318 Engine upgrade... please help
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318 Engine upgrade... please help
Hello!
I am a '89 Chrysler Fifth Avenue owner from Bulgaria.
I've got the 318 engine and I'm wondering how can I increase the compression ratio and reduce the gas mileage of the car. The thing is it's hard to find books/parts in Europe, if you could give me some advice, I would be very grateful!
Current gas mileage of the car is 4.7 miles per gallon, and fuel here is 5 times more expensive
Perhaps I'm looking at new crankshaft/rods, where can I find a decent non-racing kit?
I am a '89 Chrysler Fifth Avenue owner from Bulgaria.
I've got the 318 engine and I'm wondering how can I increase the compression ratio and reduce the gas mileage of the car. The thing is it's hard to find books/parts in Europe, if you could give me some advice, I would be very grateful!
Current gas mileage of the car is 4.7 miles per gallon, and fuel here is 5 times more expensive
Perhaps I'm looking at new crankshaft/rods, where can I find a decent non-racing kit?
Last edited by AirBorne; Mar 25, 2008 at 12:55 AM.
Mopar Lover
Joined: Nov 2007
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Some ramblings from the west
Your poor mileage figures are not going to be solved my major engine surgury. While increased compression ratio may help mileage and power somewhat, any gains well be offset by the requirement you have created to use good quality (premium) fuel, and the fact that "pinging" (knock or detonation) will require timing to be retarded.
Frankly, if you mileage is this bad now, it's because of some fault with the present engine, such as:
mechanical issues, difficult to guess
worn camshaft
improper cam timing
improper carburetion/ injection
improper spark advance
poor spark voltage, worn plugs, cap, wires, etc.
You can probably gain more "performance per price" by going to a different camshaft than by spending money on crank, pistons, etc.
(In the U.S. after somewhere around 1973 or so, many cars had screwed up camshaft timing, that is, the factory "smog" cams were retarded BY THE FACTORY. The only way to cure this to "pre smog" conditions is to either replace the cam with an aftermarket product, or by buying special timing drive sets that allow cam timing to be changed)
Your poor mileage figures are not going to be solved my major engine surgury. While increased compression ratio may help mileage and power somewhat, any gains well be offset by the requirement you have created to use good quality (premium) fuel, and the fact that "pinging" (knock or detonation) will require timing to be retarded.
Frankly, if you mileage is this bad now, it's because of some fault with the present engine, such as:
mechanical issues, difficult to guess
worn camshaft
improper cam timing
improper carburetion/ injection
improper spark advance
poor spark voltage, worn plugs, cap, wires, etc.
You can probably gain more "performance per price" by going to a different camshaft than by spending money on crank, pistons, etc.
(In the U.S. after somewhere around 1973 or so, many cars had screwed up camshaft timing, that is, the factory "smog" cams were retarded BY THE FACTORY. The only way to cure this to "pre smog" conditions is to either replace the cam with an aftermarket product, or by buying special timing drive sets that allow cam timing to be changed)
Guest
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Thanks a lot!
So in few words, if I do anything to crankshaft/rods/pistons I might get more HP but not better gas mileage.
Any idea where can I get this camshaft you mentioned? And also, does someone know from where can I get a good manual on this engine/car?
So in few words, if I do anything to crankshaft/rods/pistons I might get more HP but not better gas mileage.
Any idea where can I get this camshaft you mentioned? And also, does someone know from where can I get a good manual on this engine/car?
Guest
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I'm stupid, but the very first thing I would do is check the compression on each cylinder on your engine. Followed by installing for troubleshhooting, a vacum gauge to see if your engine has air flow, are the valve opening and closing fully, if the valves are not closing, it probably is hard to start or won't start. Make sure it is breathing, check for intake obstructions, clogged air filter, fuel in oil as a fuel punp leaking into the crankcase. Your using way too much fuel for that engine even in the worst case.
Don't even think of hoping up that engine till you get the obvious resolved. Maybe there's a fuel regulator dumping raw fuel thru a diaphram vent in to the intake manifold.
Don't even think of hoping up that engine till you get the obvious resolved. Maybe there's a fuel regulator dumping raw fuel thru a diaphram vent in to the intake manifold.
Last edited by Mopar Guy in Delaware; Apr 6, 2008 at 07:30 PM. Reason: Spelling
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thanks, already did some tests:
compression is 9.6-10.0... [edit: 10.0 bar]
the engine starts instantly, the air filter is brand new.
So I guess the engine is modified in some way..
what then? you are right, I should revise the carburettor.
By the way, I plan to use LPG instead of gasoline on this engine.
compression is 9.6-10.0...
[edit: 10.0 bar]the engine starts instantly, the air filter is brand new.
So I guess the engine is modified in some way..
what then? you are right, I should revise the carburettor.
By the way, I plan to use LPG instead of gasoline on this engine.
Last edited by AirBorne; Apr 14, 2008 at 06:00 AM.
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Are you looking at running straight LPG or duel fuel
If you run duel fuel there will be compromises.
You will need to get your distributer recurved for best econemy/performance.
you will also want to rum hotter sparkplugs
In Australia if you run straight LPG you can remove all of the smog control
If you run duel fuel there will be compromises.
You will need to get your distributer recurved for best econemy/performance.
you will also want to rum hotter sparkplugs
In Australia if you run straight LPG you can remove all of the smog control
Guest
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no, no dual-fuel. I am planning only LPG. I want economy.... so I need another distributor, or do I just need to tune this one?
I have Bosch Super-4 quad-electrode spark plugs, anyone are these good? Do I need special ignition for them? In the shop they said NO but I doubt it
I want to remove any smog control, how can I do this?
I have Bosch Super-4 quad-electrode spark plugs, anyone are these good? Do I need special ignition for them? In the shop they said NO but I doubt it
I want to remove any smog control, how can I do this?
Guest
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You dont need to replace your existing distributor it just needs to be recurved.
Any sparkplugs will work just that LPG runs hotter so a hotter plug works better. I am not familar with these plugs you talk of. this does not mean there good or bad I have just never used them.
Since you are going to run dedicated LPG you will be better of getting rid of the carburetor totally.
Over here the gas conversion to get is GAS RESEARCH, do a search on them and it should help you out.
Also you should have your cam shaft ground to suit the gas.
I am by no means an expert in this field this has just been my experiances.
also get 2 or 3 quotes there can be some substantial differences in price and quality of the equipment used.
Any sparkplugs will work just that LPG runs hotter so a hotter plug works better. I am not familar with these plugs you talk of. this does not mean there good or bad I have just never used them.
Since you are going to run dedicated LPG you will be better of getting rid of the carburetor totally.
Over here the gas conversion to get is GAS RESEARCH, do a search on them and it should help you out.
Also you should have your cam shaft ground to suit the gas.
I am by no means an expert in this field this has just been my experiances.
also get 2 or 3 quotes there can be some substantial differences in price and quality of the equipment used.
Guest
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Thanks. It turned out that I am with the 4bbl Rochester stock carb.
I bought the car with a plate over the carburettor for LPG feeding, it looks like a good one.
How/why can I get rid of the carb? What should I use then? The goal is to improve gas mileage.
I bought the car with a plate over the carburettor for LPG feeding, it looks like a good one.
How/why can I get rid of the carb? What should I use then? The goal is to improve gas mileage.
Guest
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Gasoline carbs need the liquid to ensure that all the seals dont perish
you get a dedicated gas carb to avoid these problems (I believe that they work better also)
I dont know what info is available in Bulgaria but there is bucket loads over here.
There are quite a few performance cars running LPG over here especially now that gasoline has hit $1.56 per litre and LPG is at 61 cents
you get a dedicated gas carb to avoid these problems (I believe that they work better also)
I dont know what info is available in Bulgaria but there is bucket loads over here.
There are quite a few performance cars running LPG over here especially now that gasoline has hit $1.56 per litre and LPG is at 61 cents
Guest
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Hello!
I am a '89 Chrysler Fifth Avenue owner from Bulgaria.
I've got the 318 engine and I'm wondering how can I increase the compression ratio and reduce the gas mileage of the car. The thing is it's hard to find books/parts in Europe, if you could give me some advice, I would be very grateful!
Current gas mileage of the car is 4.7 miles per gallon, and fuel here is 5 times more expensive
Perhaps I'm looking at new crankshaft/rods, where can I find a decent non-racing kit?
I am a '89 Chrysler Fifth Avenue owner from Bulgaria.
I've got the 318 engine and I'm wondering how can I increase the compression ratio and reduce the gas mileage of the car. The thing is it's hard to find books/parts in Europe, if you could give me some advice, I would be very grateful!
Current gas mileage of the car is 4.7 miles per gallon, and fuel here is 5 times more expensive
Perhaps I'm looking at new crankshaft/rods, where can I find a decent non-racing kit?
You can get a complete service manual from Mopar on CD. I strongly suggest you use the internet to source your parts and there are millions of 318's out there and parts as well.
It was one of Chyrslers best built engine and they put it in everthing.
Bringing up the compression is as easy as 1-2-3;
1.) You could get thinner head gaskets,
2.) Install flat top pistions but remember if you work on the top end you need to consider the bottom end,
3.) Install a set of 340 heads if you can find them.
What's your budget? How do you intend to use the vehicle afterwards?
Good luck,
MM
Guest
Posts: n/a
Some ramblings from the west
Your poor mileage figures are not going to be solved my major engine surgury. While increased compression ratio may help mileage and power somewhat, any gains well be offset by the requirement you have created to use good quality (premium) fuel, and the fact that "pinging" (knock or detonation) will require timing to be retarded.
Frankly, if you mileage is this bad now, it's because of some fault with the present engine, such as:
mechanical issues, difficult to guess
worn camshaft
improper cam timing
improper carburetion/ injection
improper spark advance
poor spark voltage, worn plugs, cap, wires, etc.
You can probably gain more "performance per price" by going to a different camshaft than by spending money on crank, pistons, etc.
(In the U.S. after somewhere around 1973 or so, many cars had screwed up camshaft timing, that is, the factory "smog" cams were retarded BY THE FACTORY. The only way to cure this to "pre smog" conditions is to either replace the cam with an aftermarket product, or by buying special timing drive sets that allow cam timing to be changed)
Your poor mileage figures are not going to be solved my major engine surgury. While increased compression ratio may help mileage and power somewhat, any gains well be offset by the requirement you have created to use good quality (premium) fuel, and the fact that "pinging" (knock or detonation) will require timing to be retarded.
Frankly, if you mileage is this bad now, it's because of some fault with the present engine, such as:
mechanical issues, difficult to guess
worn camshaft
improper cam timing
improper carburetion/ injection
improper spark advance
poor spark voltage, worn plugs, cap, wires, etc.
You can probably gain more "performance per price" by going to a different camshaft than by spending money on crank, pistons, etc.
(In the U.S. after somewhere around 1973 or so, many cars had screwed up camshaft timing, that is, the factory "smog" cams were retarded BY THE FACTORY. The only way to cure this to "pre smog" conditions is to either replace the cam with an aftermarket product, or by buying special timing drive sets that allow cam timing to be changed)
Mileage should be around 18 mpg but with a faulty control system it could just run out of the tail pipe with nothing wrong with the engine.
MM
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Posts: 6,204
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From: Brooklyn, N.Y.
Compression ratio is a commonly used term for internal combustion engine piston/cylinder compression and file compression. Ratios differ depending on the type of engine or the type of file being compressed.In file compression, 7zip has the highest compression ratio.my friend says that if you want to perform your air filter at best. You should used aem air air filter recharge kit. It will boost up your horsepower and increase your torque.
please check the date of the previous posts
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You can get a complete service manual from Mopar on CD. I strongly suggest you use the internet to source your parts and there are millions of 318's out there and parts as well.
It was one of Chyrslers best built engine and they put it in everthing.
Bringing up the compression is as easy as 1-2-3;...
It was one of Chyrslers best built engine and they put it in everthing.
Bringing up the compression is as easy as 1-2-3;...
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