Simple/Budget Stroker Build 2000 WJ 4.0 to 4.5

[rradford9]

OK, so dumb question here but if I get a 4.0 re-main kit, it'll have 4.0 rod bearings. Are those the same piece I'll need to use the 4.2 rods, or are the 4.2 and 4.0 rod bearings different?

EDIT: Nevermind, brain fart! The 4.2 crank kit is already coming with the proper rod bearings...but I can't use the main bearings, I have to get some to fit the 4.0 correct?

[Mgardiner1]

The rod bearings are the same from the 4.2 to 4.0 do it doesn't matter. You are correct on the crank bearings. 91+ main bearings required

[rradford9]

These are the correct rods right? They're about half the price of everywhere else I've found...
https://secure.pawengineparts.com/shopp ... &catid=951

[Mgardiner1]

They appear to be the correct rods, and you are right, they are a lot cheaper then i have seen offered from most

[rradford9]

Wow, and they do free UPS Ground shipping for orders under 150 lbs ($10 handling fee though)

[rradford9]

I called Falcon (from ebay) today to get prices b/c I was having a hard time finding parts locally and my enginetech vender wouldn't return my phone call. I'm so glad he didn't though! Pricing everything through Falcon looks like it will save me $100-150. I do have another question though. I found the H802CP pistons in the FAQ section. Charlie at Flacon said this was a better piston than the 677CP. I noticed that there are a few differences between the two. The H802CP has a pin height thats .007" higher than the 677CP, but also has a 1.5cc larger piston dish. Its my understanding that the H802CP piston will give me a better quench height (albeit only .007) but slightly lower compression due to the larger dish...is that correct?

[rradford9]

OK, trying to finalize parts before ordering with falcon. This is what I get from the CR Calc, please let me know what you think.
Parts are:
4.2 Crank and Rods
Standard Bore
H802CP Pistons
Victor .043 Head Gasket
Stock Cam

There really wasn't a section that I thought adjusted for the extra pin height of the H802CPs vs. the 677CPs, but I did change the piston dish volume.

[Mgardiner1]

yeah the deck height is where you take your pin height into account. a .007 higher pin height would give you .007 smaller deck height

BTW i see you using 6.123 for the connecting rod length, but you said you are going to use the 4.2 rods, which are 5.875. That will change your DCR a little bit

[rradford9]

Good catch, that changes the DCR to 8.11:1.

[Mgardiner1]

if you do not deck the block, a .007 higher compression height (over stock) on the piston will bring your deck height from .0215 to .0145. Recalculate. Make sure you write down different combinations that you calculate when trying to draw a conclusion on pistons. Try the CC and deck height for the 677CP - check SCR/DCR. Then enter in the 802CP's and see the difference. Try to use the same cam for now, whether it be an aftermarket cam you have your eye on, or the stock specs.

[bratcop]

From what I am seeing on your screen capture, I would want my quench tighter. You seem to be pushing up on .060 for quench. I would try to get that down to the .040's as that will increase your chances of running on 87 octane without ping. If it knocks from pre-ignition ping, the computer will retard your timing and negate some of your gains from your performance build. I would be a bit leary about getting a dynamic compression of 8.x:1 and not having a quench under .052ish. I have obviously only done this build one time, but the research I did said that DCR of around 8.0:1-8.2:1 was target range for pump gas, but you needed a tighter quench (.04x ish). I would suggest zero-decking the block and using the thinnest gasket you can get. I will probably result in needing to dish the pistons, but how many tanks of gas on 92 octane vs 87 octane will it take to make up the additional cost of piston dishing?

Bratcop

[rradford9]

Sorry, I messed up on that calc. Here's a corrected one. I PM'd oletshot and I think he can dish the 802's to 20cc. My quench and DCR are a little bit better...



http://img.photobucket.com/albums/v366/ ... /calc4.jpg if the image is too small

[Mgardiner1]

Oletshot dished my 802's to 20 CC's. They were 60 over in the bore, but that shouldn't made a difference

[SilverXJ]

If it knocks from pre-ignition ping, the computer will retard your timing and negate some of your gains from your performance build.

The PCM won't retard the ignition. They ditched the knock sensor when they got rid of the Renix system.

[bratcop]

Silver, I have an 01 with 4.0 and it definately has a knock sensor. It is attached directly to the block above and behind the CPS on the right side of the engine. It most definately will retard the ignition. I even looked up the torque spec for the knock sensor on my engine so I was sure it wouldn't be too tight and therefore too sensitive. Maybe they quit using it for a while, but it certainly is on mine and I believe on his as well.....not trying to start an arguement...


Bratcop