This Freaken Car!

jjzepplin

Well Known Member
So I took "Thelma" on a cruise yesterday for Christmas and she did pretty good. I had my wife and my daughter and even packed the dog "Molly" into the car with a bunch of room to spare. It has a bunch of torque for and old 2 peed car. It winds up pretty good at 50 mph so I think it has steep rear gears. I couldn't imagine it has steeper than 4.11's. Anyway it lags a bit when it shifts to second so I am thinking it might be the modulator or a modulator adjustment. It also has a weird noise kinda like blowing in the top of a beer bottle at one point while accelerating just off idle a bit but it goes away. It accelerates fine. The mixture needles are in a fair amount but that was the only way it would run good. Some tinkering is in order I think. The AC however is working well except the blower motor bearings may need a little lube or something as they growl if I turn it on high. It cycles good though on low. My wife wanted to sell this thing but now she calls her Thelma and wants to sell one of my trucks. She says we just have too many cars. I dunno as my 1970 4x4 shortbed has been in my possession for quite some time and my 1972 Blazer has been around since 1989. Well any input on Thelma would be helpful. It has a 16 lb radiator cap and I am pretty sure it should be a 13 lb? Oh and I hope you all had a very Merry Christmas!
 

Don Jacks

Well Seasoned Member
Supporting Member 3
The 16 pounder is fine as long as you radiator is in good shape.As far as the mixture screws are concerned,1 1/2-2 turns from lightly seated is fairly normal.That lagging on the upshift goes,it's more likely a throttle valve linkage adjustment that's off but that car needs a transplant to a 700r4 anyway.There's no way to lube the fan motor,once the noise that you described starts,it's nearing time for replacement.
 

jjzepplin

Well Known Member
My mixture screws are in a bit more than that. I'd say they are out maybe a half turn. Still chasing what I think is a vacuum leak possibly on the intake thus the question about a new one. Modulator maybe? break somewhere in the vacuum hose to the modulator making the weird noise?
Could the manual linkage to the trans be out of adjustment because I replaced the carb? (shifting issue)
I am looking for a 700r4 to build for it but wifey wants to just drive now!
I am going to try to lube that damn ac motor anyway. I can't hurt it I think. (hard headed)
 

Don Jacks

Well Seasoned Member
Supporting Member 3
Yes changing the carb can change the linkage settings.While your at check the band adjustments.If you didn't use an adapter for the carb change,you'll likely have a vacuum leak.The noise sounds like a vacuum leak so check all possible points like carb mounting,any and all vac.hoses,ect.
 

jjzepplin

Well Known Member
I have an adapter on there (again the need for a different manifold) And a new carb. I guess I will have to read up on band adjustments. It does sound like a vacuum leak and I have been chasing it for quite some time. It seems to be on the choke side of the card near the base. I have tried new base gaskets and still nothing. I will have to put my thinking cap on and go after it mad dog style. I am almost wondering if the manifold is cracked or something.
 

wristpin

Well Known Member
Some adapters dont seal properly to carb or manifold because there may be a port line on bottom of carb that extends past adapter plate. Mix up some dish soap in a spray bottle and look for leak with that. Or use spray whipped cream. Leak sucks in the foam so its much easier to find than with something starting fluid
 

jjzepplin

Well Known Member
HMM. Well ok. Haven't heard of that one yet. Anyone care to comment on this method before I try it? Will this risk giving my old girl Diabetes? Sugar free whipped cream? Shaving cream? Will it hurt the engine versus a combustible liquid?
 

Don Jacks

Well Seasoned Member
Supporting Member 3
Yes that method works,and a lot of those adapters leak.That won't fix your idle circut being too rich though.What size Holley Street Avenger carb are you using?
 

La Hot Rods

Well Seasoned Member
Supporting Member 15
I use spray carb cleaner, use the little straw that come with it, sometimes you have to use a rag or something to shield the carburetor top from picking up the spray.
 

wristpin

Well Known Member
What is the gap during idle for the excellerator pump? More times than i could count a rich idle is accellerator pump to tight. Go for 0.07-0.10 gap. When you find the leak ill bet money your idle air screws will need to be set out 1 1/4 +- 1/4 turn.
 

jjzepplin

Well Known Member
What is the gap during idle for the excellerator pump? More times than i could count a rich idle is accellerator pump to tight. Go for 0.07-0.10 gap. When you find the leak ill bet money your idle air screws will need to be set out 1 1/4 +- 1/4 turn.
Will check that. Checked it. Seemed kinda tight so I adjusted to about .08 and no change. Sprayed some carb cleaner around suspect area and no change. Fungle!
 
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La Hot Rods

Well Seasoned Member
Supporting Member 15
Careful setting the accelerator pump linkage with any play, you will end up with a stumble.
The proper setting is at WOT, you want .015 clearance from bottoming out the diagram.
 

wristpin

Well Known Member
I doubt if the leaks are because of carbs. Adapter has leak either at manifold or carb base. Find the leak then set carb adjustments.
 

jjzepplin

Well Known Member
Took her on a cruise. All was good but I restarted her after about an hour and the front float got stuck somehow and flooded her out. The fuel pressure gauge was pegged. I gave her a little rap on the top screw of the float and all was well, A couple hard hits on the accelerator (at 40 mph) to check the kickdown and was pleasantly surprised with the launch and so far everything is back to normal. Go figure. This Freakin Car!
 

wristpin

Well Known Member
What are you running for fuel pressure?! Not only will excess fuel pressure cause rich conditions or erratic conditions there is serious potential for engine fire. Get a regulator or something on it stabilize fuel pressure 4-8psi
 

Don Jacks

Well Seasoned Member
Supporting Member 3
What are you running for a fuel pump? You said that the gauge was pegged? It sounds like either a fuel line is too close to a heat source,or that fuel pump may be having issues.Most Holley needle and seats will blow away at about 10 psi,that Street Avenger that you have likes about 6-7.
 

jjzepplin

Well Known Member
Ok so I put a regulator on it (stock type fuel pump) and it calmed down the jumping of the pressure needle and I cranked it down to 6lbs. No change to the mixture needles and I suspect a possible manifold leak. I ran out of carb cleaner and had no foam so it will have to wait. Freakin car!
 
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