LMM: Ever Seen a New Engine Do This?

[WolfLLY]

My buddy (who is a boat fanatic) told me they had a 1400hp bbc marine engine that wasn’t making the power it should, turns out couple of the cylinders were too high on compression, they drained the oil and ran the motor for 45secs, it evened out the compression on all cylinders and got the motor making the 1400hp it was supposed to make. Boat still runs 130mph to this day, 14 years later. Crazy ass stuff right there. Sorry for the off topic post.

[malibu795]

Originally Posted by WolfLLY

My buddy (who is a boat fanatic) told me they had a 1400hp bbc marine engine that wasn’t making the power it should, turns out couple of the cylinders were too high on compression, they drained the oil and ran the motor for 45secs, it evened out the compression on all cylinders and got the motor making the 1400hp it was supposed to make. Boat still runs 130mph to this day, 14 years later. Crazy ass stuff right there. Sorry for the off topic post.

Stuff they don't teach in the classroom

[duramax on fire]

Originally Posted by THEFERMANATOR

Old timers did some crazy stuff. Borax was another one they used.

Wasn't borax heated with atf and water then poured down the carb. Called the 20 minute overhaul. Borax took off the glaze. Trans unstuck rings and water knocked off the carbon. Knew guys that swore by it.

[jlawles2]

Borax was used on band brakes to stop them from squealing in the old friction rig machines when they were glazed over.

Some of that old school stuff is way easier and more useful when far away from home.

[DmaxLMM]

So just wanted to post an update in this thread. Oil analysis and engine analysis came back. Sending out the injectors today for testing. The tuner was one the engine builder recommended and is extremely well respected in the industry, it is not believed to be a tuning issue.

Oil:
ELEMENT TESTS
Water Neg
V100 14.02
Fe 249
Cu 8
Pb 9
Sn 3
Cr 14
Ni 1
Ti 0
Al 3
Si 32
Na 2
K 5
B 75
Ca 1380
Mg 759
P 782
Zn 851
Mo 1
Li 0
Sb 1
Ba 0
Cd 0
Mn 4
Ag 0
V 0
pqL Index 24
Soot 6
OXI 14
NIT 8
Sulf 20
AW 17
FT-IR Glycol 0
FT-IR Water 29


COMMENTS
Silicon (Si) is high. Silicon to aluminum (Al) ratio is acceptable. Dirt entry is not indicated. Silicon may be due to chemical leaching from silicone gaskets, seals or sealer compound. Has there been recent repair activity? If so, these results are typical after a recent repair.However iron (Fe) and chrome (Cr) are extremely high indicating piston ring and liner/cylinder wall wear.Total Ferrous Debris (pqL) index appears acceptable.These results could be due to the break-in period. However this is very severe wear which is not likely due to the break-in period. Additional inspection - including disassembly and inspection - may be necessary.



Motor was torn down by a 3rd party builder, then shipped 2 pistons back to Mahle for analysis. Initial response from the motor builder was that it was put together very loose. Here is the Mahle report:

Description of Running Conditions:
Street driven and used for towing trailer.

Run Time:
Freshly assembled motor with approx. 2600 miles.

Description of Failure or Concern:
Motor had low power and started burning excessive amounts of oil soon after break-in. Pulled heads and found all piston bore’s were scorched equally.

Parts returned:
Pistons, pins, clips and rings from 2 cylinders (#4 and #5).


1. Build-up of carbon on the fireland was making contact with the cylinder and can result in carbon cutting at the cylinder surface.
2. 100% face wear of the top ring was observed around the entire circumference.
3. 50% face wear of the second ring was present in most areas. Wear percentage of the 2nd ring showed some variation around the circumference and was near 100% at the gaps.
4. MAHLE second ring had been machined to accept a spacer rail for a gapless conversion (assumed to be Total Seal). Depth of the spacer register was visually correct (no rail protrusion).
5. 100% face wear of the oil ring scraper edges. Non-tapered design, but each scraper edge is radiused when new. Edges were worn sharp.

Possible causes of abnormal, premature ring wear:
 Ring butting
 Introduction of debris/abrasives through the intake system
 Poor cleaning prior to assembly; foreign debris remaining in engine
 Improper honing or incorrect cylinder surface finish
 Dilution or lack of proper lubrication

Probable causes that can be eliminated by analysis:
 Ring butting – No evidence of ring butting. The top ring in particular had a significant build-up of carbon present at the gap surfaces.
 Introduction of foreign debris, either through intake or remaining in engine – relatively good condition of skirts, ring lands and crown do not support this mechanism.

Probable causes that CAN NOT be eliminated by analysis:
 Improper Honing
o Typical description: The piston rings present scratches on the running surface, mainly the ones in the first groove.
o Probably Causes: Too high roughness will result in high wear and will be abrasive to the running face of the piston ring. Too low roughness makes piston ring seating difficult and retains less lubricating oil on the cylinder walls. Cylinder surface after honing should be measured to characterize the surface finish in terms of Ra, Rz, Rpk and Rvk.
Cylinder wall finish with smeared material: If graphite in the cylinder material became covered by smeared metal due to poor honing process, proper ring operation is compromised and can lead to scuffing due to a decrease in oil retention. Exposed graphite provides lubrication but also acts like a sponge to absorb and hold lubrication.

 Fuel dilution
o Typical description:
(1) The wear pattern on the skirt is wide, shiny and shows deep scoring marks along the entire piston skirt.
(2) Scoring marks on the piston rings, possibly additional burn marks on the piston ring surface.
(3) The honing in the cylinder liner or cylinder running surface is heavily worn.
(4) Heavy wear marks are visible at the piston pin w/ visible pitting in the pin bore.


o Probable Causes: An excessive amount of fuel in the oil dilutes the oil film, thus drastically reducing its load bearing ability and increasing engine component wear. This type of damage can have the following causes:
The injection system is set incorrectly
Cold start enrichment is too rich
The injection nozzles are functioning incorrectly, e.g. due to a clogged fuel filter
Due to an excessive protrusion, the piston hammers the cylinder head, causing uncontrolled injection.
The compression is weak. This can be further attributed to the following conditions:
A leaking valve
The cylinder head gasket is leaking
The timing is set incorrectly
The protrusion is too small
One piston ring or several piston rings are defective

[LBZ]

So end of the day it is either poor machining or fuel dilution then?