Stroker renix/ho advantage?????

Ok my motor is toast so Im going to start on my stroker. I have a 87 bare block that I may have machined. Or sould I get a junkyard 96+ becuase it's stronger and I wont have to swap all of my accessory brackets [COLOR=blue! important][FONT=Verdana, Arial][COLOR=blue! important][FONT=Verdana, Arial]oil [/FONT][COLOR=blue! important][FONT=Verdana, Arial]pan[/FONT][/COLOR][/FONT][/COLOR][/COLOR] etc. Plus I dont have a head I heard 91-95 are the best 96 up are the same but dont have the colant temp hole. So what should I do?? also since My jeep is a 90 sould I use my head I have now that is ported and my [COLOR=blue! important][FONT=Verdana, Arial][COLOR=blue! important][FONT=Verdana, Arial]stock[/FONT][/FONT][/COLOR][/COLOR] intake with the bored tb I allredy have or sould I use a 99 up [COLOR=blue! important][FONT=Verdana, Arial][COLOR=blue! important][FONT=Verdana, Arial]intake[/FONT][/FONT][/COLOR][/COLOR] and convert my sensors. My reasoning is is it worth it will the newer head/intake really make a big diff over what I have now??? Beacause anything is better than my current motor so is it worth the time money and effort fot that little extra???

From what i have read (I my be way off base) I would us your Renix block so that you can retain your Renix electronic(Knock censor) and your Renix head(cus it free and it probably already flows better then the stock early HO head but, if ya ported it........... and the early or late HO manifolds flows better but the req mod to make it work. Have also been told that the HO manifold don't work to well with Renix head, do to the ports not matching to well.
HO head would also req a HO header. due to the same port alignment problem

EGR problem two

Flash

That link showed a ex manifold(stock)not a header........I would go with a header my self.

Parts I'd like to accumulate for my stroker, when I get around to it...

"Heavy" RENIX block casting (I'd like to know I can go out to 4.000" - leaving a minimum .100" wall. This is all but impossible with later blocks...)
OBD-I cylinder head, casting #7120. Retains coolant temperature sensor hole, and flows better than the RENIX head.
AMC258 crank - prefereably (for me and my needs - half-throttle or less) a 12-counterweight version.
1996-up main bearing caps, studs, and main bearing brace. Align hone in place on RENIX block (or make new ones out of slab steel, perhaps, and machine block and mains for four-bolt, rather that two-bolt. Haven't looked into this yet. However, this could also mean a potential to modify the brace for all four main screws - but I'm not sure if I want to go to all that trouble...)
Need to check my notes (where'd I put those...?) for cam selection. I've also got an idea to design an intake manifold, since I want to mount a Whipple (on its side) forcing in about an atmosphere at full boost - I want to make room for the thing to fit. This would require a bracketry change as well, and I haven't decided how I want to route everything just yet...
I probably want to design a header as well - I just haven't gotten enough notes to figure out how I want to do that just yet...

Kelley,

Reading your post makes me wonder what I might have missed on my stroker build.

I used 7120 head, 12 counterweight 4.2 crank and rods. 1990 renix block with main caps and bolts. Balanced assembly, ported head and had machine shop set compression to 9.5:1. As my motor wont turn 7k rpms at all, I figured main studs were out. And the rod bolts checked out ok as did the rods. I did stud the head though as head bolts were the same price from Mopar Performance as the studs from ARP.

On a side note on the blocks...I have a 95 block in my 90XJ right now. The knock sensor hole was plugged with a pipe plug. I unscrewed the plug and put the sensor in the hole. May not be true for all blocks but figured I would add that info in there.

Thats good to now. that mean thay used the same block......or atlest casting untill the last 4.0 desine for NVH reasion....right?

flash.

Well I dont think im going to bother putting a newer ho head and intake seeing that I put a bored tb and aftermarket header on my engine in Sept not to mention the time I spent porting it. If I want more power down the road ill just swap out a newer head later on.. My jeep has enough power for me now so any imporvment over what I have now is great. My rings are gone and this thing blows by like crazy. I got a quote for $200 at the machine shop to have everyyhing done I just need to get the parts and assemble it.

They revised (read: "lightened") the 4.0 block casting a couple of times for NVH reasons - for 1991, 1996, and (I think, but I'm not sure) in 1999 or so. That's why you can't bore later blocks out as far as earlier ones - AMC engines were known for thick cylinder walls - which they did mainly for durability. I've checked a RENIX block against an OBD-I block at school, and the cylinder wall thickness dropped a good .050" all around!

Apart from that, there was really no change to the basic block design. Also, bear in mind that the knock sensor does not communicate with a fluid passage - therefore, the pipe plug found in the hole wasn't really needed.

Later blocks retained the cast boss for the knock sensor hole, so it would be a fairly simple matter to drill and tap. Just don't go all the way through...

Bouncy said:

On a side note on the blocks...I have a 95 block in my 90XJ right now. The knock sensor hole was plugged with a pipe plug. I unscrewed the plug and put the sensor in the hole. May not be true for all blocks but figured I would add that info in there.

Click to expand...

The 93 block in my 90 was the same way too.

I want to run 87 if possible.. 9:6:1 seems a bit high for that Does anyone know if this combo works well??? it's what im considering im doing alot of reading on quench height and tryting to decide what the best option is.



Jeep 4.2L 3.895" stroke crank
Jeep 4.2L 5.875" rods
Jeep 4.0L 3.875" standard bore pistons
9.7:1 CR
CompCams #68-231-4 206/214 degree camshaft
Ported HO 1.91"/1.50" cylinder head
Stock 0.051" head gasket
0.081" quench height
Ford 24lb/hr injectors with adjustable FPR or MAP adjuster for '87-'95 engines, Ford 24lb/hr injectors with stock 49psi FPR for '96 and later engines
266hp @ 4950rpm, 322lbft @ 3500rpm

4.6L Low-buck stroker

Option 1: Same as above except:
Speed Pro H825CP +0.030" bore pistons
9.6:1 CR
Mopar/Victor 0.045" head gasket
0.083" quench height*
265hp @ 4900rpm, 325lbft @ 3500rpm

Option 2: Same as "rockcrawler" except:
Piston dish volume 22cc
9.5:1 CR
Crane #753905 204/216 degree camshaft
Ford 24lb/hr injectors with adjustable FPR or MAP adjuster for '87-'95 engines, Ford 24lb/hr injectors with stock 49psi FPR for '96 and later

traitor5150 said:

Well I dont think im going to bother putting a newer ho head and intake seeing that I put a bored tb and aftermarket header on my engine in Sept not to mention the time I spent porting it. If I want more power down the road ill just swap out a newer head later on.. My jeep has enough power for me now so any imporvment over what I have now is great. My rings are gone and this thing blows by like crazy. I got a quote for $200 at the machine shop to have everyyhing done I just need to get the parts and assemble it.

Click to expand...

how was the improvement of boring the throttle body and head porting......or was this dun after you eng dyed or was pulled out?

was there any strange quirks with the way it ran when the TB was enlarged. and adapter bored......what size did ya go with!

any problem or pit fall should i look out for?

Flash.

traitor5150 said:

I want to run 87 if possible.. 9:6:1 seems a bit high for that Does anyone know if this combo works well??? it's what im considering im doing alot of reading on quench height and tryting to decide what the best option is.



Jeep 4.2L 3.895" stroke crank
Jeep 4.2L 5.875" rods
Jeep 4.0L 3.875" standard bore pistons
9.7:1 CR
CompCams #68-231-4 206/214 degree camshaft
Ported HO 1.91"/1.50" cylinder head
Stock 0.051" head gasket
0.081" quench height
Ford 24lb/hr injectors with adjustable FPR or MAP adjuster for '87-'95 engines, Ford 24lb/hr injectors with stock 49psi FPR for '96 and later engines
266hp @ 4950rpm, 322lbft @ 3500rpm

4.6L Low-buck stroker

Option 1: Same as above except:
Speed Pro H825CP +0.030" bore pistons
9.6:1 CR
Mopar/Victor 0.045" head gasket
0.083" quench height*
265hp @ 4900rpm, 325lbft @ 3500rpm

Option 2: Same as "rockcrawler" except:
Piston dish volume 22cc
9.5:1 CR
Crane #753905 204/216 degree camshaft
Ford 24lb/hr injectors with adjustable FPR or MAP adjuster for '87-'95 engines, Ford 24lb/hr injectors with stock 49psi FPR for '96 and later

Click to expand...

You'll need to overbore the cylinders anyway so you could consider a lightly modified version of my "poor man's" stroker instead:

Jeep 4.2L 3.895" stroke crank
Jeep 4.2L 5.875" rods
Sealed Power 677CP +0.020" pistons
9.2:1 CR
Stock 4.0 camshaft
Ported Renix 1.91"/1.50" cylinder head
Bored Renix TB
Mopar/Victor 0.045" head gasket
0.090" quench height
Ford 24lb/hr injectors with stock 39psi FPR for '87-'95 engines
MAP adjuster

It uses as many OEM components as possible so that should make the stroker more reliable than highly modified versions.

So that setup would be a decent running reliable motor that will run on 87 no prob?? The .090 quench it the dist from the top of the piston to the head sufface correct? It seems a bit hight but the cr seems low enought be ok am I right or am I not understanding this correctly. Also the only way to figure out my quench height is to assembly the motor then mesure it??