4.1 engine

[Loswages05]

So I'm looking at a low Mile short block this is the info It has a nitrated crank reconditioned n shot peened stock rods bore is 4.0 and built mains is this something worth looking at? I have a set of gn1 heads to slap on it and go from there any insight will be nice thx

 

[SHADOWII]

Is it a complete short-block w/pistons, etc? The more desirable blocks are 0291 and 484, however I'm using a 553 for my build. Just check around the bolt holes for cracks/pulled threads. look for the obvious hairline cracks on the deck and in the cylinders. If you know and trust the people you are dealing w/I would invest in it.
Mike at FTS offers pistons and crank assemblies for upgrades w/4" bores.( which can be a problem if the bore is out of round or tapered too much.) But the potential is there. Nick of ArizonaGN has a lot of experience w/the 4.1's and can add to your post as well.

 

[Loswages05]

Is it a complete short-block w/pistons, etc? The more desirable blocks are 0291 and 484, however I'm using a 553 for my build. Just check around the bolt holes for cracks/pulled threads. look for the obvious hairline cracks on the deck and in the cylinders. If you know and trust the people you are dealing w/I would invest in it.
Mike at FTS offers pistons and crank assemblies for upgrades w/4" bores.( which can be a problem if the bore is out of round or tapered too much.) But the potential is there. Nick of ArizonaGN has a lot of experience w/the 4.1's and can add to your post as well.

Ya it's a long block with 900 miles but with stock ported heads I have a set of gn1 alumni heads I got and smome other parts. I think it has stock rods to

 

[Nick Micale]

So I'm looking at a low Mile short block this is the info It has a nitrated crank reconditioned n shot peened stock rods bore is 4.0 and built mains is this something worth looking at? .....

Since you do not know anything about the rotating assemble, just my opinion, but I would not use any of it.

The minimun we do when building any production 4.1 block is custom pistons, forged crank, forged rods and 2 steel center caps with studs.

We will never again use a 4.1 "kit" from any vendor as we did use a customer-suplied kit once.

We spec our custom pistons to the customer's build and performance specs, and use other parts that have been proven in our builds.

Many of our 4.1 production builds have easily and reliably run at the 600+ RWHP level, including the one now in my race car.

 

[bigballsbilly]

Not to jack this thread, but what are these 4.1s coming out of?

 

[Boost231]

Buicks

 

[bigballsbilly]

Buicks

Gee thanks. Can anyone expand on that?

 

[87GNSteve]

Not to jack this thread, but what are these 4.1s coming out of?

BUICK ELECTRA (1980 - 1984)
BUICK LESABRE (1980 - 1984)
BUICK REGAL (1982 - 1984)
BUICK RIVIERA (1981 - 1984)
CADILLAC DEVILLE (1980 - 1982)
CADILLAC ELDORADO (1981 - 1982)
CADILLAC FLEETWOOD (1980 - 1982)
CADILLAC SEVILLE (1981 - 1982)
OLDSMOBILE 98 (1981 - 1983)
OLDSMOBILE TORONADO (1981 - 1984)
PONTIAC BONNEVILLE 1982
PONTIAC GRAND LEMANS 1982
PONTIAC GRAND PRIX 1982

 

[bigballsbilly]

Gotcha thank you for the list.

And whats the deal? All our accessories, headers, intake etc just bolt right up to this motor? I assume it has a bigger bore and the same stroke?

 

[buddy]

Same exact thing except pistons.

 

[bigballsbilly]

Interesting. Thank you.

 

[87GNSteve]

Same exact thing except pistons.

Front cam bearing of those years is different too.

 

[ek02]

The oil pan is 14 bolt, not 20 like a 109. There is also no oil passage behind the front cam bearing. If you use a cam with no groove to feed the drivers side lifters in the front journal, you need to grind a passage in the block or use rear groove cam bearings from TA Performance.

 

[007gn]

It's not worth the trouble . Just stick with a stock stroke 9:1 comp. 3.8 with good heads & new tech turbo & you can make reliable low 10/9 second power easily.

 

[Boost231]

It's not worth the trouble . Just stick with a stock stroke 9:1 comp. 3.8 with good heads & new tech turbo & you can make reliable low 10/9 second power easily.

I disagree. Was at the track yesterday with nick micale he's running a production block 4.1 and was running 9.86 @ 136 on 16.3psi of boost. Try doing that with a stock stroke 3.8.

His car is very reliable and has more passes on it then most have on their cars. Nothing wrong going to a 4.1 if your starting fresh.

 

[Ktbregal]

Just curious would the bullet caps off a 3.8 fit the 4.1?

 

[Ktbregal]

Heads also?

 

[Nick Micale]

Billet caps as well as stock caps are the same for the 4.1 and 3.8 blocks.

What could be an issue when fitting used billet caps on another block is not all blocks are the same and billet caps are machined for specific fitment and proper register on each block.

If the used billet caps were machined for a block with a larger dimension than the recipient block, they will be too loose to fit properly.

Heads are the same pattern and fit for 3.8 and 4.1 blocks.