1g 7 bolt swap

[L0ckett]

Okay so here's the deal. I've owned this car for the last 9 months and am on head gasket replacement number 4. The first time or two I could have contributed to poor install jobs but now this is just getting crazy. I'm really starting to believe that there is a crack in the block that the shops just aren't noticing. A buddy of mine has a 1g 7 bolt motor that he would sell me for $200. I've done several searches and everyone with similar posts wants to swap from a 2g 7 bolt to a 1g. Now I'm trying to swap from a 6 bolt to the 7 bolt. I know that the swap is essentially the same as doing a 6 bolt but what about wiring a cas and whatnot? I know nothing about the 1g 7 bolts and if they differ from the 2g (except the oil squirters being in different spots) and the reliablity of the 1g. Please help me!!

 

[L0ckett]

Okay, after doing some more research, I've found a few people say that the 1g 7 bolts have higher compression and aren't very much suited for running more than 20 psi. Can anyone verify this or correct me? I'm still awaiting my head to come back from the machine shop to make a decision if I want to drop this motor in my car or not.

 

[BLKGSX23]

You currently have a 6 bolt in the car?

 

[L0ckett]

Yea but I'm pretty sure the block is cracked causing me to keep blowing head gaskets. The deal for the 7 bolt just can't be beat but I don't know too much on the 1g's.

 

[bigpoppa694lyfe]

have you checked to see if the head is warped? I see that being a good possibility since you've gone through so many head gaskets

 

[Dsm4lyfe12]

agreed ^ that would make the head not sit flush on the headgasket and making coolent to leak into the resevoir5. Cylinder pressure leaking to another cylinder

Go here to diaganose your problem
http://www.dsmtuners.com/forums/articles-engine-fuel/336535-do-you-have-blown-head-gasket.html

thats a good writeup on why the headgaskets are blowing, you might need a new head instead of a crack in the clock i dont think that shops would looks to closely into a warped head seeing that the headgasket was your main problem. Good luck keep us updated

 

[19Eclipse90]

Okay, after doing some more research, I've found a few people say that the 1g 7 bolts have higher compression and aren't very much suited for running more than 20 psi. Can anyone verify this or correct me? I'm still awaiting my head to come back from the machine shop to make a decision if I want to drop this motor in my car or not.

1G 7-bolt (and 6-bolt also) engines have a lower compression ratio (7.8:1) and lower overall standard compression pressure (164psi) than a 2G 7-bolt (CR 8.5:1, 178psi). I'm sure a 1G 7-bolt is just as capable of 20+psi as a 1G 6-bolt.

There are some advantages running the 7-bolt engine in your car if you hadn't already swapped a 6-bolt in, little things that would make the 1G engine in a 2G swap... less troublesome. But since you've already had a 6-bolt in there running, it would not make sense to undo what has already been done.

If you choose to use the 1G 7-bolt engine, you do not need to change anything from when you had the 6-bolt in there. Understand that the largest issue with a 6-bolt swap is the electronics -- CAS, CPS, MAP sensor, firing order, etc. A 6-bolt engine is (for all practical purposes) electronically equivalent to a 1G 7-bolt engine. So however you had all those things set up for a 6-bolt engine remains the same for installing a 1G 7-bolt engine.

 

[L0ckett]

Thanks Brian, that was exactly the info I was looking for. As far ad the head being warped, its been to 4 different machine shops, milled flat each time. I will hopefully hear something back today from the shop and they are supposed to let me know when they get the head back and give me the results of the pressure test.