to over size or not to over size???

[supramic]

im recently won some pistons on ebay with "chrome" rings. im trying to figure out if i shoud go with over size pistons and get the crake balanced. i don't have time to waite to see what the internals look like.
the provious owner explained to me the he had his boost controler se to " a. fuckin around and B. for really fuckin around (scarry when you see his wire and vacume work)so i just try to find the answer to my question her

-do i really need to get the crake balanced with the new piston?

-is chrome "chrome moly"??


-what can the stock internals take ?

-if i get the crake balanced would i also need to go with bigger bearings

- where can i get a bottom end gasket kit at if it posible

- what is the maximum you can overe bore the 7mgte motor?

http://cgi.ebay.com/ebaymotors/Toyo...015QQitemZ250016589252QQrdZ1QQsspagenameZWDVW

 

[IJ.]

"Chrome" to me would indicate Hard Chromed rings which SUCK in a 7M due to the Bores being a very hard Cast Iron that glazes and may not ever break in using those rings.

But they could mean CroMoly rings I'd double check and make sure.

Balancing is a personal preference thing in this case but for me I don't build a motor without getting it done.

Balancing has nothing to do with OS bearings

E-Bay?

+ 0.040" is a "safe limit" in most cases

 

[supra90turbo]

Just know that you're not going to gain anything by boring the shit out of the block... you can go .050" over when .020" over was plenty, scratch a bore and have to start from scratch again as you can't go OS again...

Bore as necessary. that's all.

 

[JustAnotherVictim]

IJ beat me to it.
He is so fast....

 

[supramic]

when the crank is balanced do i have to go with os bearings???

can some one explain "shot been" and where i can do it at and how much the stock rods can handel from what i rember its like 400hp right

 

[IJ.]

"Chrome" to me would indicate Hard Chromed rings which SUCK in a 7M due to the Bores being a very hard Cast Iron that glazes and may not ever break in using those rings.

But they could mean CroMoly rings I'd double check and make sure.

Balancing is a personal preference thing in this case but for me I don't build a motor without getting it done.

Balancing has nothing to do with OS bearings

E-Bay?

+ 0.040" is a "safe limit" in most cases

"Shot Peen" is a process where the Rod Surface is pelted with steel shot this compacts the surface increasing it's strength and removing any imperfections that could create a stress riser (crack)

 

[suprahero]

I couldn't live with myself if I was that smart..................lol


Neither could Vonda....................

 

[supramic]

I just talked to the companythat im buying the pistons from, they explained that the rings are chore moly. and esured me that the ring will handle well over my hp goals

 

[jdub]

IJ beat me to it.
He is so fast....

Faster than a speeding bullet...able to leap tall buildings in a single bound...

:biglaugh:

 

[supramic]

how is some one going to build a 7m right if they don't ask the guys that have been doing it for a while if you don't want to help then please don't make comments, im just trying to build my motor th right way!!

 

[supradan22]

Faster than a speeding bullet...

:biglaugh:

Yeah im sure thats what she said :naughty:

 

[jdub]

how is some one going to build a 7m right if they don't ask the guys that have been doing it for a while if you don't want to help then please don't make comments, im just trying to build my motor th right way!!

Chill Dude...IJ already answered your questions. If you want more detail, read the reference section and do a search. Everything you asked has already been covered in detail in various threads on this site. We don't mind noob questions, but you gotta put some effort in to learning this motor...and that means you have to read and research before you ask questions.

You might want to read the "Dealing with the Old School Guys" thread.

Now...In case it's not clear. The only reason to go with OS bearings is if the crank journals are turned, and the decision to turn them is based on condition...i.e. how much are the bearing journals worn. You will not know that until the crank is pulled. As IJ said (twice), balancing the crank has nothing to do with the bearings.

Bearing size is determined by the clearance spec in the TRSM...you want the clearance on the tight side of spec. The best bearings for this motor are Clevite 77's or Toyota. Don't forget the main bearings and oil pump bearing as well. Changing the oil pump is not a bad idea while you are there.