by jrinaman Mon Aug 08, 2011 9:26 pmthe choice of cams will make a difference. i am guessing 650-700 rpm for stock. longer duration cams need higher idle. if you was refering to adjusting air/fuel mixture, i have always set idle as low as i could, adjusted a/f screws in until it slows, turn out to highest rpm i can acheive and add 1/4 turn. then turn idle back up. is it a new carb?
+13
Digz
Nightmoves
RodStRace
savage
itruns
Kakster
ViewMaster
BvrWally
m1dadio
donivan65
mo_1040
sasktrini
Scott
17 posters
All Systems STOPPED...
jrinaman- Number of posts : 890
Location : zelienople,pa.
Age : 59
Registration date : 2011-03-10
Scott- Number of posts : 1651
Location : Anoka, MN
Age : 54
Registration date : 2008-05-20
It was used on a Monty Carlo for about 7 months, then moved to this engine.
Right now it idles at 2500 with as little choke as I can give it without dying. I have the spec's of the cam buried someplace, but it's an RV cam if that makes a difference.
I appreciate y'all
Without people like you two I wouldn't have been able to do half of what I've done so far on this van.
Right now it idles at 2500 with as little choke as I can give it without dying. I have the spec's of the cam buried someplace, but it's an RV cam if that makes a difference.
I appreciate y'all
Without people like you two I wouldn't have been able to do half of what I've done so far on this van.
jrinaman- Number of posts : 890
Location : zelienople,pa.
Age : 59
Registration date : 2011-03-10
2500 is way off. are you saying it stalls below 2500 or that is all the idle adjustment you have? if you have no adjustment left, then it is likely sucking air somewhere or something restricting carb from closing. do you have an extra carb you can bolt on to rule out the carb itself? edelbrocks have a port dead center on front and back at base plate, are they plugged? rv cam should idle like stock cam, i have 268 duration, couple sizes above yours, and i run it around 800 rpm but it will sit and idle around 500. 2500 isnt a small leak in a hose, its an open port, leak at carb to intake, intake to engine or the carb is needing repaired.
Scott- Number of posts : 1651
Location : Anoka, MN
Age : 54
Registration date : 2008-05-20
Sorry for the slow replies, I've been putting in extra hours to knock out some overdue projects at work. Today it didn't get over 100 here, and hopefully tomorrow it wont either. The A/C died on the house so I'm killing time at home until the A/C guy gets here. Maybe I can get some van time in, right after I replace a starter in my daughters Kia. It really never ends does it?
I'll climb around and check the vacuum hoses, but off the top of my head I know the dead port is plugged, and the other feeds the PVC in the valve cover. I didn't want to plug that one, but if that's the fix. I have to check that idle screw, I think it's backed all the way out. I don't have another carb to use as a test, this is it.
I'll climb around and check the vacuum hoses, but off the top of my head I know the dead port is plugged, and the other feeds the PVC in the valve cover. I didn't want to plug that one, but if that's the fix. I have to check that idle screw, I think it's backed all the way out. I don't have another carb to use as a test, this is it.
Digz- Number of posts : 3794
Location : United States Six Lakes MI
Registration date : 2008-05-17
I went back and saw that this carb was pulled off a running engine and put on ? Was wondering if anyone had been into it for a rebuild,, I once sent one out and got it back with the bowl jets reversed,, it wouldn't idle,, To long ago to remember about trying it at a higher RPM. that was on an AFB Carter.
Scott- Number of posts : 1651
Location : Anoka, MN
Age : 54
Registration date : 2008-05-20
No, it hasn't been rebuilt, just pulled from a V8 and put on my L6.
I pulled the idle pins, cleaned them up, and gave a couple of shots of carb cleaner down the idle pin holes.
Once the engine gets good and hot I can get the choke all the way off, but it idles rough at about 500rpm, and giving it any gas makes it die. Adjusting the idle screws doesn't increase the idle.
I have fresh gas in it, but I've got gas treatment mixed in, and am now wondering if it's got to much in it. So today I'm mix in some gas to dilute it.
I pulled the idle pins, cleaned them up, and gave a couple of shots of carb cleaner down the idle pin holes.
Once the engine gets good and hot I can get the choke all the way off, but it idles rough at about 500rpm, and giving it any gas makes it die. Adjusting the idle screws doesn't increase the idle.
I have fresh gas in it, but I've got gas treatment mixed in, and am now wondering if it's got to much in it. So today I'm mix in some gas to dilute it.
Scott- Number of posts : 1651
Location : Anoka, MN
Age : 54
Registration date : 2008-05-20
Fresh gas didn't make a difference. :\
jrinaman- Number of posts : 890
Location : zelienople,pa.
Age : 59
Registration date : 2011-03-10
500 rpm is much better. if a little choke smoothes it out, then rejet a couple sizes larger. not sure how adjusting idle screw doesnt adjust idle, did you mean the air/fuel screw? "if" the jetting is wrong, the a/f screw wont help much.
Twinpilot001- Number of posts : 6186
Location : spokane ,Wa.
Registration date : 2009-09-28
pull the carb= clean it & put a kit in it - sounds like the acclerator pump isnt working( dies @ off idle) and the idle screw wont adjust to make any difference. Be sure to use compressed air when cleaning and be sure to clean just under & above the butterflies-thats the idle & off idle ports. Happy Vanning
Scott- Number of posts : 1651
Location : Anoka, MN
Age : 54
Registration date : 2008-05-20
When I noticed that my temp gauge wasn't working right I put this off until I could be sure it wasn't overheating.
Now I'm going back through this thread and trying to put together a plan.
Here's where it's at now..
The intake is heated, and these results is the engine running with the temp at 190.
I haven't been able to get it to idle @ 500 like I said before. Right now at about 90% choke it idles at about 1500rpm. I think this is down from the 2500 since I plugged the PCV port on the carb. The idle screws make no difference, all the way in, or out.
I haven't tried to keep it at idle with the carb. spray yet, like Donivan suggested, I will try that tonight or tomorrow. And I haven't gone around the intake and carb. base with propane, I will try that too.
I just seems to me that the obvious problem is that it's sucking a bunch of air from someplace. I'm wondering if since I started running my engine the lifters pumped-up and are now letting some are suck in the intake valves..?
I also noticed that it's building air pressure inside the valve cover when it's running. I left the PCV in the top of the intake with the hose hanging. When I shut the engine off it hisses for 20 or 30 seconds as the pressure leaks out.
Since I don't really know the history of the carb. I know it should be rebuilt. I don't know if the jets have been changed, and since it's sat for a while, it could probably use a good cleaning. But checking the Edelbrock site shows me that I should be running a 500cfm, not a 600. So can I simply change the metering rods and jets to make this one a 500, or is the carb chassis different?
Or do I rebuild and leave it at a 600cfm because it should be fine.
Or do I eliminate the carb as being the problem by going out and buying a new 500cfm since I don't know what all may have been done to this one?
Now I'm going back through this thread and trying to put together a plan.
Here's where it's at now..
The intake is heated, and these results is the engine running with the temp at 190.
I haven't been able to get it to idle @ 500 like I said before. Right now at about 90% choke it idles at about 1500rpm. I think this is down from the 2500 since I plugged the PCV port on the carb. The idle screws make no difference, all the way in, or out.
I haven't tried to keep it at idle with the carb. spray yet, like Donivan suggested, I will try that tonight or tomorrow. And I haven't gone around the intake and carb. base with propane, I will try that too.
I just seems to me that the obvious problem is that it's sucking a bunch of air from someplace. I'm wondering if since I started running my engine the lifters pumped-up and are now letting some are suck in the intake valves..?
I also noticed that it's building air pressure inside the valve cover when it's running. I left the PCV in the top of the intake with the hose hanging. When I shut the engine off it hisses for 20 or 30 seconds as the pressure leaks out.
Since I don't really know the history of the carb. I know it should be rebuilt. I don't know if the jets have been changed, and since it's sat for a while, it could probably use a good cleaning. But checking the Edelbrock site shows me that I should be running a 500cfm, not a 600. So can I simply change the metering rods and jets to make this one a 500, or is the carb chassis different?
Or do I rebuild and leave it at a 600cfm because it should be fine.
Or do I eliminate the carb as being the problem by going out and buying a new 500cfm since I don't know what all may have been done to this one?
Digz- Number of posts : 3794
Location : United States Six Lakes MI
Registration date : 2008-05-17
Scott, I just went back thru this whole thread. I gotta ask do you have the breather on the Rocker cover unplugged? or is it still sealed off? I noticed the the old engine had the breather tube from the cover to the air intake above the carb and the new set up is not like that? thta might get rid of your pressure problem, Let It breathe. I have no idea if this would have an effect on anything else tho, Its possible it is trying to pull air from someplace its not supposed to?
Scott- Number of posts : 1651
Location : Anoka, MN
Age : 54
Registration date : 2008-05-20
I pulled the PCV valve out to keep the pressure down, but am a little concerned that it's building. My plan, if I don't ever connect it back to the carb, is to replace the PCV valve with a breather.
Digz- Number of posts : 3794
Location : United States Six Lakes MI
Registration date : 2008-05-17
You should havea port in the cover for the PCV and a breather? The PCV wont make it build pressure that is a direct vacumn to the engine intake. It has to have a breather besides that in order to have a draw across the inside of the block to pull air and keep the engine from creating internal pressure. I had to do this to mine also , I forgot to give it that fresh air vent source and was pushing oil out of the crank seals.
donivan65- Governor
- Number of posts : 12220
Location : San Diego, California
Registration date : 2008-05-12
If the valves are too tight, it won't idle,,,,,are they adjusted correctly? Have you done a recent compression and cylinder leakdown test on each cylinder recently,,,,,pressure in the valve covers aint good,,,,,,could be rings that are not seated, bore has a taper in it or a head gasket leak,,,,,,,
Scott- Number of posts : 1651
Location : Anoka, MN
Age : 54
Registration date : 2008-05-20
I haven't done a recent compression or cylinder leakdown test. Now that you got me thinking, I remember hearing bubbling water at the back of the block. I know where this is going, blown headgasket..
Also, I was hearing tapping from the back of the engine, I was hoping it was a lifter that wasn't pumped with oil, and would work itself out. Now you got me wondering if it's a valve hitting the cylinder.
The Oil is still clear right now.
I'll do a compression test tomorrow..
Also, I was hearing tapping from the back of the engine, I was hoping it was a lifter that wasn't pumped with oil, and would work itself out. Now you got me wondering if it's a valve hitting the cylinder.
The Oil is still clear right now.
I'll do a compression test tomorrow..
donivan65- Governor
- Number of posts : 12220
Location : San Diego, California
Registration date : 2008-05-12
Weird stuff happens to those rocker arms,,,,those studs can pull up or the rocker arms can eat the end of the valve stem off,,,,,so find the clacker, remove the rocker and check the end where it pushes on the valve stem,,,for a test of a loose rocker stud,,,, while its clacking, tap the stud down to see if that knocks the lifter back into adjustment,,,,,
Scott- Number of posts : 1651
Location : Anoka, MN
Age : 54
Registration date : 2008-05-20
I went bought a compression tester today. The last time I used one I rented it from Autozone. Since I can't stand them, and because I wanted one that had some quality to it, I bought one today.
I got it home a little while ago and read that the engine is supposed to be hot when you do the compression test. Since I am short on time tonight, but anxious to get some answers, I tested the cylinders I suspected of leaking, 5 and 6. They both pump up to 150 pounds after three cycles of the engine.
Then I figured out that my compression tester won't do a leak-down test. It holds the highest pressure until I hit the button. I'm digging around now to see if I can somehow make it work with what I've got.
Tomorrow I will go back out to see what I get after it's warmed up, and test all the cylinders. I'm also going to pull that valve cover and check the rockers.
There's no coolant missing, and no oil floating in it either.
I got it home a little while ago and read that the engine is supposed to be hot when you do the compression test. Since I am short on time tonight, but anxious to get some answers, I tested the cylinders I suspected of leaking, 5 and 6. They both pump up to 150 pounds after three cycles of the engine.
Then I figured out that my compression tester won't do a leak-down test. It holds the highest pressure until I hit the button. I'm digging around now to see if I can somehow make it work with what I've got.
Tomorrow I will go back out to see what I get after it's warmed up, and test all the cylinders. I'm also going to pull that valve cover and check the rockers.
There's no coolant missing, and no oil floating in it either.
Scott- Number of posts : 1651
Location : Anoka, MN
Age : 54
Registration date : 2008-05-20
A neighbor of mine took a look at the carb. and suggested a rebuild before moving on anything else. Working on his drag car has given him plenty of experience with carbs.
Check out the four four-barrels he runs..
http://www.sparkyscarbs.com/QQ1.htm
Check out the four four-barrels he runs..
http://www.sparkyscarbs.com/QQ1.htm
RodStRace- Number of posts : 3046
Location : Chino Valley
Registration date : 2010-01-21
You do realize a compression tester and a leak-down tester are 2 different tools?
Scott- Number of posts : 1651
Location : Anoka, MN
Age : 54
Registration date : 2008-05-20
Yeah, I figured that out.. When I bought the compression tester I thought that it could be reconfigured to do either one. I found plenty of how-to examples of how to make a leak-down tester using simple parts.
Scott- Number of posts : 1651
Location : Anoka, MN
Age : 54
Registration date : 2008-05-20
Well, I've been out of touch for a while, there's been a lot going on at work. Not much time for my own thing.
Since I last got on I re-torqued the head, found two side by side bolts under torqued by half a turn.
The good news is that a rebuild of the carburetor fixed my idle problem. Once warmed-up it idles at about 500 with the choke off. When I cleaned it up there were a couple of blocked passages, and the rubber plunger was ripped in half.
Since I last got on I re-torqued the head, found two side by side bolts under torqued by half a turn.
The good news is that a rebuild of the carburetor fixed my idle problem. Once warmed-up it idles at about 500 with the choke off. When I cleaned it up there were a couple of blocked passages, and the rubber plunger was ripped in half.
Digz- Number of posts : 3794
Location : United States Six Lakes MI
Registration date : 2008-05-17
Good deal on the carb fix , I was wondering what ya have been up to.
Scott- Number of posts : 1651
Location : Anoka, MN
Age : 54
Registration date : 2008-05-20
I took the Van down to get it inspected yesterday. I pulled in and they didn't know what to do with it. After the guys that worked there put their heads together for about five minutes they asked me to pull it into the bay. They didn't check lights, horn, brakes, anything. They just gathered around and drooled over it. After about ten minutes they just did the paperwork and stuck a sticker on it.
Now that it's on the road, I have a few things I need to tweak. One is the engine heat, when it sits in traffic, or at lights, it doesn't take long to go from 180 to 200. And it's pretty cool out here right now. I have a remote oil cooler w/fan that I can mount, but what sandwich adapter have y'all used on your oil coolers? A few searches are telling me the thread size and count on a GM Inline-250, for the filter, is 13/16-16, but I don't know for sure.
Next up is getting electric fans mounted on the radiator.
Hopefully those two things will keep it cool while sitting in traffic when it's over a 100 outside.
Now that it's on the road, I have a few things I need to tweak. One is the engine heat, when it sits in traffic, or at lights, it doesn't take long to go from 180 to 200. And it's pretty cool out here right now. I have a remote oil cooler w/fan that I can mount, but what sandwich adapter have y'all used on your oil coolers? A few searches are telling me the thread size and count on a GM Inline-250, for the filter, is 13/16-16, but I don't know for sure.
Next up is getting electric fans mounted on the radiator.
Hopefully those two things will keep it cool while sitting in traffic when it's over a 100 outside.
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