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  1. #1
    Myself's Avatar
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    4-tec rebuild advice please.

    Going to do a basic rebuild on an '03 GTX non-sc. Had some rattling noise at the rear which seems to be a loose timing chain and bad starter drive. It was also starting to loose a head gasket. Was thinking I could just replace bearings, rings, gaskets, timing chain, bendix, and valve seals (lap the valves back in). Any thoughts on this or particular things I should look out for?


  2. #2
    Mighty Mouse's Avatar
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    Replace these sodium filled valves, 3 angle valve/seat grind, install ARP head studs, hone cylinders before you replace rings, replace flywheel bolts, might even want to have injectors cleaned, maybe someone else will jump in ....

  3. #3
    Myself's Avatar
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    I thought just the supercharged ones had those valves?

  4. #4
    All 4-tec engines have the bad valves from 03-06

    you might as well replace them while your on, I'm doing mine soon.

  5. #5
    Replacing the valves, and doing a 3 angle seat job are highly recommended. Every 4 tec I have worked on has had some degree of widened seats with carbon build up. Seat width is more critical than most people are aware on these engines. Too wide and you get carbon build up and leakage. Too narrow and you get loss of heat transfer.

  6. #6
    shrabber's Avatar
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    Three angled valve jobs are never something that is reccomended for a stock motor and or the longevity of a motor. A standard valve job with seals ( springs tension checked) is the way to go.

  7. #7
    Quote Originally Posted by shrabber View Post
    Three angled valve jobs are never something that is reccomended for a stock motor and or the longevity of a motor. A standard valve job with seals ( springs tension checked) is the way to go.
    I guess you don't quite understand what a 3 angle valve job is. The purpose is to control the width of the seat face and the position of the face relative to the valve. As I said, most 4 tecs I have seen have way too wide seats and suffer with excessive carbon build up. If you just do a "standard" valve job, you are making the problem worse by widening the seat.

  8. #8
    Mighty Mouse's Avatar
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    I three angle valve job will not reduce engine life or longevity if done correctly.there is alot of science and techiniques on valve/seat configurations. In fact most cars now have 3 angle seats. Now if you are talking a 5 angle or 7 angle, that may be a different story. But in all reality, as long as they dont leak, you wont see much difference in stock performance. It would flow a better though.

  9. #9
    ncdoo's Avatar
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    Just lap the new valves in, and you'll be good to go.

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  11. #10
    Quote Originally Posted by ncdoo View Post
    Just lap the new valves in, and you'll be good to go.
    This is really terrible advice. You should never put new valves in without reconditioning the seats, unless you know how to inspect them properly and are assured they are perfect. Since the other guys on this thread apparently don't understand what a 3 angle valve job is, please read the Sea Doo manual which explains the process. The Sea Doo heads are built using a 3 angle process. This isn't done to have the head flow better, this is done to control the seat width and to get the valve face to fit properly in the seat.

    The Sea Doo manuals give the specs for valve seat width, and I have not seen a head that wasn't at the limit, and most I have seen have some degree of carbon build up and erosion. If you just lap in new valves, you will have a leaker in short order.

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