Welp, my little mild slant was running the best it ever had... for a whole 1.5 hours.

Last Friday, Dad and I re-adjusted on the valves(they were clattering a little) , played with the springs in my distributor, and bumped my advance from 6* to 8*BTDC. We also installed my new AEM wideband.

That night, it ran a little better, but had a bog off idle, and an exhaust leak that was throwing off the o2 reading. The next morning we fixed the leak and fiddled with the idle adjustments, got it in the low-14s. It ran great! We had jets to install (was bogging down real bad when the power valve opened, has 61 jets, I ordered a set of 56s) but it was running so good I decided to put it off (had a 12-13 afr, which I thought was a little odd, figured it'd be richer).

I then needed to run some errands, so I decided to take the Dart. On the way to Sedalia (30 mile drive) I was running it a little harder than normal; ~3500rpm running down the road. When I got to the first light in Sedalia, I noticed it was running REALLY poorly. Missing hard, wanting to die, popping through the carb some, and puffing a little smoke. I limped it across town, and parked it. I then did what I needed to do, came back and hour later, hit the key...

And blew the valve cover off in one big cloud of smoke.

The picture don't really do it justice. If you look closely though, you can see it pulled all the bolts through on the lower side.

I called the emergency dad hotline and asked him to run to town and bring me my spare off of my old motor. We then limped it across town to my uncles shop. After fiddling with it for several hours, and gaining no ground other than the fact that the problem was with the front 3 cylinders, we limped it back home.

After letting it set a day, I thought maybe we had adjusted the valves too tight. Sure enough, the front 2 were a hair tight. Fixed that, ran a compression check, and had 130-135 on all cylinders. Except for 3 that is. 3 didn't even wiggle the needle, and you could hear it wasn't compressing at all. We threw the air to it, it blew back at us from the galley.

Over the next few days, we got it to our shop (Yep, I still drove it! ) and last night we got the engine pulled out. Here are the findings:






And I got ahead of myself and cleaned the aluminum off of the head before I took a picture. You can see how all the others were running pretty rich. Another note is those plugs aren't the same plugs that were in it. We changed the plugs and put the 55 jets in as well, for grins. Looking back, that was bad for throwing in variables.

Here are some others misc. casting numbers and such. This engine befuddles me, as it is a late 70's motor (unsure of actual year, possibly someone could decipher that from this) and has the narrow rod journals, but the crank rings as clear as a bell when tapped with a hammer. I know MoPar made a forged crank for the cast crank block, I thought it was in the racing manual but I can't seem to locate it.






All I've heard that could cause this is too lean and detonation. I can't imagine it was too lean, judging from the other cylinders, and I can't imagine 48* of timing would cause it to detonate like that (8+18 mech+22 vac) UNLESS the mark on my balancer/timing tab is off and I have a lot more initial than I thought. I'd hate to get it all put back together just to torch another piston. If that happens the car will sit for a VERY long time...

Here are the specs for the engine:
3.4" bore, hone and re-ring
OCG 819 cam, ground with 4* advance
.030 off the deck, .020 off head
I was shooting for 9.1:1, I think I'm around 8.8. I will remeasure before I do anything more though.
I did some minor bowl porting/valve guide narrowing, stock valves
Aussie Hurricane w/350 Holley
Dual Dutras w/ 2" dual exhaust
Stock 904
2.76 in an open 7.25

Here's my parts list of things I have:
Std Sealed Power pistons with moly rings (RockAuto was having a sale, $5 a piston and $43 for the rings, +5% coupon code)

I figure now's the time for upgrades, here's some things that have crossed my mind:
I've got my head to a local fellow who does some reasonably priced port/polish work. I'll most likely use stock valves still, as he don't seem like he would like to install new seats. I also re-used the stock springs. Bad call? Any recommendations for better ones?
I've just got a stock stall converter, it didn't really seem to start pulling HARD till ~2700rpm. I would like some more stall, and really some more gears, but I don't want to sink much into either. I figure, short tires (21/22"? ) might be a cheap alternative to gears, along with sticky tires. Ain't figured the converter yet.
I re-used the original harmonic dampener the first time around. If I'm wanting to spin it to ~5500rpm should I look into a new/aftermarket one? For some reason I think the BBM uses the same balancer, am I wrong? Would the TDC mark be the same?
I didn't have the rods 'reconditioned' last time. What all does this consist of? When does it become necessary? Same with new rod bolts (ARP or stock style), when are they needed?
Balancing and such is good, but would it be worth the cost for the gain I'd get on my fairly mild build? The guy that is doing my head also does all of his own balancing. Would it be something worth looking into?
I think I'll have some more taken off the head (unless I end up pulling the crank out of the block, then I'll most likely take it off the block) to get me to the 9.1 that I was shooting for. Unless that .3 ain't worth the trouble?
What about a windage tray? Don't worry about it? I think I'll put some baffles in the oil pan, I don't think it'll launch hard enough to uncover the pickup, but I would rather be safe than sorry. I don't want to pull this motor again for a few years...
Alright, last one. Would adding a small carb spacer be worth anything on that big ol intake? Would a 2 hole spacer give a little more low end, or would it be simply adding to plenum size? After reading on the H-Pak and ram tuning, it makes me wish the runners were actually a little longer so I could take more advantage of that. Bowling and Grippo says That is, if I remember correctly that head+intake runner=15". The highest I'd ever spun it was 4500...

It was runnin so good, I'd like to get it running like that again or even better, but without the whole blowing holes in the rotating assembly part, ya know what I mean?

Thanks to all who've read this novel didn't know it would end up being that long... As you can see, I need all the help I can get!

Ouch!
That sounds festive…
What is the stamped engine ID number?
Not a reliable test for forged vs. cast crank.
None such, don't believe so.
Those are two prime suspects.
Single-cylinder vacuum leak will make one cylinder run too lean.
New ones (plain or fancy) are available and don't cost too much.
Yes, it's not the same.
Checking for cracks, checking for bend, checking big and small ends for dimensions and out-of-round, grinding rod end and cap mating surfaces and reboring as necessary.
After one pulls apart (i.e., not usually).
True. The better everything's balanced, the smoother the engine will run and the less stress it'll put to itself.

Also, if you quit using those "brand orange" oil filters you'll reduce your odds of having to go back in and do the bottom end again.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Im sorry for your troubles. I dont know what causes the hole in the piston. I did do the same thing you did with your valve cover though. My number 4 had a hole as well and the fuel mix with the oil. I hope you dident do to much damage to where the cylinder needs sleeved.

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~Nic

Sounds like fuel from that hole entered the crankcase and when you hit the switch it lit off and blew off the valve cover.

Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

...sounds right, I was trying to figure in my mind how that happened, it must have been an explosion of high volume to warp and discharge the valve cover like that - gas in the crankcase detonated by the spark plug in #3 via the hole in the piston...wow, sorry for your woes..

I wonder what it would have looked like if you had a cast valve cover on there...

brian

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https://tinyurl.com/yynpj4v2

If you were running it with gas in the crankcase for very long it may have signs of wash down. This usually happens when you're car is flooding and gets too much gas in the cylinder i.e. it washes down from the top of the piston and this can cause undue wear on the rings and cylinder walls. I suppose the same effect can occur when there's gas in the crankcase. So, it's not likely just #3 that has issues...if you're already planning to swap out the rings, hone the cylinders, etc OK, but if not you should at least pull another piston and check the rings. Wash down has tell tale signs of beveling/wear on the edges of the rings. Check the oil from the crankcase if you may see thousands of little bright metal specs in the oil, a pearlescent effect, they are very small.
brian

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https://tinyurl.com/yynpj4v2

I had an piston look like that however it was #6. I had a crack in the brake booster hose and ran #6 lean but the others were good, if you still have the intake gasket you might look for evidence of a leak on #3. if you find it you will know what happened and know what to watch to keep it from happening again. Could the hold down washer seat on the exhaust have been a little thick keeping the nut from putting enough pressure on the intake runner? Or could the washer have been sitting crooked? Poor clamping, then a lean backfire in that cylinder could have blown the gasket way out of place.

If I'm wrong I'm sorry, not trying to put anyone down. I just think if I find the cause it is easier to avoid it in the future.

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Dave

1977 d-200 crew cab ex-army pickup wants it's /6 back
1962 Valiant 2 door, 170, three on the tree
1972 d-100 parts truck
80 volare wagon now a parts car

Ha. One of the many things that I did the first time and now regret. If it's the numbers stamped on the machined part of the deck that you are referring to, I believe I had the block decked before I made record of such. If there is record of it somewhere, it is in a very safe place
I wondered such. Very well could be a cast crank then. Not that it matters either way, they each have their pros and cons and either would work well for me
Ah. I guess I should've said 'I think so'. Not the first time I've been wrong!

Thought of this. And as nuttyprof pointed out, the intake gasket not sealing possibly could've caused such. Visual observation shows nothing out of the ordinary that I can detect, though it isn't quite ruled out.
Ah. Further research reveals an OE style made by Dorman or Pioneer Automotive. Not much details though... Care to specify? Part number maybe? Plain and fancy offerings?
Yeah... That was something I forgot to mention. We also changed the oil last Friday, and in a moment of... well, stupidity, I grabbed one of those 'brand orange' things. Downgrade from the WIX I had. And, surprise surprise, my oil pressure was noted to be oddly low when all of this happened. The real bad part? That wasn't even the first time that had happened to me. After break-in, I pulled the filter and put on a... you guessed it, orange filter. Within a day I had pressure problems like I just had. Where I normally have 50psi@2000rpm, it took 3000rpm to make... 30psi. The rest of the low rpms were uncomfortably low at around 10psi. The bearings looked fine on #3, we'll see how the rest are.
That's what I've come up with as well.
I'd hope the cast would hold together enough that another weaker link would break. Either way, its gonna be the cover, oil pan, or filter. I'm happy it was just the cover and that I have a spare.
Plan on replacing all pistons and rings, honing all cyl too of course. That was part of the reason I ordered the smaller jets. Inspection of the rings is in order, right after deck height is measured and recorded.
My thoughts exactly. If I can find the cause of the problem, I have a better chance of fixing said problem to prevent it from repeating. This is why I like this forum, a very knowledgeable group of people to run thoughts and problems past.

Oops. Well, maybe you'll get lucky and find numbers stamped on the (distributor) side of the block -- some engines had stampings there starting in the late '70s.
Dorman has a generally good reputation, but many of their hard parts are overpriced Chinese shtuff I have a hard time paying a high price for. I'd sooner buy a PowerBond Australian-made unit or a new OE item (they show up from time to time on eBay with prices ranging from reasonable to stupid). There is also the super-nice steel Romac unit from Australia, but most of us don't come close to needing one, and they're very costly.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Well, I called up the fella who's got my head, and he didn't have much good to say.

He says the valve guides are shot, and it needs new seats. Since it needs seats, he figures might as well put bigger valves in it as well. Sure, I'm alright with that, I was wanting to do that from the beginning. His idea of bigger valves though... 273 valves. When I ask him isn't he worried about it fitting in the stock bore, his reply: "Nah, it's 1.78 and yours are 1.6 somethin. Shouldn't have to worry about interference as it's only a couple of thousandths."

Now, I ain't ever done nothin' similar to this before, but I've done a bit of reading. From my understanding, 1.78 is a rather large valve, and even if it doesn't interfere, it'll be crazy shrouded, no?

Which brings me too... what is the best sized valves for a stock bore? engnbldr valves? 1.72 Chevy valves? A mixmatch combo of any of the above? (1.7 intake, stock exhaust?)

Also, he relies on Dynomation 5 pretty heavily I think. Using the specs from my cam card, and a little of my input, it said... 93hp@crank (me thinks something was put in wrong). According to him, he put CompCams 264 cam specs in there and it magically jumped to 183. Oh, and a 600 4-barrel because 'that 350 ain't squat'.

Another thing, he sez head work and cam specs are completely independent, how far the valve is off the seat isn't valve lift, retarding a cam produces torque while advancing produces power, amongst other things that don't seem to quite jive to me. But he's a GM master tech and has built 600+ hp 327s, so what do I know

Should I run the other way as fast as I can? I can tell you I certainly don't think I'll have him do the balancing, or anything else for that matter. I am starting to question his porting abilities, even though he's got a flow bench. I asked for before/after numbers, so maybe I'll be able to tell if something's way off.

In other news, RockAuto sells PowerBond dampeners. I plan on getting one of those, and possibly some valve springs. Still waiting to pull the trigger on those. Bought a 23-2500 stall torque converter. Payed way to much for it.

I'm trying to fab some way to measure deck height. Bought a degree wheel, and seen it had a dial indicator in it. I thought 'Great, now I can measure the deck height as well!' Problem is, its a 'head-on' kit, so I'm trying to figure out how to make it work. Any tips/ideas will be greatly accepted As of a rough measurement it appears I have ~.150 height. More than the .130 I was hoping I had. We'll see how the head CCs before proceeding. I think I remember it ~53 when I first put it together, but double checking will let me know for sure.

Another interesting note: the Federal Mogul replacement pistons are shorter than my stock ones. Approximately .020 so. So I probably will need to shave quite a bit more off. We'll see.

I agree, but my assessment is of the quality of his advice, not the condition of your cylinder head.
Entirely possible.
Not necessarily unreasonable, but do be careful of feature creep.
How come?
"Couple" means two. The difference between 1.62" and 1.78" is one hundred and sixty thousanths. For a slant-6, the smart money is on 1.70" intakes and 1.44" exhausts. Such as the ones Engnbldr sells.
Don't let him talk you into a Comp cam.
Way too big.
Bulk wrap.
Bulk wrap.
Piles and puddles and lakes and rivers of bulk wrap.

This guy's a clown. Smile, nod, retrieve your parts from him and go elsewhere.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

One of the items people tend to forget is that long ram manifolds aren't necessarily efficient in certain ways. Until it's heated up to get the proper fuel air mix at the cylinders the carb has to run a bit richer than that same setup on a short runner manifold...this can lead to fuel puddling in the plenum and sometimes you can "slug" the cylinders with a load of fuel until the engine and manifold are warm enough to keep the fuel vaporized....even then fuel sometimes will run along the runner walls as a liquid and only lean amount gets to the cylinder...when you shut the engine off and all that fuel drops to runner floor, or runs to an open valve, the engine can be hard to start up again due to being over rich...this also can wash down the cylinders causing wear. I noticed that with street driving the hpak manifold, the O2 sensor preferred to be a little on the rich side always to keep things happy, and if the carb was adjusted to be more in the "normal" range that the readings while driving after proper warm up tended to be on the lean side all the time....

I would check the manifold with a machinists edge to see if all the runners are "flat"...with casting being what it is, sometimes one runner is a little off compared to the others, even on a "good" early clifford hyperpak casting I had my machinist take a scrape to make sure the mating surface was all good, but still used a composite gasket since the exhaust manifolds expand adn move at a different rate.

Back to your subject at hand:

Dynomotion is an OK program, but unless the guy using it has hard data from flow benches and drag runs (and hands on a few slant builds to understand it's not a V-8 and it's not a Chevy), his variables will be set up for a V-8 and not very real world for your engine....(Sure you could get that engine to run on a 600 cfm carb...it would work best with only 2 barrels, and streetwise your mileage would be about 10-11 mpg....).

You would have lots of shrouding with those size valves...I would procure a set of engnbldr valves off ebay....at 1.70/1.44 they will work fine for street and strip. (1.78...since you didn't pull the pistons and scibe the bore outlines on the head bolted to the block, with the std bore and any core shift...if the lift is enough and the edge of the valve hits the deck...you will be parking the car for a long time to save up for another go at it with a competent machinist....You also have to watch porting the runners, if you take a lot out of the ports you could loose velocity of the air/fuel going through the runners at lower rpms...which will not help you on the street...given that you are using a relatively mild cam, it will not take much to improve the flow and keep it streetable and make mo-power.

I would very much be concerned if he's plugging the numbers and not giving you a DCR calc for quality of fuel to use, and if cylinder pressures are within reason...I could use the COMP 264 with a 12:1 engine and all the trimmings..and it will calc at 250 hp at the rear wheels...but I will need a fuel that costs about $9/gallon to keep it from pinging, and in dialing the advance back to keep that from happening, I will lose some power and lots of mpg.... so be warned...

If you are porting and degreeing the cam, and adding O/S valves...all these are "adders" and you get more out of them if you can raise your compression to something higher, but without turning it into a diesel engine...you need to get everything put back together and have 9:1 or better to start seeing benefits of this...that being said...once you go better than stock on a cam, the engine will have a higher rpm power/torque band...so while this is all going on...the 2.76's need to go...all the 264 equipped engines I've driven in the 9:1 SCR area liked to "come on" about 2000 rpm... (the Comp 252 comes on a little off idle...).


And no he's very backwards from all the Hot Rod GM cam articles written in the past...advancing a cam opens and closes the valves earlier...which gains low-end torque earlier in the rpm band...good for street driving and heavy vehicles....retarding the cam opens and closes the valves later, which shifts the engine powerband higher in rpm, and gains you horse power (awesome if you are running a NASCAR race at 7K on the clock)..... Torque = launch, and HP = top end power....so I'm going to say you might get your head and find an old timer bread and butter machinist before this yo-yo screws your head up....and costs you some real $$$....

Cam and compression are interrelated, head flow can be interrelated to cam lift and duration (if the port flows, you might get "more" if you leave the valve open longer or lift the valve higher...which also can change how the engine acts with rpm band, idle quality due to "overlap"...it can also change your required timing curve to light the spark at the right time to make the most efficient use of the "boom" for more power).

Valve lift is valve lift...be it, that there are really 2 numbers to work with the lobe lift... which is the amount of rise comparing the base circle of the cam lobe compared to the peak of the lobe when the lifter would be at max lift....valve lift is actually lobe lift times the rocker arm ratio...so if the lobe catalog says the lobes max lift is .300, and your rockers are a 1.5 ratio...the .3* 1.5 = .450 lift at the valve (plus or minus lash on mech cams, and variance in rocker arm manufacturing...)....so if you went all hot rod and used a set of 1.6 RAS rockers the lift would than change to .300 * 1.6 for a .480 lift (and a change in push rod geometry, and duration possibly, but lift is always lift...)

You can get a machinist's edge and use it as a straight edge to check your block deck for "flatness", for degreeing and as a piston stop on a block without a head I get a piece of angle iron that is smooth, drill 3 holes in it (two outers to bolt it to the block where the head bolts go diagonally across the bore, and one in the middle to put a short bolt in place to act as a piston stop....this configuration should also leave enough room to set up a magnetic dial gauge holder so you can check the deck height and piston travel....withe piston stop you can set the degree wheel then remove it to run the #1 piston up to TDC, and check your deck height.

Another item of concern is your bores...if they need to be rehoned, and you are going to do it yourself, make sure you get a good hone and the correct stones for it...with moly your final passes will be with a fine grit hone....the last one I did I tickled the bores to get the finish back, but I also invested in a dial bore gauge as I tend to be a meat fisted blue collar worker with the 1/2" drill...I could easily have wiped out my bore taper just going to town listening to some Led Zeppelin and plowing the 80 grit stone through the bore without paying attention....if uncomfortable with the operation some machine shops will ask for a small fee to chuck the block up and break the glaze on the bores and refinish them since they aren't having to tie the machine up for a longer amount of time doing a full over bore....if you have a set of calipers and inside bore gauges, I would check to make sure the bores are not egged while the pistons are out.

Good Luck,

-D.Idiot

Nice write-up DI; it's going in my "engine stuff" three ring binder.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I know it's a lot of info to digest (distilled from a book case of bedside readers, and hands on experience and working with some very open minded machinists who took the time to explain the whys and hows).

Most importantly, I don't like to see a member get hosed by a guy making a quick buck off him, and does not know standard engine theory. And every bit of shared education and knowledge does not go to waste here. My post isn't highly encompassing and definitive, and do encourage others to comment if something is a little lacking....

Use in good health.

Yes, I do have to reign myself in sometimes, as every once in a while I catch myself having that problem. Which is why I now have an Aussiespeed intake when and adapter on the supersix I had would have done me almost as good most likely. But hey, $300 is a steal, and if it looks cool, it must make more power, right?
I'm assuming because Chrysler made them, and he found them in one of his old manuals (Motor's Auto Repair Manual maybe?)
Yeah, I've read enough to know that in no way shape or form will I get any cam from Comp. He then tried to tell me that my cam must be nothing more than a late 70's stock cam, just because the power number it put out was on par with the late 70's slant power.


Yep, called him today to tell him to cease all work on my stuff, that I've changed my mind. I'll be out to pick up my parts as soon as possible. Thank you guys from stopping me from following through with something that I was beginning to think was questionable, before I ran up a bill!

And thanks D.I. for the post, even if you felt it was long winded. Long posts like that have gobs and gobs of information in them, and are the stuff I like to read!

I didn't realize at the time of purchasing my intake that it wasn't the optimal intake for street use. It was more of 'Wow! Go fast exotic lookin part for half price!'. Live and learn I suppose. If I wanted to come into ownership of an Offy, I've got an old Carter on a shelf off of a 273 Commando. It may be around 450cfm, just something I'd like to experiment with sometime after I get tired of my current junk. I would have saved a bit financially and time wise if I'd went that way right off the bat. Now that I've got what I do, I reckon I'll run it for a while and tinker with it.

I've read of your adventures with a street h-pak, and while I can't say for sure, I wonder if my hurricane ain't a little better warming up wise than a h-pak. Take this with a grain of salt now, as mine was running pig rich, but I didn't have too much grief with cold starts. I also didn't drive it below freezing conditions as well. I haven't recorded how long it takes to warm up per say, and I don't know just how hot the intake needs to be, but I'd say the intake gets to be 120+. The intake also is more wide and less long, I think it sets over the exhaust more as well... And while I did have a problem with it smelling nauseatingly gassy, it wasn't to often it gave me much trouble firing back up shortly. Cylinder walls also appear to be alright, hone marks still visible. I'll have to ask around and see if I can get a valid second opinion on that (whilst weeding out the clowns in the area)

Huh. It never occurred to me to check if the intake was flat. I just eyeballed the gasket and seen it appeared to be sealing alright. Something I will certainly look into.

'Hard data' HA! You mean like the 'Low Performance/Stock Ports and Valves' setting? (Unsure if that's what it's called on Dyno5, that's what my Dyno2000 calls it and he used what I would call the equivalent of such). If his is like mine, the worst option still flows 196@.500, nowhere close to what a slant head actually flows. And thinking back, I'm not too sure he wasn't talking about some 600cfm 2 barrel.

After realizing that I was most certainly going to want a compression bump. I know you had said 9.1-9.3 before, I figured I'd try to reach the lower end of that spectrum with 9.1. After this incident, I'm going to be taking extra precautions. Mainly, I think I'll be setting my timing more towards the conservative side, less toward wringing every last bit out of it, and quite possibly paying a little more for 89/91 octane. I consider it cheap insurance if it helps prevent what I accomplished.

The gears are something that I know is a sore thumb, and they are reserved for the dumpster, but that's a bit down the road unfortunately. I'd like to go LBP/discs/better rear axle/higher spring rate/better shocks all in one fell swoop. This whole incident has taken a chunk out of the budget that was building for that though, so it appears it will be farther off than I hoped. This situation will be worsened in the near future by the fact that the 265/50/14 (24.6"?) rear tires are in dire need of replacement, with nothing similar being offered anymore that I can find. The replacements will likely be an inch taller. All in good time I s'pose...

The bores I had checked out and a final hone put on by a somewhat-local machine shop. I had only planned on doing a light re-hone myself. Now, I'm not sure what I'll do. The block may be at the machine shop anyways, if so I may just have them do it.

Which brings me to... I'll be going back for another scrape for some more compression.
1. Is it better to have the piston farther down the bore, and a smaller chamber, or vice versa? (as in, shave it off the head or block?)
2. How much can I shave off before I start to worry about pushrod length?


Thanks All!