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Old 11-08-2019, 11:08 PM
sagem57 sagem57 is offline
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new a4 owner ???

just had my first summer with the a4. love it! since I am refurbishing the whole boat I decided to pull the motor and go thru it and give it some updates. after disassembling much of the motor I have a few questions
. first, which end of the engine is the front? all of the pistons are in the correct holes 1234. how ever all of the arrows on the pistons point towards the transmission end . I should mention this is a late model direct drive. are they in the correct orientation ?

secondly ,compression test was done after I removed motor and so I had to hand crank . cylinders 1 thru 4 are as follows 63,63,68,69 high/low ???

what's my best move?
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Old 11-09-2019, 02:25 PM
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The standard reference for compression testing is :
  • All 4 plugs out
  • Throttle wide open
  • Choke wide open
  • Crank with starter

Failing to observe any of these will result in lower numbers.

That having been said, the usual rule of thumb is anything in the 80s or higher is fine, although the A4 will run (with reduced power) down into the 60s.

Since you hand-cranked, your numbers can't be compared, but the fact that they're all very consistent is a good sign. They're going to be higher with the starter, but can't say exactly how much.

Its pretty easy to remount the starter and hook up a battery and a solenoid switch to crank the engine on the bench, but it sounds like you've already got the head off.
@(^.^)@ Ed
1977 Pearson P-323 "Dolce Vita"
with rebuilt Atomic-4

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Old 11-09-2019, 09:40 PM
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The transmission is the front of the engine, so if the arrows point to the transmission you are good.
Pearson 10M
Gloucester, Va
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Old 11-09-2019, 09:48 PM
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Al Schober Al Schober is offline
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Welcome to the forum!
You need the 'Bible': Contains MUCH good info.
Oh yes, 'Front' of an engine is the end with the timing gears. Works with most engines, not all. I've worked on Fairbanks-Morse diesels with upper and lower crankshafts, coupled by vertical shaft in the 'middle' of the engine - no timing gears as such.

Last edited by Al Schober; 11-09-2019 at 09:59 PM.
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