newtlicious

I am planning on pulling my engine the second I get it home from the dealership and installing forged pistons and rods and APS TT. I have a few questions for those with more experience than me.

1 - If the engine only has about 15 miles on it, do I really need to have the cylinders torque plate honed and new main and rod bearings and all that jazz? Seems like overkill to me on a brand new engine.

3 - I downloaded the nissan FSM and the engine section seemed to be missing. Is there a separate manual dealing specifically with engine assembly/disassembly.

4 - What (if any) problems could be encountered by installing new internals and FI on an engine that was never broken in? I should be fine if I break it in carefully after the installation right?

Any help would be appreciated!

booger

iTrader: (6)

Something to think about.....IMO..I would find a used motor out of a wrecked car, and rebuild it for FI . Then you can sell your new motor and recoupe some money....Bill

newtlicious

That's a darn good idea. Rebuilding a used engine would definitely require a full compliment of machine work and a greater initial investment though. I wonder if I could get enough for a brand new engine to break even on an SGP racing buit shortblock (+/- $3,900). Thanks for presenting a good option!

BLKturbo91

1- There will be no need to hone anything at all...just mic everything and check all ring and bearing clearances during the reassembly process..
2- Do not do this unless you are a professional!!!!! or have a PROFESSIONAL do it!!!!!
3- Get another engine like booger stated if something should go wrong you will have a new car sitting and this will drive you nuts...
4- You will have to break the motor in as nothing has had any heat on it....The cylinder sleeves,block,crank anything ....Again breaking in a hopped up motor is going to drive you nuts!!!!
Again DO NOT DO THIS UNLESS YOU ARE A PROFESSIONAL!!!!

JCat

iTrader: (4)

I am planning on pulling my engine the second I get it home from the dealership and installing forged pistons and rods and APS TT. I have a few questions for those with more experience than me.
If the engine only has about 15 miles on it, do I really need to have the cylinders torque plate honed and new main and rod bearings and all that jazz? Seems like overkill to me on a brand new engine.
Honing does not require a torque plate, boring does. Forged Pistons require greater clearance in the cylinder bore, so most builders would say you need to bore and hone the block. You may be able to use the rod and main bearings, but they really do not cost that much.
I downloaded the nissan FSM and the engine section seemed to be missing. Is there a separate manual dealing specifically with engine assembly/disassembly.
I don't know.
What (if any) problems could be encountered by installing new internals and FI on an engine that was never broken in? I should be fine if I break it in carefully after the installation right?
Without proper piston to bore clearance you can overheat and crack a piston skirt or even the block. Also, the piston rings may not seal properly.

Sharif@Forged

iTrader: (92)

If the engine has even one mile on it...I would bore it out .020. As soon as you start that motor, the cylinder walls will start to slightly oval themselves. Most good engine builders will tell you that only a brand new block should be used with standard sized pistons. Boring is very inexpensive...might as well have it done correctly. Bore it out .020, then have it honed, then you can install your .020 overbore pistons and set the ring gap and clearances to spec. Most forged pistons need 2-3 times the clearance of stock pistons....your engine builder will known exactly what the specifications should be.

The rods bearings definately need to be replaced. They need to be spec'ed and fitted to the new rods. As mentioned, the bearings are cheap.

The crank bearings should be fine....you are reuse those.

Hope that helps.

newtlicious

Thank you everyone for your responses. It seems to me that the majority of objections have centered around piston to wall clearances. The minority revolve around my abilities as a mechanic. With that in mind I have a few more questions.

1 - Doesn't the piston manufacturer (arias, SGP, CP etc) account for the fact that more clearance is required with forged pistons.
For example, the Arias 8.5:1 standard bore pistons should have the extra clearance worked in right? Correct me if I'm wrong but otherwise, they couldn't be called standard bore because they would require an overbore for proper clearance.

2 - Is it really that hard to find new rod bearings? There aren't any rod manufacturers that supply new bearings (or at least suggestions) with the kit?

3 - I'm not too worried about getting this done in a hurry. I have 62 days of leave saved up so I'll probably take a month off just for kicks. Any engine downtime will be used installing stereo equipment (door panel fabrication, covering everything with alcantara etc. etc.)

Regarding my mechanical abilities...I'm not claiming to be an expert on piston engines but I have spent the last 6 years as an aircraft mechanic in the US Air Force. I'm an FAA licenced Airframe and Powerplant mechanic and spent several years doing Phase level inspections on B-52 bombers requiring extreme attention to detail, complex rigging procedures and strict compliance with technical data. I'm not saying I'm some kind of badass because I admit that my experiance with piston engines is limited. I am saying that this kind of project doesn't intimidate me at all compared to some of the things I've done to airplanes. As long as I have a good service manual, or at least know all the spec's, I'm not worried. Many of our procedures with aircraft are the same concerning detailed work, i.e. measuring bolt stretch instead of torque, re-torquing 3-4 times to polish the threads for greater accuracy, measuring high tolerance clearances with a variety of gauges including plastigauge. I have a fully equipped garage, dial gauges, torque wrenches etc. etc. Am I being over confident here? If so then please tell me honestly.

Brandon@Forged

Sounds like you are building an awesome Z, keep us updated.

newtlicious

Thanks, I've got a healthy budget and plenty of time, now I just need advice...............Anyone???

Sharif@Forged

iTrader: (92)

1) The clearance comes from the piston rings. The piston itself self is designed correctly. For instance, a standard bore piston is designed to fit a standard bored motor. The .020 overbore is desiged to fit an engine that has been overbored .020. The ring gap and clearance are adjusted and set by the engine builder. and yes....they account for extra expansion that forged pistons will experience. Any pistons you buy will come with instructions on how to install them and take measurements very precisely.

2) The rods bearings you will need are just OEM nissan bearings. But there a are 3 different grades of bearings, and each motor has different beargins in it. So you will need the numbers off the block and crank before you can order the exact set of bearings you need. Other engine builders will just tell you to order them whatever grade of bearings he says...and then he will fit them to the rods.

Based on your description of your mechanical accumen and tool collection, I have no doubt you could perform most of the work yourself. But you MIGHT want to leave the engine assemble and balancing to someone that has done this 100 times before. Just my personal opinion.

Maybe you can do all the engine removal, dissassembly...etc.....

JCat

iTrader: (4)

There are many dimensions or high-tolerance specifications for a piston. It's metallurgy, diameter at top/middle/bottom (skirt). Is it coated with a friction inhibitor? Different types of pistons rings are available too. All these variables affect your bore diameter. Most machinists will custom fit each piston to their very own bore (and label them as such). Manufacturers do this too. If you put any piston in any bore, I guarantee your compressions between cylinders will vary undesirably.

An experienced builder will know what type of combinations work.

I do not think you will find any more specific information than this on a forum.

newtlicious

Thanks for the vote of confidence gq_626! While I'm sure it is the best idea to leave the work to someone with more job specific experience, I'm going to have to start somewhere. I would prefer to directly control every aspect of my engine build. It would break my heart to know that a machinist let something go because it was close enough. I'm very much a perfectionist. I will certainly leave the balancing to a pro since I lack the equipment.

newtlicious

Biz to the izzump