mikeage2

well i spent weeks making sure al my tolerences were right,made sure eveything was super clean and lubed.it ran for 150 miles then started knocking(thrust loose on mein bearing.I tore it all back down,and all the bearings are down to copper already.I dotn know if the mechine shop didnt clean out the oil passages enough or whatever.
My crank is bad now(scored up,there went $200)im going to have the block hot tanked AGAIN and new cam bearings in AGAIN,etc.
How hard is it to make a stroker out of this thing?its a early 70's 350,2 bolt.i know i can buy a crank cheap enough.Can i use the 6" rods,or do i have to buy 5.7 inch rods?can i use my trw forged pistions,or do i need "special" 383 pistons?DO i have to machine the block any or will the crank clear on the sides?I know somebody else has built a 383,i just want to know what im getting into.i hate to buy $700 worth of crank+rods to find out i could buy a whole kit(crank,rods,kb hyperutectic slugs,rings,bearings,balancer,etc) from summit for $899
PLEASE HELP IVE ALREADY SPENT 3K ON THIS MOTOR ONLY TO HAVE IT BLOW UP IN MY FACE

EO273KiD

Wow, good timing, I was just searching the message board for 383 info. Someone please hurry and give him info!

burnoutrpm

a 383 350 block .030 over with a 400 crank(or a aftermarket 3.750 stroke crank) if you use a 400 crank have it turned down to 350 mains use 5,7" rods with a special 383 piston.or you can use any 350 piston and use a 5.5" rods an 400crank. or use 6" rods and speaical 383 6" pistons all of these ways are correct but the 5.7 rod is the easiest way to go

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89 firebird formula


360 10:1compression (350 .060 over)/fully balnced and blueprinted
comp cams xe262 cam
performer rpm intake/port matched to heads
#1405edlebrock 600
sportsman 2 heads 64cc 2.02/1.60 valves 200cc intake runner/cnc pocket ported
msd 6al/msd8.5 super condutor wires
h.e.i. proform 50,000 volt vac. advance ditributor
700r-4 with 3.08 first gear and 3.23 posi 7 5/8 rear end.
b trans shift kit(will kill shifts...suck dong!!)
shorty heddman hedders with custom 3" pipe y-pipe back(no damn cat!) with 40 series flowmaster!
griffin daul1" core rad.cutom fabrication to fit(but no cutting )


future mods: 406 roller REALLY REALLY REALLY RADICAL!!!!!

RB83L69

This happens all the time. It's a combination of everybody in the chain trying to cut corners and save money and work, including the engine's owner (you). Most shops who don't do race work, but only stock repair type work, will tank a block with the cam bearings still in it, and let the tank eat the bearings. Meanwhile, all the passages in the block that are full of metal particles from the last 3 times the motor blew up, stay full of metal particles. Then they stick the cam bearings back in and deliver the block, full of metal, which you can't see and don't even suspect because it's all closed up and looks nice and spotless on the outside.

Piece of advice:

Take your block to the machine shop. Have them do whatever they do to it, and return it to you with ALL plugs removed and without cam bearings. Then take it to the car wash; buy a can or 2 of engine degreaser (diesel fuel in a spray can), and a gun cleaning kit and some rifle brushes (.22, .30, and .410 shotgun bore size are about right) and clean out every single oil hole with the cleaner, then spray them all with the max blast. Use a small (toothbrush sort of size) wire brush, also available at the gun shop, to clean out the groove behind the cam bearings. Then take it back to the shop and have them put the cam bearings and plugs back in.

Putting a stroker crank in that block isn't going to fix the problem you've got, especially if the same shop does the block work. It will just eat that one too. Clean the motor up right no matter what crank you go back with, or pour more money down the drain.

[edit:] They will protest innocence, tell you all about how they do this all the time and it always works, that it's unnecessary and a waste of time, they've done hundreds of motors this way and had no problems, etc. Ignore them. If they persist, remind them whose money is paying them, and that they are being paid to follow instructions, not to argue. If they still refuse, take your business elsewhere.

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"So many Mustangs, so little time..."
ICON Motorsports

[This message has been edited by RB83L69 (edited June 25, 2001).]

mikeage2

Ok i know that....i was going to have them do everything and them i was going to clean all the passages out(buying oil galley brushes...i have a pressurewasher.i will spend a whole day cleaning it all out a bunch of times,I DONT EVER want to do this again!!
Ok,i found out i have 5.7"rods now.so i need:
1 383 crank for 350(new,made by eagle $280 new!!)
8 .060 over special 383 pistons
So i can use my 5.7"rods?????
will this rotating assy clear the block,or does it need to be ground out in spots?
?????????????
thanks all for the info,im sore this gets asked all the time...oh and when i first got this motor it had a spun rod bearing,and they linebored,bored out,and decked this block..and SUPPOSEDLY cleaned the oil galleys like hell(obiously not)
i changed the oil 3 times in a 150 mile period,and it obiously still want enough...in not a hack,i didnt build this in a pile of oil dry either....i washed my hands before i worked on it,and kept everything super clean!!
thanks all for the help

Grand Prix

Did you wash the crank and its passages before dropping it in? The oil on them can collect dirt, and no matter how clean the block is as soon as you light it up its all over. Crank could also have been turned wrong and wipe out the bearings in a short time. I don't buy in to the trash in the oil passages idea completely. 150 miles is awfully fast, like wrong bearing size fast or something. Who turned the crank? Maybe it wasn't straight or round. Both would kill the bearings fast, and could easily slip by plastigauge or even a few quick mic checks.

5.7" rods for a 400 crank are the way to fly. 6" rods get in to your rings, bad idea for street motor. Block has to be ground to clear, not a big deal. 383 pistons are not factory but far from special these days, getting to be almost as many as 350 pistons. Rods have to be ground too, they'll get in to the cam unless you use a really reduced base circle. Also need a 400 flexplate and damper since they have counter weights to help balance the engine. Then have it all balanced by a real machinest.

[This message has been edited by Grand Prix (edited June 25, 2001).]

mikeage2

i got a reman .010 under crank from cloverland(now out of business,imagine that).it was clean but i cleaned it more,all the clearances were checked by me with green plastigauge,and were dead on.i did it right.either there was metal left in the gallies or in the crank passages where i couldnt see.the thrust was .011,but if i got a .010 over thrust bearing,the clearance wouldve ben to tight.ive seen motors alot looser and still run fine for a long time(got another 350 with 300k and .040+thrust and it didnt make noise and ran great.Of course not its really tired(can you blame it?)

RB83L69

Like i said, I've seen this happen all too often... somebody trusts the machine shop to do a good job, but the shop takes the lazy way out.

Grand Prix's description of what to look for when building a 383 mostly covers it. One thing that can be added: if you decide to go with longer rods, it becomes possible to use a balanced crank, which means you can use a regular 350 balancer & flywheel or flex plate. The reason for the unbalance situation is that the factory wanted to avoid compromising the longevity of the ring package in the 400 by either moving them up too close to the top of the piston, or locating them too close together, or using narrower rings, or by having the oil ring overlap the piston pin (all of which occur in a 6" rod / 400 stroke application). So instead, they left the pin height the same as a 350, and shortened the rod. But when they did that, there was no longer enough room between the bottom of the piston and the crank centerline when the piston is all the way down, to accomodate enough counterweight. The counterweights are of course directly opposite the crank throws that they counterbalance. So they are "up" when the piston is "down". With the piston coming so far down into the crankcase, it doesn't leave enough room for them, they have to be shaved off at a strange angle. So they used the external balance method. With 5.7" rods and a slightly compromised ring setup, there's enough room to fit enough counterweight, so the crank will internally balance without Mallory metal. You can buy a pretty decent crank for fairly cheap these days, already set up right for that, from Eagle and others. In fact I have the stock 400 version of the Eagle part in my 400 right now, ext bal, but it's a pretty decent piece as far as I can tell.

You will have to grind on the block for clearance, and probably on the rods and/or rod bolts for clearance to the cam. Stock 350 rods often require considerable grinding. Some of the cap-screw ones, as opposed to the bolt-and-nut stock style, are narrowed down enough in the right place to where they'll fit.

If there's metal in the oil passages, no amount of changing the oil will fix it... when it's already in the block, downstream of the filter, it only has one way to go in order to get out: through the bearings. I'm as near positive as I can be without actually seeing the block that that's what happened to ou, as I mentioned about blowing up before this build; you confirm that in fact that happened.

"The simplest explanation that fits all the facts is usually the right one"
— Occam, c. 600 B.C.

Better luck next time! Get a cam bearing tool, and then you can have the shop deliver you a totally stripped-down, tanked block, and you can take it from there.

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"So many Mustangs, so little time..."
ICON Motorsports

mikeage2

ok cool my rods are srom summit...stage2( i think0 rods with arp bolts ansd the rods are all polished and the end caps have a polished flat spot on them.(so thelyy clear the cam i hope?) where do i need to grind on the block,so i can do it now(cleaning and honing it tommorow)
thanks all
mike

mikeage2

Ok thank god,i was working on my motor at work,and one of my co-workers told me he used to build 383's all the time...he showed me where to grind with a little carbide burr on a die grinder....took me about 1/2 hour to do...if i can figure out how mabye il post a picture so you can all see.
mike