4.1 liter shortblock

[AKTURBOTA]

I am showing some of my ignorance, but I am ready to be educated. I am interested in putting a 4.1 litre shortblock in my TTA. The block is a 291 casting number, will it fit just like the stock 3.8 does now, or are there "issues" to contend with?

 

[Razor]

It will bolt on the same. Oil pan is different, and the theory is the sides of the block are not as strong. Dunno.

The TTA heads will work on it.. finding a girdle for it may be tough tho..

I usually leave the blocks at the junkyard and snatch the cranks out of them.

There is a lot of casting flash in the lifter valley area.. at first looks weird, but theyre all like that.

HTH

 

[87GNSteve]

You CR will go up unless you have custom pistons for it. Very few off the shelf pistons to begin with on the 4.1 for the Buick.

 

[AKTURBOTA]

It will bolt on the same. Oil pan is different, and the theory is the sides of the block are not as strong. Dunno.

The TTA heads will work on it.. finding a girdle for it may be tough tho..

I usually leave the blocks at the junkyard and snatch the cranks out of them.

There is a lot of casting flash in the lifter valley area.. at first looks weird, but theyre all like that.

HTH

Will the oil pan from the 3.8 in the TTA bolt to the 4.1?

 

[AKTURBOTA]

You CR will go up unless you have custom pistons for it. Very few off the shelf pistons to begin with on the 4.1 for the Buick.

The CR issue was one thing that I was aware of and that custom pistons would be required to arrive at 8.0 to 1 compression with 38cc TTA heads.

 

[ledzeppac]

do a search on tbs.com... there are alot of people running the 4.1 291 in their GNs... there is also a write-up on a budget 4.1 build for like 1700

 

[Lee_Burough]

Sorry to hyjack your thread....But, I see you're in Eagle River. We used to live on Meadow Creek Drive (1982-86). We miss Alaska and the fishing and hiking. Are Pizzaman and China Lights still in town. Nobody's pizza crust is as good a Pizzaman's!

There is a build up for the 4.1 block on Gnttype.org, but I can't call it up right now to find it for you.

Stay well

One more thing, I linked your best to the TTA FAQ List :biggrin:

 

[AKTURBOTA]

Lee,

Yes Pizzaman and China Lights are still in business. Pizzaman still has the best pizza in town. China Lights has gone through several changes of ownership...so the food quality isn't quite as good now.

I used to live at 4 mile Highland Road, but with my 3rd child we need more space and bought a 3400 sq foot home on 11.5 mile Eagle River Road (1/2 mile from the Eagle River visitor center). The commute is 27 miles to work in Anchorage, but well worth it since it is gorgeous in the "back valley".

I used to have friends that lived on Meadowcreek, but that was from 1995 to 1998.

It is good to hear that you were once in Ak. Did the military bring you here?

Mark

 

[87GNSteve]

Will the oil pan from the 3.8 in the TTA bolt to the 4.1?

No, the 4.1 will be a 14 bolt pan and the 3.8/TTA pan will be a 20 bolt that means the front cover will be different too.
Although they make the new front covers with dual bolt pattens and seal that can be installed/replaced with out pulling the front cover for $90.
Which is what I went with.
The GNttype.org article states that the 484 block is the most desirable which is not the case. they are prone to cracking from bolt hole to water jacket. Look here:
http://www.turbobuicks.com/articles/4point1ForCheap

 

[AKTURBOTA]

No, the 4.1 will be a 14 bolt pan and the 3.8/TTA pan will be a 20 bolt that means the front cover will be different too.
Although they make the new front covers with dual bolt pattens and seal that can be installed/replaced with out pulling the front cover for $90.
Which is what I went with.
The GNttype.org article states that the 484 block is the most desirable which is not the case. they are prone to cracking from bolt hole to water jacket. Look here:
http://www.turbobuicks.com/articles/4point1ForCheap

Thanks for the information! What I am planning is to use a "291" shortblock with reconditioned "515" cylinder heads and drop the combination into my 89 TTA. So to drop this into my TTA I will require the following:

1. 14 bolt oil pan.
2. Different front cover.

Is there anything else that is different on the 4.1 versus the TTA's 3.8?

Mark

 

[87GNSteve]

You need to use the balancer and flexplate from the 3.8
and then get the assembly spin balanced because the 4.1 balancer doesnt have the interuptor rings for the crank sensor, and is weighted differently (the crank too) so its not a "direct" swap*.....
but you were getting it balanced anyway.... right?

* all these parts fit, work and will run without machining but will probably need a little weight removed here and there.