The timing cover for the 2.5L had two designs. One included two nuts welded on for front oil pan attachment. When using this timing cover, use the early design seal #3923440 and fill the bolt holes with RTV sealant. The following vehicles used the same timing cover:
Buick Century '82-90 2.5L Buick Skylark '82-85 2.5L Camaro '85-86 2.5L Chevy Blazer S10/GM Jimmy S15 '85-88 2.5L Chevy Celebrity '82-90 2.5L Chevy Citation '82-85 2.5L Chevy Lumina Car '90 2.5L Firebird '82-86 2.5L Olds Ciera '82-90 2.5L Olds Omega '82-84 2.5L Pontiac 6000 '84 2.5L Pontiac Astro '85-90 2.5L Pontiac Phoenix '82-84 2.5L Pontiac Safari (GMC) '85-90 2.5L Pontiac Ventura II '77 2.5L S10/S15/GM Sonoma '82-93 2.5L
'85-86 2.8L The timing cover for these engines is unique. Will not interchange with '87-88 Fiero.
'87-88 2.8L The timing cover for these engines is unique. Will not interchange with '85-86 Fiero.
'84-86 2.5L: Harmonic balancer not used on these engines.
'87-88 2.5L: A harmonic balancer from the engines below will transfer:
Buick Century '87-91 2.5L Chevy Celebrity '87-90 2.5L Chevy Lumina Car '90-92 2.5L Olds Ciera '87-92 2.5L Pontiac 6000 '87-91 2.5L
The harmonic balancer for the V-6 has been discontinued by GM but part number 14085401 will fit if the timing marks from the old harmonic balancer are transferred carefully to the new one. Don't try to use the timing marks from the new balancer; they are 60 degrees off!
'85-86 2.8L: The harmonic balancer for these engines is unique. Will not interchange with '87-88 Fiero.
'87-88 2.8L: The harmonic balancer for these engines is unique. Will not interchange with '85-86 Fiero.
Harmonic Balancer, Aftermarket: Some aftermarket balancers for the Fiero are shown below.
Harmonic Balancer, 2.5L, '87-88 Dorman 594-027 Harmonic Balancer, 2.8L, '85-87 Dorman 594-013 Harmonic Balancer, 2.8L, '88 Dorman 594-008