I would think at 50% you would have major issues. I would have tried a different leakdown tester before I tore it apart. Only thing I see, using the supplied formula, is the top ring gap is wider than they recommend. I know the KB's require a pretty loose top ring, but the 2nd ring is pretty good. Ring gaps are not very consistent either. What do the cylinders look like? can you see the finish hone marks?

 

Looking for questions to answer. Tear down was couple hours not to bad. I figure to take a peak. I see honing marks. Minor scouring which I cant feel with a nail. Looks like wear ring gaps were riding. You see pics of hot exhaust valves. And burnt looking pistons sides. I had a major fuel problem at start up. Holley card was not floated good plus Pressure was a little high. Did flood bad for intial start up.

View intake valves on one pics. You can see pretty burnt looking.

 

Did Leak down on hot motor. And was at 50 percent loss.

Means nothing, depending on leakdown tester used.

What is tolerance out of round. Does this seem correctly rounded. ?


1/2 inch down bore is 4.02865 ( 12oclock), 4.02925 (3oclk), 4.0291 ( 4 clok), 4.02865 (6 clok).

How do you reliably measure to five decimal places when using a gauge that only goes to half-a-thou?

Also Attached is Bore gauge from SUmmit it 50 points around dial.
says measures .0005

I see 100 slashes. Shortest ones are half-a-thou, medium ones are one thou, longest ones count thousandths by five--five, ten, fifteen, etc.

One revolution of the big needle is .050, by half-thousandths.

Keith black .030 Claimer -4 cc 76cc iron chev heads 350 bored .030
cam 230/230 480/480 109 sep.

Top rings over gapped per instruction on KB using .065 x 4.030 bore

Are you using the gap specs for KB hypereutectic pistons on a non-hyper piston???

 

Means nothing, depending on leakdown tester used.


How do you reliably measure to five decimal places when using a gauge that only goes to half-a-thou?

I see 100 slashes. Shortest ones are half-a-thou, medium ones are one thou, longest ones count thousandths by five--five, ten, fifteen, etc.

One revolution of the big needle is .050, by half-thousandths.


Are you using the gap specs for KB hypereutectic pistons on a non-hyper piston???

.0005
You Say one circum is .050? why does it say on gauge. 0 - 0.25
I thought enscription is wrong on gauge. should be 0 - .025 Is gauge writing incorrect?
And yes using .o65 x 4.030 bore per KB top ring specs. But Machineist made a little larger. I gave measurements above.

 

With a 2 point bore gauge your not going to measure roundness of a cylinder!!! With that much blowby I would have to say that block was not plate honed, I am big advocate of plate hone and if your block is an OEM block its a pretty weak block compared to a Dart block and we see up to .003 distortion in cylinders once a torque plate it put on the deck and also the bigger the bore job the more distortion. Your block should be sonic tested to see if the cylinders are thick enough for a performance build as thin cylinders will distort more!!


We see alot of builds done by the local jobber shops that we have checked the leak down and to find up to 40% leak down on a new build and the only way to fix it bore and hone with torque plate. Hopefully the block was bored of a squared deck and not of the original decks!!

On a stock build you don't have much dynamic pressure and blowby does not show up as much now you add a performance cam, dome pistons ETC. now you have alot of dynamic pressure and blowby will show up more.

Hyper pistons in MHO are not a quality piece compare to a Mahle, SRP ETC. any hypers we have seen the rings are very sloopy in the rings which will effect ring seal.

Here is a link we did on plate honing a few years ago.
http://www.camaros.net/forums/showthread.php?t=58964

Here is a couple of links on newly built engine with up to 40% leak down and he complained about dirty oil in less then 100 miles. that we had to fix the customer said the engine has never run better and he made trip to every state in the U.S. last year.

http://forums.corvetteforum.com/c1-and-c2-corvettes/2289212-oil-pressure-problem-saga.html

http://forums.corvetteforum.com/c1-...um.com/c1-and-c2-corvettes/2374823-engine-rebuild-oil-pressure-saga-update.html

 

pretty easy to see the problem-ring gap @ .065 x 4.030-man, your talking 1/8" or so
unless you meant .0065 x 4.030

 

What does the Bolts do without a Torque plate on boring. Curious.

I have to ask machinist this question. But he may lie anyway.
Can I remeasure with a bolts installed. And measurement will change?

 

Its not going to give you an accurate torque value or distortion!

 

http://www.kb-silvolite.com/assets/claimer_installation.pdf

According to the KB Claimer instruction sheet, you've got piston-to-wall clearance that is...generous. Shouldn't be "excessive", but it's more than what the manufacturer calls for.

Your ring gaps are enormous.

 

http://www.kb-silvolite.com/assets/claimer_installation.pdf

According to the KB Claimer instruction sheet, you've got piston-to-wall clearance that is...generous. Shouldn't be "excessive", but it's more than what the manufacturer calls for.

Your ring gaps are enormous.

This is where Im confused. Says. .0065 x 4.030 (bore) = gap.
This is .0026 for normally aspirated. Top ring.

I see they show clearance next to the ring gap. A little confusing if you dont look close. Generous on the Clearance for piston to wall. and gap.
Would this cause excessive leakdown ( 45% loss) and 200 psi compression. I dont want to put back together til I feel I figured this out.
I probably should have retorqued head and checked. Just as precaution.

Also. will these measurements. Change when head is bolted on. ( like a torque plate.)>?

 

Usually the only time you run into right and left pistons on a smallblock is with a dome.

 

These are dome.
Keith Black.
Claimer. Looks to me viewing dome. One side may be larger. I want to see documentation if its factual. Im curious.

9904HC-030 -4cc