TomP

Okay, so I'm not getting the times I think I should with my 2.8.. and all I can figure is, it's because of the 207,000 miles on the motor.

I know rebuilding a motor isn't as easy as rebuilding a distributor, but is it rocket science? I imagine the hardest part is getting the clearances correct with plastigauge. I mean, the machine shop takes care of the hot-tanking & honing (& boring if necessary), right?

This sounds silly, but is there a good book regarding engine building out there? I've never done it before, and I'd probably rebuild mine to "stock", so I don't need any high-performance tips in it. Know what I mean?

Also what special tools are needed? I have the general stuff, like a torque wrench, sockets, pullers, BFH , etc... do I need a dial gauge? "good" calipers?

Thanks!


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

Jim85IROC

iTrader: (2)

When I built my 350, other than the thingie to put the pistons into the bore with, I didn't use any special tools. Plastigauge is pretty simple to use. You put a piece between the bearing and the (insert rotating apparatus name here) and torque it down. Then you take it back apart and compare the width of the squished plastigauge to the chart to determine tolerances. There should be a million-and-one books on how to rebuild a SBC, and for the most part you'll be going through 99% of the same procedures. But, there are books specifically for the 60* V6. Hit amazon.com and see what you can find. Worse come to worse, get a Helm manual. That will have all of the torque sequences and ft/lb numbers that you'll need.

But a stock rebuild? You at least gotta put a better cam in there, and maybe think about some port work on the heads.

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Birmass

Best book I've seen is the one by David Vizard on "Rebuilding Small Block Chevy Engines". It has many good explanations and lots of pictures. Some further research is needed for newer blocks but he gives you all the torque specs and sequence.

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3.1 firebird

hey TomP go to amazon.com they have a book for 60 GM V6's. My grandpa and I rebuilt my motor after a rod bearing spun,.....and let me tell you its PITA! I let him do the bottom end, then after he did that I did the rest. If your going to rebuild it you'll probably want to send it to the machine shop and have them hot tank it there and install the cam bearings and new freeze plugs. You might as well take in the pistons, rods and crank to have them sized up, but that could get expensive. It might be just as cheap to get a 3.1 crank and pistons(the 2.8 and 3.1 use the same rods I think.) and have then size up the main journals only.

I think after the hot tanking,valve job,bearings,gaskets,resizing of rods and polishing crank, it costed a little over 500 bucks to get it done.

TomP

Jim, sounds good! What do you do after you measure the plastigauge clearance? If it's too large, don't you need to get new bearings and crank work done? I'd like to put a better cam in, but I'm worried about emissions.. I guess I'd have to do research on that.

Birmass, thanks, I'll go hunt that book down!

3.1Firebird, I'd probably get one of those "generic" engine rebuilding kits that I hear PAW sells. What do you mean by getting the rods & pistons re-sized? Does that go back to the whole "clearances" issue? Damn, $500 isn't bad at all. There's a junkyard I go to frequently that I'd like to think would give me a great deal on a 2.8 motor.

Only problem left is finding the spot to work on the thing. How heavy is that motor? Maybe I can drag it through the house on boards, and down into the basement on boards with my dad's old boat-motor lift. Man, mom will love that!


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

five7kid

iTrader: (14)

Drag the engine through the house? Are you deliberately trying to get on your mom's bad side?

Piston resizing means knurling the skirts so they fit in the worn cylinders better. Not the best practice. Better to bore it out and get oversized pistons and rings.

Resizing the rods is a machine shop job. They take off the cap, grind the mounting face down slightly, torque the cap back on, and hone out the big hole to the right, round size. It's a good thing to help your bearings last a little longer. The small end can also be re-bushed, but that isn't typically necessary.

If you're putting the engine back together yourself, you'll need a ring compressor. Not too expensive, and can be rented/borrowed. A dial indicator is a good thing to have to check the crank thrust clearance when you put it together. Oh, a balancer puller is different than a regular pulley puller, and an installer is much, much better than the BFH, too.

If you're considering an engine replacement, the 3.4l crate engine is a nice hop-up. Technically, it isn't emissions certified for 3rd gen, but it's not too likely you'd fail the sniffer, and visually it won't stand out (take off the stickers, of course). More money, but also more power than you'll ever get out of your 2.8, especially with the heads they originally put on them.

TomP

Can you picture my mom's reaction at her son dragging an engine thru the kitchen with a block & tackle? (snicker) Oh man, if only I could laugh out loud where I am...

I really don't have the cash for a 3.4, and there's none to be found in nearby junkyards. The next engine for me will be a v8, not another v6. Plus, I kind of like the 2.8! I also have a spare set of heads that I'll port eventually, so I'm not too worried about that.

Thanks for clearing up the "piston resizing" and "rod resizing" issues. I'd probably get new pistons anyway- does that eliminate the need for piston resizing? My GM service manual mentioned fitting pistons to bores- would that also be eliminated by using new pistons?

I was going to ask if I should look into ARP's wavelock rod bolts, but if GM can use normal rod bolts for big v8's, then they'd certainly be fine in my v6.

I suppose I need to hunt down those books and start reading, then flood you guys with my questions, eh? Thanks!


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

five7kid

iTrader: (14)

If you're getting new pistons, then it is best to get oversized pieces and have the block bored out for them. Either take the new pistons to the machine shop so they can final hone the cylinders for the proper clearance with the new pistons (and they need to have the pistons, at least one, to do this properly), or just buy the pistons from them. Unless you have at least one piston with a problem that warrents a new one, and the cylinders aren't worn at all, it doesn't make sense to buy new standard size pistons.

The advantages of buying the pistons from the machine shop are two-fold: 1) You might get a better deal on the total package (but that isn't guarenteed), and 2), if there is more taper than .020 or .030 inch oversize will take out, they can bore to the next oversize without you having to return the pistons and get the next oversize. This happened to me several years ago when the 8th cylinder didn't clean up at .040 over, and the shop had to go on to .060. I was getting the pistons from them, so it wasn't a big deal.

I understand your feelings about the 2.8. I had one in an '80 Citation (of all things), and it went over 250k miles (on synthetic oil) before the speedometer quit working. My brother had it by then, drove it for a couple more years before the rest of the car fell off around the engine. I didn't have any complaints about the engine.

TomP

Seeing as how I'll be rebuilding a junkyard engine, and not my own- Could I have them do work on the block, and -then- order whatever oversize piston I need? I wouldn't really have to order the rebuild kit until after the machine work's done.

Sorry to drag on and on about this piston clearance deal, but, I thought the scenario would go like this:

1. I bring them the block to be hot tanked, magnafluxed, bored, honed, press in new cam bearings, etc.. (is there anything else I missed? sand-blasted, maybe? Ah, that's not worth it, I've got a wire brush. )

2. They tell me they went 0.030 over to clean up the cylinders.

3. I order a rebuild kit with 0.030 pistons.

Would that be the end of it, as far as piston clearancing?

Hey did they just overbore the 8th cylinder? They had to do them all at 0.060, right?

Not that I don't trust machine shops, they'd do a better job than I, it's just that I'm funny- I'd rather do the bulk of the work myself; that way I get a little more satisfaction out of the deal. Plus I could brag about it! Thanks again!


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

five7kid

iTrader: (14)

It is possible to have the shop measure the cylinders to get an idea what overbore will be required. If the wear/taper isn't too bad, it shouldn't really be a problem. But, they really should have the pistons in hand before they do the final hone to get the clearance right. You might tell them the price you're going to pay for the kit, including all the part quality details, and see if they'll match it. They just might, and that would save you some hassle.

You'll want them to hang the pistons on the rods, too, by the way. Not a do-it-yourself job. If you have the heads done, the valve seals from the rebuild kit will need to be supplied to the shop before they put them back together.

One other comment you made earlier: You probably don't need wavelock rod bolts, but you should use new rod bolt nuts. They aren't that expensive, and are good insurance.

On that rebuild I mentioned, they didn't measure all the cylinders before they started boring - the type of mistake that shop wasn't known for making. When the 8th didn't clean up, they got the .060's and rebored all 8 cylinders. I was dealing directly with the shop owner, who built Pikes Peak-winning engines, and he was real cool about it all. Threw in the rod bolt nuts, as I recall.

I prefer assembling the engine myself as well. The one time I had one assembled, the oil control rings and rear main bearing were one size undersized. That did not make for a good-running engine.

Vader

TP,

The engine without heads and oil pan can easily be carried up or down stairs by two people. It would still be much better just to do the rebuild right in the kitchen, since the sink is a lot more convenient. The lighting is probably better there, too.

Seriously, if you don't have a garage in which to park a spare engine, you can strip the engine down to a bare case and rotating assembly, then hand carry it to a suitable destination or your pickup truck bed. A headless 2.8L V-6 should weigh in at about 250 lbs. (A bare CI SBC V-8 case is about 185 lbs. Add 53 lbs for the crank, 20 lbs. for the rods and pistons, then subtract 1/5 the total for the lack of two cylinders.) It will be a task, but two people can move one around fairly easily.

If you don't have a set of micrometers and telescope gauges (or an inside mic) you'll need to rely on the machinist to check all your dimensions.

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Later,
Vader
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TomP

Five7kid, Maybe I will buy the pistons from the shop... like you said, the prices should be comparable. I was going to go after forged pistons, but if cast units have lasted me this long, they should be fine! By rod bolt nuts, you don't think I should get all new rod bolts? Oh, well, I guess that drives the price up (installation), eh?

Vader, thanks for the weight info, and the kitchen tip. I'd be closer to the beer, too. Now I just have to rent a pick-up truck!


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

five7kid

iTrader: (14)

Unless you're going nuts with power adders like juice or huffer, the cast pistons should do you fine.

The rod nuts are softer than the bolts, which is why they deserve replacement before the bolts. But, I've had several engines rebuilt without replacing either. I didn't take any chances with the 396, though, the latest I've done, and had both the nuts and bolts replaced. The labor to replace them is next to nothing - I wasn't charged since I was resizing the rods anyway.

TomP

Well, the juice was a plan for later down the road. NOS claims the 2.8 can take a 90 shot, but most guys run a 50 shot instead. If the stock pistons were cast and can take the nitrous, new cast pistons should also be able to, right?

I replaced the pump in Summer of '97, so I know it's fine. Low (or no) fuel pressure is what kills pistons with nitrous, right?

Thanks again! I ordered the PAW catalog just to see what's out there for my motor, but looks like it'll take 4-6 weeks to get here. (I still can't believe I had to pay for a catalog- geez.)


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

TomP

Wow, I can't wait to get home! I found that "Rebuilding your GM 60 degree V6" book- the suckers out of print! I went to Barnes & Noble's website ( http://www.bn.com ) and found it under their "Rare/Secondhand/Out of Print" book suppliers. Oh it's by Tom Currao if anyone's interested. I didn't bother with Amazon books, those guys screwed up my account big time- long story, but forget them!


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
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