SLANTY BLUES

-
I wish I had something positive to contribute.

I guess if it was me I'd carefully check the block deck and head surface for flatness. Check the fit of a new head gasket and give it another try. A lean condition is not good.
Sounds like you pushed the little engine pretty hard with sustained 70 mph cruise, pulling a load through hills and she got a hernia. I did that lifting a refrigerator by myself.

What rear gear are you running? 2 of the race car tow vehicles at the Clay City race were slant powered so it can be done.

I'm really surprised Big Daddy didn't throw a 392 Hemi into it overnight.


i have 3.23 gears. I'm kinda surprised they let me part it there overnight. I wish he woulda made me an offer on it ! LOL
 
Certainly possible, when you list all the factors;
Heavily loaded, hilly terrain,towing,lotsa frontal area pushing air, very high cylinder pressure, pumpgas, hot-running,automatic,
unknown rpm and timing.

There is nothing wrong with running a hi-Scr......... at part-throttle. Because your Ecr (Effective Compression Ratio) is usually still well below the detonation limit of the pumpgas you are using, and at the rpm and load settings being experienced. But as the load increases, you have to increase the throttle opening to maintain speed, which increases the Ecr, which might or might not still be below the detonation limit of the gas.Eventually tho, if the carb size is big enough, the detonation limit will be found.
This limit can vary with rpm and load, and timing.
It is possible for an engine to approach the limit several times throughout its rpm band. It is possible to ease the level of detonation with performance gearing, or to keep it in detonation with too low an rpm , or to put a bordeline engine into detonation with too-high a water temperature, or with a head that cannot shed heat fast enough, or with a poor chamber design, or too much timing.

So yes, before you bolt that head on, you probably want to recalculate the Scr, and more importantly, the Dcr which will require you to know the ICA (Intake Closing Angle).
Dcr is what the engine sees..... at WOT.
Scr is how we build the engine to achieve that Dcr.
Ecr is what the engine sees at any/all throttle settings other than WOT. It varies on a moment to moment basis with load,rpm,air density, and your bolt-ons.
That last one is very important. The root cause of Detonation is too high a temperature in the chamber. Remember that only about 1/3 of the energy in the combusted fuel makes it to the road. Another 1/3 goes out the tailpipe as heat, and the final 1/3 goes into the cooling system, and into the airstream as heat.
So you have several ways to deal with detonation, in a combo that is predisposed to it.
If you put a tiny carb on a hi-Dcr engine, the load might never get high enough to spawn detonation. Or if you put headers on it and a free-flowing exhaust perhaps that exhaust system will get rid of the heat fast enough to allow a bigger carb. And last is the cooling system; bigger is always better, and remember that the thermostat sets the MINIMUM water temp, and limits the coolant circulation by the size of the effective area around the pellet mechanism. And don't forget; tha automatic is pumping heat into the lower tank, sending it's heat straight into the waterpump.
And of course ignition timing. But this is a two-edged problem.Taking timing out reduces the power, and the engine has to work harder, creating more heat, possibly putting the engine into worse detonation. Sometimes more is less; more timing might create less heat.
____________________________________
I like as much cylinder pressure as I can get away with because it makes the engine much more responsive when transitioning from one output level to another, and because the engine is more efficient, burning less fuel at steadystate, and because it makes more power at part-throttle settings.
But the key is getting away with it.
I build my personal engines with what I always think is too much pressure, and am prepared to run an anti-detonant injection system. So far I haven't had to .
The cam's ICA for me, has been the pressure relief system, for the most part.Also; a lightweight car with a big engine and easy gearing, and a total lack of traction reduces the load drastically.Plus My engine operates at 930 ft plus/minus about 100 ft ; I live on the prairies. This makes the tune easy, and limits the load. The manual trans puts no additional heat into the cooling system. The easy gearing lets the engine spool up faster, reducing the chance of detonation. Twin full length 3" pipes take care of the exhaust heat. And the cooling system is Rock-solid. And the engine gets cool fresh air from outside the engine compartment.All these efforts plus aluminum heads allows my engine to live at 185psi and more, on 87E10.


To answer some of your questions : I had the valve lash at .012 and .022. I didn't find my rockers worn. I am running an auto trans ,but it has it's own cooler. I have a 160* thermostat in it and once it's warm it runs around 190* A good clean radiator new 6 blade water pump. Stock exhaust pipe to a 2 1/2" muffler (free flowing ). The 1920 holley has a 54 Main Jet I think,Maybe a 56 . I ordered a new head gasket today. Cleaned and checked the head and cylinders up. I didn't find any cracks but there seemed to be some "flecks" of metal on the cyl walls above the piston travel. Cleaned that all off. The plugs showed no flecks. I pulled the starter off to check the ring gear and starter drive for missing teeth, all good there. AJ I've been going over your info Thanks again. Here are a few pics of the gasket and #1 piston. Let me know what you think. AL
Gasket was ok on #1 piston. 5 & 6 is the ones melted and pushed.
20181024_165629.jpg


20181025_151759.jpg


20181025_151815.jpg


20181025_151820.jpg
 
I see multiple problems.
In this pic, is the firering burned thru? or was it torn at removal?
20181025_151820-jpg.jpg

In this next pic, the cylinder beside it, there seem to be two issues, a burned thru firering and reverse failed area, which I assume happened at teardown?
20181025_151815-jpg.jpg

So I bet those burned thru areas are next to, or close to, the exhaust valves.
In any case, the compression pathway between cylinders is clearly visible.
20181025_151759-jpg.jpg

So it looks like those two were clearly failing before the compression failure between them happened.
Now, look at those little 1/4 inch holes between the cylinders, do those have corresponding holes in the heads?
Do you have a catch can plumbed to your rad overflow, and was it empty when it overheated?
Next look at the gasket imprinted on the deck. Did you use the proper torquing sequence?
Ok lets look at the pistons; Is that #1 the only one with carbon on top? What happened to the carbon on the other 5?
Can we get a pic of the head, showing the exhaust valves in #1, and also of #6,
and/or 5, plus the area between 5 and 6, with a teensey bit more lighting. And a pic of numbers 1 and 6 plugs showing the porcelains.
How does the hot air from the rad get out of the doghouse? and is the carb forced to breath that hot air?
About what rpm were you running at? If no tach, can you measure the tire diameter or just give me the size so I can estimate the rpm at.....did you say 75mph?, indicated or actual? I'm estimating 3200rpm. Do you have a clue what the advance was at 3200rpm?
Don't put this engine back together just yet, please.
 
Last edited:
Nice van, and I will tell you this,,
I tow a 15 second 1/4 mile drag race only 68 Barracuda, slant six powered with a 83 D150 also slant six powered and have never lost a head gasket on either.
I can average 15 mpg towing with the D150, slant with a a833 OD and a 3:73 rear gear.
Don't want to get into the 68 B motor, but the 83 D150 slant has been on a chassis dyno and turned 148 hp at the rear wheels.
I set it up for low rpm torque, small cam, 212 @.050, 8.5 static compression, 2 bbl carb, dual dutras with a very tuned and free flowing exhaust, I have a Casper Electronics detonation sensor that has proven to be very predicatable.
Static compression is 185+ and I run regular gas when not towing. The detonation sensor will light on long upgrades.
When towing I run a good grade of premium fuel, BP or Shell, the detonation sensor does not light on upgrades.
And I have pushed it hard, towing through the mountains, no head gasket issues. I did use the Mahle head gasket.
I am a retired automotive engineer, on a side by side comparison, I thought the Mahle head gasket looked a little more robust,
but I have no test data to support. I am also very critical on deck flatness, cleanliness and bolt torque.

B1.jpg
 
I see multiple problems.
In this pic, is the firering burned thru? or was it torn at removal?
View attachment 1715239908
In this next pic, the cylinder beside it, there seem to be two issues, a burned thru firering and reverse failed area, which I assume happened at teardown?View attachment 1715239910
So I bet those burned thru areas are next to, or close to, the exhaust valves.
In any case, the compression pathway between cylinders is clearly visible.
View attachment 1715239909
So it looks like those two were clearly failing before the compression failure between them happened.
Now, look at those little 1/4 inch holes between the cylinders, do those have corresponding holes in the heads?
Do you have a catch can plumbed to your rad overflow, and was it empty when it overheated?
Next look at the gasket imprinted on the deck. Did you use the proper torquing sequence?
Ok lets look at the pistons; Is that #1 the only one with carbon on top? What happened to the carbon on the other 5?
Can we get a pic of the head, showing the exhaust valves in #1, and also of #6,
and/or 5, plus the area between 5 and 6, with a teensey bit more lighting. And a pic of numbers 1 and 6 plugs showing the porcelains.
How does the hot air from the rad get out of the doghouse? and is the carb forced to breath that hot air?
About what rpm were you running at? If no tach, can you measure the tire diameter or just give me the size so I can estimate the rpm at.....did you say 75mph?, indicated or actual? I'm estimating 3200rpm. Do you have a clue what the advance was at 3200rpm?
Don't put this engine back together just yet, please.


AJ I will get some pics and post them ASAP along with the info you need . Thanks.
 
are you re using stock style head bolts? with that much milled off do you need a washer on the head bolt? I know with mine milled a total of .125 I ran arp studs.
that way the bolt bottoming out before full clamp force was not a question.
 
I'm no expert but I'm thinkin' you pushed it too hard with too much weight . Also, with .080" milled off did you use .080" shorter pushrods ? suggestion: if everything checks out o.k. and you didn't hurt anything consider using a marine head gasket .
 
I'm no expert but I'm thinkin' you pushed it too hard with too much weight . Also, with .080" milled off did you use .080" shorter pushrods ? suggestion: if everything checks out o.k. and you didn't hurt anything consider using a marine head gasket .

No, I reused the stock pushrods. With the rockers being adjustable I figured they would be good .
 
You can make the adjustables work,right up until the pushrod hits the arm and gets spit out. But you lose lift and duration cuz the geometry is screwed up. You can prove this with a dial-indicator and a degree wheel.
But worse is the side-pressure this puts on the valve stems, and the guides, perhaps wearing them out prematurely.

EDIT;
See posts 39 and 40 below.
 
Last edited:
You can make the adjustables work,right up until the pushrod hits the arm and gets spit out. But you lose lift and duration cuz the geometry is screwed up. You can prove this with a dial-indicator and a degree wheel.
But worse is the side-pressure this puts on the valve stems, and the guides, perhaps wearing them out prematurely.

I do not have a catch can on the radiator. On torquing the head down I snug them down@ 45 # starting in the middle and working out left and right, then again @ 75 # I believe was what it's was. ( what ever the specs were that I looked up)

The dog house just gets fresh air from through the grill, The van still has the sheet metal underneath to direct the air through the radiator and dog house. NO cool fresh air to the carb.

first thing I did was pull the plugs.( I had already drained most the coolant out the petcock .)
spun the engine over with the starter, 2-6 spit coolant out, didn't notice any out of #1 (?) Which might explain the others being cleaner. #1 is more burnt looking than carboned up. (Note the white specks at top of piston).
20181026_121147.jpg

Here are the plugs #1 - 5 -6
20181026_103017.jpg



20181026_103039.jpg

20181026_103111.jpg

and the head
20181026_103505.jpg
20181026_103512.jpg
20181026_103602.jpg
20181026_103713.jpg
20181026_103751.jpg


These last 2 are with the gasket. No hole in head as in gasket. The push spot on the fire ring I believe was from comp. Head came off easy.

I had the timing at 10* at idle don't remember what the full advance was at. I remember on the original engine I had it at @34* full advance and wanted this new engine lower, maybe it was around 30*. Let me throw this in the mix, I also installed a Oregon Cam everyone recommended .Not much , but thats all the specs I have on it.

I'm going to drop the oil pan and put new rod bearings in while it's down. I didn't like all the hydrolocking going on while trying to load the van the day I towed it home. And I'll check the push rods for clearance . Thanks AL.
.
20181026_122008.jpg
 
Last edited:
Did you clean those chambers .or is that the the way it came off?

In post 35, the very first pic, of the piston, it seems you are calling #6, yet it appears to match the one that you previously identified as # 1 in post #27, and that I can clearly see in that post as being the frontmost #1 cylinder.I did notice the flecs in 27.
So I'm confused
From the headshots,It's clear to see how water got into the #6 chamber, and how it could have transferred over to the #5. But numbers 2 thru 4 are also steam cleaned,
#1 sparkplug looks normal but rich.#5 and 6 are glazed from overheating, too clean, and appear to have traces of aluminum on them. Go back to #27 and look at #2 piston, see that brown trace at the bottom around 7 o'clock ? Roll that piston to the top, push it up as far away from the cylinder wall, and check that top land. And any others that might have such a brown discoloration.
Are you running a vacuum advance?

Ok, my guess is the decks are not flat, and are too smooth. I think it all started with a bit of detonation, and the clamping force could not keep the gasket in place with the super high cylinder pressures, the pressure lifted the head and it escaped into the cooling system, where it blew some water out and this started a chain reaction.
First you saw the steam, pulled over, and shut down. This allowed water from the higher pressure rad to now escape into the cylinder(s). After it cooled down, you added water, and hit the starter, at which time the engine had to battle the water out of there. Then for as long as you had it running with water running out of the tailpipes, steam-cleaning was going on.

This is my OPINION, I could be wrong.
But if I am right,
there are at least two pistons that have lost some aluminum.
there may be 5 bent rods
you need to check the deck and the head for flatness, in every direction, and probably re-machine both a little rougher.
You need to figure out your exact Static compression ratio at the time of the failure, and figure out a way to reduce the Dcr/cylinder pressure, so this doesn't happen again.
Then you need to fix your cooling system. You have a 30* rise from minimum running temp of 160, to a running temp of 190, before pulling a load; your system was in compromise before you ever left home.
Then you need to feed your carb fresh cold air. By it's being in that hot doghouse in an overheat situation, your engine became a thermonuclear meltdown machine.

IMO
you need to pull every piston (but specifically 6 and 5) outta there and find out where those flecs came from and if the pistons are still usable.
And you need to check your camlobes. If the intakes are going down, this will decrease your ICA, increase your Dcr, and subsequent cylinder pressures. And it might only take a few degrees in an already high Scr engine.
And in the end you are gonna need to know exactly what your timing system is doing. Your carb seems fat but close to right, but impossible to tell for sure with those plugs.
This is my opinion.
Feel free to invite others to chime in. These kinds of failures, we all like to try and figure out.

Now, just to ease your pain, I took a a bunch of metal off the top of my 1977 block,and head, totaling about .100; and installed it into my car in 1994, with less cam than you have,(and therefore an even earlier ICA), and it is still motoring around today, with nearly half a million kilometers accumulated (that's over 300,000 miles to my American friends).
It's only money........
 
Last edited:
I don't understand how the pushrod length would effect the side-load on the valves since this is a shaft mounted rocker. rocker to valve contact is unchanged. I do agree it does effect the total lift due. mine has .125 taken off and im just squeaking by with the stock pushrods. will probably order a custom set in spring just because.
 
I don't understand how the pushrod length would effect the side-load on the valves since this is a shaft mounted rocker. rocker to valve contact is unchanged. I do agree it does effect the total lift due. mine has .125 taken off and im just squeaking by with the stock pushrods. will probably order a custom set in spring just because.
If the cam was unchanged then You are correct that side remains the same. It is only the pushrod side that is slightly messed up. And on a slanty, this doesn't seem to matter as much as on a small-block.
Thanks for the correction. Previous post edited, please excuse my ignorance.
 
Alrighty then, . Thank all you guy's I will disassemble , check it all over, regroup , and go from there.
 
I agree with:
1)getting cool air to the intake to make pre ignition less likely.
2)measuring piston recession, chamber cc and getting a real grip on the static and dynamic compression.
3)checking for too smooth head gasket surfaces, bent rods, blown pistons,,,
 
I agree with:
1)getting cool air to the intake to make pre ignition less likely.
2)measuring piston recession, chamber cc and getting a real grip on the static and dynamic compression.
3)checking for too smooth head gasket surfaces, bent rods, blown pistons,,,

I have new rod bearings ordered. When i get the pistons out I can check your #3. Just had this block and head machined.
yea I've been want to get something for cold air induction. Need to find a 1 barrel snorkel air cleaner if they made em.
And all this compression ratio talk is over my head. as is all the detonation , preignition. Once i get it all checked out and get all this info deciphered into something I can understand I'll put it back together. LOL. Thanks AL. By the way your pick up is nice. I used to have a about 4 or 5 older ones.
 
Al I may have a snorkel air breather, yours for nada, what is the carb diameter?
Good luck.

I have new rod bearings ordered. When i get the pistons out I can check your #3. Just had this block and head machined.
yea I've been want to get something for cold air induction. Need to find a 1 barrel snorkel air cleaner if they made em.
And all this compression ratio talk is over my head. as is all the detonation , preignition. Once i get it all checked out and get all this info deciphered into something I can understand I'll put it back together. LOL. Thanks AL. By the way your pick up is nice. I used to have a about 4 or 5 older ones.
 
Al I may have a snorkel air breather, yours for nada, what is the carb diameter?
Good luck.
Steve I measured my air cleaned. Heres the scoop.
Hole in the base plate for the carb is 2.35" or 2 11/32"
Outside DIA is 9 1/2" could be a little bigger but not much. Thanks bud.
 
here is a link to a static compression calculator
RSR Static Compression Ratio Calculator

the BR site also has a dynamic compression calculator and other useful info.


This is what I came up with on SCR. Looks low enough to not be a problem. The dymanic C R ( not sure if I calculated correct) came in at 7.57 .

Bore
3.43
inches Diameter of cylinder
Stroke
4.125
inches Distance piston moves
Head Gasket
thickness
.040
inches Measure your head gasket tthickness. It's usually 0.040", but not always...for example, on K1200 BMWs it is 0.070". On 113/135" ORCA motors it is 0.00 because they use metal seals and no head gaskets.
Deck Height
.17
inches Move piston to TDC, and measure the distance between the flat top surface of the piston (not the top of a dome or the bottom of a valve relief) and the top of the cylinder. Enter a negative number if the piston's flat surface sticks up past the top of the cylinder. At TDC the piston will "rock" so be careful in your measurements. ORCAs are .035".
Piston top
volume
0.00
cc's You'll have to calculate this value the hard way i.e. do it yourself or call the piston manufacturer. Enter a negative number for a domed piston. Enter a positive number for a dished or dimpled piston. If you have a flat piston with no valve reliefs enter 0.00.
Combustion
Chamber
63
cc's Get out your 100ml burette, your light, non-nasty grease, your handy dandy plexiglass or lexan sheet, your Marvel Mystery Oil and a six pack and get ready to party. Don't forget to cc the combustion chamber.
Static Compression Ratio:
7.58
 
You can't have a Scr and a Dcr that close together. You need to get the cam card for this baby, to either figure the ICA or estimate it, or measure it in your engine.
20181026_122008-jpg.jpg
 
Last edited:
You can't have a Scr and a Dcr that close together.

Figured that !. The calculator wanted the Cam specs of " seat to seat " would that be asking for the duration of the cam? And would that be 444 on the pic of the paper?

Dynamic Compression Ratio Calculator
(Use seat to seat or advertised specs for Intake spec for best results)
Number of Cylinders :
Bore in Inches :
Stroke in Inches :
Rod Length in Inches :
Static Compression Ratio :
:)1)
Inlet Valve Closes ABDC : °
Boost Pressure in PSI :
Target Altitude :
(Feet)



20181026_122008.jpg
 
I went to the Oregon site but could not find the 2106
None of those numbers can be used to calculate your Dcr
The 444/434 numbers are valve lift, probably design lift.
The 214/210 ar probably duration at .050
the 254 COULD be an advertised number, it looks about right, but it straddles the preceeding numbers so can't say which it belongs to. Maybe both I just don't know.
And without an installed centerline, you could still only guess at what number to plug in, and because it's a solid with no net installed numbers we're kindof screwed
 
Last edited:
-
Back
Top