Change font size
It is currently Fri Mar 29, 2024 2:00 am


Post a new topicPost a reply Page 1 of 1   [ 9 posts ]
Author Message
 Post subject: restricted orifice
PostPosted: Sun Aug 08, 2010 3:36 pm 
I like cake

Joined: Mon Aug 02, 2010 11:44 am
Posts: 3
Hello everyone,
Just joined the club. I live in Calgary and own an 1996 850R and a 1973 1800ES.
The 1800ES has been converted to SU HIF6 carbs, which makes the car go like gangbusters now. The remaining issue is the high idle (1400-1500 rpm's), which is probably related to the crankcase breather. The person, who rebuilt the SU's says that it needs to have a "restricted orifice" in the intake manifold; a fitting that looks to have a large ID, but has a small ID internally. Who are the best mechanics in the club and reside in Calgary? Who has a longer moment and the gusto to help? Please let me know. Cheers, Ray


Top
 Profile  
 
 Post subject: Re: restricted orifice
PostPosted: Sun Aug 08, 2010 6:48 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
User avatar

Joined: Wed Dec 21, 2005 8:40 pm
Posts: 3492
Location: Calgary, Ab
Saying "restricted orifice" makes me giggle like a twelve year old...

However, I'd think you have one already (besides the juvenile dirty kind) - most seem to, anyway.

Where abouts do you live? We've got guys all over.


Top
 Profile  
 
 Post subject: Re: restricted orifice
PostPosted: Sun Aug 08, 2010 7:15 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
User avatar

Joined: Wed Dec 21, 2005 7:14 pm
Posts: 1875
Location: Missing my garage in Sunnyside
Welcome and sorry i cant help with your orifice! Not sure how crankcase and idle arr connected but hopefully one of the even older guys around here can offer some advice. Only carbs i have are on my bike and i havent had to touch them yet!

_________________
Hi, I drive a fictional star wars character with rear wheel drive. His name is Darth Wagon, he has a shiny helmet.
Image


Top
 Profile  
 
 Post subject: Re: restricted orifice
PostPosted: Sun Aug 08, 2010 7:58 pm 
I can fix the world
User avatar

Joined: Thu Dec 22, 2005 12:18 pm
Posts: 1461
Location: Calgary
Sounds fun, I got to tune a couple su's at work on some older models. Good luck with getting it running right. Post some pics!

_________________
2006 Subaru Sti


Top
 Profile  
 
 Post subject: Re: restricted orifice
PostPosted: Mon Aug 09, 2010 6:44 am 
Strapping on extra booster rockets
User avatar

Joined: Tue Apr 22, 2008 5:43 am
Posts: 387
I'll look at my spec book but you should have a restricted orifice.. in some cases.

_________________
Bert & Jacks Auto Service
129 17th ave S.E
228-7078
Paul


Top
 Profile  
 
 Post subject: Re: restricted orifice
PostPosted: Mon Aug 16, 2010 6:13 pm 
Somehow completely sideways in 4th

Joined: Mon Aug 06, 2007 10:27 am
Posts: 211
Location: edm
Your D-jet must have been some messed up that SU's are an improvement....


Top
 Profile  
 
 Post subject: Re: restricted orifice
PostPosted: Mon Aug 16, 2010 10:33 pm 
Strapping on extra booster rockets

Joined: Sun Sep 03, 2006 8:46 pm
Posts: 360
Location: B-Ham WA/Portland, OR USA
iadr wrote:
Your D-jet must have been some messed up that SU's are an improvement....

I'd argue that SUs are a slight improvement to the D-jet for power. They don't require extremely frequent attention once rebuilt very carefully on an engine that isn't worn out junk (most OHVs are by now). By this time, they are probably easier to keep on the road, since they are pretty much a known entity with parts available and people available to rebuild them very nicely.

On a fairly "cookie cutter" 2.1 B20 with an R-cam and some fairly minor well done head work, the d-jet will really lean out as the RPMs climb. The SUs with the proper needle to go with that cam and some headwork will keep on pulling and put down decent power.

The d-jet works fairly well and reliably when all is right with it. Good luck finding a completely good wiring harness, injectors or MAP for it though. Fuel pressure regulators also do interesting things if adjusted up much from stock (not saying that is good or bad).

As to the SUs, one ought to be able to find the correct needle to run them with a D-cam B20, if that is what the car has. If the shafts haven't had bushings done and the carbs rebuilt, unless yours are in time capsule condition from 196x-1974, they probably need to be re-bushed before one tunes them or worries about orifices *chortle.*

Worn out carbs or engines won't ever tune correctly. Fresh stock carbs on a stock spec motor are quite painless to set straight and mostly stay that way. SUs are sensitive to elevation changes however, which would definitely describe Calgary-surrounding terrain many times. I used to lean them out a bit (2-3 flats from sea level to sun river (high desert) IIRC).


Last edited by 945_James on Tue Aug 17, 2010 2:12 am, edited 3 times in total.

Top
 Profile  
 
 Post subject: Re: restricted orifice
PostPosted: Mon Aug 16, 2010 10:46 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
User avatar

Joined: Wed Dec 21, 2005 7:14 pm
Posts: 1875
Location: Missing my garage in Sunnyside
sorry, had a couple of scotches, so can't contribute much. just want to say- james, **** you're smart.

_________________
Hi, I drive a fictional star wars character with rear wheel drive. His name is Darth Wagon, he has a shiny helmet.
Image


Top
 Profile  
 
 Post subject: Re: restricted orifice
PostPosted: Mon Aug 16, 2010 11:20 pm 
I can fix the world
User avatar

Joined: Thu Dec 22, 2005 12:18 pm
Posts: 1461
Location: Calgary
On an unrelated related subject. I have a complete D-jet computer/harness from a 71 142E for sale.

_________________
2006 Subaru Sti


Top
 Profile  
 
Display posts from previous:  Sort by  
Post a new topicPost a reply Page 1 of 1   [ 9 posts ]


Who is online

Users browsing this forum: No registered users and 27 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron


Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
610nm Style by Daniel St. Jules of Gamexe.net