Jump to content

stroking a 91 high output 4.0L whats the best combination


Recommended Posts

Mine are all Renix, not HO, but the issues remain the same. The stroker is created by using the crank from the older 4.2L engine. Due to minor differences in deck height and wrist pin height between the two engines, there's an issue of higher compression to be dealt with. After a LOT of research (because the idea of a stroker and the resultant torque sings a siren song in my head), I finally gave up. I can't afford a HESCO, and there are too many issues involved for me to attempt doing it on my own.

 

That's not because I'm afraid to build an engine -- I've done two for my old autocross/hillclimb cars. It's just that you can't simply buy parts and assemble them without creating problems. And the notion of trying to solve a high compression problem by decking the block (thus INCREASING compression still more) to optimize "quench" is just too much for my little brain to deal with.

 

Start saving your lunch money.

Link to comment
Share on other sites

how much can u stroke a 4.0l

I have seen them past 5.0L. Just because you can, doesn't mean you should. You should really study jeepstrokers forum.

 

From my research, all aftermarket pistons for the 4.0 have a deeper dish than the stock 13.1cc. This is important to consider because once you deck the block to attain the appropriate quench, these deeper dished pistons could make up for the additional compression caused by decking the block. In addition to the basic compression ratio calculation, you must take in account the valve timing. I studied stroker builds till I was blue in the face for my truck. I decided against it and will build my second 4.0.

 

Yes, you can build a reliable stroker. It's been done several times. But the important thing to do is research and make your own decision. Asking for the best stroker build plan is like asking what is the best tire/wheel/lift combo.

Link to comment
Share on other sites

I've pondered the stroker topic for a few years, and every time I think about

starting to assemble the pile of parts, that old addage pops into my head: "Speed

{power} costs money, how fast would you like to go?" And I'm sure there's

a corrollary that says; The higher the HP/TQ, the shorter the life. How long would

you like it to last? And then there's (for the do it your selfer) the uncertainty factor,

no matter how much you plan ahead, there's a good chance that factors will

conspire to cause you more time and money than you planned.

Link to comment
Share on other sites

how much can u stroke a 4.0l

If you have a good block, with no core shift issues, you can get to 4.6L and probably 4.7L. Going beyond that requires sleeving the block.

 

Dang! I worked on this so long ago that my spreadsheet is (was) in Quattro Pro ... and I no longer have anything that'll open a Quattro Pro spreadsheet. IIRC, the rule of thumb is that using the 4.2L crank, a .030 overbore gets you 4.5L, .060 over gets you 4.6L, and .090 over gets you 4.7L.

 

Anything beyond .090 over gets you into deep pockets territory.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...