Out with the G in with the swirl

[turbo84voyager]

I am just about complete with the head swap on my 2.5. I would have had it done but I didn't realize the washers don't come off the mopar performance head bolts and since I had felpro bolts i needed to order washers ( I threw all my old head bolts / washers away a few weeks ago ) One thing I noticed with the g-head is the combustion is definitely not efficient. All 4 pistons has a coating of black carbon but the backs ( firewall side) of every piston was clean. It has got to be the head, even with all the extra timing needed. I will update this with how it runs after the swap.

[turbovanman²]

Hurry up and get it done already and don't forget to change the cal,

Take pics of the piston tops.

[SUPER60omni]

Swirl head is where its at!

[turbo84voyager]

Hurry up and get it done already and don't forget to change the cal,

Take pics of the piston tops.

I already changed the chip. I wouldnt want to start it up with the amount of timing I had in there for the G. I am starting with Rob's 2.5 MP turbonator set up for 3bar and +40's

I forgot to take a picture of the pistons and the head is already on. I should have it all done tomorrow, as long as nothing else turns up. I just have to get the hoses and accessory belts on and fill it with oil.

[turbo84voyager]

I started the van last night. I only drove it up the street 2 blocks and did not get on it but it is running good and the engine sounds better. I am having a tough time getting all the air out of the cooling system. I believe its mainly because of the heater core being so high on these vans. With the engine not running it is still slowly taking coolant and when I came back from my 2 block trip the gauge climed to between 1/2 and 3/4 and the fan did not come on. WHen I removed the cap there was air in the system. I originally bled it by keeping the gauge temp sensor out until coolant came out, then I left the bolt at the top of the thermostat housing out until I had coolant. I had a similar problem to this with my 84 when I changed the engine. I bled the system by filling the remainder through the heater core line. I am going to try this tonight and see if I can get it all out and the fan to come on.

[GLHNSLHT2]

I just take the rad cap off and start the car, let it run till the fan comes on, you'll see when the T-stat opens fully. All of a sudden the coolant will be gone and you just have to pour a bunch in. works everytime.

[turbovanman²]

All I do is drill the stat with a 1/16" hole, self bleeding after that.

Is the rad cap any good?

[GLHNSLHT2]

1/16" is too big IMO, car takes too long to warm up with a hole that big.

[turbo84voyager]

Thats what I do on all of my other cars I have had a problem like this twice where there was an air in the heater core or lines and I was not able to get it out. The heater core on the vans is much higher than the cars.

Tonight I am first going to throw in my old gauge sending unit because I know where the gauge was with that one. I am going to check the cal for the fan temps and last I picked up a T with a cap for flushing, I am going to put this in the heater line and see if I can bleed the air out.

[turbovanman²]

1/16" is too big IMO, car takes too long to warm up with a hole that big.

Never had a problem with warming up too slow, even at -15 deg c.

I drill every thermostat with that size on all my customers to help bleed out.

[turbo84voyager]

Turns out the new sending unit was bad. I put the old one in and it runs temps like it used to.

[turbovanman²]

So, how does it run?

[turbo84voyager]

I posted a new message.

It runs great! The engine also sounds better. It has more bottom end and does not need to go into boost as much around town. I didnt throw a timing light on the engine and timed it by ear which is probabily very close because the cal i was using was too rich with the coolant temp sensor disconnected it would not idle smooth enough to set it with a light, so I didnt want to get on it too much but the swap was worth it. I am going to write up a new message when I get a chance about the swap and why I would not recommend the g on a 2.5. Hopefully it will save someone the aggrivation I went through the last 2 years and just use a swirl.

[GLHNSLHT2]

for a heavy van that is running low boost as a daily drive the swirl is better. If you're going for all out power then the 655 G head is the best. I do understand why you like the swirl better and for your setup and from your description of your driving style the swirl is a better fit for you.

[turbovanman²]

Awesome, glad to hear,

[turbo84voyager]

for a heavy van that is running low boost as a daily drive the swirl is better. If you're going for all out power then the 655 G head is the best. I do understand why you like the swirl better and for your setup and from your description of your driving style the swirl is a better fit for you.

I agree for an all out race only engine the g may be the way to go but it does not work for a daily driver. On a 2.5 it is too tempermental to tune for a DD.

Does anyone have numbers to prove that the G including the 655 really makes more power on a 2.5 than a good ported swirl even at high boost levels? From what I can see the g-head is much less efficient during combustion. I am asking this because Simon and myself both tried this combination and both of us have not been satisfied with the results.

[GLHNSLHT2]

the 655 Ghead flows a ton of air. Terry has a 655 on his 2.5 now.

[turbovanman²]

the 655 Ghead flows a ton of air. Terry has a 655 on his 2.5 now.

But his is a track van and he's only done a few pass's and his setup is completely different from anything he's run, just sayin,

[turbo84voyager]

I probabily should have just added this to this message but this is a writeup I did last night about my experiences with this setup.

http://www.turbo-mopar.com/forums/sh...ad.php?t=42977

I am not saying that the g-head is bad, I would just like to post this for someone in the future who may be considering this combination to know the issues I have experienced. There are several sites stating that it is the wat to go even with the van's, but there is very little or nothing out there explaining the problems one may encounter. If I knew this before I put the engine together I never would have used the head.

[Juggy]

its funny everyone talks trash about the G heads.
I brought a 655 to my machinist one day, and he had NEVER seen a complete oval port 2.2/2.5 head.

he told me this is the head i want to run if i want to make more power. and also said the bathtub chamber is a much better design then the swirl as it, (not his exact words but) moves teh quench area more towards the center of the combustion chamber, and then said chryco just changed to swirl chamber to help with emmisions and fuel mileage.

i dont know much about the n/a dodge 2.2/2.5 cars....but im almost certain any of those cars that actually made decent power, were all milled down G headed cars

so how come they never bothered with the swirl head?? it has "better" combustion chamber, also more compression!!! sorry looks like im starting another G/swirl debate here