when you guys get your engine rebuilt, they put in an engine that they've already built, right? How do you know if the engine isn't some previously blown pos, with 100k miles on the block, that's been rebuilt? If your new car's got only 5k on it, wouldn't you rather rebuild your own?

 

It depends on how you want to do it. If you have a good block in your car, you can send it out for the rebuild. Some shops have built blocks in stock that they will ship you, then you pull your motor and swap a few things, and ship your block back. They will then refund the core charge (usually $1500-$2000).

 

You are replacing the parts that have taken the wear and tear and will take it in the future as in the rods, pistons, bearings and resurfacing the cylinder walls. The block itself doesn't deteriorate with time and use or will it be a problem down the road. But if you can wait a few weeks for yours to get rebuilt and get the peace of mind it is your time and money so do it the way you want to..

 

LOL @ this post. More learning is in order...

 

true.. still don't want a 03 engine on a 07 model, or conveniently have a rebuilt engine, done a year ago when skill level of the peeps and parts were less desirable.

 

ask todd at built z motors, he bought a couple blocks with messed up crank bearings and stuff like that and couldnt use.


i think he is asking an alright question, just wording it like he doesnt know what he is talking about...

 

A bad bearing alone wouldnt be enough not to be able to use a core. But if it had damaged the crank to the point of not being able to be repolished, or the main journals then sure. Jeremy <---knows his stuff, but worded that wrong so it sounds like he doesnt know what hes talking about

 

well, what i did , i got a used block from Builtzmotors and i sow the pics. it was as new man, thanks for todd .

 

when a spun bearing melts the bearing housing, the block is at times, unusable...

we have several different quality blocks that we receive, from cores, or from various core suppliers...if they are not in order to be rebuilt, they are not used..simple as that! we dont use a block that would compromise the integrity of the build, its not worth it...

that said, there are several problems with a block that can be worked out with proper machining...

the fact that the cylinder is bored and honed, and the main bearing journals are align honed if needed, these blocks and cranks (and heads) are in perfect new working order before we use it for a build.

TODD

 

when someone buys a built motor, they typically specify what parts they want (pistons, rods)...the bearings will remain the same, the gaskets and o rings will remian the same, the rear main seal and front seal are the same...

the skill of building a vq, now that's another story, fortunately, that's our expertise

 

so it's not a common practice for someone to request to have their motor pulled for the rebuild?

edit: actually, I know it's not common, but on special request, they'd do it, right?

 

we can do it, for sure, but that involves the wait...mostr of our customers like to be able to pay a deposit for a core charge, have a built motor show up to their shop, have it installed, get back on the road, and then , when they have time, pack up the motor in our crate and ship it back to us...

but, if someone wanted to rebuild their exact motor, we can definately do that as well just involves more down down for that individuals' car.

-TODD

 

^ cool thanks for the reply.. if I have a daily driver, waiting wouldn't be a problem.. unless it's a few months?

 

If or when I need mine done, I would use my own core. I know its history and now days its old fashoned, but I like the fact that I have a "Number Matched" Motor in my car

Id have it chked for cracks along with the heads and Crank. If I had it sleeved Id send it out and have it fitted with the pistons and then do the reassembly myself.

If u are doing an exchange though, and using a reputable builder like many in this Forum then it dosent matter if the core they are using has 10 or 100,000 miles on it. Specs are specs,either it measures up or it dosen't. If it does, then when its done it will be Brand New.

Any good builder would understand if u wanted to use ur original. Even 15-20 yrs back it was a Sin not too.

 

I had my engine done at built z motors. Todd knows what he is doing. Mine is basically everything but sleeves. I have 1/2 inch head studs, hks gaskets and cams. My heads took extra time because they were pretty messed up and then i wanted cams at the last minute heh. I have 2500 miles on my engine so far and its running great.

It would be possible to do it cheaper if you had a low mile stock block that didnt need bored and sliped new pistons in with new rods, and bearings.

 

In all due respect,unless there is something unique about the Z motor, anytime u change a piston the cyl has to be matched to that piston. #1 piston that is marked by the builder is fitted to #1 cyl and so on and so on. Six pistons can have six diameters, Not much difference but difference none the less. Unfortunatly a cyl never gets smaller--always larger .

Sometimes u can play with the numbers but not often

 

with several piston manufacturers, you are 100% correct..we always take every measure to fit each psiton to each cylinder (if variances exist)...with the Arias ED pistons, we havent had a need... the pistons are all identical, to 2 or 3 ten thousandths of a variance (translates to not enough to be able to match to a cylinder via honing)...

with these high grade pistons, the cylinders are honed all identical, if we had a variance in a set of pistons, we would then number the piston per cylinder..we balance the rods all the same, so any rod could be used in any cylinder, as well as the pistons (balances identical)..the motor is internally balanced (crank)..so that a flywheel and crank pulley can then be further balanced (if one was so inclined)_ to further exact the balance of the engine!

-TODD

 

Keep in mind, Im talking bout a Nats *** build-----Notherwords, Blueprinted.

If u go with Forged Pistons then u mite be able to Hone to size. Boring/Honing is not only for the "perfect" circle but also eliminates the inevitable Taper AND Squares the cyl to the Crank

 

No need for me to use ur Quote Todd----I missed that as I was typing that last post ---But thats interesting ----Theres a lot that is new to me as far as very late model engines.

One thing I was curious about was the Balance procedures with the Z motors---------Is it still, weighing Crank pulley ,rods,pistons,rings,pins,flywheel etc. ???? And then removing metal to acheive Balance

 

we build ALL of our motors blueprinted. nat's a$$...many have told me its overkil, but we are perfectionists

and, with that said, the extreme duty pistons are/have been all DEAD on, making them interchangeable per cylinder...