I need help deciding what to do...4.1 built or 3.8 built

[SHADOWII]

I can't find...

I believe that is also a good block to use. do you have some pics of the valley?

the flash-bulbs for my camera! ...lol:biggrin: Even if I owned one, I wouldn't know how to use put the pic's on the forum. but the valley is still rough like the the other blocks, w/holes in it. Maybe I can get my son to take pic's and post them?

 

[Nasty Wendy]

I have is not the 484 or the 291, it's a 553 However, next to the sg-1, it looks almost the same except for the missing holes(oil return, knock sensor, and the perferated valley of course) There's no cracks in the deck, and they appear to have the same deck thickness. the ribbing is thicker than the sg block. Can't find a reason not to use it. I believe this the block used by cadillac.

I do not think that any of the different divisions had specific castings that only that division used. The 484, 291, and 553 can be found anywhere that a 4.1 was called for. I did a lot of digging for info on a 4th casting number that is hard as hell to find - 25520044. This casting is listed with the other three under Cadillac but one of the only two I've ever known about came from a Pontiac.

 

[tom j]

This a touchy subject for many people, but mostly a lot of speculation. I feel if you don't have first hand knowledge of this then stay out it. I feel that can mislead people who have blocks that want to do something with it or to obtain one. I have had two 4.1 and been fast with both of them. Much faster if I took some weight out.


Now I have talk to one person with a bad experience and will not say that the 4.1 is the answer to all of problems. They are still a production base engine that I have made good power with. And they are not for everyone. But I am one who still runs one and will say that I will not go back to a 3.8 unless something drastic happens.

Amen:wink:

 

[coldair85GN]

Just picked up my block. It passed a sonic/magnaflux and the cylinders also cleaned up surprisingly well at .030 over so it looks like I just joined the 4.1 club:biggrin:
Now I gotta decide what pistons to use, decide if I want to go roller or keep it old tech flat tappet, gotta order a girdle, front cover, timing set (holy hell this is gonna start costing some green )
Here come the 10's:biggrin:

 

[boostingbuick]

I am a huge JE fan. I just can't seem to hurt mine, I have tried. Roller cam, really. I have lost too many cranks from the cam going south. It is well worth the money. I had the stock rods made full floating and still run a stock crank. So unless you get crazy it will only cost an arm.

 

[49-blues]

I have a few new sets of new forged 4.00" pistons-Diamonds and Ross- let me know if you re interested.

 

[Powder]

I went with JE for my 4.1 project but I'm still putting it together so no first hand results past this stage. They look great!:biggrin: My machine shop highly recommended them and they seemed to be competitively priced at the time. In case you're interested, I bought 4.00" bore pistons P/N 271718 and worked with salesguy Randy who seems very knowlegeable and is easy to work with. I'm using stock rods and crank with ARP studs and rod bolts. Good luck with your project.
MH

 

[coldair85GN]

Okay...anyone got any pros and cons of one brand piston over another? I would like to keep cost reasonable...but I don't want junk pistons either. I've pretty well decided to go with a 4 inch bore because of the vast choices. Stock crank, stock turbo rods. Trying to decide also which front cover to get.

 

[49-blues]

do you know what the comp height is on the JEs?

 

[coldair85GN]

49-blues...I sent you a PM.

Okay...I have done some limited searching on the internet and have discovered that for the most part the various piston makers on the market have decided the 4.1 did not exist unless you want crap hyper pistons. Anyone got a source for any GOOD pistons for this motor? My motor cleaned up so far to a .030 bore. That doesn't mean I have to go .030 if going larger makes finding pistons easier. What about using SBC pistons? I would like some EDUCATED opinions here.

 

[87GNSteve]

To date no one has found ANY off the shelf piston for the 4.1 to fit the requirments we desire.
Except for the "crap" hyper pistons which I use, and many others and are using and are holding up well.
Mine haven't blown up by now, then they never will-- ABUSE is not the word.
I would not hesitate to use them again-- hypers got a bad name from way back in 1995, Keith Black pistons for SBC's the technology was brand new.
The ones today have better metalurgy and have the dry film lubed skirts too.
I think hypers are perfectly matched for a pressed pin stock rod, street/strip build.
I do have plans for another 4.1 when this one dies and I will get floating forged pistions, to match my steel crank, K1 rods.
But if you are keeping the budget on the low end, dont be afraid of the hypers you wont be the ginuea pig by a long shot.

 

[coldair85GN]

The "crap" term I used doesn't imply that they can't hold up to any power. Its basically that we have all been brought up and have been told over the last prolly 20 years that the hyper pistons wouldn't work in our cars very well. Even now..I have been told by several people that I needed forged pistons and its frustrating to get so many different answers from so many different people on the same questions. If 49-blues doesnt reply to my PM by the end of the day I may just order some .030 over hypers and take my chances. I want this damn car finished.

 

[87GNSteve]

I have 5500 hard miles on the engine now; Cometic gaskets too. ( 9441's would have blown eons ago due to a fuel issue, etc) I followed Mike S's Budget Build on TBs.com. he praised the hypers so I fugured I'd try them.
My machinist was even anti-hypers, but I ordered them to see what they looked like and was pleased. I'm confident i will get many years and miles of enjoyment from them.
This 4.1 thing was really an experiment for me, I just paid attention to the important stuff like balance, clearances and assembly.
I still had my low mile built 109 short block to fall back on....recently I have been trying to sell it.

 

[coldair85GN]

Well I just ordered a full roller cam kit from Weber racing along with a new front cover. Still trying to make up my mind on rocker arms....roller rockers or stick with stock arms and buy some shaft braces. While roller rockers look pretty and all that...I'm not sure they really have a major performance advantage PLUS I will have to buy valve cover spacers.
Where should I look for a good set of Hyper pistons? My machinist told me the block was good for .030 over, but it wouldn't bother me at all to go a little more.

 

[87GNSteve]

Summit.
Speed Pro H471CP .030 is what I used.

 

[coldair85GN]

They've changed part number slightly on those Speed Pro's but they are probably the same thing....and I will probably end up going that route as I don't easily see any other options.
Nother question since you have obviously done this conversion...what are the suggestions about the oil return line from the turbo...since there isn't one on the 4.1 liter? I am planning to use a 6776BB turbo in one of its many hundreds:tongue: of versions and I'm not sure if I can use the return setup I have now anyway. I bought one of those fancy braided return lines with my old setup and if I cant use it I might as well sell it or find another use for it (spare engine ).

 

[87GNSteve]

I drilled a hole in the block for the stock location return other guys have it going into the pan.
I wished I had put it in going into the pan.
Since the 4.1 block doesnt have the Boss for the drain, the reinforcment ribs dont allow the stock brass fitting to get in when tightening, I had to use pipe adapters-- a male straight and a double female 45* then the stock brass fitting then, the convoluted drain line, compressed some at a difficult angle. I had to wrestle a little to get it on; then dealt with a leak, that I had to double up on gaskets and add RTV to stop. You really cant see all that stuff unless you crane your neck inthere to look but if I was to do it again I would put it in the pan, OR I have kicked around the idea of welding a return port in the front cover, I figure it would help oil the cam sensor gear--but thats a little over the top.

 

[boostingbuick]

I run the stock drain fitting in the stock location. You will need to drill and tap a 1/2 npt hole, and use a round grinder and clearance the ribs to get a thin wall socket on it. I have done it to two of them with good luck.

Glad to hear more are doing this build. Congrats guys.

 

[sixgun86gn]

I run the stock drain fitting in the stock location. You will need to drill and tap a 1/2 npt hole, and use a round grinder and clearance the ribs to get a thin wall socket on it. I have done it to two of them with good luck.

Glad to hear more are doing this build. Congrats guys.

I just drill and tap the 1/2 npt hole and use one of the braided drain lines. Never had a problem with the fit,just drill right between the ribs on the front and make sure you thread it into the block BEFORE putting on the timing cover.

As for the hyper pistons,they will be fine ,Jeff. Try enginekits.com thats probably the cheapest place to get them. I got a 214/224 hyd. cam for like $65 from there and all my bearings.....WAAAAY cheaper than the buick vendors.

 

[coldair85GN]

Summit and Enginekits.com have 2 different pistons if you go by part number. Looks like Enginekits.com offers more flexibility with bore size by offering several bore options where summit only offers the 4.025" bore. Summit is slightly cheaper for six. Check em out.

Summit: Federal Mogul H471P60 - Speed-Pro Hypereutectic Pistons - summitracing.com

Enginekits.com: ENGINEKITS.COM® - Stock and High Performance Engine Parts | 661-861-0167