knock knock

[dodgedifferent2]

whos there?

i was tinkering away and driving the dart all last week when all of a sudden a knock started. At first i thought i may have wiped a lobe on the camshaft:doh:
but i noticed the header was touching the frame so i reworked the pipes to clear the frame.

I started up the 340 again only to hear the knock so i decided to take off the intake to check the camshaft. Everything looks awesome under there so i was somewhat happy :giggedy:

With the view from a local ex dirt track racer who built his own engines. He suggested i drop the oil pan again.
I did and i found all kinds of metal flakes in the bottom of the oil pan :doh:

Now the scary headaches begin :doh:

I am planning to pull the engine out of the dart so i can work on the engine stand instead of on my back.

I noticed the connecting rods that are stamped with the piston number and two of them seemed to be swapped. Number 4 is in the #1 position and the #1 is in the #4 spot. Could this be the culprit? or is that just minor?

now the day dream (sometimes turn into nightmares) Depending how the crank looks should i just go 416 and use the heads i have till another day? or replace all bearings and keep it 340? Have i messed up a connecting rod?
I have only drove the 340 for about 40 miles:hmmm: and whatever restoman ran it for.

I know i have some digging to do so see what is up. (will come later)

what is your thoughts and views with a 340 vs 416 or 372 and mostly stock J heads with 2.02 intake and 1.6 exhaust

 

[Dr.Jass]

You don't have enough cylinder head. Even with maximum porting done by a professional shop, you don't have enough cylinder head. Very few people make a cylinder head that will support a stroker small-block, and you probably don't want to pay that much. Edelbrock, etc. do not fit the bill, no matter how much you have them ported. The intake pushrod will always be in the way with a production-pattern rocker arm. Think W-series, and maybe the Indy heads that use their own specific valvetrain. Now start pricing all that, and in the case of W-series heads above W5s, have fun figuring out the valvetrain and intake you need. Confusing is an enormous understatement.

Easy way to tell if you have enough cylnder head for a stroker LA/Magnum: If it accepts a production-style intake rocker arm, you don't.

Period.

Next!

I have not seen a LA-based stroker with production-pattern rockers to date that I've felt warranted the expense in either horsepower or torque output. I am actually considering a stroker engine myself, but I also have a set of '70s vintage B1-BA Pro Stock W2 iron heads in my garage. I've mentioned it 10 times previously: My buddy runs very-low 11s (best of 11.03) with a stock-stroke, X-head 340 in a 3,500lb. '73 Duster... on 92-octane pump gas... with a dual-plane intake (RPM Air Gap). That's on 10.5" slicks with the exhaust uncorked. In street trim, 11.6x. Stock crank, rods, ported X heads (your Js are actually a better start), etc. His only concession to being "unstreetable" is 4.56 gears, and he doesn't have nitrous oxide either.

Stroker LA/Magnum engines with production-based cylinder heads are for dumb guys with small dicks who want to tell people how big their engine is instead.

 

[68R/T]

Boil the block to get all the metal out, check cam bearings for scoring, turn the crank as needed, resize #1 & #4 rods, install in correct holes.....simple....:huh:

Having pistons in the wrong holes is a time bomb, yours just had a short fuse. :doh:

 

[v8440]

Here, put a set of those on there. That'll shut his ass up about not having enough head. Oh wait, wrong engine family.

 

[Dr.Jass]

The stamping on the connecting rods is factory. If the stock pistons were still in it, yes... be afraid. If not, well, putting the #1 rod in the #4 hole is no big deal since the chamfer would still be facing in the correct direction. That's assuming of course that someone who paid no mind to the stamped numbers on the rods paid attention to a less-obvious detail like, I dunno, which way the chamfers go. :doh:

The more that happens with this engine, the more I'm convinced it needs to be pulled and completely gone through, to your specifications, top to bottom. Tales like this are why I never take a seller at his word on an engine, and I much prefer to just start with a core and build it myself, be it a hack job like my 360 or full-tilt no-expense-spared buildup like my 340 will be. At least I know what I did.

 

[Dr.Jass]

Here, put a set of those on there... Oh wait, wrong engine family.

Yeah, no kidding. I'm fairly certain you could chuck an X head through one of those intake ports.

 

[v8440]

Speaking of that engine, hopefully the aluminum block has had the 2 retarded sleeves cut out of it. 2 were 4.600" bores, the other 6 were for 4.5" bores. I should find out tomorrow whether the machine shop has done that, and hopefully figured out what sleeves it will actually need. It should be a good combo, a 572" motor that's about the same weight or maybe less than an iron smallblock. Ok, /threadjack

 

[restoman]

...and whatever restoman ran it for.

I never ran it... in fact it wasn't even in a car since I got it.

I'm pretty sure Perfection Engines by the old shop did the short block assembly - he's always been pretty careful on his machine work and assembly. ? My former friend/employee did the rest of the assembly.

When I got it, it needed a crank and two main caps replaced. He sized mains and caps, as far as I know. I don't have a copy of his invoice anymore.

Shit Man, sorry you're having so many issues with this. I would have sworn that engine was good to go.

 

[68R/T]

...... putting the #1 rod in the #4 hole is no big deal since the chamfer would still be facing in the correct direction. That's assuming of course that someone who paid no mind to the stamped numbers on the rods paid attention to a less-obvious detail like, I dunno, which way the chamfers go. :doh:

.....or if he paid attention to the notch on the piston designating front. That would put the chamfer wrong and also the offset of the wrist pin.

Even with the chamfer in the right direction the offset of the wrist pin would be incorrect. But then again, if the offset was correct the chamfer would be wrong. :hmmm: Just can't win, can ya. :huh:

Like Doc says, time for a complete tear down.

 

[dodgedifferent2]

tear down is in the plans.

Just have to get engine out on the stand and have some spare time to tinker

 

[Dr.Jass]

.....or if he paid attention to the notch on the piston designating front. That would put the chamfer wrong and also the offset of the wrist pin.

Even with the chamfer in the right direction the offset of the wrist pin would be incorrect. But then again, if the offset was correct the chamfer would be wrong. :hmmm: Just can't win, can ya. :huh:

Like Doc says, time for a complete tear down.

If the chamfer was correct, the mark would be incorrect (and vise-versa). Of course, you're also assuming factory pistons and even then forgetting that the piston can be reversed on the rod in seconds with nothing more than a pair of snap-ring pliers (all 340s have full-floating pins). Very few aftermarket pistons have either the notch or the corresponding pin offset. Even then, getting the pin offset/notch wrong is no big deal. It's there only to quiet the engine, and in fact an old racer's trick was to reverse all the pistons on the rods so the notches faced backward. There's a slight power gain there, believe it or not, with the negative effect being noisier engine operation (piston slap). It certainly wouldn't cause any sort of catastrophic failure.

Regardless, it needs to come all the way down. With the new (to me) information about the main caps, it absolutely, positively needs to be line-honed. That's probably why your bottom end is failing already. It's a cardinal rule: When you don't have the original main caps, no matter how much you check, measure, etc. it simply must be done. If your chosen machine shop can't do it, find a new machine shop.

 

[68R/T]

Well, apparently, whoever assembled the engine wasn't paying much attention to details, seeing as he put a couple pistons/rods in the wrong holes. :huh:

 

[dodgedifferent2]

i would be safe to assume they are new pistons since they are .03 over pistons.

 

[Dr.Jass]

That was my thinking as well, but if they're stock-replacement cast pistons they may have the offset pin. If so, they should have the notch. You'll know as soon as the heads come off. If you're really lucky, you might not need to bore it but don't make any assumptions there until you run a hone through it, even if it's a 3-stone type you use in your drill (use low speed and move it up and down fast to maintain a correct crosshatch). Minor scratches are one thing, but if you can feel it with a fingernail or see a low spot then it's off to the boring bar. If you have access to a dial bore gauge, for God's sake use it!

I would not re-use those pistons, no matter how new, in an engine about which I gave a damn. You've obviously got bottom-end problems and Lord only knows what undue stresses were imparted on those pistons. Unless they come out of the bores looking like they just came out of a box, I would consider them scrap. If you're ordering replacements and have to bore it, try like hell to get .040" over rather than .060", for a couple of reasons. First, at .060" you're actually losing power to cylinder wall flex. This has been proven, even though the engine runs fine at .060". More importantly, .060" is as far as you can go (it's already outside factory-recommended spec) and leaves no room for future work should it be needed. .040" is not an uncommon oversize but it's probably not in stock, either, so you may have to wait. To me, it's worth it. I only wanted to go .020" on my 340, but it added hundreds of dollars to the piston price so I went .030".

I know machine work isn't cheap up there, but believe me you do not want to skimp on this. It's worth every penny, even if you have to ship the block across the border to have it done within reasonable pricing. Obviously you need a shop that can align (line) hone it; make sure that shop also uses deck plates in the boring and honing process. If not, keep shopping.

 

[restoman]

Pretty sure the owner previous to me said they were forged slugs, at around 10:1 compression. ?

Also reasonably sure the caps and block were line honed, but without the receipt, can't say for sure...

 

[Dr.Jass]

At this point, I would assume nothing you were told about that engine is true except that it's a 340... and that's only because I assume someone along the line looked at the side of the block.

 

[restoman]

I got it from XL... pretty sure he wasn't fibbing me.

The machine work... well, who can say?

 

[Dr.Jass]

Oh, well you should've said that earlier. :doh: I don't doubt XL's word one bit... I just wonder if he was being fed false information.

 

[68R/T]

... I just wonder if he was being fed false information.

That could happen to anyone. Hell, I could feed Doc a line of pure manure and have him relay it to someone else. :toot:

Not that I would ever do that though. :liar:

 

[69.5CUDA]

this is why i wont let anyone assemble my engines...atleast if i screw up i know who to blame..but even better..i know every thing about the build