Need some help on a low HP/Low comp 1441 build.....

[ZX-ALAN]

Guys I built this 1441 for a buddy of mine, everything went real smooth, the engine runs great, and he has put about 1000 miles on it.  We finally went to dyno it and it made no freakin power..... 186hp/103tq....AFR was around 12.9-13.0 across the board.  

The build is a Gen II engine, Gen 1 cylinder (3mm), decked .003":

JE 13.5-1 3mm pistons
Williford ported head w/gen 1 valves and 65# springs, deck surfaced
Cams are 415/395 webs@106/108*
APE studs, cometic head gasket, stock base gasket

The compression test(cold, WOT, 2 diff gauges) AND LEAK DOWN w/ a cheap tester.  The leak down was at least 2-3 mins on each cyl and numbers were steady and holding.
#1--180, 5%..... WD40 shot in the cyl and retested == 220psi (<---potential problem cylinder)
#2--200, 7%..... WD40 shot in the cyl and retested == 212psi
#3--200, 9%..... WD40 shot in the cyl and retested == 210psi
#4--205, 9%......WD40 shot in the cyl and retested == 217psi

From what I could tell, the slight amount of leakage sounded like it was coming up through the intake valves...we could hear a slight "fizzing" as the air was bubbling up past the seats.  Nothing detectable from the exhaust or crank case.

So...obviously the cranking PSI is WAY off and I am sure that is where the missing HP is at.....But why is the compression so low?  Here is a pic of the shortblock before I put the head on it.  The numbers written on the block are the deck height for both the intake/exh sides of the pistons and the numbers on the pistons are the ring gaps.

With no base gasket, the deck height was between .002-.004 on average...adding the .010 compressed height of a stock base gasket put it at ..012-.014 on average and that was not really even with the gasket fully compressed.




I was fully expecting cranking PSI to be 220-230 psi....maybe more... Ring orientation is correct, the letters on the rings are pointed up, gaps are staggered.  I had spun the engine over many times with the head off watching the pistons travel in the bores, there was no rings folded or acting funny.......Everything seemed perfect....

I checked the valve lash again last night and all were still in spec, althought a few had tightened up a couple thou but still in spec so.....



I am lost on this one now so....any thoughts, suggestions or experience is appreciated...

[Predator]

are they gen I cams and if so are you running an off set cam pin like the one from Brocks? if not try the degreeing at 105 int 107 or 108 exh youlll be suprised how much it will pick up, what fuel is it on?

[ZX-ALAN]

Gen II cams, 93 octane.  cams at 106/108.  Gen 1 valves with the dished heads. (<-- We are suspecting maybe these dished valves are loosing CCs in compression )

[mike46]

9% leak on a fresh engine?

[mountainmotor]

Here's a dumb question - is that a one in a million block that got sent out without any bore coat ?

The stuff's not very thick and Milleniums was always darker than that as i remember. Might be the flash 

[RansomT]

Can you post the dyno sheet?

[Rossco]

Did you get actual measured Piston to head and piston to valve clearances?
Shouldn't be getting any leakage past valves on a brand new build head.

[ZX-ALAN]

Did you get actual measured Piston to head and piston to valve clearances?
Shouldn't be getting any leakage past valves on a brand new build head.

No....I didn't measure piston to head or piston to valve..... I just measured/adjusted the deck height, then added in the .030 for the head gasket to calculate quench.

As for the leakage %, this was using a US General leak down tester so I wasn't putting much stock in the numbers as absolute but....  Yes the valves were leaking some....very slight but leaking. I was not impressed with the valve job nor the lack of valve lapping that the assembler did.....(Not Williford, he only ported the head, it was assembled by another shop that I will keep anonymus).

The cylinder was fresh from the same vendor as the assembled head, we assumed it to be plated by millenium. The plating and hone job was very nice and has a good final pattern in the hone.

We will be pulling the engine back out, inspecting all of the rings/bores....as well as likely replacing the rings on #1 after a a slight ball hone job...... Lastly and most importantly, I will be disassembling the head myself and checking valve run out as well as lapping all of the seats until there is not a drop of liquid leaking.....Finallly I will go back with a .005 base gasket to get the deck height under .010.....  I still dont think this is gonna make much difference but....

None of this still explains why we only have 200psi on a 13.5-1 motor...... we should be seeing 220-230psi atleast, especially with the cams at 106/108.  No doubt there reason for low HP here is the lack of compression..... but the lack of compression is what I can not figure out..



I would love to see some cranking PSI numbers from some of you guy's 1441 engines for comparison.

[FlatlandBusa]

Did you get actual measured Piston to head and piston to valve clearances?
Shouldn't be getting any leakage past valves on a brand new build head.

No....I didn't measure piston to head or piston to valve..... I just measured/adjusted the deck height, then added in the .030 for the head gasket to calculate quench.

As for the leakage %, this was using a US General leak down tester so I wasn't putting much stock in the numbers as absolute but....  Yes the valves were leaking some....very slight but leaking. I was not impressed with the valve job nor the lack of valve lapping that the assembler did.....(Not Williford, he only ported the head, it was assembled by another shop that I will keep anonymus).

The cylinder was fresh from the same vendor as the assembled head, we assumed it to be plated by millenium. The plating and hone job was very nice and has a good final pattern in the hone.

We will be pulling the engine back out, inspecting all of the rings/bores....as well as likely replacing the rings on #1 after a a slight ball hone job...... Lastly and most importantly, I will be disassembling the head myself and checking valve run out as well as lapping all of the seats until there is not a drop of liquid leaking.....Finallly I will go back with a .005 base gasket to get the deck height under .010.....  I still dont think this is gonna make much difference but....

None of this still explains why we only have 200psi on a 13.5-1 motor...... we should be seeing 220-230psi atleast, especially with the cams at 106/108.  No doubt there reason for low HP here is the lack of compression..... but the lack of compression is what I can not figure out..



I would love to see some cranking PSI numbers from some of you guy's 1441 engines for comparison.

That will do more harm than good.

[entropy]

after a a slight ball hone job......

That will do more harm than good.
[/quote]

FLB:
are you saying a slight ball hone job will do harm?????

On my built 1427 Zx12, i routinely did "slight ball hone jobs" to freshen up cyls, get rid of streaks, improve cold leakdowns (get em to 2-3%-ish). 
Honing would increase Piston/cyl clearance only a tenth or 2.
Don't know if it really did any good, but certainly didn't hurt anything, and made me feel better assembling fesh looking cyls.
Karl

[busagreek]

Dished gen 1 valves costs aprox 0.4 compression

[entropy]

Dished gen 1 valves costs aprox 0.4 compression

same thing i saw on my 1427 ZX12; pissed me off when KWI stopped selling flat faced ss OS valves.

[Pat Dietrich]

Flatlandbusa- could you explain this. Im curious too as to how or why this would hurt??

[glenn71]

Did u dyno with a welded hub in it,put the btl
Back in for dynoing ,youll be shocked at the
Difference.

[FlatlandBusa]

after a a slight ball hone job......

That will do more harm than good.

FLB:
are you saying a slight ball hone job will do harm?????

On my built 1427 Zx12, i routinely did "slight ball hone jobs" to freshen up cyls, get rid of streaks, improve cold leakdowns (get em to 2-3%-ish).  
Honing would increase Piston/cyl clearance only a tenth or 2.
Don't know if it really did any good, but certainly didn't hurt anything, and made me feel better assembling fesh looking cyls.
Karl

Flatlandbusa- could you explain this. Im curious too as to how or why this would hurt??

A ball hone makes the cylinder look good but does nothing to make it straighter or more round, any imperfections or wear get masked and made worse by a ball hone.  

A rigid does not go into the imperfections in a cylinder.
Guy that got me to stop using a ball hone built 410" 920 HP late model motors back in the day, I was at the shop replacing a set of pistons in a nitrous small block and was using a ball hone to make the cylinder look good when he came though and started chewing my ass about it.

The cylinders had crosshatch all the way to the top yet so I didn't think they were worn enough to worry much about, but after seeing how much of the  cylinder a rigid did not touch on the first couple of passes I was a believer.  

[Pat Dietrich]

Makes sense

[glenn71]

Why such heavy valve springs,just wearing things
Out.

[mountainmotor]

Alan, gas check valve seal < before disassembing the head >, check pip marks on the rings and everything - look that bore over and it shouldn't need even touched at those miles/time ran.

Dietrich,
Old cast iron bore honing techniques don't apply to Nikasil type bore coatings . That coating is tough and the original cross hatch is <cut into the glass > of the material . Alot of times when the original hatch seems gone, it's just piston aluminum in there . I just either clean the aluminum out or send the block back to Millenium for re-hone. Those hones makes a mess of things when i tried it on a nickel ceramic bore way back and none of the machine shops around where i live to take them to . Wiseco again,way back was supposed to start selling a cost effective hone for those of us not wanting to buy a Sunnen . I never saw it happen.

Glenn,
I more than wish there was new clean wire technology and a truck load of alternate springs were available for the Busa  . For these cams , do you know of something else besides the Carpenter 60's ?

Anyway , i hope he posts whats found on teardown - and pics of it. I think we would all agree those dish head gen 1 valves ain't costing that much HP . Dyno sheet or run files would have been nice.

[mountainmotor]

I was not impressed with the valve job nor the lack of valve lapping that the assembler did.....(Not Williford, he only ported the head, it was assembled by another shop that I will keep anonymus).

I am confused - did this head get a valve job or are the seats factory untouched ?  You tore the head part to look then put it back together and whats with the corrosion on a couple of those valves?

I'd be looking at seat angles + big wide valve margins and the likes  . In other words , it's a <it either got a valve job or it didn't> kinda thing as i read it.

[gixxre750]

Im guessing there were used gen 1 valves put into it.

Also, Kilbble White makes a nice dual valve spring. 

[entropy]

A rigid does not go into the imperfections in a cylinder.

I don't know if this consideration would cause me to stop using the ball hone.

If the cyl is warped or gouged to the point that a rigid is needed; i'm thinking it would be time to get it re-plated and re-honed (obviously with a rigid.
Rigid honing which brings back cyl shape is likely to open up the diameter beyond .003 or whatever max piston/cyl clearance you are comfortable with.

Everytime i pull a motor, i carefully clean & inspect it looking for deep scratches & gouges.
Also measure the cyls, looking for out of round & taper (warping)

Warped or damaged cyl go back to Millennium for replating & honing = $600

[glenn71]

I run the ape 47lb springs on 395/378,s and after
2 years on teardown they barely lost a few pound
So im reusing them,also using them with a ti valve
Motor with cams as well.

[mountainmotor]

Glenn, since you've checked those shoot me a message with what open pressure was at .400 on the nose and how much more before coil bind.

Somewhere on another computer i've got same for the  used 65lb spring. I'll go look. We'll compare notes   

[Pat Dietrich]

So here are my cranking #s from Couple days ago
255
260
263
265

[surprenant]

Damn...it has compression...prepare for liftoff.......it's gonna fly for sure....