I have put in a fueling oil pump, S&S cams, S&S 89 cc Performance heads, and Keith Black 10.6/1 domed pistons. This is in a 2005 Dyna Twin Cam 88. My mechanic asked me to do 1000 mile break in b4 we remap the motor, so I put on about 1300 miles below 3500 rpm. During that time I used just a little better than 2.5 quarts of oil. My mechanic and I did compression test and what he called a leak down test. The leak down wasn't a true leak down, just waiting a while to see if the compression bled off. The compression readings were 160 on the front cylinder and 170 on the rear cylinder. My mechanic, whom I trust, felt these were great readings and, initially, so did I. I have since been presented with the information that, with the equipment we installed, we should have readings more in the 200 and above range.



Any thoughts or comments from some of you experienced builders out there? Where do you feel my compression readings should be and where did that much oil go????

 

no way to know where the compression readings to be without knowing what cams your running,as far as putting 1000 miles on it before "re mapping",do you mean you ran 1000 with NO tune at all?? was it dyno`d or just remapped? im seeing some big red flags over this "mechanic"

 

It had the stock tune for a stock 2005 wide glide EFI. He felt it wouldn't hurt anything until we got it on the Dyno and remapped after a 1000 miles.
BTW, the cams are S&S 510 C

 

1) Find a new mechanic
2) Rebuild top end due to probable scuffed pistons
3) Have it properly tuned immediately to prevent #2 from happening again.

The idea that a stock map would be adequate is absolutely insane!!

 

I also have misgivings about your mechanic but before doing anything you need to verify that the 160/170 compression readings are accurate and what is the true leak down percentage.

If the motor is still 88" the piston dome would have to be 20ccs with 89cc chambers to push CCP to 200psi; pretty sure that the piston dome is much smaller than 20ccs. You meed to call Keith Black, with the piston PN and get the dome volume so you can calculate CCP. Once you have an accurate caculated number you can compare that to actual. A proper leak down test will tell you how much compression is leaking down and from where. Once you have that information, you can make a decision on what to do next.

A stock map for a new performance build is very wrong; too much timing, so that could be an issue. You could have rings installed wrong, upside down, etc. but 2.5 quarts is a sure sign that something is wrong with the top end. Are you absolutely sure about the consumption?

 

I was on a 1000 mile break in ride. I put 2.5 quarts in by the time I returned home with a little better than 1300 on the motor. We pulled the plugs and they were a light tan and seemed to be burning well. the pipes look like it is running rich. We are going ahead with the remap and he has stated he will pay for a second dyno and remap in addition to another rebuild if something comes up wrong. I am going to look into a proper leak down gauge online before that though. todd, my mechanic does not have one.

 

Thank you for all the responses. A lot of that info I do not have. The cams are S & S 510 C, the honing was standard cross hatch honing, The heads are S & S 89 CC performance heads, The plugs are light tan and seem to be burning properly, although the pipes are sooty. Todd, my mechanic, has built a number of performance engines. He admits he cannot explain the oil consumption, but has assured me that, if we go ahead with the remap and dyno, a costly affair, and something fails he will stand behind all of it, rebuild, reremap, and what ever else is necessary. I have ordered a leak down tester and a bore scope as he does not have either. we will employ them before we go forward with the remap.

 

chromium rings??
the hone for them is a tad diff.
sometimes it take a good while for them to seat in, in fact, seen them never seat so a little trick was done to see if they would.
in the olden days, we would use some cleanser called bon-amie but it HAS to be the one with a chick on the box and says WILL NOT SCRATCH. this was added to the oil and run short term and then flushed.
sometimes a statue, sometimes a pigeon
along other lines, rich fuel burn will wash critical oil film off the cyl walls. if it does not improve, a look-see would be a good idea.

 

A leak down test may not going to show you where the motor sucking oil. It might if the rings lines up but it won't find a bad valve seal, might not find piston ring groove issue or say a second ring upside down issue or 1 broken ring. If you are still stock bore and the domes are say 6cc, you'd have 170 psi cranking compression. IIRC the KB 10.6s 95 ci pistons are 11cc. It could squeak out 195. No way would I run that with a stock efi map.

At that oil consumption, the motor should come apart.

 

:wtf: I finally got to using the new leak tester and the bore camera and we found no leaks and with the camera and scope the cylinders look beautiful and like they are just starting to seat. No high spots, no low spots. there has been no oil usage in 120 miles and the pipes are clearing up :scratch: We are going to go ahead with the remap and dyno and hope for the best.

My deepest appreciation to all who tried to figure out this conundrum with us and offered excellent advice. Thank you very much.