little looser and even more so with fresh water cooling so my 489 with hypers is set up .004" to .0045" and it's a closed water cooled engine.

I'm pretty sure you will find cast pistons if you take it apart. My block number is the same as yours. if you put those 100cc edelbrocks on your flattops you will probably want something better than a cast piston so use the same heads you have and put some domed pistons in it.

I'm planning on just polishing and reusing my crank as well. IMO once you need a crank you may as well go stroker so this is actually going to be a pretty budget build. cam, Lifters, TC and gearset, oil pump, pistons and rings.

If you go stroker IMO you will get better bottom end torque with a short or standard length rod kit. If your only looking for 500 HP@ 5600 once again IMO a cast crank should do it however the forged cranks arn't that much more. Main studs for sure. My airboat 489 is actually a long rod with cast crank, flat tops and 063 heads and certainly no shortage of torque however I have discussed long rod/short rod with people whom I respect and have come into agreement an engine that spends most of it's time at 2000-5000 rpm should use the shorter rods.

http://www.cnc-motorsports.com/produ...238&CtgID=9236

http://www.cnc-motorsports.com/produ...320&CtgID=9259

Total seal gapless rings work great in a constant load engine that operates at lower RPM's

Small carbs work fine on a boat and I prefer them because of drivability. easier to adjust that 1 MPH change in towing speed. Have an 850 dP on my 489 airboat but keeping my eyes open for a 750dP.

Nice boat! a Barefoot Natique was in consideration however I just love mine, mine is a flat bottom so yours is better in the rough but nothing like an inboard!

My 489 airboat I built!
http://www.youtube.com/watch?v=zmIAWEdrgVg



engine in mock-up only

Attached Thumbnails
Click image for larger version

Name:	Airboat-27.jpg
Views:	981
Size:	127.2 KB
ID:	41419   Click image for larger version

Name:	Airboat-43-1 (Custom).JPG
Views:	1449
Size:	36.4 KB
ID:	41420  
Reply With Quote Quick reply to this message
  #21 (permalink)  
Old 10-26-2009, 11:53 AM
Registered User
 
Last photo:
Join Date: Aug 2009
Location: CT/MA
Posts: 30
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Heres the only (terrible) picture Ive got of the engine:



Techinspector, thanks for the offer to run the software! Im afraid I dont know quite enough about what Ive got (compression ratio, cam, flow specs on the 990's) to try and gauge any potential changes. Still trying to get brought up to speed on this BBC stuff...

If money were no object, Id be throwing cubic inches at this engine and reusing the rectangles... and that may be what we end up doing eventually. Right now we're disassembling the boat to do structural work- so while we would like to make any sensible changes while the engine is out, the budget for this winter is mainly going into the hull. Unfortunately, I dont think a stroker is in the cards unless we deem the bottom end to be in marginal shape.

We did a compression test over the weekend and saw roughly a 10% variation between all 8 cylinders (134-150psi). Not too bad. While the engine is out we're going to pull the pan and take a look at the bearings. We'll also pull a head and see what we've got for pistons so we can determine our CR. Measure the valve lift too, so we can get a rough idea of what we've got for a cam. Once we do that, Ill report back to see what kind of changes (if any) make sense. Not sure if new pistons would be in order as long as the CR is at least on the range of the stock 8.1:1, but a new cam might be in the budget if the one in there is super tame. Probably a new intake too. Heads would be a big maybe- though Id want to hang onto the rectangles for future use at a minimum!

Olnolan, a SC would be an interesting direction to go- I only see 3 semi-major problems with that. 1) Engine box clearance (its tight already and going higher would require vinyl and fiberglass changes, as well as create ski pylon interferance problems). 2) Engine rotation- can a SC be set up to run on a reverse rotation motor? I assume it only wants to spin one way! 3) Cost... we'd be looking at $3k+ for a complete set up, right?
Reply With Quote Quick reply to this message
  #22 (permalink)  
Old 10-27-2009, 09:47 AM
OLNOLAN's Avatar
Registered User
 
Last photo:
Join Date: Apr 2009
Location: Louisiana
Posts: 1,048
Wiki Edits: 0

Thanks: 399
Thanked 102 Times in 84 Posts
Bassakwards Engine

Hey TRB, Whew, I did a little reading on the reverse rotation engines, there is a bit more involved than I originally thought. I suppose the roots style blowers are directional? Seems that any major mods(stroker,cam,etc.) are gonna be real expensive. Big block parts ain't cheap to begin with, then you have to deal with the reverse rotation thing adding additional cost. If the 177 will work, Summit has a kit for $2300. IMHO, the single best bang for the buck on your engine would be the exhaust sytem I mentioned earlier. It should be the first item on your shopping list regardless of any other modifications you decide on. I'll be around later, got last minute things to do cause we're going to Talladega. olnolan
Reply With Quote Quick reply to this message
  #23 (permalink)  
Old 10-27-2009, 10:05 AM
Registered User
 
Last photo:
Join Date: Aug 2009
Location: CT/MA
Posts: 30
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by OLNOLAN
Hey TRB, Whew, I did a little reading on the reverse rotation engines, there is a bit more involved than I originally thought. I suppose the roots style blowers are directional? Seems that any major mods(stroker,cam,etc.) are gonna be real expensive. Big block parts ain't cheap to begin with, then you have to deal with the reverse rotation thing adding additional cost. If the 177 will work, Summit has a kit for $2300. IMHO, the single best bang for the buck on your engine would be the exhaust sytem I mentioned earlier. It should be the first item on your shopping list regardless of any other modifications you decide on. I'll be around later, got last minute things to do cause we're going to Talladega. olnolan
Olnolan, what did you find out about the reverse rotation BBC cams? Thats the one area I lack specific knowledge... Im much more familiar with my RH Ford set up. If the RR cam blanks exist (presumably hydraulic flat tappet) like Comp tells me, then I should be good to go. The only other trick (besides the starter and dist gear) are the oil control at the rear main seal (some cranks have wick lines cut in them, other times its in the seal) so a stroker wouldnt be a problem. Just gotta make sure the pistons are installed backwards if the wrist pins are offset... other than that, no big deal on the reverse rotation- I havent found parts to be much more expensive.

While the SC is interesting, thats a huge $$$ to spend, plus I will encounter clearance issues. This is a ski boat first and foremost, so while a SC is cool, it cant block the ski pylon! The reverse rotation also complicates things, so Ill be going all motor, I think.

As far as exhaust goes, thats usually one of the big ticket items on a boat with wet exhausts. You can spend $2k-6k on a nice set of manifolds if you go new. Still looking at $1k+ for good used. Ive seen otherwise stock boats (330hp flavor) pick up next to no performance with just an exhaust upgrade. Ive also seen stock cast iron manifolds cut in half (albeit Ford flavor) and the runners dont look terrible- so Im inclined to believe that the hp return for dollar spent on the exhaust is relatively low. Trying to do the smartest things with our limited engine budget for now, so a big dollar exhaust upgrade isnt in the cards, at least this winter.

Right now its looking like a cam and intake upgrade are most likely, maybe a piston change to bump CR if it can be done cheaply- depending on what we currently have, of course.
Reply With Quote Quick reply to this message
  #24 (permalink)  
Old 01-23-2010, 03:30 PM
Registered User
 
Last photo:
Join Date: Aug 2009
Location: CT/MA
Posts: 30
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Im digging up my old thread!

We're knee deep in the structural work on the boat, but we've finally started digging into the engine. A few months ago, we did a compression test and all cylinders were within 10%... so no excuse to rebuild the short block yet. We still have to pull the pan and inspect the bottom end, but everything we've found so far looks good.

Today we pulled a head to see what we have for pistons and we were surprised... these things have a monster dome on them! These definitely arent stock pistons. The number cast into the top is L2349 STD. I cant find a good source for info on these, but from what I gather, I believe these were made by TRW. The L indicates that theyre forged. One source listed the dome to be good for 29.4cc. According to the calculator I used, that should be good for a CR of roughly 10.6:1 with our 118cc 990 heads. Other sites listed CR to be around 10:1 with 118-119cc heads, so I think Im in the ballpark. Thats quite a bit higher than the 8-8.5:1 I thought we might have!



I still havent measured the valve lift with the current cam- I assume that might provide some useful info? Im still assuming that this is the weakest part of our engine as it sits- I think it should have been good for more RPM than it was... so going more aggressive with this piece should yield better performance. Assuming that to be the case, can anyone give me a decent recommendation on a bumpstick that will give me some more top end power without killing the bottom end? Ideally, Id like to turn the engine up to 5500-5800. Off idle power isnt a concern to me- as long as the power starts coming in by 2500-3000, the boat should still come out of the hole just fine.

Thanks in advance!
Reply With Quote Quick reply to this message
  #25 (permalink)  
Old 01-23-2010, 04:28 PM
airboat's Avatar
Registered User
 
Last photo:
Join Date: Mar 2006
Location: Canada
Posts: 286
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Sweet!
Reply With Quote Quick reply to this message
  #26 (permalink)  
Old 01-23-2010, 07:45 PM
Guy Hiltz's Avatar
Member
 
Last photo:
Join Date: Sep 2005
Location: Nova Scotia Canada
Posts: 1,003
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
With those heads,pistons & intake,it appears to be a LS-6 crate motor.
Guy
Reply With Quote Quick reply to this message
  #27 (permalink)  
Old 01-23-2010, 09:24 PM
airboat's Avatar
Registered User
 
Last photo:
Join Date: Mar 2006
Location: Canada
Posts: 286
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The cylinder bore has been relieved for the intake valve. Don't think they did that on crate engines... Sweet! You shouldn't have to do much...

Just check the cam out carefully, I found a couple lobes on mine starting to go flat...

Last edited by airboat; 01-23-2010 at 09:34 PM. Reason: cam
Reply With Quote Quick reply to this message
  #28 (permalink)  
Old 01-23-2010, 09:59 PM
Guy Hiltz's Avatar
Member
 
Last photo:
Join Date: Sep 2005
Location: Nova Scotia Canada
Posts: 1,003
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
My LS-6 crate motor had the relieve in the cylinders
Same pistons & intake too,but the 188 heads
Guy
Reply With Quote Quick reply to this message
  #29 (permalink)  
Old 01-24-2010, 08:11 AM
Rickracer's Avatar
ASE Master Tech, Fabricator
 
Last wiki edit: Taurus 2-speed fan control wiring diagram Last photo:
Join Date: Jan 2010
Location: Kissimmee, Florida
Age: 55
Posts: 937
Wiki Edits: 8

Thanks: 0
Thanked 3 Times in 3 Posts
Personally, I'd find a set of passenger car oval ports and do some porting, you can get nearly as much flow on top with MUCH better torque/low end. Couple that with the right choice of cam, intake and carb and you could add at least 25~50 ft.lbs. of torque right where you need it, and still have more top end as well. The Edelbrock Performer would be the ideal intake, IMHO, maybe add a 1" open spacer for a little more top end if you have the room. I'd look for an 800DP carb. Big blocks LOVE free flowing exhaust, so anything better you can do there above what you have now will be a worthwhile improvement. If you can add enough torque in the mid range, you may be able to prop up a little as well.
Reply With Quote Quick reply to this message
  #30 (permalink)  
Old 01-24-2010, 08:27 AM
Registered User
 
Last photo:
Join Date: Aug 2009
Location: CT/MA
Posts: 30
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Cool... looks like the LS6 crate motor was rated at 425hp?

Just a reminder- this motor was set up for reverse rotation, which would have been original on the boat. I dont know what the specs are on the existing cam, but I wouldnt be surprised to find out that its pretty tame. Im still being told by Comp that they can custom grind any RH cam I want- so if you guys could give me an idea of what would work best for this combo with an intended powerband of 2500-5800, that would be a huge help! Ill be sticking with hydraulic flat tappet for cost and availability reasons.

The plan right now is to put a Performer RPM on instead of the GM intake. I'm also considering roller rockers- Ive had good luck with Crane in the past and have heard good things about Scorpion as well. Any BBC-specific info I should be aware of here?

Edit: Rickracer, thanks for chiming in! We're still keeping an eye open for some 781's or 049's for a reasonable amount, but I wouldnt be disappointed if we stick with the 990's. The holeshot wasnt terrible last year, and the boat will be 400lbs lighter now due to all the waterlogged foam we removed- so that should provide a nice improvement all by itself. I forgot to mention that we're actively searching for a new set of exhaust manifolds, and we plan to upsize the 3" hoses to 4". The cam is really the piece of the puzzle I need the most help with.

As far as the carb goes, we put a newish 750cfm Holley Marine on there last year. Its a 4160 (vaccuum secondaries) with a rear metering block conversion kit and a milled off choke horn. According to the CFM calculators Ive used, that should be sufficient to turn the 454 up to 6000rpm at 95% VE, so I expect that to be OK for the time being. We have a short angled carb spacer on there now- if I remember correctly, its an open one. We were maxed out on headroom last year, but with the floor rebuild we should be picking up at least a 1/2", so we'll likely go as tall as we can.

Last edited by TRBenj; 01-24-2010 at 08:43 AM.
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
bbc what gears to run.? chevelle4542speed Engine 5 12-07-2006 05:47 PM
96 to 00 BBC Question Mustangsaly Engine 6 02-20-2006 07:03 PM
BBC Big Block Questions Mustangsaly Engine 6 01-21-2006 06:59 PM


All times are GMT -6. The time now is 06:30 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.