1999 4.7 valve spring issue
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Model: Cherokee (XJ)
1999 4.7 valve spring issue
Hi,
Just realized I posted in the XJ forum, if a mod needs to relocate it.
1999 WJ 4.7 (no H.O.), (VIN engine model (n)), 300K miles, well cared for. During a head gasket repair I elected to change the valve springs to avoid high mileage failure. This model Grand Cherokee had conventional straight valve springs, ~ 1.93 inch free length. When attempting to order new springs the ONLY springs we can find at ANY vendor are "conical" type, not straight conventional type. The dealership cannot help as Jeep has discontinued parts support on this model year.
Haynes manual shows conventional and does not comment on conical, but does reflect a different spring spec for 1999 versus 2000 and greater model years.
Wondering if anyone else has run into this or if there is a specification to move to conical? The spring ID with smaller conical coils downward, appears it would not clear the OD of the valve stem seals. I'm not sure if the more narrow end of the conical shape should point down, or if it should have the smaller OD/ID at the top of the valve retainer near the rocker arm. It does seem the lower mass conical spring might be appropriate for a high mileage engine.
Please comment with any suggestions for either conventional springs or moving to conical.
Thanks in advance.
Mike
Just realized I posted in the XJ forum, if a mod needs to relocate it.
1999 WJ 4.7 (no H.O.), (VIN engine model (n)), 300K miles, well cared for. During a head gasket repair I elected to change the valve springs to avoid high mileage failure. This model Grand Cherokee had conventional straight valve springs, ~ 1.93 inch free length. When attempting to order new springs the ONLY springs we can find at ANY vendor are "conical" type, not straight conventional type. The dealership cannot help as Jeep has discontinued parts support on this model year.
Haynes manual shows conventional and does not comment on conical, but does reflect a different spring spec for 1999 versus 2000 and greater model years.
Wondering if anyone else has run into this or if there is a specification to move to conical? The spring ID with smaller conical coils downward, appears it would not clear the OD of the valve stem seals. I'm not sure if the more narrow end of the conical shape should point down, or if it should have the smaller OD/ID at the top of the valve retainer near the rocker arm. It does seem the lower mass conical spring might be appropriate for a high mileage engine.
Please comment with any suggestions for either conventional springs or moving to conical.
Thanks in advance.
Mike
Last edited by mikewonders; 03-07-2024 at 11:36 AM.
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