I have a 01 witha cracked head and wiped cam bearings, I want to swap it for a pre 0331 head engine. I have read that the 91-01 cherokee and 93-97 grand cherokee blocks are the same, Is this true? What year Wrangler blocks will work? Other than the coil pack mounting you have to fab to use the 01's distributorless ign, is ther any reason an older motor wouldn't work?
I have yet to confirm all of this independently - it's all reports from the field - so take it with a grain of salt...
- There are mounting differences (block-to-chassis) between the YJ/TJ version and the XJ/MJ/ZJ/WJ version. This can't generally be swapped.
- Within models, mounting did not seem to change through the years, so they may be swapped freely.
- ANY 6-242 head can be mounted to ANY 6-242 block, regardless of model or model year.
- The 0331 head up through mid-2001 was fit only for scrap - look for a replacement with the TUPY foundry mark under the oil fill cap, this is the revised head that should last. Available late 2001-2006, this can be retrofitted in place of an early 0331 head without difficulty.
- If you "roll back" to an earlier head (0630, 7120,) know that you may need to fabricate an adapter plate to use the 0331 exhaust header with the earlier head - with each revision, the size of the exhaust ports was reduced, ostensibly to improve catalyst light-off time. The "adapter plate" would actually be a block-off, meant to cover the bits of the port that aren't covered by the primary tube entry. This may easily be fabricated using decent mild steel (I'd go at least 0.090" thick,) use the correct gasket for the head on the head side, the correct gasket for the exhaust on the exhaust side, and make the exhaust holes in the plate match the holes in the EXHAUST MANIFOLD (
not the cylinder head!)
- Further, if the above is done, brackets are usually readily fabricated from sheetmetal to support the coil rail, attaching them to the screws for the valve cover.
- While the 2686 head (1987-1990) WILL mate to the block, its use is NOT recommended, due to the shift in location of intake ports for the 1991-up model years. Easier to just get a later head.
Anything further you'd like me to dig around for?