I was wondering if I built my own motor would it last? Of course I would still need a machine shop to micropolish my crank and bore/whone (maybe sleeve) my block and crank. But if I followed all instructions (torque specs, clearances, etc.) would it be ok? I know this is a kinda dumb question, but I have freinds that have assembled their own motors (old school V8's though) and they have last 50k miles so far (still running fine though). I am comfortable with my skills at assembling things (definetly not boring or micropolishing or anything of that sort though). Other than balancing the crank (with flywheel and pulley) and having the pistons and rods balanced, is there anything that I would be better off having a machine shop do?

TIA

 

Done well it would last just as long as done at a shop, after all, they're just people.

One question is, can you do it well, isn't it? More specifically, are you mechanically inclined, careful, decent at learning, willing to take the time to do it right... ?

Other factors are parts chosen (quality), design goals (radical won't last 200k), and how you drive (mainly 1/4 mi w/NOS won't last as long as 'normal' street driving).

If the quality of worksmanship is comparable, then perhaps a simple answer would be that you will get similar results to the degree you stick to the same design goals as the factory folks had in mind. The more you deviate (compression ratio, HP, boost, redline, type of driving) from the original design goals, the less your engine's life will resemble the factory one. You can compensate with better materials than they would use in production (forged pistons, stronger rods, etc) -- but that won't make up for all the impact of extreme use. No magic formula.

That said, unless you do something silly like trying to get 100k from a standard set of titanium retainers (a wear item, it seems, unless coated) -- you should *at least* be good for 50-100k as long as you aren't too radical with your driving.

Mark

 

well here are my goals:

11.3-11.7:1 CR (if I sleeve the block, then these will be forged as well as Probe rods, if not then stock LS rods using arp rod bolts with arp fasteners and P30 or PR3 pistons)
sleeves (not sure yet)
ITR cams

daily driver mostly, and I mean mostly (very rarely taking it to redline, ~4 times a week maximum)

 

Like above, the motor can last a good amt of time if you build it correctly. Everyone needs to learn somewhere right? So if you have the drive, the patience, and the money, then it might be well worth your effort. Good luck

 

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Any ideas?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Twenty36_1 &raquo;</TD></TR><TR><TD CLASS="quote">

Any ideas?</TD></TR></TABLE>

1. Micropolish Crank

2. Line Hone crank bore -- even if all you do is make certain they're straight, you don't necessarily take off any metal. This will knock off the high spots that would otherwise cause the shiny spots on your main bearings. Could extend life and avoid the 'spun' bearing... of course, the whole reason for it being necessary is that castings often change shape with time and use.

3. Check deck for flatness (it's a challenge w/o the right tools) -- avoid blown head gaskets.

4. Hone cylinders -- even if the cylinders are within service limits, the proper surface is important to seat new rings. If you don't, you get those gummy, sticky piston skirts and blow by.. not to mention higher crankcase pressures, reduced compression, increased junk burning along with the gas (oil has real poor octane rating!)

5. Check head surface for flatness.

6. Valve job -- unless you're a pro or have the right tools. It's too cheap to pass up, even at a shop.

7. Turn flywheel. If there is any hotspots or scoring. Otherwise, you'll get chatter and decreased wear on that nice new clutch...

The pattern here is to farm out any machine work requiring tight tolerences, or special tools you might not want to throw the money at.

Hope this helps.

Mark

 

You can do it. Its not rocket science, it just takes some care. Go slow, and follow the steps and itl be as good as any shop. Let the machine shops do the machining (durh), Get it bored, crank micropolished, resurfaced all that good stuff. PUting it together isnt that hard. Get the right crank bearings, plastigauge it to be sure, make sure the pistons arent in backwards. Use a decent tourque wrench, (snap-ons the best), follow the specs, put in new seals all around.

 

Cool thanks guys, I figure if I assemble it myself and only have the machine shop do machine work then for the price I save on labor I can get it sleeved.