Looking for a good engine shop

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George S
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Joined: Thu Apr 27, 2017 9:37 pm

Re: Looking for a good engine shop

Post by George S » Sat May 06, 2017 1:03 am

Hey W0J0 - thanks for looking at this. I don't have much experience with internal engine wear, performance, etc. but learning some already just tinkering with this engine. Looking back at past projects over the years (cars, house stuff etc.), I've realized that the process was the best part; after the work's done the end result is usually just icing on the cake.

Yeah I had the previous owner do a compression test prior to purchase. The numbers were very consistent around 125 psi (cylinder 7 was the highest at ~133; #8 lowest at 120). The engine was cold for the test. I'll look into a blow-by test; wasn't familiar with it before but it looks like actually measuring the leakage flow would be easier to compare to others' tests. Thanks for mentioning it.

I should probably explain how I did the leak down test. Starting with the TDC pressure reading, I carefully bumped the crankshaft over with a big a$$ breaker bar and held the shaft in place at several stops, making a mental note of the pressures at each stop. For each of the cylinders, there were maybe 20 or so stops/readings as the piston made its way down. The table shows the range that I saw for the resulting cylinder pressures ("P2 low" and "P2 high"). Most of the cylinders were consistent throughout their travel. But for cylinders 7 and 2, the worst readings were at the top half of the cylinder, so that's what is noted in the table - the range for the "bad" portions of 7 and 2. The lower half of those two cylinders read closer to the other cylinders, around 90-94 psi. Most of the leaking air was coming out of the crankcase breather tube, with barely any out of the intake or exhaust valves.

One thing I don't think I mentioned yet - cylinders 2 and 7 have a bit of oily residue in the exhaust ports which is also on the spark plug threads (the spark plug tips look clean/dry). It appears that the leakage from those cylinders may be enough to foul up the combustion chambers over time. Here's a photo; what do you think?
DSC_0068 Compressed.jpg
Cylinder #7 oily exhaust port (#2 similar)
DSC_0068 Compressed.jpg (179.48 KiB) Viewed 52 times
Here's what the "healthy" ports look like:
DSC_0070 Compressed.jpg
"Good" cylinder exhaust ports...
DSC_0070 Compressed.jpg (160.3 KiB) Viewed 52 times
Totally agree on not fixing something if it's not broken. I am a little concerned that the engine may have been removed from a good chassis - after finally finding the partial VIN code on the block, I managed to narrow the full VIN down to two possible 2016 Chargers (trial-and-error guessing on some of the other VIN digits). But get this - neither car shows up as a total loss or salvage, etc. Kinda wonder if it was giving the car owner some kind of trouble (possibly consuming oil, knocking, or something else?). Do you know of any common reason that a fairly new engine would be swapped out? This one supposedly has ~9,000 miles on it.

I do have to open the crankcase (eventually) to replace the oil pan, windage tray, and pickup tube so maybe that will reveal something else, who knows. Maybe an oil analysis, never had one of those done so that would be interesting.

Thanks again for reading and commenting. I really appreciate the tips, suggestions, etc.

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Joined: Wed Apr 26, 2017 7:56 am

Re: Looking for a good engine shop

Post by W0J0 » Sat May 06, 2017 12:28 pm

That is a strange story on the engine! At 9000 miles, that thing should be just broken in, not in need of work like that.
Thanks for clarifying your testing procedure--that does shed some more light on the results. I was thinking high and low were piston positions in the hole and not the range of the measurements. A blowby test is likely only to confirm what you found from the leakdown test and that is that you have substantial blowby into the crankcase.
As for the oil and potential plug fouling, what do your intake valves look like for those cylinders? Often oil in a cylinder will come from worn guides/seals. Not likely with the supposed low miles on this engine but looking to rule out other variables.
You mentioned having to replace oil pan and pickup tube? Was this engine damaged and starved for oil?
An oil analysis is a good tool for keeping track of a running engine's health and is generally used to track and compare to previous analyses. A one-off is useful for determining if the current oil has contamination such as antifreeze or alarmingly high levels of wear metals in it. I used them to establish safe oil change intervals for my TDi. By analyzing the protective qualities of the oil, I learned that I could safely extend OCI's to 12k miles or more.
All in all, I think you're on the right track in looking for a qualified engine machine shop. I hope that your project's scope doesn't get too far beyond what you bargained for.

Sent from my mobile look-at device

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Joined: Thu May 04, 2017 2:56 pm

Re: Looking for a good engine shop

Post by mikeyboat » Mon May 08, 2017 9:05 am

I used Custom Crankshaft on Chapman - happy so far

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George S
Posts: 7
Joined: Thu Apr 27, 2017 9:37 pm

Re: Looking for a good engine shop

Post by George S » Mon May 08, 2017 10:35 pm

Thanks for the replys! Yeah at ~9,000 miles and a compression test, I figured the engine was a fairly safe purchase. Oh well, win some, lose some. Let's call it a win (please, before the repair bill comes in...) because without the questions we wouldn't be here talking engines and I probably wouldn't be meeting a professional engine guy in the near future. :) I've been watching "Nick's Garage" on Youtube - Nick's been building engines for 40+ years; recently he built an ALL ORIGINAL 426 Hemi (that is, as true to the original as it could possibly be). The engine is going into a '71 Challenger that he hadn't yet found as of the recent video. Awesome.

Anyway, hopefully I'll get this engine sorted out. It's going into the Jeep, so the car oil pan, pickup tube and windage tray will be swapped out for the truck hemi version (rear drop oil pan). Going to try to get it to a shop sometime this week for inspection etc. I'll take some oil for a sample before handing it over to the doc. :lol: I was going to have a look at the intake ports, but figured there's enough mystery and signs of potential trouble to get it to the shop already. I'll post the diagnosis and treatment plan when I get it.

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