EXPERIENCED ENGINE BUILDERS : Come in!

[blcknspo0ln]

Ok, so where do I begin? Some call me a wiseman, but I'm an extreme novice when it comes to engine building. Sure I can assemble a full motor without even breaking a sweat, but the rotating assembly is a whole 'nother ball game. I need experienced engine builders to help guide me through the process and if you could, help me form an official 'build a shortblock' tech article that me & dsmtuners needs! I'll be sure to ask a lot of questions and I hope you guys can offer some brutal truth + advice to me. Where do I start?

I spun rod bearing #1 and trashed my entire cyl walls + crank to go with it due to low oil pressure.

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plenty of metal shavings:

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as it sits:

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I just picked up a virgin crank, so that is good to go. I also know I need to rehone the cylinder walls and along with that, get new piston rings for the set.

I am researching and soon will decide on a machine shop to go to, but for now, what do I need to ask the machine shop to do for me assuming that I want to assemble the short block myself?

1. Hot tank
2. Check surface for flatness, deck if necessary (shouldn't, just got machined 2k miles ago!)
3. Check/polish crank
4. Rods? Recondition rod #1; what else can they do to check the rods for usability? Check for roundness?
4. Pistons? How are the piston skirts fixed ?

If I tell the machine shop that I want to assemble this thing myself, what are the minimum requirements that the shop needs to do to make sure all of my clearances/tolerances are in check? If that something the engine builder (myself) would have to do?

I'll stop there and do more poking around, any advice would be great, especially if someone can give a clear, concise step-by-step on this topic!

 

[1992awdlaser]

I don't know about fixing the rods or pistons. So, I am not going to comment on that.

You will want the machine shop to measure the pistons and make sure the honing process isn't going to make the piston/wall clearance too loose. This will depend on what clearance was used when the engine was first assembled. If it was set on the looser side, then you might need to buy new/bigger pistons since the hone could take away too much material.

Make sure they use the piston with the 1 on top to meaure the clearance for cylinder one. Same with the other ones. Don't let them measure just one piston. When the engine is assembled again make sure the pistons go in the cylinder that it was measured for. I like to recheck the piston/wall clearance once I get the block back from the machine shop mainly because I don't trust any particular machine shop enough to just put the engine together.

Hope this helps some. Do you have more specific questions?

Also, 92awddsm is an engine builder. You might want to talk to him.

 

[Zack Huffman]

Where do I start?

Make sure you have all the measuring tools you'll need: a set of micrometers all the way up to 4 or 5", a good set of feeler gauges, a dial indicator with a magnetic base, expandable/telescoping and locking bore tool, a cam wheel, a straightedge, a scale and a really really good torque wrench.

I also know I need to rehone the cylinder walls and along with that, get new piston rings for the set.

Measure the walls for bore size, out-of-round and taper first, then determine how much of an overbore will be needed to correct #1.

I am researching and soon will decide on a machine shop to go to, but for now, what do I need to ask the machine shop to do for me assuming that I want to assemble the short block myself?

1. Hot tank

Check.

2. Check surface for flatness, deck if necessary (shouldn't, just got machined 2k miles ago!)

Check this yourself by laying a straightedge corner to corner (2X, -both ways) on the deck and using feeler gauges to see if there is any point where you can get more than 0.001" under it.

3. Check/polish crank

And balance it.

4. Rods? Recondition rod #1; what else can they do to check the rods for usability? Check for roundness?

Roundness of big end bore. Also check for con rod stretching by measuring center to center length. Replace the rod bolts if they're stretched. After that, have them weighed and ground until they are within acceptable specs of the same weight.

4. Pistons? How are the piston skirts fixed ?

They usually aren't. If the skirt is broken or badly marred, trash it and buy new. You may have to buy a new set anyway if you require an overbore. I would measure very cautiously what the skirt's diameter is. If it's not within a few thousandths of the others, I'd replace it. Don't skimp on the pistons.

If I tell the machine shop that I want to assemble this thing myself, what are the minimum requirements that the shop needs to do to make sure all of my clearances/tolerances are in check? If that something the engine builder (myself) would have to do?

I'd double check their work anyway. The main thing is the crank. Make damn sure you get the main journals within the correct clearances with the main bearings.

I'll stop there and do more poking around, any advice would be great, especially if someone can give a clear, concise step-by-step on this topic!

I don't know about step-by-step, but I'll try to help you as much as I can. I know it's related more to domestic V8 engines, but I recommend "The Engine Builder's Handbook" by Tom Monroe. One of the better engine building books I've read, I think it was like $30-40 at the local bookstore. Makes for interesting reading at least, if you're like me and are interested in these sorts of things.

 

[1992awdlaser]

Also, make sure the bore is measured in 6 spots of each cylinder. Top, middle, bottom, and 90* from where you measured initially.

 

[Zack Huffman]

^ Measure them parallel and perpendicular to the crank throw. That's where they will be out-of-round, front to back not along the long axis of the block. Definitely do not measure at 45 and 135 from the crank centerline, as these will not show true out-of-round. The bore diameters on the long axis of the block should be your reference for out-of-round and have the least amount of wear.

 

[iluvmy4g63]

make sure you get the crank caps align honed. this is very important.(if you up grade to ARP bolts) even an .001 in an inch'' outa round will place uneven load on one side of bearing causing premature ware. its about 90$. also having your con-rods magnafluxed is a good idea. its pretty much an x-ray of your rods to look for cracks.

 

[sb7775]

If this were my motor this is what i would do

Check the bore to make sure its still round. Check the main and rod bearing mating surface to make sure there is no damage. If these are ok i would hone the cylinders and measure them to make sure they are with in spec to use with your pistons. If its with in spec after the hone i would just install the new crank with some new bearings and file fit the rings to your liking and call it a day.

Now if the bore is out of round or the clearences are two loose (after the hone) you need to bore the block and get new pistons or find a new block for your pistons to fit. The pistons look aftermarket to me so i would try and keep them.

Steveb

 

[bluegs03]

To kinda help i wanted to put in my .02 and compile some of the info into one post people are giving ya.

First before you ever order any parts get some measuring done.
1st measuring. Measure cylinder's out of round, check with specs if outside of them you might need to go .20 overbore.
2nd measuring. Pistons, it sounds like they are damaged, if thats the case then dont reuse them, but if you think they are salvageable then measure piston diameter, on the skirt, out of round etc etc, and compare to specs

3rd Rods, measure the big end bore for out of round and diameter, if they are too much outta spec then replace that one. Just from looking at it, it seems that your gonna need a new rod on number one. Dont worry i got my rod for $15 (god that sounds dirty) anyway... rods are usually ok and reusable. Its mainly the bearings that get damaged. One quick way of telling is to see if there is any scratches on the actual rod cap.

4th crankshaft. Again it seems like there is a fair bit of damage to the crank but it might be salvageable. measure the rod journals for out of round and diameter, if they are too far out of round you can send it to a machine shop to get turned or you can buy a new one. I went through this dilema and ended up just getting a slightly used good crankshaft for $100. This depends on how much you have into your crank, if its an eagle crank then i would get it reconditioned because its cheaper than a new one. If its stock honestly it will be easier to buy a slightly used one. This would get you on the road alot quicker, but thats my .02

5th measure the block deck for warpage. Borrow a straight edge and a feeler gauge and go at it from 9 angles or as many as you can. Since its only got 2k miles on it, it should be fine but you never know.

Now of course you can have the machine shop do all of this for you but if you do it yourself you will save a ton of $$.

After you have done those measurements then you will know what parts are bad and what are reuseable. Then order all the parts you need and get that dsm back on the road! yeehaw!

 

[TSIfreek]

I would have gone with a good after market rod like scats or manley. Your problem was eather the cap wasnt assembled in the right direction or the rod was out of round. Guys forget all the time to mark the accual rod and cap (on the same side) before it is first disassembled so they go back on the same way they come off if not the caps get mismatched or they go on the wrong way or the wrong rod.
With how cheap you can get a new set of forged rods these days it doesnt make any sense to use the 1g rods any more. As race preping 1g rods costs around 250 anyway.
There is only one way a motor can go together any other way and the pics above show the outcome.

 

[blcknspo0ln]

I forgot to mention that these are a set of ross pistons and eagle h-beam rods.

front of piston 1 & 2:

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back 1 & 2 :

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front 3 & 4 :

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back 3 & 4:

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Thank you all for the information so far, it's a bit overwhelming to me right now considering I'm trying to take in all of the info posted and accepting the fact that hours upon hours of slaving over my car has been forfeited by either lack of luck or shoddy machine work. Unforunately, I was too trusting to check clearances when I had the block assembled during my build earlier this year. For now, I'm still trying to gather the funds and time to head to a machine shop to see what I can do or opt to have them do.

 

[mach4g63t]

I went to a little shop behind a local auto parts store that was recommended by a friend. He did the machine work to several blocks that made 500 fwhp on a SOHC setup and was running 10's. He did all the aforementioned measuring and machining for me and provided a list when done. All together it cost me like 280 bucks for the work listed above. Just make sure you drop off your pistons when you're having the machine work done. Saves a 30 mile trip back to drop them off .

I then took all my shiney parts and started putting them together. I cleaned the cylinders with isopropyl acohol (acetone works as well) until my clean white rags showed no more dirt at all. I checked my ring gaps several times, on all cylinders, at various heights in the bore. I plastigaged my connected rods on the crank as well as my main caps and ensured they all came out to spec. I also just made sure everything looked like it was made with qaulity and free of defects to the naked eye (chips, scratches in bearings, knicks in pistons skirts, etc)

The really awesome part is that we did this about a month before on a friend's engine (4g63) and with parts like Wiseco, Eagle Rods, and ACL bearings, everything was almost perfect right out of the plastic. We only double-checked for peace of mind; I did the same with my build. Ring gaps were good, bearing tolerances were spot on, really good stuff.

I was recommended to use the red engine lubricant (can't think of it, but you can buy it at Autozone for like 3 bucks), and it's nice and sticky and slippery. Also, for my initial break in, I was told to run Rotella T because of the extra minerals and stuff that aid in the break in process-- no synthetics for break in.

Other than that, it's pretty straight forward and just how everyone else has stated. You just have to build up the nerve to know that YOU ARE the one reponsible for what happens when your motor comes together. That means double-check everything, and if you're still uncertain, triple check it. Don't ever skimp. Take the tedious, monotonous time to plastigage all bearings. Other than that, it all just comes down to figuring out where those damn 'extra bolts' keep coming from.

Good luck.

 

[crimsondragon]

If you wanted the shop to polish the crank and have everything fit like the rod bearings, journals, etc, do you give the shop everything on the short block?

 

[Big Woo]

Something tells me you may need a little more work & parts.

1: your #1 rod that spun the bearing is most likely junk, even if you could have it reconed back to size the heat treat is gone, so forget about it and replace it. Verify that the other connecting rods did not get too hot, this usually looks like a light brown color near and around the big end of the rod.

2:Check crank for main and rod journal size, taper, and out of round. polish as necessary,ensure crank oil holes are well deburred, verifiy condition of thrust surfaces before doing any else to the crank. You may want to consider balancing the crank. Verify connecting rod widths and crank pin thrust surfaces to ensure proper rod side clearance when assembled.

3: There is some skuffing on your pistons, therefore you need to measure them or have them measured to verify their size. When piston skuffing occurs it is quite common to loose a piston or two IE replace. It is also fairly common for the piston to not look too bad, however measuring it will show that the skirt has collapased thereby screwing up the piston to wall clearance. (It is not reccomended that piston skirts be repaired).

4: The block bore sizes will also need to be checked, to verify whether a mild hone job will clean the cylinders. Often their is material removed from the cylinders when the piston skirts were rubbing, causing a wash out.

As far as the block and pistons go it is quite simple you need to maintain the manufactures reccomended pistion to wall clearance. A little checking with a mic and a bore gauge will tell the story very quickly.

 

[blcknspo0ln]

Something tells me you may need a little more work & parts.

1: your #1 rod that spun the bearing is most likely junk, even if you could have it reconed back to size the heat treat is gone, so forget about it and replace it. Verify that the other connecting rods did not get too hot, this usually looks like a light brown color near and around the big end of the rod.

2:Check crank for main and rod journal size, taper, and out of round. polish as necessary,ensure crank oil holes are well deburred, verifiy condition of thrust surfaces before doing any else to the crank. You may want to consider balancing the crank. Verify connecting rod widths and crank pin thrust surfaces to ensure proper rod side clearance when assembled.

3: There is some skuffing on your pistons, therefore you need to measure them or have them measured to verify their size. When piston skuffing occurs it is quite common to loose a piston or two IE replace. It is also fairly common for the piston to not look too bad, however measuring it will show that the skirt has collapased thereby screwing up the piston to wall clearance. (It is not reccomended that piston skirts be repaired).

4: The block bore sizes will also need to be checked, to verify whether a mild hone job will clean the cylinders. Often their is material removed from the cylinders when the piston skirts were rubbing, causing a wash out.

As far as the block and pistons go it is quite simple you need to maintain the manufactures reccomended pistion to wall clearance. A little checking with a mic and a bore gauge will tell the story very quickly.

Thanks much for the information. Rod #1 is definitely discolored, but the other 3 are OK. So you're saying reconditioning is not an option? Kind of like regrinding a crank, eh?

I'm going to the machine shop very soon to have them measure everything out for me. I guess their answer will determine what I need to get this shortblock put back together.

Oh, and thanks for the wonderful article here. It's exactly the information that I (and I'm sure others) have been longing for.

 

[DSMunknown]

That will grow to be a very insightful guide.