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Automatic 1993 Geo Tracker 8v
When you align the marks on the crackshaft and camshaft, as Haynes suggests, put #1 at TDC. The alignment procedure is specified in the 1993 service manual as requiring a compression stroke of #4 TDC...
Assuming the assembly followed Haynes's instructions and the valves were fine-tuned, (Performs poorly)
Am I required to return to the service manual and follow its instructions for properly setting the marks and adjusting the valves?
HELP
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Issue with the Timing Belt
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Benjamin_RR
- Posts: 71
- Joined: Mon Feb 02, 2026 9:00 pm
Consider this for a second: how is the compression stroke at #1 TDC different from the one at #4 TDC?
The camshaft in a four-cylinder inline engine determines which cylinder is on the compression stroke, but in general, when you turn the crank at #1 TDC, #4 is also at TDC.
The camshaft in a four-cylinder inline engine determines which cylinder is on the compression stroke, but in general, when you turn the crank at #1 TDC, #4 is also at TDC.
In terms of the timing marks and the relationship between compression stroke and valve adjustment, I get it, but what about "both at TDC?"
Since the #4 is on the opposite stroke of the camshaft setting, the correct alignment position would be 180 degrees off, right?
Since the #4 is on the opposite stroke of the camshaft setting, the correct alignment position would be 180 degrees off, right?
Are you able to look over the thread about ground damage fire?
I started thinking about installing the timing belt about a month ago, when I started it. The simultaneous TDC of cylinders 1 and 4 is something I can get my head around. Attempts to rescue my Tracker from the trash heap have me completely bewildered... Much obliged for the time and advice you have given.
I started thinking about installing the timing belt about a month ago, when I started it. The simultaneous TDC of cylinders 1 and 4 is something I can get my head around. Attempts to rescue my Tracker from the trash heap have me completely bewildered... Much obliged for the time and advice you have given.
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Benjamin_RR
- Posts: 71
- Joined: Mon Feb 02, 2026 9:00 pm
No, because #1 and #4 are both at TDC simultaneously, you can't set #1 to TDC without also setting #4 to TDC. Accordingly, it makes no difference if you set #1 to TDC or #4 to TDC; when the cam and crank marks are lined up, #4 will be on TDC compression regardless.
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Benjamin_RR
- Posts: 71
- Joined: Mon Feb 02, 2026 9:00 pm
Another thing to look out for is if your cam pulley has two distinct markings—say, an E for 60 and an I for 80. The E/60 mark is where our timing belts are finished. The cam key is set at 6:00 and the crank key is at 12:00, with the E/60 mark at 12:00. Your #4 cylinder is actually in the compression stroke, not the exhaust stroke, as far as I can tell. Plus, make sure the distributor's ignition timing is set to compression/firing #1. The rotor on the 8v turns clockwise as your engine fires 1, 3, 4, 2.
Also, save yourself some trouble in the long run by dumping that Haynes manual. It contains a lot of false information and tries to cover too many cars in one issue.
Also, save yourself some trouble in the long run by dumping that Haynes manual. It contains a lot of false information and tries to cover too many cars in one issue.
