Boring-n-Honing, Decking, and Main Journal Honing

cgrey8 · Post by **cgrey8** » Fri Dec 07, 2007 12:48 pm

With my house closing approaching (set to Dec20th). If all goes well, I'll get my old house off my hands and can begin my 331 project.

So, one of the tasks is getting the block work done. Obviously to get to a 331, the bores need to be punched out .030" to 4.030" to 4.031" which requires some boring and honing. Is this something I can do or should I leave these tasks to a machine shop? I know I'll need plates bolted down to the decks during the process so the block is stressed in the same way that it will be with the heads mounted. I also know I'd need an inside-micrometer to measure the bore with. But I don't know the details like how far do you bore before honing. Without experience, I have no clue how long boring takes to know if it's a 5 min/cylinder exercise or hour/cylinder.

The only boring tools I've heard of being used in the shade tree shops are the ones that have the 3 arms with what look like grinding stones on the ends. A threaded rod adjusts the stone pressures on the bores. And a wrench turns the stones in the block to do the boring.

It seems I also recall a bore or honing tool that had something that look like blades and literally scraped the walls, but that seems more like a honing tool.

The honing tool I'm familiar with looks like a big brush that mounts in a drill. The tips of the brush have abrasive balls on the end that "polish" the walls out to the target diameter. To get the cross-hatching design into the walls, the drill must be pushed and pulled, moving the brush up and down in the bore creating as close to 45 degree cross hatching on the walls.

So my 1st question is....Is doing a bore-n-hone something I can do myself or should I leave this to a machine shop that has more experience and precision than I do? I don't mind buying the tools, even if it costs me more than the machine shop would cost me. I just want to know if it's worth the experience and the tools collection or is this something that I'd be better handing to someone else?

Next, given that this motor will be a daily driven motor, and not a high RPM application, how necessary is having the block decked and main journal honed? I don't expect to have the motor much over 5500RPMs...certainly not over 6000RPMs. As long as the block was in good condition to start with and ran the motor, is there any reason I should mess around with these additional, and somewhat costly procedures that I know I can't do myself.

Thoughts?

Dave · Post by **Dave** » Fri Dec 07, 2007 2:46 pm

Go with a machining shop all the way! Why not just go with a 331 short block from someone like Coast High Performance or D.S.S. all ready to just drop in? Sure would save a bunch of time and maybe money once you add up everything. Just an idea.
Congrats on getting the house off the market - Finially!
Dave

cgrey8 · Post by **cgrey8** » Fri Dec 07, 2007 3:03 pm

The plan is to buy another Explorer motor complete with accessories, brackets, and all the other stuff that comes on an Explorer motor. The intent is to have a COMPLETE motor when all this is done with, not just a long-block sitting on a stand. In addition, I want to make sure that what I end up with is identical to what's in the engine bay now since what's there fits. Also, this is an educational experience. There's no rush on getting this motor done. Sure I'd like to have it done as quickly as possible, but if it takes a year for me to get the spare time to get the motor apart and back together, so be it. But, I also realize that some things are just best left to people that have the equipment, tools, and experience since tooling myself with what it'd take would not be practical unless I was going into the business of doing that on a regular basis...and I have no intention of that.

So as it relates to boring, just take it in and have it done seems to be the consensus I'm hearing (not just from you Dave, but from others). But what about decking or main journal honing? I bring these up because these are services the machine shop is eager to sell me. But I'm not sure they are necessary for what I'm trying to do. I'm just looking for someone else to give me pros that are valuable enough to spend the money...money I'm just not convinced is necessary for a mild, daily driver 331. Perhaps these would be no brainers for a motor I planned to regularly perform at 6000+RPMs. But before I blindly made that decision, I wanted to get yall's thoughts.

Dave · Post by **Dave** » Fri Dec 07, 2007 4:05 pm

Chris,
For your intended use, if the motor is in good shape, I sure would'nt bother for the extra cost. You find another Explorer motor with all the front dress, you sure would have something to re-sell to help with the overall cost of the project when you are done. Then again, if you still have that other Ranger----------
Dave

cgrey8 · Post by **cgrey8** » Fri Dec 07, 2007 5:29 pm

The other reason is you forget/don't realize how addicted I am to driving my truck now that the V8 is in there. There's no way I could let the truck sit while the 331 was being built. Having a complete Explorer engine here allows me to do the 331 upgrade, take as long as I want/need while still driving the truck I have. And when it comes time to swap the motors, it can literally be done in a weekend since only minimal equipment would be need to be taken off my old engine to be put on the new (i.e. headers, wiring harness, engine mounts, etc). That alone is worth the cost of another engine to me. And there is the added detail that you eluded to; I have another Ranger...a 97 Ranger, which just happens to be the same year as the Explorer engine I have in my truck now. How convenient!

broncobowsher · Post by **broncobowsher** » Sun Dec 09, 2007 7:11 pm

You are not too far off from what I run. I do turn it a little faster. Usually shifting just over 6k and fuel cut set at 6600. But running a 3.25" stroker kit.

Boreing is a process that takes a cutting blade and carves chips off the cylinder wall to open the hole. Honing can be done with the 3 stones or the stick of balls. Best to leave it all to the machine shop. They will need to know what the intended application will be (street use) and the rings you are going to run to get the right piston to bore clearance and the right surface finish for the rings. Race engines are built differently then street engines which are different then marine engines, etc.

Align honing and align boring I try to avoid. just honing opens up the main bores and reduces the bearing crush (bearing crush is how well the bearing stays in the block and how well it transfers heat into the block). Align boring trims a little off the main caps then it is bored and honed back to correct bore for the bearings. But this process moves the crankshaft up into the blck just a little. This alters deck height and more importantly the the crankshaft to camshaft center lines. Since the crank is now closer to the cam the timing chain will be looser or if you do timing gear set it will be tighter. 5.0 blocks are not that speial, if the crankshaft bores are off, scrap the block and get another one.

The other machine shop work to consider is decking the block. This will affect the compression ratio and the quench of the heads. There are a few other things that can occur ranging from but not limited to valve to piston clearance, pushrod length, port alignment. My block is zero decked (.010" removed to place the top of the pistons at the exact same height as the top of the block). I can't mention what if any changes it caused as I am running aftermarket heads with special pushrods anyway.

I would find a machine shop, talk with them about what you want. Get the parts and show up with everything. They should be able to do just the machine work all the way up to a full long block depending on what you ask for.

cgrey8 · Post by **cgrey8** » Sun Dec 09, 2007 7:32 pm

I don't mind putting the engine together myself if it'll save some money. But I also want to be clear of the parts I'm just not going to be able to do myself so I can include them in the budget. So far, the machine shop has quoted me something like $225 for the block bath, bore-n-hone out .030" (to 4.030-4.031"), new cam bearings, and new freeze plugs. I've gotten the impression from others that this is a little on the high side so I'm probably going to look for other machine shops in the area and get them to price it out.

So decking the block is or isn't something you recommend? The GT40p heads are already a fairly high compression head at 59-60cc. Then add to that the added compression of another .25" to the stroke, I'm not sure I really need anymore compression. BUT you bring up a good point. It does improve quench which improves the efficiency of the burn by avoiding detonation...I think. So from that standpoint, does decking the block make sense for the added cost? I can't remember what the machine shop quoted for decking.

As for the journal honing, I'll completely forget about that one. I didn't even think about the crush or lack of that honing the journals and caps would do.

87sc302 · Post by **87sc302** » Sun Dec 09, 2007 10:35 pm

Chris,
I like you wanted to do some of the engine assembly but not having all the tools and equipment I found a machine shop through a mechanic friend.

I had him assemble the short block and degree the cam. I installed the remaining components myself. That was about 6 years ago. About 2years ago I did the same with a Toyota 22r engine.

Good shops are hard to find but are usually known the by local mechanics. They cannot afford reworks.

Putting money in the rotating assembly by an expert is money well spent.
Just my 2 cents.

cgrey8 · Post by **cgrey8** » Mon Dec 10, 2007 2:11 pm

Well, I called around and found a guy that's a fair drive from where I live, but comes highly recommended. He's far enough away from the city, his prices are considerably lower than what I'm getting around here. Do these prices sound fair to yall?

$120 Bore&Hone .030" ($15/cyl)
$40 Block Bath
$25 R&R Cam Bearings
$100 Deck
$250 Complete Short block assy (labor only) where I supply all the major parts

87sc302 · Post by **87sc302** » Tue Dec 11, 2007 7:59 pm

Chris

From what I remember the prices seem to be reasonable

A good check on a machine shop is usually his backlog of work. The better ones usually take alittle longer to get work scheduled.

Larry J

cgrey8 · Post by **cgrey8** » Tue Dec 11, 2007 8:02 pm

This place's backlog averages 10 days turnaround they said.

Dave · Post by **Dave** » Tue Dec 11, 2007 8:34 pm

Price sounds good to me, I'd have to dig up what I paid last time. Remember, if he is highly recommened, that's worth some money also. Checked on the price to do the heads while you are at it?
Dave

cgrey8 · Post by **cgrey8** » Tue Dec 11, 2007 9:33 pm

Yeah, the consensus has be unanimous that bore-n-honing has to be done professionally.

The head work I'm not as concerned about. The only part of the head work I'm concerned about is replacing valve guides. The valve seals look pretty straight forward as well as removal and install of the valves themselves. But it will take a decent spring compressor to get them on and off. If I can't get them to compress right, I may be forced to get the machine shop to do that too. But I'm hoping I can do something myself.

plowboy34 · Post by **plowboy34** » Sat Dec 29, 2007 9:51 pm

Absolutely take it to a machine shop for boring. It is a very very important job and must be perfect.

As far as line boring or honing it is really not necessary. Especially if you have no intentions of rapping it out. I have rapped 289 to 7K with over 250,000 miles on the block and never had them line bored. Just really not an issue.

Personaly I would never deck a block unless absolutely necessary. If you just wish to up compression just do it with pistons. When you start decking anything you start changing all kinds of alignments and adjustments. They can be overcome but takes more money and time.

I agree with 87sc302 on the backlog as a good sign of a good machine shop. Really so if they are in an area that has a few shops around. Do not judge it on the looks of the place though, when I was in Sacramento, Ca. I used a shop that looked like a hole in the ground and the guy's looked like serious dope heads. I mean they looked rough, but these cats could work up an engine. I sent several people there way who would not drop there stuff off there. They would call me back and ask me if I was sure....LOL. I would assure them so they would take it back. When they got there engine back they would call and say WOW.

Prices are all OK. As far as the assembly though why not do it yourself. Satisfaction of building it and a nice experience. You put gears in a rearend so I know you can put a engine together. Just take lots of pics as you tear it down just in case you need to see how something was. Main advice I will give you is cleanliness is second only to Godliness when assembling an engine. I have no doubt you can assemble an engine.

Glad your house has sold, that has to be a serious load off the mind. Along with everything else you have had on your mind. Speaking of which how are we doing?

cgrey8 · Post by **cgrey8** » Sat Dec 29, 2007 10:22 pm

plowboy34 wrote:...Glad your house has sold, that has to be a serious load off the mind. Along with everything else you have had on your mind. Speaking of which how are we doing?

It was supposed to. Turns out the purchasers have financing but their landlord renigged on his agreement to let them out of their lease early. So we still have an agreement. But we'll have to wait until they run their lease out before we can go to closing. Fortunately, it's only 3 months. But still...anything can happen between now-n-then. So it's back on hold.