BuiltZMotors Analysis of JoeDirtPharmD engine: warning->DETAILED
 

BuiltZMotors.com
JoeDirtPharmD Engine inspection 8/29/2007

Performed by:
Todd Pickman, Gerald Stratton- BZM
Andrew McGibbon, Todd Budlong, Brian (cylinder head machinist): Budlong Motorsports Machine Shop
Brody Hooper: Speedlab

Background:
JoeDirtPharmD purchased an engine from us several months ago. Performed install, tuned, various issues; please see thread: https://my350z.com/forum/showthread....96#post4311796

JoeDirtPharmD took his vehicle to GTM. I explained to him our warranty options, if we were at fault, either a machining or assembly error, that we would rebuild the engine free of charge and cover all shipping expenses but that we would need to tear the engine down ourselves- JoeDirt decided to have GTM build a new engine. Because of what GTM told him, he did not trust any future BZM product. This was based on GTM’s initial assumed diagnosis of machining errors, etc.
GTM posted the following findings:

1) Low compression cylinder #1 (explained as a valve sealing issue- vacuum gauge demonstrated approx. -9.26psi vacuum {their standard for normal begins at -10.29 according to their gauge})
2) Excessive piston to wall clearances (machining issue) allowing piston to rock in the bore excessively
3) Piston striking the cylinder heads- all 6 cylinders (blamed on extra .0005”rod bearing clearances and redecking the block .003)
4) Contamination found in the lower oil pan (blamed on poor cleaning core from BZM)

We agreed to still inspect the engine, as the initial findings were suspect and still did not not explain WHY the piston was hitting the cylinder.

Let me begin with our findings of August 29, 2007:

The engine was shipped strapped to a pallet with various pieces in a series of boxes.
http://i35.photobucket.com/albums/d1...d/IMG_7444.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7446.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7447.jpg

We first measured the cylinder bore.

FINDINGS:
Arias calls for a finished bore size of 3.780. We run .001 additional to allow for higher boost levels that will cause additional expansion of the piston. This was a practice we began when a set of original Arias pistons seized in 3 cylinders in one of my engines and fractured 3 ringlands. Soon thereafter, Sharif helped develop the Arias Extreme Duty piston, which was zero silicon forged aluminum, that out of the box called for larger piston to wall clearances because of the lack of silicon content in the metal. We error on the side of caution and run an additional .001”.

Sunnen dial bore gauge set at 3.780
http://i35.photobucket.com/albums/d1...d/IMG_7470.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7471.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7465.jpg

Cylinder Bore #1: 3.781 (+.0010)
http://i35.photobucket.com/albums/d1...d/IMG_7458.jpg
Cylinder Bore #3: 3.781 (+.0010)
http://i35.photobucket.com/albums/d1...d/IMG_7460.jpg
Cylinder Bore #5: 3.7815 (+.0015)
http://i35.photobucket.com/albums/d1...d/IMG_7462.jpg

Cylinder Bore #2: 3.781 (+.0010)
http://i35.photobucket.com/albums/d1...d/IMG_7452.jpg
Cylinder Bore #4: 3.7805 (+.0005)
http://i35.photobucket.com/albums/d1...d/IMG_7455.jpg
Cylinder Bore #6: 3.781 (+.0010)
http://i35.photobucket.com/albums/d1...d/IMG_7456.jpg


Next we measured the diameter of the piston at the level of the skirt. The findings were interesting. A normal healthy piston measures between 3.7760-3.7765”.

http://i35.photobucket.com/albums/d1...d/IMG_7500.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7501.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7502.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7474.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7475.jpg

FINDINGS:

Piston#1: 3.7755”
Piston#3: 3.7750”
Piston#5: 3.7750”
Piston#2: 3.7750”
Piston#4: 3.7750”
Piston#6: 3.7755”

As the above measurements provide, the pistons were all .001-.0015” smaller in diameter. According to our machinist experts, a piston will collapse when heated excessively, whether exhaust gas temps were too hot, or coolant temps were too hot. I chose to get a second opinion from someone that I consider an expert in this field, Jason at Arias. Jason explained that even after a few thousand miles on a fresh engine, the piston SHOULD NOT shrink/collapse in size. He stated that the only way this could happen is from excessive heat, whether EGT or coolant temps. While I had Jason on the line, I asked his experience on another hot topic: Piston to Wall Clearances. He explained that they, Arias, the manufacturers of the pistons used in the engine in question, recommend an extra .001” piston to wall clearance for high boost applications. He further explained that in excess of .004” above the recommended piston to wall clearance may begin to affect excessive rocking/ possible issue with cylinder compression.

This leads me to our next series of findings.
As Jason at Arias Pistons explained, a piston to wall clearance of +.004” over recommended can create an issue, although in the same sentence he explained that he has seen several engines built using DOUBLE the recommended piston to wall clearance with the only issue being excessive slapping at initial startup, leading to excessive wear-in the example of double the P to W clearances..

GTM claimed that the piston to wall clearance was in excess of .006-.007. We found that in one of the cylinders, the piston to wall clearance was as much as .0065. As explained above, the reason that the clearances were so excessive was because the pistons shrunk in size.

Mathematically equated piston to wall clearances: (actual bore – actual piston size)
Cylinder#1: .0055
Cylinder#3: .0060
Cylinder#5: .0065
Cylinder#2: .0060
Cylinder#4: .0055
Cylinder#6: .0055

We then proceeded to vacuum test the cylinder heads. GTM claimed that cylinder #1 was not holding sufficient vacuum, they did not indicate whether intake or exhaust. This was their primary explanation as to why JoeDirtPharmD’s engine was not making additional power as they upped the boost beyond 11psi. As many of you know, this is illogical, as every cylinder would need to produce a loss in compression to allow the power to flat line as boost pressure increased, as the other 5 cylinders would still make additional power and take #1 along for the ride, so to speak. We provide a plausible explanation later in this report. Bear with me.


GTM posted results of their vacuum test on cylinder #!. They showed that the valves were only holding -.63bar {-9.26PSI}, whereas the “green=good” indication began at -.7 to -.9bar {-10.29 to -13.23PSI}. We measure in inches of mercury, so as not to confuse, I will convert all to our favorite pressure measurement; PSI.

Our FINDINGS:

Less accurate method:
http://i35.photobucket.com/albums/d1...d/IMG_7477.jpg

Most accurate:
http://i35.photobucket.com/albums/d1...d/IMG_7478.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7481.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7486.jpg


When we initially began the vacuum test, I thought we identified the issue, agreeing with what GTM had found. We began with the valves in question, the ports on cylinder #1. We checked the exhaust ports first; they were only holding approx. -6.0 PSI. I was ready to accept that we had too discovered the issue, and then I noticed something, the position of the cam. Woops. The cam was not positioned so that the valve could close completely, so, we rotated the cam, closing the valve, and it immediately jumped up to hold a whopping -22.5” of Hg {-11.19 PSI}, well within normal limits.

I am curious if this is the same error that GTM may have made, an honest error, and when looking to justify tearing down an engine to explain power loss issues, it is understandable that one can be quick to accept any form of discrepancy, whether accurately obtained or not.

Before getting too excited, we proceeded to check all of the ports/valves to make sure they were consistent. Keep in mind, we tested all valves with the cams in place, allowing the valve lash clearances to play a role in the vacuum testing (although cold clearances). The lash settings were all within normal limits, a few intake valves were .001-.002” tight, still nothing to cause any sort of sealing issue.

*8/30/07 edit:
Please note that we are at 5500ft altitude, this will affect our vacuum test readings, as they will read lower at high altitude as compared to sea level (sea level atm. pressure:14.7, up here atm. pressure around 12.2). Just to clarify.

Our Findings:
Cylinder Head #1 (passenger side)
Intake:
#1: -11.19 PSI
#3 -11.19 PSI
#5 -11.40 PSI

Exhaust:
#1: -11.19 PSI
#3: -11.40 PSI
#5: -11.40 PSI

Cylinder Head #2 (driver side)
Intake:
#2: -11.40 PSI
#4 -11.40 PSI
#6 -11.40 PSI

Exhaust:
#2: -11.40 PSI
#4: -11.40 PSI
#6: -11.40 PSI

Detonation Cylinder #4::eek:
Obvious pitting and discoloration of the exhaust valves of cylinder #4 are consistent with detonation.

http://i35.photobucket.com/albums/d1...d/IMG_7495.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7496.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7512.jpg


After confirming that the cylinder heads were perfectly acceptable and machine 100% properly, we proceeded to investigate the piston striking the cylinder head issue.

We installed the piston #1 into the cylinder in question#1, as well as piston #6 into cylinder #6 (to have one piston on each bank to get an idea of the deck clearances)

Since GTM failed to send us back ALL of the main bearings:icon22: , I used some new main bearing halves for the block portion of the main journals (the main caps still had the original bearings).

http://i35.photobucket.com/albums/d1...d/IMG_7503.jpg

The crank was installed to spec, before installing the pistons, I inspected the rings. A healthy piston ring should have considerable spring pressure pushing it outward against the cylinder wall (enabling good sealing and compression). The rings in ALL 6 pistons were barely protruding outside the outer diameter of the piston, meaning they had lost their spring characteristics. :eek: Consistant with excessive cylinder temps or coolant temps.
http://i35.photobucket.com/albums/d1...d/IMG_7515.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7516.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7517.jpg

This happens when a ring is overheated, typically from high EGT’s. The ring is compared to a healthy new ring. This spring tension will decrease ever so slightly in a used piston/ring, but not to this extent. This is the most likely reason that the engine was losing power at higher boost levels, the rings could only seal so far!:icon11:

http://i35.photobucket.com/albums/d1...d/IMG_7504.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7505.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7506.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7507.jpg

So, the pistons were installed in the cylinders, and they slid right in, easier than any engine I have ever built, because of the obvious distortion of the rings.

http://i35.photobucket.com/albums/d1...d/IMG_7513.jpg

The crank was then rotated to bring the piston to top dead center and we took some measurements to see if the piston protruded out of the deck excessively – it did not. The piston sits approx.003-.004 below the surface, and when rocked, the piston actually moves above the surface of the deck a total maximum of .001.

http://i35.photobucket.com/albums/d1...d/IMG_7519.jpg

piston not "rocked", sitting .004 below surface of deck.
http://i35.photobucket.com/albums/d1...d/IMG_7521.jpg

Piston "rocked" bringing it higher in the cylinder:
*.0025 feeler under straightedge, .0015 slid freely between piston and straightedge, demonstrating the piston is protruding out of the cylinder by .001”
http://i35.photobucket.com/albums/d1...d/IMG_7526.jpg

So, with a .024” headgasket, there is a maximum of .023” clearance. If one takes into account heat expansion, the piston can expand a few more thousandths in height under normal operating conditions, still leaving several thousandths clearance. Under abnormal heat conditions and high rev conditions, because of the collapse of the diameter of the piston, it is feasible to assume that the piston can barely kiss the cylinder head.
Upon careful inspection of the pistons and the cylinder heads, the point of contact is extremely minimal; there is no deformation of palpable change in the cylinder head or in the piston.

Interesting to see the excessive wear/ heat damage on bank 2 (side of detonated cylinder#4) as compared to bank #1.

http://i35.photobucket.com/albums/d1...d/IMG_7528.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7529.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7530.jpg

We then applied beads of clay around the edges of the pistons and torqued the cylinder head on to 100ft lbs with the ARP ½” head studs.

http://i35.photobucket.com/albums/d1...d/IMG_7533.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7536.jpg

With head removed after crank rotated and piston at top dead center:
http://i35.photobucket.com/albums/d1...d/IMG_7537.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7538.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7540.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7541.jpg

.0020” feeler placed next to compressed clay:
http://i35.photobucket.com/albums/d1...d/IMG_7545.jpg

http://i35.photobucket.com/albums/d1...d/IMG_7547.jpg

Less accurate, but to help further illustrate that there is sonsiderable room between the piston and the cylinder head:

http://i35.photobucket.com/albums/d1...d/IMG_7549.jpg


After talking with our main machinist, Todd Budlong, he explained that on his 1500+ hp drag engines, they build them so tight that the piston will hit the head at high rpms, but that this is so minimal and insignificant that it does not cause any damage, loss in power, etc, just an intermittent slight audible that may be picked up by a knock sensor only under the most extreme conditions.
I am not saying that in our case that the piston hitting the head is acceptable, because we do not build these engines with this intention, but the above detailed data helps explain how this was possible. It is important to note that while THERE ARE signs that the piston did kiss the head at some point- this was in no way any explanation as to the problems that this engine was experiencing.

Lower oil pan copper contamination findings by GTM:

We go through several measures to insure that our engines leave our hands in excellent condition. Our core blocks are torn down, inspected, and then vatted, and then pricisely cleaned with engine brushes and simple green solution to insure every passage is clear from contaminates.
GTM stated that the engine was contaminated due to improper cleaning by BZM. I know this can not be the case. My only explanation for the introduction of the contaminates into the engine would be from a contaminated oil cooler (common spot for shards of destroyed bearing material to hide) or from feed/return line to the used turbo charger that was re-installed on the fresh engine.
Upon inspection of the bearings, they did not show any excessive wear due to clearance issues, but did show distinct signs of debris contamination wear, slight grooves carved into the surfaces; this occurs when the debris is circulated through the engine.

My offer to JoeDirtPharmD:

I assume some will say that OUR analysis was biased and untruthful; I can only tell you that we conduct ourselves with the highest level of integrity and honesty, and the above findings are 100% accurate. If you would like to have a 3rd party analyze the engine, I will be happy to package up the engine (at your cost) and ship out to whomever (at your cost as well). I can assure you they will find exactly what we have outlined above.

I offered to rebuild the engine back when I assumed from Sam’s findings that some of the data pointed to an error on our part. After precisely inspecting and checking the clearances the engine, I am pleased to find that we in NO WAY SHAPE or FORM are responsible for ANY of the issues found in this engine.
Even with this said, I am still willing to do the following:
rebuild the engine with new rings, new bearings, and have the pistons clearanced to accommodate their new diameter I will not pay shipping back to JoeDirtPharmD, if he wants it back in his possession, I think it is beyond fair for him to cover this expense. A better option would be for JoeDirtPharmD to list this engine for sale, when it sells, the buyer can pay shipping to their location.

This engine will have the following:

Shortblock Fully assembled:
Block machined for ARP ½” head studs (100ft lbs tq)
New bearings
New piston rings
Cylinders lightly ball honed (realize they show NO distortion-in perfect working order)
Block deck checked, less than .0005 variance (perfect)
Heads already been pressure tested
Pistons will have the top surface clearances approx .020 to avoid any future contact issues (unlikely to happen even if they are not clearanced).
Heads:
Heads assembled with stock cams, very little use, clearanced to accept ARP1/2” head studs
ARP ½” head studs
*Included:
Upper oil pan
Valve covers
Timing gear

*(obviously all of this is up to JoeDirtPharmD, it is his property)

I assume JoeDirtPharmD needs his APS lower oil pan back (not sure why that was sent to me), as well as the crank pully???


I have already spent countless hours defending our reputation, which has been unjustifiably dragged through the dirt by both GTM and JoeDirtPharmD. I harness no hard feelings towards the customer, as his position has been based off the findings listed by GTM. I have covered the shipping costs of the engine to our location, and I will still accept that expense in full.

Again, I feel bad for JoeDirtPharmD’s drama and extra expenses in this entire ordeal, but would like to list my time and expenses so that the community can see how I have “bit the bullet” and am EATING these expenses:

Hours spent defending myself when JoeDirtPharmD posted GTM’s findings: SEVERAL
Shipping engine from GTM to us: $230
Vacuum testing heads: $50
Hrs inspecting engine: 6 (@$80/hr= $480)
Hrs spent typing this report/pics: 3 (@$60/hr=$180)
New Piston Rings: $100
New rod/main bearings: $120
Assemble shortblock: $400
Therapist for stress relief: (priceless---joking):D

Total: $1560

To the my350z community:
I hope you all can see that I am going above and beyond what any vendor would ever be REQUIRED to do, but I wish to resolve this situation so that this issue can be resolved and over. The community can see the precision that we execute when we build an engine and how we inspect an engine. The future buyer of this engine can rest assured that this rebuilt, almost new engine will be great for anyone wanting to push high boost/ high HP numbers. It will include documentation detailing the clearances and other assembly specifics.

I hope you all find this long report informative and helpful in preventing such issues in the future. Initial break-in of a new engine is extremely important and crucial. Tuning of an engine (type of engine management) is very important in the proper function and longevity of an engine. And I hope everyone can see that there are SEVERAL variables involved in a creating a healthy, successful boosted vehicle.

-Todd Pickman
BuiltZMotors.com

Let the games begin....

Good luck Todd and very nice complete analysis.

Thanks for the very thorough analysis Todd!

holy fuk that was a lot to read.

hope every thing works out, we dont need anymore shop wars.

+1 Says alot on how you care about making things right. Good Luck!

Very well layed out.Bravo.

Great write up, hopefully this clears everything up best of luck to Todd and Joe

good job !..

Excuse my ignorace but I read the whole thing and still don't know what you determined the problem was. An incorrectly installed cam? Bad Rings? Bad tuning?

Hope everything works out also. I know Todd in person and his character reputation is worth more that any dollar amount. He will make it right and he will be building my motor.

What a read, thank you very much for going out of your way to show the 350z world what you guys are about. I live in Florida and if you guys where any where near by I would be stopping by with my car for work. Again many thanks.

I think it was overheated at some point

+1

The only thing that I gathered from the reading was that when the turbos were reinstalled, some metal shavings were circulated through the engine. Is this what BZM believes the problem is?

I know it is a lot to take in:icon38:

It appears that the cylinder temps/coolant temps got too hot. (JoeDirt had never had the car overheat in his possession, and I believe him, so I am leaning towards cylinder temps).

Combo of hot cylinder, collapsing the pistons, increasing the rocking, high revving pistons kissing the heads (really irrelevant to any symptoms the engine was producing)...

rings getting hot and losing rebound against cylinder wall explains the compression issue/power loss... JoeDirt even explained how he put some oil in cylinder #1 and the compression came back up, backing up this position.

the accusation that the heads were "machined improperly" and that the valves weren't sealing is just plain false. We vacuum tested all valves, they are all almost identical in holding -23" HG (-11.4 PSI)

So the conclusion looks as though somethign with the engine management, lean condition.. this engine would have likely ran for several 10's of thousands of miles and made over 400rwhp.. the symptoms were a lack of increasing power as boost pressure was added.

TODD

even though metal in an engine is NEVER good, this did not cause any "failure"..my above response sums up our conclusion. And yes, the copper shavings, I believe were from contamination from the oil cooler, oil pan, or turbo lines, I can only say that because I know the extent that we clean our engines before assembly, to allow that much metal to lay around in a frsh engine would be borderline retarded:eek:

Excessive heat-> Shinking of pistons+hardening of rings -> Broadening of the piston to cylinder gaps-> pressure loss in high boost + excessive piston rocking.

Wow very good brakedown and write-up. It's nice to see the photos and data to back everything up. I'm not to familiar with the whole insides of these things so what causes the high piston temps to do this?

So you are concluding that the engine ran too lean for too long causing the pistons and rings to shrink on all cylinders. Hmm...good analysis. Kind of wierd that GTM would forget to turn the cams when checking compression on the cylinders.