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View Full Version : Need help with engine/head problems - '79-'80 head differences



loyter
01-05-2012, 12:19 PM
I just picked up a sweet 1980 Plymouth Arrow. It is all original, 85k miles, and in great shape...except for a cracked head.


I have looked for parts all over and I've found that the '79 and '80 trucks have a different head and the head gasket.

I would like to replace the head, but the '79-'80 head isn't available. Does anyone know what the differences are between this head and the '82-'88 head are? Can I use the stock intake and exhaust? Are there differences in the water inlets, etc...?

Any help would be great, I am struggling to find out what the story is. I would like to keep this truck all stock.

http://needthatcar.files.wordpress.com/2011/11/plymouth-arrow.jpg?w=640

DroppedMitsu
01-05-2012, 01:39 PM
Which engine do you have? The engine id can be found on a silver tag on the firewall, is it a g52b(2.0) or g54b(2.6)?

camoit
01-05-2012, 03:17 PM
The 2.0 head will go onto a 2.6. Be sure to replace the head bolts. See this from the archive. I found a hole ATK rebuilt 2.0 engine off ebay for $20. and used the head.
http://www.mightyram50.net/phpbb3/viewtopic.php?f=105&t=1181

loyter
01-05-2012, 04:36 PM
Oh, sorry, I knew I missed something. It's a Sport (Woot) with the 2.6 4g54 engine and an auto (bummer).

loyter
01-05-2012, 05:38 PM
Oh, sorry, I knew I missed something. It's a Sport (Woot) with the 2.6 4g54 engine and an auto (bummer).

I read the post above about the 2.0 head on a 2.6 engine, but it still don't know what the difference between the early first gen 2.6l and the 83-up 2.6l head is.

camoit
01-05-2012, 09:08 PM
The cams are different. Chain to belt. We have the big cam hole in the front of the head. We also don't have an oil galley to the head. They only have spray and spray for lube. Yes they can be a little hard to find. Look for ones that don't have the air jet valve. Much better head. They came in mini vans and the Aries K cars.

loyter
01-05-2012, 11:44 PM
The cams are different. Chain to belt. We have the big cam hole in the front of the head. We also don't have an oil galley to the head. They only have spray and spray for lube. Yes they can be a little hard to find. Look for ones that don't have the air jet valve. Much better head. They came in mini vans and the Aries K cars.

Aha! That's what I needed to know. I thought they went to belt much later, like in '85 or something. Well that does make things clearer.

I found an '88 Conquest TSI with a rebuilt engine for $1200. That would be a gas in this truck. Should be a pretty easy swap too. Perhaps I should go that route.

camoit
01-06-2012, 01:27 AM
Once they went with hydraulic lash adjusters everything changed. People did not like to adjust the valves or the tick of them. When you drive one of these trucks at 65 you feel like your doing 100 in comparison to a new car. There so quiet now the sense of speed and danger of driving is nearly gone, until you get into a crash. Then 65 in a new car is just like 65 in an old car. Just the explosion is in your face. Good old air bags. I remember you could here a car crash from a mile away now they crash together and hardly make a sound, except for that air bag. It's all they remember the big BANG. No skidding of tires, no stuck throttles revving the engine, no fun for the spectators. Even NASCAR is a hole lot more quiet.

pennyman1
01-07-2012, 07:09 PM
The 2.6 heads from 79-84 are interchangeable from the standpoint of having manual valve adjusters. 85 - 89 have the hydralic lash adjusters. All 2.6 g54b motors have timing chains - the 83-89 g63b 2. have the timing belts. You can get non-jet valve replacement heads from several suppliers and swap over your valvetrain from your old head or get a complete new head, as any 2.6 head will fit with any 2.6 block. For the best 2.6 head info out there, go to www.b2600.com (http://www.b2600.com) ; it is a mazda site but it deals with the 2 years the mazda B2600 4x4 ran a 2.6 mitsu motor and has all the info on these motors.

loyter
01-08-2012, 10:25 AM
The 2.6 heads from 79-84 are interchangeable from the standpoint of having manual valve adjusters. 85 - 89 have the hydralic lash adjusters. All 2.6 g54b motors have timing chains - the 83-89 g63b 2. have the timing belts.[/URL] ; it is a mazda site but it deals with the 2 years the mazda B2600 4x4 ran a 2.6 mitsu motor and has all the info on these motors.

If they are all interchangeable for the 2.6l motors, why is there a different part number for the head and head gasket for 79-80, 81-83, and 83-89 years?

joey_crandall
01-08-2012, 12:17 PM
i have some starion stuff to get you on your way to a possible cheap swap and theres a few starion guys in utah that im sure could help.

loyter
01-10-2012, 12:21 AM
I will check on the Starion message board if I can find it, but perhaps you all can answer a few questions. Will my bottom end (block) hold up to turbo charging? Is the compression ratio different? How much hp can you get out of a g54b and still have decent reliability?

joey_crandall
01-10-2012, 01:35 AM
starquestclub.com is a great forum. trucks have flat top pistons with no oil squirter and starions have dished pistons and oils squirters. trucks 8.1 i think and starions are 7.5 on the compression ratio

pennyman1
01-10-2012, 08:23 AM
Starions also have dished pistons to lower the compression ratio. The crank and rods are forged in both motors - the starquest 2.6 is the truck block and internals as the base, with the crank nitrided in the intercooled motors and the aformentioned oil squirters added. If you can find a set, the oil squirters can be added to a truck block by drilling and tapping the oil galley in the same place as the turbo motors. You also will need the tapped spacer between the oil filter and the block for feeding oil to the turbo and the oil cooler. I am currently building a 87 starquest 2.6 motor for my 1980 and am very familier with the similarities and differences of the 2 motors. Power levels will depend on boost levels, fuel delivery, and pistons used.