03 5.7 timing procedure

Hello , JUst completed a major repair on my2003 mercruiser 5.7lt 2bcarb thunderbolt ignition lost compresion in #6 and #4 cylinders. had the head redone and found both exaust valve seats burned out pretty bad . i am suspecting that there is a timing issue that caused this damage. the engine is back together with good compression but cant set timming because there are no timming marks on chain cover just a pointer. THe seloc manual metions use of scan tool to set up base timming is this true Is there anyway of setting timing with out it ? i have heard of running boat wot advancing timming untill it pings then turning distributer back a notch .pretty risky though. any help would be apreciated .

Re: 03 5.7 timing procedure

THe seloc manual metions use of scan tool to set up base timming is this true

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Why do people buy those worthless manuals

i have heard of running boat wot advancing timming untill it pings then turning distributer back a notch .pretty risky though.

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Don't even think of trying that with the Thunderbolt V ignition.

Head up to the Adults only sticky at the top of this forum and download an OEM service manual for your engine. In the ignition section, it will detail how to put it in base timing mode WITHOUT any scan tools or anything else.
The best way to check the timing is with an advance type timing light. Another option is a decal that goes on the vibration dampner. You can find the tapes at speed shops and big automotive stores.

Re: 03 5.7 timing procedure

Thanks for your help, downloaded oem service manual and folowed timing procedure. ran engine today but only could achieve 4000 rpm wot. still suspect problem with timing re checked valve adjustment and compression is160 and better in all cyl. Engine would turn up 4500rpm no prob before repair?