109 blocks, t cranks

[WH1 85]

I am going to be hitting the junk yards trying to find a 109 block and a turbo crank. I have an 85 t-type with the original motor now, but I plan on running the car pretty hard when it's complete and don't want to risk destroying the numbers matching block. In case I want to return it to stock condition down the road.

My quesstion is what cars, besides t-types and grand nat's, (won't be any at the yards), came with the 109 blocks? And if these blocks came in non-turbo cars, will they have the provision for a knock sensor, oil return etc.. Will they be tapped for necessary accessories. What about the brackets etc.

I know that the 4.1's came with the correct cranks. Did any 3.8's besides turbo cars have them? And finally what cars are the 4.1's typically found in. Or if anyone has a 109 block and crank cheap let me know.

Thanks for the help.

 

[750H.P.V6]

WH1,

Here's a quick answer. The "109" block comes in all RWD 3.8 liter powered cars (Buick, Olds, and Chevy applications)from '86-'87. The only difference is that the N/A blocks aren't drilled for the turbo drain back.

4.1 liter motors come in '80-'84 vintage cars typically larger body styles (Le sabres, wagons etc.) They also come in Somerset Regals too, at least this is where I seem to find them.

I hope this helps.

Neal

 

[WH1 85]

Thanks for the help. And it was prety much what i wanted to hear. I am just wondering if the n/a 109's have a boss that can be tapped for an oil return? And that they have a spot for the knock sensor. Just want to be sure before i spend an entire weekend looking.)

I was also wondering that if the only difference between a n/a crank and a turbo crank is the rolled fillets, why doesn't someone who has access to a press make them. Would this be possible?

 

[750H.P.V6]

WH1,

The N/A "109" blocks are the same casting and do have the boss where the turbo drain is drilled/tapped in the Turbo block. The N/A blocks have a knock sensor already too.

As far as you question about roling the fillets on a standard N/A crank I don't know if it's really worth the effort. There are still plenty of rolled fillet cranks available.

To the best of my knowledge the metalurgy is different between the N/A crank and the Turbo crank also. The Turbo crank is supposed to be made from Nodular iron and the N/A crank isn't. I'm not a metalurgist so I can't prove or dis-prove this.

Happy Hunting

Neal

 

[b4black]

I doubt the cranks are different. I read quite a bit about the Turbo V6 developement and nothing mentions any difference metal content-wise about any difference in cranks (or blocks).

Both cranks use the same casting numbers. I suspect that Turbo cranks went through an identical process except that all the fillets were rolled instead of just the mains.

In 1978 when the Turbo V6 started, the NA even fire crank was only a year and half old. There was a concern that it wouldn't hold up well with the new split journals. Add the turbo and they were even more worried. So the rod journals were rolled as insurance. The NA crank turned out to be a fairly stout peice. I bet if it had a few more years of use behind it, they wouldn't have bothered rolling the rod fillets.

 

[WH1 85]

I went to almost every junk yard in town today. I found plenty of 86/87 3.8 blocks. And most of the yards only wanted about 100 bucks for them. I also found one 4.1 in a 84 LeSabre. Them 4.1's are pretty hard to find. They want 50 for it. So it has been a good day.

I also ran across a 79 turbo limited. Motor was pretty strip of all accessories, including the heads. It did have them air intake though. Me and my brother stared at that car for about an hour. We were thinking about taking the whole thing. But it looks to be to far gone.

My question is will that car have the correct rolled crank? Correct rods? It would be the easiest to get at. Like I said car is striped including tranny. It only has one motor mount holding it in. Me and a buddy could lift the motor out pretty easy.

Let me know what you think. And thanks a ton for the help.

 

[b4black]

They were either Limited or Turbo, not both. If it is a Turbo Sport Coupe and it is the original crank, then it would be a turbo crank.

Nothing special about the rods. Like block and heads, rods are rods, turbo or NA.

 

[WH1 85]

I could easily be mistaken about it being a limited. It was a turbo car though. It had t-tops,buckets and at one time a console. It also had the turbo 6 symbol on the dash. And it had a temp. gauge. Gauge cluster looked to be in decent shape. It also had what looked to be a computer or something in next to the engine. Was a rectangular black box, it said turbo or something like that. Can't remember.

Thats good news that the crank can be used for an 86/87 setup. It is gonna be real easy to get at.

Do you think I should grab the air cleaner, computer,(if that is what it is), and gauge cluster. I don't have any use for them, but if they are worth anything I would be willing to give them to someone that did have a need for them. I would imagine that they are pretty far and few in between. I just don't want to pay for them at the yard if nobody is ever gonna need them.

 

[FJM568]

The only thing different on the older crank may be the crankshaft bolt that holds the balancer may be a smaller size than the later model cranks...but that can be drilled and tapped out to the bigger size to match the later cranks when you have it at the machine shop getting cleaned and checked out/worked on...

As for the turbo oil return, if you will still run the hotair setup in your 85, the turbo oil return is on your intake under the turbo and not on the block...

The NA and turbo cranks are identical metallurgically, they both were cast off the same molds, it's just that the turbo cranks have the rod journal fillets pressure rolled where the NA cranks don't...

As for the 79 turbo motor, pull the pan and a rod cap and check for the rolled fillet on the rod journals...check the backside of the bearing for an undersize marking to see if it's been turned down yet...I wouldn't be scared of it if it's already at .010 under...If it will clean up at .020 under, it should still be okay...If it needs to go .030, then you have to be sure that the rolled fillets are still intact and not touched...