Philip Coetzee

Hi There,

I read an article on a 4.6L stroker jeep 4.0L engine re-build.
http://www.fourwheeler.com/how-to/en...0l-inline-six/

My motor is stock and has never been opened til now - (had some overheating issue) - There was no oile and /or water mixed at any time, but there are some gas leaks into the water system. So I removed the head for inspection.

From what I can see , the head is warped and theres a gap between cylinders 3 and 4 and I will need to remove between 0.013 and 0.020 inch to level it up.
Is this head still useable keeping everything else the same ?
I can not see any markings on the head for the "max skimm amount"and there's nothing in the jeep manual either.
We I live we only get 93 and 95 octane fuel.
Any advice?

ECamacho

Depends in the year. If it is from 1999+ you more than likely have an "0331" head which usually cracks from the overheating. Ask me how I know...

Best bet is to get a better head preferable from an older model or better one that has a "TUPY" casting. You will also have to deck the head a considerable amount if you are going to go for the stroker build. It is very involved and pricey but worth it.

Search the forums there is a crap ton of info on it.

Worst case it will cost like 350 ish depending on where you live it can be much much cheaper.

Philip Coetzee

Hi There,

It is a 1999 (in "South-african years" ) , meaning normally In South-Africa we are a couple yeasr behind with everything.... ;-) .. I checked the head and the head is a 0630 head - I don't want to stroke the motor - I just want it running again

Regards,
P

cruiser54

I searched but couldn't find the specs on milling the head. Off the cuff, I can't see .015" being a problem.

Philip Coetzee

Cool, thank you-
Once I get the head back from engineering i'll check for clearances anyway
Thanks for the advice

fb97xj1

I got this out of the FSM for my 97, under the 4.0L Engine Specifications.

Flatness - 0.03 mm per 25 mm (0.001 in. per 1 in.)
Flatness - 0.05 mm per 152 mm (0.002 in. per 6 in.)
Flatness Max: .020 mm - max. for total length (0.008 in. for total length)

Same info for the block. I can only assume those numbers are what the machine shop would need before milling them.

cruiser54

That's discouraging....I once had .100" milled off a Nissan Patrol engine to raise the compression from 8 to 1 to 10 something to 1. Worked great......

cruiser54

Look what I found!!

https://www.jeepstrokers.com/forum/viewtopic.php?t=4412

Philip Coetzee

Thanks cruiser54 ... thats looking positive.

Philip Coetzee

Hi fb97xj1 , yeah my manual said he same, does not mean much for engineering shops.

dave1123

Yeah, it only matters a if you're installing a high lift cam and milling the head a lot. Then you have to worry about valve-to-piston clearance. A .020 cut on a jeep head is enough to straighten a really bad head. If the block deck is damaged just a little, you can get a slightly thicker head gasket that should seal it.

Philip Coetzee

Hi dave1123,

yeah, thanks - will keep in mind.

Regards,
phil

Philip Coetzee

Hi Everyone,

I just want to thank everyone for all your advice.
I eventually got the head (0630 type) back from the engineering shop. In the end they took off just about 0,19" of the head. I out the head back in place and did the pre-load check and it seemed still within the 0.40" to 0.60" range.

So I continued to assemble the rest and test the engine and she's driving nice and smooth, no tappet ratling or backfires or mis fires.

Seem's all is good now.

thanks again to all.

P.S. Does anyone know where I can get a thermostat housing urgently DHL' shipped to SA? use or new, as long as it is in usable condition?

Kind Regards,
Phil

Philip Coetzee

Hi Everyone,

I just want to thank everyone for all your advice.
I eventually got the head (0630 type) back from the engineering shop. In the end they took off just about 0,19" of the head. I out the head back in place and did the pre-load check and it seemed still within the 0.40" to 0.60" range.

So I continued to assemble the rest and test the engine and she's driving nice and smooth, no tappet ratling or backfires or mis fires.

Seem's all is good now.

thanks again to all.

P.S. Does anyone know where I can get a thermostat housing urgently DHL' shipped to SA? use or new, as long as it is in usable condition?

Kind Regards,
Phil

cruiser54

Thanks for the update!!

Glad it worked out.