Neil,
The oldtime adage from long ago stated, "If it is not on time or doesn't fit, must be racecar parts..." still applies today. The finalization and detailed inspection of fit and finish is on the consumer, even if the parts are highly touted CNC super duper stuff. Important things such as valve seat concentricity are high on the hit parade for needing a detailed inspection to maintain any kind of QC. As I understand it you worked in aerospace stuff. The lack of QC is somewhat common in most (but not all) aftermarket parts. Buyer beware good old caveat emptor, my friend.
Looking at the bright side, at least you found the problem and it is easy to fix.
Continue being careful and it will always pay off.
Best of Luck!
Regards,
HB2
x 2!! or x 3!!!
Neil,
I don't want to carp on this, BUT, there is no detail too small to check . . . . .
And it is
NOT that the guys producing these parts are doing "shoddy" work. The castings are especially complicated. OR, your tappet bore in your block
may be "out of position" by some amount that makes a difference. Which is it? The only guy who can say for sure is:
the guy who assembles it.Part of my "sign off signature" used to be the phrase:
"Does checking all the little details matter? I dunno, but I think you should ask the guy who finished second . . . . ."I removed it from the bottom of my posts because I got tired of "folks" messaging me telling me I was wrong. And then "they" wanted to argue with me about it . . . . . . ( not going to "waste" my time on those "folks" . . . )
But, because I see this stuff
ALL THE TIME, I'll provide you with a couple of examples:
1/
Just yesterday, a long time friend and client brings me a Cosworth BD head recently redone by a guy experienced in all things Cosworth. All that was to be done was to check out a new set of valve springs, check the installed height, shim the springs and assemble the valves, springs, etc. When checking, I noticed that the distance from the bottom of the retainers to the top of the seals seemed small. So I checked a "little detail". YUP, negative (-.040" 1mm) clearance between the bottom of the retainer and the top of the seal!! This is not a cam grind change situation and the cam lift is .41" gross and ~ .40" net. Further checking revealed early type guides installed in a later type head casting, so the guide top is .10" higher than specification.
When the client contacted the person (shop) that performed the work, his reply was: "No problem, just run it." So, I then asked the client to bring me his dry sump pan. In the trough, were 8 of the 16 valve seal collar springs . . . . .
2/
A few weeks ago, a client from a couple of states away dropped off a Cosworth BDH to be check over and then dyno tested. This is a late 70's spec engine, now for vintage racing. Replacement value ~ 35K to 40K . . . .
Needed to set the Lucas MFI, check a couple of things out, look it over, etc. Having a problem setting cam belt tension . . . . . .
14 shop hours later: (and these are just the "high points" . . . . .)
A/ Cams and tappets assembled with only "a smear" of assembly grease, no oil. Oil flow to the top end of this engine is "restricted" . . . . . . .
2/ Wrong length or missing mounting bolts for the FI metering unit. This engine is a "shaker". Correct bolt length is critical to retention.
d/ Cam belt, as sold by a "Cosworth specialist" was a regular thickness (XL) belt. Not thick enough to obtain correct belt tension adjustment . . . . . Belt needs to be a XLH or better yet a special XLHH. Inadequate belt tension on these engines can be a cause of belts "jumping" teeth and causing cam timing problems which result in a engine full of bent valves . . . . . .
and on, and on, etc . . . . . When everything was corrected though, engine ran well on the dyno and achieved target bhp & tq. Proving, to me at least, that: "little details matter".
And this is not just Cosworths that I see this on. The shop I am affiliated with is drag centric. Some "recent" issues:
A/ BBC drag engine comes in for dyno test. Won't roll over smoothly, no dyno. Valves hitting pistons as engine is turned by hand.
2/ SB Pontiac comes in for dyno test. Rolls over OK initially. When filling with water, water rains out between the heads & block. Customer customer wants to add "block seal". I suggest rolling engine again. Won't turn by hand. Removing spark plugs results in jets of water shot out of several spark plug holes. Uh, NO dyno . . . . .
d/ SB Ford for dyno test. Disappointing bhp. Cam timing check reveals cam 8 degrees advanced from cam grinder's spec. Owner builder states: "he lined up the marks", why is there a problem?"
I could go on until you puke, but I'll spare everyone. I think everyone will agree that some of these examples are not "little details" . . . .
Almost 50 years ago, my first mentor opined the a really good engine builder is just: "A perfectionist looking for a place to happen." It was sage advice then, as it remains today . . . . .
Neil, do not despair. Checking all the "little details" is
ALWAYS the right thing to do. It can be a PITA, though.
Fordboy