Help with blown bbc

I'm at my wits end and need help. Here's the scoop. 1471/enderle buzzard/431 bbc. Ran great last season. Tore down for inspection and decided to replace the bearings. Reassemble for this season and now this dog won't hunt. Right now, it's 7 tenths (yes that is tenths) down from October of last year. It does not misfire. It simply will not rev. What the hell happened in the shop to the parts over the winter? Here's what I've done:

checked all bypasses for correct operation
checked all nozzles for obstructions
checked for correct cam timing
checked for correct ignition timing
replaced coil / ignition box (msd 7al2 to msd 7al3)
replaced crank trigger wheel
leakdown 10 to 15 % on all cylinders
checked valve spring pressure

What I have not done:

replace mag pickup
replace cap
replace wires
replace entire operation with pontoon boat and summers supply of beer

 

I know they are on your list but the first two things to pop into mind are that a high speed isn't opening (maybe in backawards) or some valvesprings are getting too weak.

What about boost. Are you getting the same boost numbers you did last year? Maybe there is a boost leak.

 

Check the degree ring in relation to TDC. It could be that something changed so that when the piston is at the very top, the wheel is not at the 0 degree mark and the ignition timing is not right even though it appears so with a timing light. I have seen this happen before. What does the motor sound like? Does it sound like it is laboring and lazy?

 

boost # are the same
spring pressure is good (at least on one head)
Can check deg wheel although everything seem to line up correctly. (i.e. mag pickup / wheel)

also forgot to mention that EGT's are down about 80deg

 

Oh.... and VERY lazy. 60' times are .08 to .10 off

 

sounds like a timing issue i have had the degree ring move before i would set the timing with a buzz box start it up it would sound good put the light on it and see it was off WTF set if with the light it wouldnt run worth a fk i went to two race before i figured it out i dont even know how it run as far off as it was but it did but it was a pig

 

more info:

tdc is correct
timing mark at 35deg btdc
won't be able to verify distributor until all is put back together

..... oh... something else.... I did something that I used to do 20 years ago. I checked static compression. I expected about 100psi but got 60. Is there something there?

 

Cam timing ???

 

double... triple... quadruple checked to make sure marks were lined up same as last season. Cam is very old Clay Smith model. Symetrical lobes. Card says Int opens 50 deg BTDC. I was told this was probably @ .005 lift Can't find any other info on it. Did a quick check and it appears 50 deg at 005 is right.

 

Do you have a fuel filter on it? If so check the direction.

Any chance you have 2 pills (stacked) in the barrel valve?

Is the fuel tank vent open/working?

Almost forgot, check roll pin in mag/distributer gear. Had one bend once and it retarded timing by 20*

 

Sounds like soming going on with timing for sure. Need to check this out when running etc.

 

60 psi of compression sounds like the problem. Did a set of shorter rods get in the motor? Is the block, crank, pistons, gaskets, heads, etc. all the same stuff?

 

All internal components are the same (sans bearings). I thought 60# was low too. This is what led me toward a retarded cam. I cannot find any indication that this is the problem though.

 

I would expect the boost numbers to change if the cam was in different.

Are the spark plugs the same part number (as last year) and is the gap small enough?

 

The only thing that would lower you static compression, (besides the ring-valve issues) is cam timing. What timing set do you have? Some have so many different key ways and markings, they are a pain to know where your at.

 

Not the same plug. Still ngk 10. gap is .014

timing set is Erson gear drive with removable inspection cover. PITA to install and get the marks lined up correctly which is why I suspected cam timing. So, is 60 psi static WAY too low like I suspect?

 

Are you running a converter or clutch? I had a similar problem and the converter was junk. But my compression was never that low.
My two cents.

 

convertor. My data says it's ok... but my partner swears convertor. Gonna pull it.

 

Sounds like retarted timing. If it were mine, I'd pull the driver's side head and put a dial indicator on and find TDC. You could do it with a stop too but I like the indicator. Make sure the hub lines up at TDC for sure with the timing marker. Then run the degree wheel to verify cam timing. That will cover cam timing.

My RCD gear drive cover's timing mark is 10 degrees off. I moved the same hub and degree ring from my Dart block with a Milodon gear drive to a KB Olds block with the RCD drive and the timing was off the 10 degrees. I cannot adjust it out so I need to compensate for the 10 degees when I set the ignition timing.

Not sure if you have the same issue but based on what you have said you've done, I would check the cam timing and the ignition timing pointer for correctness. Good luck.

Tom

 

camshaft

for those that have asked about the cam, here's the specs

Clay Smith grind # r-316-8-sb (or 5b can't tell as it's hand written)

int opens @ 50 closes @ 86
exh opens @ 86 closes @ 50
duration @ 0.050 286 (both)
lift on 1.7 rocker 0.765
lash 0.024

also written on card:

Install at 106*
2* advanced

Oh... BTW, TDC mark is correct on the deg wheel.