 Engine Clatter, New rebuild and Cam |
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| 2-OH! |
 Jun 11 2007, 01:59 PM
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#1
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Senior Member  Group: Members Posts: 552 Joined: 17-October 03 From: Santa Clarita, Kalifornication Member No.: 1,253  |
When we rebuilt the 73 1.7, I wanted to re-use the D-Jet so we put just the next step up from stock, Web Cam and lifters in the motor...
I have advanced the timing just a little to get rid of the clatter but it's still there if I really get on it... Should I continue to advance the timing or should I retard it ??? Already using 92 octane... 2-OH! |
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| PeeGreen 914 |
Jun 11 2007, 02:03 PM
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#2
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Just when you think you're done...wait, there is more..lol Group: Members Posts: 10,219 Joined: 21-September 06 From: Seattle, WA... actually Everett Member No.: 6,884 Region Association: Pacific Northwest 
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Are you sure all of your valves are adjusted? Just checking.
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| 2-OH! |
Jun 11 2007, 02:22 PM
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#3
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Senior Member Group: Members Posts: 552 Joined: 17-October 03 From: Santa Clarita, Kalifornication Member No.: 1,253 |
Yea, think so...We adjusted them at about 700 miles after break-in and it's now at 2500...At this point, I think they are good...
2-OH! |
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| Cap'n Krusty |
Jun 11 2007, 02:32 PM
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#4
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Cap'n Krusty Group: Members Posts: 10,794 Joined: 24-June 04 From: Santa Maria, CA Member No.: 2,246 Region Association: Central California |
Web Cam's "next step up from stock" does NOT work satisfactorily in the "real world", despite what the salesman is telling you. Recalibrating the MPS provides a small improvement in drivability, but you still have large HC numbers at the tailpipe. HCs are unburned fuel. No amount of fiddling is going to get rid of the "tip in" performance problem off idle. The ONLY aftermarket "performance" cam about which I've heard good things in actual use with Bosch EFI is Jake Raby's cam, but I have no personal experience with it.
As for your noise, advancing the timing is going to promote detonation, as well as causing a heat problem that's invariably fatal to air cooled engines. You ned to properly adjust the valves, set the point dwell and timing to specs, and see what happens. Other sources of clatter are sloppy piston fit, improper backlash in the cam gear, the gear coming loose on the cam, the bolts hitting the oil pump, rods with too much side play, loose wrist pin bushings, and a host of other things. The Cap'n |
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| Jake Raby |
Jun 11 2007, 02:34 PM
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#5
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
Did you correctly complete valve train geometry, or are you just expecting to toss the cam and lifters in and go from there.
Making ANY camshaft alteration REQUIRES the valvetrain geometry to be reset and that means non stock pushrods must be used. |
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| Jake Raby |
Jun 11 2007, 02:41 PM
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#6
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
I lost power before I finished my post!! here is the rest.
I'd be willing to bet that the geometry is way out and thats why the clattering exists and thats killing the valve train and valve guides. The cam that the Cap'n refers to that I sell has the intake characteristics of the Web 73, but it has an altered exhaust profile that I specifically designed for stock FI. |
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| 2-OH! |
Jun 11 2007, 02:45 PM
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#7
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Senior Member Group: Members Posts: 552 Joined: 17-October 03 From: Santa Clarita, Kalifornication Member No.: 1,253 |
Cap'n:
I agree with all the above...I'm watching the temp, but so far, she's never been over 210...So, I think we are good there...But I do agree with Blood red and you about the valves so I am going to look at that again... Jake, Can't answer that question, engine builder did the complete Long block for me...We did go to swivel foot adjusters so we did have to make the adjustments for that in with the rockers and mounts etc... 2-OH! |
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| Aaron Cox |
Jun 11 2007, 09:47 PM
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#8
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
show us your pushrods rick.
if they are stock.... you most likely found that your wrench didnt do the geometry right (or that 1% chance that they were the right length to begin with) |
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| Jake Raby |
Jun 12 2007, 10:32 AM
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#9
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
Sounds like another case of incorrectly set geometry... Making adjustments for the swivel feet does not magically correct geometry, it can make it WORSE!
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| Joe Ricard |
Jun 12 2007, 10:56 AM
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#10
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CUMONIWANNARACEU Group: Members Posts: 6,811 Joined: 5-January 03 From: Gautier, MS Member No.: 92 |
It clatters under load. when I advance the timing it clatters more.
Just about the funniest thing I've heard or read all day. Little bit more advance it will get quiet. REAL QUIET (well after the big boom) |
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