Milwaukee Midget

[fordboy628]

Midget,

It's probably just the darkness before the dawn.  But, seeing how we live in the midwest, the darkness might be a tornado!!

F/B

[Milwaukee Midget]

Midget,

It's probably just the darkness before the dawn. 

I sure hope so - All that's left to come out is the crank, the rods and the pistons.

If I'm seeing daylight through the block, then I've got REAL problems . . . 

You know, this thing was running before I started taking it apart . . .

[Ron Gibson]

MM
  Is there any chance you were bottoming out the valve spring retainers on the guides. That could cause excessive pressure and could scuff the cam. Any relationship between the hammered valve seals and the scuffed lobes?
  FWIW  Just some questions that came to mind. Good luck on your quest.

Ron

[Milwaukee Midget]

MM
  Is there any chance you were bottoming out the valve spring retainers on the guides. That could cause excessive pressure and could scuff the cam. Any relationship between the hammered valve seals and the scuffed lobes?
  FWIW  Just some questions that came to mind. Good luck on your quest.

Ron

Thanks, Ron.  No, not directly, near as I can tell - the scuffing is pretty consistent from lobe to lobe, and I only ran seals on the intakes. 

But that did raise a question in my mind, which I just ran out to the garage and checked.  It appears the lobes are ever so slightly worse on the back side of the cam than on the front.  This cam throws the valve awfully fast. 

More to ponder.

[fordboy628]

Midget,

I know this doesn't help much, BUT, it is ALWAYS better for you to disassemble your engine, than for your engine to "disassemble" itself.

Yes I know it was running.   The question has to be:  How much longer would it have run and how expensive would it be to fix?  Welcome to the world of engine development.

Keep all the bits in order, even the bits that are obvious junk.   Everything is useful when doing a post-mortem.    You can always toss stuff later on, it's tough to retrieve bits from 2 week old trash.   Retainer to seal/guide clearance at full lift should be checked again, just to be certain.   Do you have any notes on this or anything else that has come into question?   It is possible you have had a problem with valve spring "surge" or valve train "toss".   I have suspected one or both from the start, based on your original valve spring full open pressure.   My previous experience is that the valve spring pressure was too low for the accellerations of a SPVP5 cam @ the rpm you were running.   When I spoke to Dema Elgin, that was also his opinion.   I listed the reasons in a previous post.  (reply #958, pg 64)

The notion of "clearance" between the retainer and the valve seal @ full lift is based on the presumption that the valve train motion is following the cam profile without either "spring surge" or "toss".    Based on the evidence of the damaged valve seals, any "presumption" of clearance would be optimistic.   You have at least 1 problem here, possibly as many as 3.   Do you want to fix them one at a time or all at once..............    (BTW, I think you have 2 problems for certain. )
 
More (adequate) valve spring pressure may (most likely) require stiffer (tubular) pushrods.   I know you did not want to hear that, but, Mistress Helga advises to get all the "shpanking und vipping" done at the same time.............

I used to get asked a lot (by competitors) about all the measurements, calculations, records, dyno time, etc.   The question was usually phrased: "Is all this time, effort & money really necessary?"   When I started answering: "It's why we are kicking your a$$."   The questions stopped.    Go figure.

I'm willing to drive up for a look, let me know if or when your schedule calms down.

Egghead jr.

[fordboy628]

Midget, et all,

Valve spring videos from a Spintron.   V-8 engine, but the result is the same if you have inadequate valve spring pressure.  Take note of the constant "surge" condition of the spring @ & above a certain rpm.   "Surging"/"valve bounce"/"valve train toss" (all different but related valve train problems) can occur from inadequate spring pressure and/or the spring's harmonic freqency at rpm, whether "damped" or not.

<iframe width="420" height="315" src="http://www.youtube.com/embed/_REQ1PUM0rY" frameborder="0" allowfullscreen></iframe>

<iframe width="420" height="315" src="http://www.youtube.com/embed/cfGg15WgSEU" frameborder="0" allowfullscreen></iframe>

Gives one pause for thought........

Fordboy
 

[fordboy628]

Midget,

Sorry, hypnotized by the influence of U-tube.   Hope this makes your bad day more bearable by comparison..................
I believe some of these might get classified as "your engine disassembling itself".   With the result of saving you the time, trouble and expense of actually going racing.

<iframe width="560" height="315" src="http://www.youtube.com/embed/OzFGUUR1UDI" frameborder="0" allowfullscreen></iframe>


Fordboy

[Milwaukee Midget]

It's not a bad day - it's just all part of "the Grand Experiment". 

I'll pull the caps tonight, and then I'll determine if this part of the movie ends like "The Wizard of OZ" or "Reefer Madness".

[Milwaukee Midget]

On a lighter note . . .

http://www.mossmotoring.com/

The print copy hits the mailboxes this week. 

[Captthundarr]

Good read Chris. Some writer has the same name as you.

[4-barrel Mike]

Nice, Chris!   

Mike

[Graham in Aus]

Great read Chris, loved the historical references too, MG's have history on the salt!
 

[Milwaukee Midget]

Thanks, guys.

But the rest of the story is not quite so rosy.

Preliminary post-mortem findings.

Here’s the lockplate that holds the cam in place.  I don’t know why this is happening.  And this is one of those BMC things that you kind of wonder about, and you look at the books, and you think, “Gosh, I’m not sure I’d have done it this way”, and then you shrug and just bolt it in place like EVERY EXPLODED DIAGRAM AND REFERENCE MANUAL SAYS TO, and this is what you get –



With the corresponding groove in the cam face –



I remember putting it together, thinking, “Wow, steel against steel.  Well, I suppose if there’s no load bearing going on, that shouldn’t be an issue”.  But I also remember looking up to see if there was some sort of brass shim or insert that goes between these two surfaces.  There isn’t.

I need to figure out why this happened – and I see a tuition increase in my future.

Yet virtually all of the wear on the lobes is toward the front of the lobes – here’s the worst one -



The lifters, on the other hand, were not nearly as hammered as I thought they would be.  Nevertheless, I do have circles on #’ 1,3,5 and 7 –





The bearings are about what I think I should expect after a brutal break-in –



The # 4 throw and the rear main aren’t passing the fingernail test.  No grooves, but while I remember cleaning the block, my recollection of cleaning the oil holes in the crank is nonexistent.

If I don't get this any more wrong, I think I can get it right.

[Rob]

Bugger Chris! 

What don't kill you makes you stronger!! or so they say. Watching developments and solutions with interest.

Cheers,
Rob

[fordboy628]

Midget,

Some quick thoughts on your disassembly photos:

1   Steel cam + steel thrust plate = non-compatibility.   Probably need a bronze or silicon aluminum bronze thrust plate to bear against
     the steel cam thrust face.    How much end play did the cam have on build-up?   (should be .003"/.005")   These types of material
     compatibility problems are common when "upgrading" parts.   Guys put titanium valves in cast iron guides & then wonder why the
     valves seize in the guides, regardless of clearance.   Does APT have a non-steel cam thrust plate?   Now you know how steel friction
     welding works.

2   Flat tappet cam lobes are ground at a shallow angle, which combined with radiused bottoms (75 inch radius) of the tappets, is what
     induces the tappets to spin.   That prevents the tappets from wearing out too quickly.   This is why the wear/scuffing is on only one
     side of the cam lobes.   Inspection of the scuffing with a 10x/20x magnifier probably will reveal the actual metal failure condition and
     the root cause.   Refer to my PM.

3   Tappets look better than I thought they would.   If they still have a radius they probably can be polished & reused.

4   Was block line-bored or line honed after the main cap strap was fitted?   You may want to check the main bearing housing bore sizes
     with the main caps/strap torqued in place to be certain they are within spec.

5   There are a few oil passages in the block that are impossible to clean unless the brass plugs are removed for a thorough cleaning.  Not
     just the main oil galleries, you must include the sub-galleries as well.   The oil pressure relief valve bleed galleries of BMC's can send
     loads of swarf and grit back into the oil pan.   Cleanliness before and during assembly is more important than most builders think it is.
     Proper cleaning requires brushes/solvents/compressed air/pressure washer to loosen/remove stubborn deposits of debris.   You will
     want to disassemble your oil pump to check the internals...as any swarf that made it the main/rod bearings went through the pump
     first.   What sort of swarf is in the oil filter element?   You may want to consider blocking the oil filter bypass if you have not done so
     already.

6   The salts used in nitriding/"Tufftriding" can remain in the crankshaft oiling passages/holes.   It is extremely abrasive.   Metal gun
     cleaning brushes can remove it.

7   The only other talent for engine builders I heartily recommend is a masterful command of the language and slang.   I swear by it.

Fordboy