First question / Early A

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Your doing a great job Wedgy!Is it hard to get parts shipped overseas?I see a Summit bag,so I guess Summit will ship!LOLDuh.
 
If you are using a 78 318 crank with the 273 pistons and rods I believe you will be out of balance. The later 318 rods are heavier than the 273 rods, pistons are probably the same weight. Crank will need to be rebalanced to the 273 parts.
 
66dartgt said:
If you are using a 78 318 crank with the 273 pistons and rods I believe you will be out of balance. The later 318 rods are heavier than the 273 rods, pistons are probably the same weight. Crank will need to be rebalanced to the 273 parts.
Click to expand...

I am having 16 heavy 318 rods and I hope eight of them are in good condition. Next week I will check them.



I will use my 273 stock pistons and assembly the 318 heavy rods with the press fit. So I will take the pistons without piston pin lock ring. (I hope my English is ok?!)
Do I have to upgrade my old pistons with a oil drill for better lubrication?



 
I have some data for you from the oem service manuals. I have a 77 (close enough to a 78) and 66 service manual - here are the weights for rods and pistons.

77 318
rod weight 726 grams or 758 grams
piston weight 594.6 grams

66 273
rod weight 726 grams
piston weight 530 grams (2bbl)
piston weight 569 grams (4bbl)

Somethings to consider

1) The two rod weights for the 77 are for a 318, and a 360. If you have the heavier rod its obviously going to be 758 grams. I am not aware of chrysler having used the lighter rods past about 1972 in 318's, so your rods are probably the heavier version. Weigh them to make sure !

2) 273 pistons used an extremely heavy wrist pin. I believe the reason they did this was to make up the balance weight for the crank. The cranks I think were originally balanced for the early 318 (so called wide block engine), which uses the lighter rod and piston weights as the later 318 (like the 73 and newer motors). Again weigh the piston with the wrist pin to be certain. I think these specs above do not include the wrist pins, rings or bearings.

3) You can press the wrist pins or bush the small ends like the 273 rods were originally. Drilling a few oiling holes in the piston is not a bad idea.

4) Whatever you decide, choose the rods you want to use, rod bearings and piston rings, the pistons and the wrist pins, harmonic balancer, crankshaft, and flywheel (if manual) and have the whole set balanced together at a machine shop. The original balancing job done in the factory was not a truly precise job. You might also consider using 318 wrist pins to cut the piston/pin weight down on a 273. Lighter weight = durablity and quicker rpm. If you use the lighter wrist pins, make sure they are not too long - such that they might protrude from the piston and hit the cylinder walls.

good luck !
 
welcome to FABO--- what is your beer of choice? I stumbled across paulaner salvator dopplebock-- stuff is good---

if you have problems getting stufff shipped--- I can try to help, Lawrence
 
66dartgt said:
I have some data for you from the oem service manuals. I have a 77 (close enough to a 78) and 66 service manual - here are the weights for rods and pistons.

77 318
rod weight 726 grams or 758 grams
piston weight 594.6 grams

66 273
rod weight 726 grams
piston weight 530 grams (2bbl)
piston weight 569 grams (4bbl)

Somethings to consider

1) The two rod weights for the 77 are for a 318, and a 360. If you have the heavier rod its obviously going to be 758 grams. I am not aware of chrysler having used the lighter rods past about 1972 in 318's, so your rods are probably the heavier version. Weigh them to make sure !

2) 273 pistons used an extremely heavy wrist pin. I believe the reason they did this was to make up the balance weight for the crank. The cranks I think were originally balanced for the early 318 (so called wide block engine), which uses the lighter rod and piston weights as the later 318 (like the 73 and newer motors). Again weigh the piston with the wrist pin to be certain. I think these specs above do not include the wrist pins, rings or bearings.

3) You can press the wrist pins or bush the small ends like the 273 rods were originally. Drilling a few oiling holes in the piston is not a bad idea.

4) Whatever you decide, choose the rods you want to use, rod bearings and piston rings, the pistons and the wrist pins, harmonic balancer, crankshaft, and flywheel (if manual) and have the whole set balanced together at a machine shop. The original balancing job done in the factory was not a truly precise job. You might also consider using 318 wrist pins to cut the piston/pin weight down on a 273. Lighter weight = durablity and quicker rpm. If you use the lighter wrist pins, make sure they are not too long - such that they might protrude from the piston and hit the cylinder walls.

good luck !
Click to expand...

Thanks for the data. I will weight all parts to make the right choice.
A balancing job is sadly not in my budget, so I have to weight the parts.

News are coming
 
VDART said:
welcome to FABO--- what is your beer of choice? I stumbled across paulaner salvator dopplebock-- stuff is good---

if you have problems getting stufff shipped--- I can try to help, Lawrence
Click to expand...


Hi Lawrence,

that is a really nice offer - thanks!:cheers:
 
Welcome!

Woohoo! Another 70 Dart Custom 2 door!

DSC02743.jpg

DSC02742.jpg
 
Ah ! the wrist pins do weigh a ton!!! Maybe you can use a 318 pin and get pretty close to the oem balance weights. Do you have any old 318 pins sitting around ?
 
66dartgt said:
Ah ! the wrist pins do weigh a ton!!! Maybe you can use a 318 pin and get pretty close to the oem balance weights. Do you have any old 318 pins sitting around ?
Click to expand...

I have to take a look!

66dartgt said:
I have some data for you from the oem service manuals. I have a 77 (close enough to a 78) and 66 service manual - here are the weights for rods and pistons.

77 318
rod weight 726 grams or 758 grams
piston weight 594.6 grams

66 273
rod weight 726 grams
piston weight 530 grams (2bbl)
piston weight 569 grams (4bbl)

I think these specs above do not include the wrist pins, rings or bearings.


good luck !
Click to expand...

If I add the weights I am comming to the following result.

Old 318 combination (without pin)= 1352,6g

New combination (273piston, 360 heavy rod, no rings/no pin) = 1286g

So I will have a difference of 66.6g, if I would use the same wrist pin.

:-?
 
Welcome to FABO!
Drop by The 70-71 Dart GT Registry and register your Custom if you like.
www.7071dartgt.net Just use the info from the Register page and email it direct to me. For some reason the Register page has decided to quit on me again!!.

Later,
Bruce B.
 
Time for a update.

























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A lot of pictures, i hope you enjoy.
But now I am thinking, bigger is better. So I decide to build a 340 :-D

News will follow
 
The project must go on!
Last weekend we had a really nice time and welded as much as possible :razz:

First inspection
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and the aktion




mg7690.jpg


mg7712g.jpg
 
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