Milwaukee Midget

[WOODY@DDLLC]

Does this car make my as$ look fat?

Chris, that should be, "Does this car make my as$ look fast?" 

[Milwaukee Midget]

This seems loose – especially for a new chain.  Click on the pic for the short video.



The cam gear is locked down tight.  I’m not seeing any undue wear on the teeth.    

[Captthundarr]

Wow Chris that is as limp as my.... never mind. I've never seen one that loose with no more time on the motor than yours has. Hows the oiling to the chain?

[Milwaukee Midget]

Wow Chris that is as limp as my.... never mind. I've never seen one that loose with no more time on the motor than yours has. Hows the oiling to the chain?

Judging by the oil dry I had to spread on the floor of the garage when I pulled the cover, I'd say there's no issue there.

A high five to Amy on her Willmington runs from Kate and me.

[Milwaukee Midget]

Okay, I just wedged and C-clamped the cam gear and attached the degree wheel - I'm looking at just shy of 3 crank degrees of slack in the chain.
 

[Captthundarr]

 

[fordboy628]

Midget,

That's way too much.      Especially for the amount of run time.   Probably a break-in/initial fire-up issue.  You are going to have to correct this.   A Triumph Spitfire or a F/F tensioner may be the cure for the slack.   With the valve to piston clearance you will have to run, you can't allow the cam to have 3 crank degrees of slack.    Based on the info we generated, 3 crank degrees is at least .014"/.015" valve displacement on the opening/closing flanks of the int/ex cam lobes @ B/A TDC.   That would mean that factor would need to be ADDED to the minimum valve to piston clearance you will need to run.   Not my idea of Maximum Cram.   Sent you a P/M.

E/H jr.

[Milwaukee Midget]

That would be crank degrees.  I've got an MGB tensioning boss, spring and plunger that might be able to be modified.  Even at the time I put it in, the new chain seemed loose, but I had nothing to compare it to.  I'm just now figuring out that I wasn't as critical of it as I should have been.

I'll be dropping off the head, the Lexan plate and cylinder liner during lunch today over at C&S -they can whip up the flow bench adapter with those - I'll have them check flow on chamber 1.  I've got heavy springs on the intake side of 2 to prevent leakage.

Oh, yes - I did put a spark plug in the hole.

Yours truly,

Greenhorn 

[fordboy628]

Midget,

Have a couple of "Payen" big bore head gaskets in my bits if you decide to go the o-ring route.   APT has listings for Payen as well.   Ask C&S about their experience with ultra high compression ratios on the Cometic MLS gaskets.   And you might want to ask Dave Anton as well about what gasket he recommends.

E/H jr

[Milwaukee Midget]

Today, boys and girls, we learn another valuable lesson about running a loose valve train.

1&2


3&4


5&6


7&8


Which leads to . . .


Which has magnetic properties . . .


Sure looks like chilled iron to me.  Can’t wait to see the tappets. 
 
I haven’t the guts to pull the caps tonight.

[Peter Jack]

Did you start it up initially and let it idle? A flat tappet cam requires that when the engine is initially started up that the revs be kept up for the first little while before it is allowed to settle down to an idle. We used to use about 2500 for the first half hour before we let it idle. The lube you put on the cam before start up is also critical. Everyone seems to have their own magic formula for that although moly is often one of the components.

Pete

[gearheadeh]

Today, boys and girls, we learn another valuable lesson about running a loose valve train.

1&2




Which leads to . . .



Sure looks like chilled iron to me.  Can’t wait to see the tappets.  
 
I haven’t the guts to pull the caps tonight.

Oh CRAP,     as soon as I saw the blue color and the scoring in the first pics I knew there will be no investment recovery for that particular piece. Really feel your pain, hope the crank made out okay!

[Milwaukee Midget]

Well, seeing as it initially wouldn't even RUN below 2500, I guess my default answer is "yes".

But as I dig deeper, it's clear that there's more going wrong here than just that.  Loose springs, loose tolerances.

If this were a Kalashnikov, it wouldn't be an issue. 

I should have head flow figures for Forboy next week.  Without getting too far ahead of myself, I'm hoping there's enough meat left on the cam I have to regrind it into a set of lobes at an appropriate LCA that will work with a 2.45 rod/stroke ratio, and still open the valves fast enough to make a few ponies.

I suspect that if I had taken this combination to Bonneville, I'd have been trailering back a lot of scrap.

Oh CRAP,  :- as soon as I saw the blue color and the scoring in the first pics I knew there will be no investment recovery for that particular peice. Really feel your pain, hope the crank made out okay!

Worry not - that's an optical issue, not a heat issue.  The face of the lobe is scuffed, but the blue color you see is just flash reflection.  It didn't get hot.

[fordboy628]

Midget,

I tried zooming in on the photos you posted to get a better look @ the bits, but I lost too much resolution to see anything.   Will need to see bits in person for a definative post mortem.   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.

Also, billet steel flat tappet cams with chilled iron or steel tappets is the most difficult & dicey break-in of all cam/tappet combos/types.  The only procedure that would work for me was:

1)   Parkerize cam or Specify Parkerizing to Cam Mfg.   If parkerized tappets are available, use them.   Chrome faced tappets ($$) best.
2)   Assemble engine with cam & tappet faces coated with moly-based assembly grease/lube.   (DON'T GO CRAZY WITH THIS.)
3)   Assemble cyl. head to run-in cam/tappets on outer springs only!   VALVE LASH CANNOT BE "LOOSE", RUN "TIGHT" if necessary.
4)   If possible pre-heat engine oil & coolant prior to firing.
5)   Pressurize oil system BEFORE fire-up, make sure oil gets to rocker shaft & valve stem tips.
6)   The oil you use for run-in matters, DO NOT USE A SYNTHETIC OIL.
7)   You MUST use an oil additive that contains ZDTP.   (zinc dithiophosphate, not sure on spelling, probably Haz/mat now.)
8]   IMMEDIATELY on fire-up run engine to 2500 rpm.  Vary rpm between 2500/4000 for 10 minutes.   No idling or high revs permitted.
      If possible, check tappet faces/cam lobes for scuffing @ 10 minutes.   If scuffing is encountered, or valve lash opens up, STOP.
9)   If OK, continue run-in for 10 more minutes.   Inspect again, and if OK, change to regular valve springs.
10) Run-in for an additional 10 minutes @ full spring pressure, vary rpm 2500 to 6500.   Inspect for final time, if OK, you can evaluate  
      ring seal/ring bed-in.   (Via blow-by meter OR Leak-down checker.)
11) If ring seal is OK, change oil filter.  It will be partially plugged/plugged with moly/greases/etc.  It will probably still be too soon to run
      a synthetic oil.
12) Check valve lash and adjust if required.  Check other aspects of engine that require attention, ie: retorque cyinder head, etc.  Now
      you are ready to dyno-test or run.
13) Above presumes that you are checking everything else you need to check on run-in.  Different engines types need attention in  
      different areas.   Know what yours needs, and use the Cosworth axiom:  IF IN DOUBT, ASK.

Pray if you must, but only in ADDITION to the steps above..................

As you can see, this type of procedure is most easily done on an engine dyno, and yes, I know this procedure is a GIANT PAIN IN THE KEISTER!!  It also works.

Fordboy

PS,  I'm sure cam can be reground on a smaller base circle diameter.  You are probably going to have to go to a "lesser" duration @ overlap, so that will help too.   How badly is cam lobe nose radius damaged?
F/B

[Milwaukee Midget]

The lobes are just scuffed - a polish would probably put it back to rights.

Seeing as it's scuffed, I think we're looking at my regrind blank.