Improve mileage 350 with Quadrajet

[kikkegek]

OK,
did some more research.

It seems my car stays cold?
it alwasys stays at the temperature shown in the picture. Just underneath 155F?

I already checked the thermostat. When the engine is cold, it is closed. I have no clue though at which temperature it opens. But after a little drive the coolent flows through the radiator, so the thermostat has opened.

I used a IR thermometer to check temperatures.

I measured 167F at the thermostat housing where the big hose connects.
and I measured about the same 165F at the top of the radiator where the big hose connects.

isnt 165F a bit cool for an engine to run and shouldnt the thermostat be closed?



Somebody I know is shipping me a fanclutch and cooling fan. I am gonna take the flexfan off and install a regular fan again. Because we drive our car all year, the flexfan is unnecessarily cooling the engine at low rpm during winter (cool) times.

[rayfinseats]

Put your thermostat in a pan full of water with a thermometer and bring to a boil. Then you can see exactly when it opens. Maybe your radiator is just too big. I have made that mistake before.

[Cue-Ball]

Originally Posted by rayfinseats

Maybe your radiator is just too big. I have made that mistake before.

That is just patently false information. There's no such thing as a radiator that is too big.

The radiator's job is to dissipate the heat from the engine into the outside air. It's impossible for this job to be made too quick or too efficient, since even 100% efficiency would be sending air-temperature water back into the engine. At that point the engine would cool off to the point that the thermostat closed, the water would start to heat up again, the thermostat would open, and the whole cycle would start over again.

I'd be willing to bet the OP's problem is caused by the thermostat either opening too early or staying open all the time. 80's engines generally use a 195* thermostat. If you're only reading 165* at the housing and radiator, it seems like it's opening too fast (Though, having never used a laser thermostat on my own truck, I'm not sure how much heat loss is normal between the water temperature and the temp of the housing. I'd guess both would be about the same temp). Another clue would be watching the temp of the housing/radiator hose as the truck warms up. If they slowly get hotter, the thermostat is stuck open. If they stay cold, then suddenly get hot, then the thermostat is opening correctly, but might still be opening too early.

[kikkegek]

thanks cue-bal, I am gonna change the thermostat to a 195F model, just to make sure!

I'll keep you guys updated on the result.

[billnorman]

I saw in your earliest photographs that the vacuum hose to your EGR valve is not connected. This engine runs poorly with it not connected and operational. You can't run decent timing without EGR or it will ping. Initial timing on this engine is recommended at about 8 degrees BTDC if I'm not mistaken, but you need to set it at total advance to do it right and for this you need a degree wheel and timing light. I'd run the total at 34 degrees unless it pings at partial load. If you don't have EGR all bets are off. Also, the flex fan is dangerous I had a friend that (literally) lost his head when one disintegrated. Any Mercedes mechanics that work on older ones will know how to set the timing at total. Also, I put a 210 degree thermostat in my '85 and have had no problems. Find a thermo clutch fan.

[kikkegek]

Originally Posted by billnorman

I saw in your earliest photographs that the vacuum hose to your EGR valve is not connected. This engine runs poorly with it not connected and operational. You can't run decent timing without EGR or it will ping. Initial timing on this engine is recommended at about 8 degrees BTDC if I'm not mistaken, but you need to set it at total advance to do it right and for this you need a degree wheel and timing light. I'd run the total at 34 degrees unless it pings at partial load. If you don't have EGR all bets are off. Also, the flex fan is dangerous I had a friend that (literally) lost his head when one disintegrated. Any Mercedes mechanics that work on older ones will know how to set the timing at total. Also, I put a 210 degree thermostat in my '85 and have had no problems. Find a thermo clutch fan.

he thanks man! but can you explain to me how the EGR would influence the timing?

As far as I am informed this valve only recirculates Exhause Gas when activated. And should do this only to reduce emissions.

please explain to me what you mean?

[billnorman]

It doesn't influence the timing. It warms and helps disperse the incoming air/fuel charge. Believe me I had to find out the hard way, these motors like warm air inserted into the manifold. I chased a ping for a long time until I found out my EGR valve was defective. Cleaned valve, no more ping. It's a cheap fix, if you don't like the outcome, just leave it disconnected. There should be a map of vacuum lines on a decal under your hood to show you which carburetor port to hook it to. Also, if it's dirty or clogged, it won't function. It's relatively easy to remove, clean and reinstall. I used spray carburetor cleaner. Let me know if it helps. Also, it can be tested when off the vehicle with vacuum.

[kikkegek]

Originally Posted by billnorman

It doesn't influence the timing. It warms and helps disperse the incoming air/fuel charge. Believe me I had to find out the hard way, these motors like warm air inserted into the manifold. I chased a ping for a long time until I found out my EGR valve was defective. Cleaned valve, no more ping. It's a cheap fix, if you don't like the outcome, just leave it disconnected. There should be a map of vacuum lines on a decal under your hood to show you which carburetor port to hook it to. Also, if it's dirty or clogged, it won't function. It's relatively easy to remove, clean and reinstall. I used spray carburetor cleaner. Let me know if it helps. Also, it can be tested when off the vehicle with vacuum.

He Bill, thanks man!
what do you mean by " Also, it can be tested when off the vehicle with vacuum."? (I am Dutch, sorry)

[billnorman]

Below is a generic EGR test. It tests the mechanical opening and diaphragm of a typical EGR valve. In order to test one for function, it either has to be removed and inspected or the engine running and vacuum applied to the port. If it works, the RPM should change when vacuum is applied, probably drop. It is important to get the vacuum source from the proper carburetor passage so it will activate at the correct time.
......An exhaust gas recirculation valve, or "EGR" valve, is an emissions-control devise which reduces the amount of nitrogen which escapes into the atmosphere. The EGR does this by routing a portion of the exhaust gases back into the intake manifold, where those chemicals are burned for a second time in the combustion chambers. A defective EGR valve commonly results in a rough idle and a decrease in power and fuel efficiency. Chevrolet equipped its 1990 passengers cars with a ported-type EGR valve. Fortunately, this type of EGR valve is the easiest to test.
Difficulty:Moderately EasyInstructions
Things You'll Need:
Hand-vacuum pump


1
Apply the parking brake and shift the transmission into either "Park" or "Neutral."

2
Start the engine and allow it to reach operating temperature.

3
Turn the engine off.

4
Inspect the rubber vacuum hose that attaches to the top of the EGR valve for signs of cracks or kinks. A damaged EGR hose should be replaced.

5
Pull the rubber vacuum hose off of the top of the EGR valve.

6
Press the hose which extends from the bottom of a hand-vacuum pump over the nipple on top of the EGR valve. This is the same nipple from which the rubber vacuum hose was attached to.

7
Apply 10 inches of vacuum to the valve with the hand-pump.

8
Position a mirror underneath the top of the EGR valve to inspect the valve's diaphragm. The diaphragm should remain open under the 10 inches of vacuum for a minimum of 20 seconds. If the diaphragm does not open, of if the needle on the hand-pump gradually drops before 20 seconds have expired, the EGR valve leaks and must be replaced. You can also do this by checking the movement with your finger if the valve has reliefs cut in it. ....



Read more: How to Test the EGR Valve in a 1990 Chevy Car | eHow.com http://www.ehow.com/how_6098936_test...#ixzz18wAvnmkP

[kikkegek]

I got a fan clutch from a buddy, painted the fan ad wanted to install it today. I noticed the flexfan was cooling the engine unnecaessarily during winter. but when I tried installing it I noticed it turns the wrong way!

damn!

[motornut]

Can't turn the blade around onto the clutch?
Posted via Mobile Device

[kikkegek]

Originally Posted by motornut

Can't turn the blade around onto the clutch?
Posted via Mobile Device

no. It will just be on backwars. and the fan clutch has a set direction also. see picture.

take a fan and check for youself. They cant run backwards.





guess I'll be looking for a fan and fan clutch!

[motornut]

ok gotcha
no trucks at the house right now

[kikkegek]

oke, got the thermostat today and replaced it (195F)

first disconnected the upper hose on the radiator. check out the dirt that came out. If you take into account that I just had the cooling liquid refreshed this summer. Shouldn't it be a lot less dirty?




I cleaned the thermostat houding and took a good look. NEver had this piece loose yet.



here you can see hoe dirty the cooling liquid is. about a quart came out of it. I tried to catch as much as I could in a little bucket.


when it gets warmer and the days are longer I am gonna have to rinse my cooling system....damn its dirty....previous owner probably had wather in it for a while I think? or never changed it...

these two bolts??? weer holing the thermostat housing. for now I reused them, but I want to change the housing and bolts this summer sometime.


anybody ever heard of Restone Thermostats? I got it at a local shop.



this bucket was clean when I started. Look at the dirt!



the old thermostat. Seemed to be a 180F.



the new thermostat, 195F




just cane back from a testdrive. Al stays dry. So that makes me happy. Now I a will keep an eye on the temperature the next few days and see if the engine gets warmer!

[kikkegek]

ow!

I take notes of the gallons I get at every trip to the gasstation and the miles we drove.

I made a graph out of it. It seems my work is payng of, because there is a postive sloped trend visible in the mileage. how cool is that!

[billnorman]

I have made some more observations.
1. It looks like you have the dreaded GM no darn good pink coolant, recalled and destroyed. What do the rest of you guys think?
2. There are two timing reference stationary references on your motor. One is way ahead of the other. If LPG uses more timing advance than gasoline, perhaps that's what the bigger one is used for.
3. The vacuum advance IMHO softens the spark curve and allows advance in at high vacuum settings (low throttle positions) for economy. I may be wrong in this hypothesis, but if it's hooked to a below the throttle plate source, it will decrease timing when you step on the throttle, and increase it when you drive gently. If it's hooked to a vacuum port AT the throttle venturi, it will increase timing as the engine increases speed. The timing increase function on a Chevy v-8 is by the centrifugal weights.
4. I am not familiar to the functional envelope of a dual fuel engine. I would recommend you research on line the requirements and limits.
5. Personally, I think you need to operate this engine as warm as possible, and if LPG will tolerate an EGR system, hook it back up,
6. Turning the fan around won't change the way it functions. As you are in a very cool climate, why not do away with it altogether and go with electric? The kits can be ordered by mail, I've used them with no adverse effects and they are easy to install or you can get one off of a wrecked car.
7. Just as an aside, I have used Seafoam oil additive to clean and fix my wife's car. If it is possible to use all the time, I'd check the can to make sure, one can added to the oil will thin it out and clean the internals of your engine. This MAY improve your mileage.
8. Your photographs are exceptional. You are persuing this scenario with scientific analysis; cause and effect. I think if you stick to it you will get the best out of the truck.

[kikkegek]

He BillNorman, thanks for the extensive reply.

some questions on your points:
1. what do you mean? I am dutch and dont understand this.
2. I dont understand this point either. what I can say is that here in the NL they say you should set basic timing to -12 BTDC and disconnect the vacuum advance on LPG.
3. I have the distributor connected to the ported vacuum port on the right of the carb like on the pictures in this topic. Is that right?
4. what do you mean by functional envelop?
5. I have two EGR things on my engineI believe. The EGR valve (currently disconnected) and the Heat riser valve. the last one is currently set to OPEN all the time. Why would I want to run this engine as warm as possible?
6. oh man! I'd love an electric setup. But they are expensive over here. I'll ask around!
7. I'll look into this.
8. hahaha, thanks man! yeah I wanna help others with the info Igather. So good photos help a lot.

hope you can help me some more!

[billnorman]

1. General Motors had a pink anti-freeze that they recalled because it tended to sludge up cooling systems. I hope that isn't the type in your engine.
2. The photograph you posted 11-10-2010 at 3:59am show two pointer reference timing markers. The shorter of the two sets occurs in advance of the larger one. It is the one that is all dirty. If you use the one closer to the camera, the timing will be more retarded. Now in a gasoline motor, 12 degrees retarded will just about destroy performance, most like 8 to 10 degrees advance at idle. I will have to read up on LPG conversions, like I said, I don't know anything about them. They might like retarded timing. Which degree mark references do you use when setting the timing? How does this motor run? Is it smooth and powerful? I would estimate that if you use the short dirty timing mark numbers the motor will run about 15-20 degrees retarded compared to the long clean references. The marks nearer the camera look like an add-on set that if used would considerably retard the timing.
3. If it was a gasoline motor, There would be a diagram of vacuum hose routing for proper operation. As I previously said, when you said the motor runs at 12 degrees retarded, I realized I'm lost because this is a complete departure from my experience.
I'll read up and try to learn something and get back to you.

[motornut]

i duno bout it being the pink rad fluid,
(i wondered a mix of red and green or even a sealer?dribbles on the belt?)
i see rust and crud that will block not only the rad but the heater core too.
If you have it inside warm somewhere be sure to remove the lower rad hose and FLUSH this crud out or what you put back will be a waste.
do the heater core too.
You may wana get new bolts for the stat housing,seen those bolts seize and snap off
around hee we have green and red anti freeze,you can't mix them, i believe it wreaks the fluid .....the red is long life so some people figure i can wait even longer lol then the green,what i understand the red breaksdown and wrecks the gasket in some CARS lol like my Grand Am ,the v6 is known for this prob,thank god i got the 4 it just blows the crank seal(thats what i got for Xmas lol)

cheers

[billnorman]

O.K. here's what I've determined through research. You are getting 10 MPG plus or minus in a Chevrolet truck with LPG conversion. This is about average. LPG conversions historically get less mileage than a gasoline engine, it's just the nature of the beast. Some LPG conversions eliminate the vacuum advance, some leave it on. I read a report about ignition timing with LPG on a Chevrolet that was turbocharged, which raises the effective compression ratio and packs more air/fuel into the cylinders. The owner experimented with ignition timing and ended with 6 degrees BTDC initial timing. He tried various timing settings and advanced it until he heard pinging, then retarded it until it went away in all load arenas. He was satisfied with the results.
LPG does not require nor respond well with warming of the charge (EGR) but gasoline does.
Anything you can do to remove parasitic drag, such as electro fans, tire inflation, free flowing exhaust should benefit you in the long run.
I'm sure your friends call you if they need anything heavy moved, pulled, or bulky items transported because you have a truck, a REAL truck, a Chevrolet truck. Enjoy it, it's no tinny Eurosled with a 1000cc sewing machine motor. Ride in comfort, and look down at them in their low to the ground econoboxes.
Seafoam says their product improves any engine, especially older ones. I use it in my cars and boats.
Looking at the U.S. gasoline future, I am considering an LPG retrofit on my own 1985 or 1996 Pick-up truck.
In summary, forget the EGR valve, run your engine warm this winter, but in the summer drop the thermostat back to 165 f. If it were me, I'd get a good timing light, decide which set of timing marks is appropriate, and experiment with timing. Disconnect the vacuum advance and see where it's set right now at low idle. Then change it, usually in an advance direction by about 4 degrees. If it pings, go back 2 degrees until it stops. This may change in extremely hot weather, it may ping more if warmer. Each engine is different, each advance system is slightly different due to age and manufacturing tolerances.

[kikkegek]

he Bill,
really appreciate the time you are taking.

This is my timing mark:



and I looked up this picture, to find the marks for 4, 8 and 12 on mine, because mine is so dirty and I cannot reach it to clean it:


Today I took the vacuum advance of, because our fuel pump is broken end I will not replace it until end of januari. I bought a Equus 3568 timing light recently and found the timing was set to "0" ZERO. hahahaha. I then set the timing to 11 BTDC. I couldnt get it to i12 on my own, because I had no one to help me. So I stasyed with 11. Here on the dutch forums they say the best on LPG is about 12 BTDC and that you need to disconnect the vacuum advance. Because it is already so far advanced.

It runs just fine at the moment. No pings, pretty good idle. Just after a drive the engine would idle high. And I guess that because the distributor was still connected to the vacuum advance.

thanks and I will let you guys know how the mileage for the next few weeks advances...

ps. could you point me in the direction of the stuff you read on LPG. I love reading upon knowledge!


@ Motornut: thanks for the heads up. I'll make sure I rinse the complete system when it gets warmer up here. I have no clue though how to clean it in front of my house.

[motornut]

they sell solutions to clean out the rad system
if you can't flush it clean with water
have you used a hydrometer to check how low it will protect you?
If it was my truck i would worry it looks quite rusty
looks like a lot of water in the mix or contaminated with stuff
rad fluid should be coloured but clear -ish (clear like you could almost see through a jug of it)
too much water is bad and can freeze/crack a block,gets slushy and won't pass threw the rad so something has to give

[kikkegek]

okay, okay, true! it would probably be better to flush and clean the cooling system. But still...

isnt it strange that a dirty cooling system cools this good? my engine temp doesnt go over 155 on the highway and through town?

I'll call the local shop to see if they have some stuff that can help me with this.

[motornut]

yes the cooling might be icing....
surprised no one else here said anything
either to say yes or no
i'd hate for you to do all this work and lose the block

[kikkegek]

Originally Posted by motornut

yes the cooling might be icing....
surprised no one else here said anything
either to say yes or no
i'd hate for you to do all this work and lose the block

what do you mean by "the cooling might be icing?"?