Re-use Connecting Rod Bolts?

[Exodus_2pt0]

Engines are very very simple. Hell it only takes 4 things to run. Oxygen, Fuel, Compression, and Spark. Air in, inject fuel, compress, boom, exhaust. Repeat.

My brother is a computer programmer, I helped him do an engine and next thing you know he does all of his own work.

BTW, if you ever need help I work for beer.

[TexasTerp]

That's what I figured. I mean I've already disassembled 3 full engines and a 4th bottom end. I understand the ins and outs of these engines really well by now. There are a good number of e30 guys in VA that build their own engines and are full time mechanics. I'm sure one of them can come by to help me out with the pistons.

These really are fairly simple engines, Thanks for the encouragement! I'll let you know how everything goes!

[nando]

the M20 isn't hard at all and is a good engine to learn on. I'd go ahead and give it a shot. just make sure your piston ring tools are good. I cheaped out and ended up breaking a ring putting the pistons into the block. instead of having a $50 tool and a completed bottom end, I had a $75 overnight charge for a single new ring and still needed to buy a good tool so I could finish..

[TexasTerp]

Thanks y'all. I knew it wasn't a good idea but I'm glad I got confirmation. I'm trying to decide if I want to build the bottom end myself or have the machine shop do it for me. I need to send out the block when I get back to MD in two weeks.

I'll be buying a Brownline digital torque wrench when I get back too. the only tool I won't have is for the pistons rings, but I can get one. I've never built a complete engine before.

Edit: Just an FYI here is my build list:

Maxsil Seta Pistons (.48mm overbore)
Eta 130mm rods
Eta crank
Main Bearings (post 3/88 Production Seta)
Connecting Rod Bearings (Seta)
OEM Main Bolts (M10x75 #11111735525)
OEM Con Rod Bolts
O-ringed block
Stock seals and gaskets
ARP Headstuds
Rebuilt 885 Head (<5k miles from one of my donor engines. Still has all the Sharpie markings!)

[Exodus_2pt0]

you could almost eyeball the torque angle and it would be fine..

Ive never used anything but my eyes on the angle part of tty bolts... Never had an issue.

On another note, I re-used mine on 1 rod. I had to pull the cap to inspect the bearings, and just re-torqued them to 40ft lbs. No problems yet, but then if I do have a problem I have a entire spare engine to fix it with.

What I did isn't what I would recommend to others... Just sharing experience.

[nando]

they should be replaced. it's so not worth trying to re-use them. they are designed to be used only once - people don't understand TTY bolts, but they're perfect in a rod bolt application IMO (no worries about torque wrench error, no worries about having to retorque after heat cycles, etc).

You also get a 10-20% margin of error once you've reached the yield point of the bolt, basically the clamping force flatlines after a certain point. you could almost eyeball the torque angle and it would be fine..

[Bearmw]

If you do replace them be careful to make sure the new ones are fully seated and properly torqued to spec. My machinist said that failures are more often caused by under torqued rod bolts than slightly over torqued.

There is talk about being able to re-use rod bolts one or two times depending on how much they may have stretched but for high RPM use I definitely wouldn't chance it to save a little money. For a basic cheap rebuild you could probably get away with it though.

[MR 325]

It's a must, period. Throw away all of those used bolts.

If I were you I would drop the extra money on ARP bolts, that's what I did.

[TexasTerp]

I know this sounds stupid, but how risky is it to re-use connecting rod bolts on a complete rebuild?

I'm already rebuilding the rest of the engine with new everything, so it's kind of silly not to get new ones. I'm going to be boosting it eventually. I'm just curious about everyone's thoughts since I have about 40 used con rod bolts from my 3.5 donor engines.

I'm ordering new main & con rod bearings and pistons soon. If don't need to spend the extra $100 for bolts it'd be nice, but I dont mind the expense either for peace of mind.