Bratcop's Stroker Build

[bratcop]

So as most of you know, I bought an '01 GC Laredo with the 4.0 knowing that it had engine trouble. As I investigated, I found it had a blown piston skirt (all the way to the bottom ring). Pulled the motor intending to only rebuild it as stock, but caught the stroker bug and decided to build it up some as long as it was apart. Here are the specs...

258 crank with 4 counterweights
707 rods
P3071 Hypereutectic pistons with coated skirts from Enginetech catalog
0331 head, relief and match ported intakes, relief ported and polished exhausts, fresh valve job
Ford Mustang Cobra 24# injectors (XR3E-C5B w/ EV6 connector)
01 Jeep intake port matched
Split Second PSC1-003 piggyback computer
Zeitronix ZT-2 Wideband O2 and datalogging setup
looking into some type of CAI, maybe K&N
stock exhaust (so far)
High flow thermo
stock rebuild oil pump
reman water pump
Victor High Perf Gasket

View the specifics here...
http://www.jeepstrokers.com/forum/viewt ... f=15&t=438

so it is currently apart, completely apart....

Got my crank through O'Reilly Autoparts, mains .030, rods .040, thank god it included the rod bearings, ordered new main bearings to match the block

boughts the 707 rods from TallPeter, Thanks

Ordered the pistons. metric rings and gasket set from Enginetech (http://www.jeepstrokers.com/forum/viewt ... ?f=5&t=472)

Ebay'd the injectors and the PSC, still working on the Zeitronix

Head was given 3 angle valve job, reused valves...head was milled .008 to get it flat

Block was honed and hot tanked, but is within specs and doesn't need boring...Std pistons

No CAI yet....

Bored out the "choker" at the base of my stock throttle body...

Will move the Air Temp Sensor into the intake tube......

Waiting on the machine shop now. My machinist really seems to know his stuff, as he has been building all the racing motors in our area for many years. Therefore, I am willing to wait on the work (for a little while) in the hopes that it will be superior...

Planning to deck the block to get the quench between .040 and .050, but will likely result in a need to dish the pistons further as they come with only a 14.1cc dish. I am hoping to get them to 21cc to keep scr around 9.5 with dcr at 8.1...I hope to run pump gas(87 octane).

I know the concerns about my head, but I am crossing my fingers that it will never crack...

keeping the stock cam and lifters, valves and springs, may need to get shorter pushrods, or can I just take a little off the valves, like .030? Would that maintain the valve train geometry?

While I am waiting on the machining...I have been painting....here are some pics....exciting, eh?

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[bratcop]

some more pics....

This is the injector boss on the intake after I ported it. What I noticed was that when the stock injector was inplace prior to porting, the stream of gas would hit the overhang at the edge of the intake, probably disrupting it's spray. I removed that overhang to allow the mist to go uninterrupted and reduced the boss some. I also matched the gasket which matches the head now.....

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throttle body now matches the intake in size...

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and finally take a look at my oilpan...was going to go black, but thought since the block was going to be black, why not metallic silver for the pan...it is actually the wheel paint available at Autozone...tell me what you think...

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[yuppiexj]

Shiny... I like the oil pan in silver. if nothing else it'll make leak finding easier

[Mgardiner1]

When you install it, put a neon light under the oil pan so it makes the road glow LOL

Sounds like the beginning of a good build! I hope you get the quench you are after! i was slightly dissappointed when i had requested a 0 deck, and then assembled everything and found .007 clearance with pistons/rods/crank installed.

[SilverXJ]

I liek silver. However you will probably have to clearance the pan to fit the main girdle with the hardened washers to space it out. Are you using the 01 0331 head?

[bratcop]

I am using the 0331 head, against everyones advice I imagine, but I am crossing my fingers that it won't crack. What do you all think about shimming the rocker arms or should i look into relieving the valves stems?

[Mgardiner1]

I think the majority of people here advise against shimming the arms. Find out how much will be coming off the deck and the head and make the call from there. My Yella Terra rockers came with spacers, and then with a washer that they said was to be used if proper adjustment couldn't be achieved. I needed to use them. I felt comfortable using them as they are supplied and suggested by yella terra.

[seanyb505]

I ordered the Crane shim kit from summit. Total block and head decking for my build was .060, so the .060 shims came in handy. I havent experienced any issues yet. It was only 20 dollars shipped. It works, but I would look into shorter pushrods for better peace of mind. Theres a list of various lengths of pushrods and pns in the FAQ section.

[bratcop]

Well, I finally have some progress. Rods were line honed and checked for straight...
Wednesday, I assembled the head. First my machinist checked the spring pressure and free height and found that they are still fine and within specs. Lubed the valve guides with engine assy lube and slid each in it's place. The porting I did made my intakes look really huge. I really hope to gain some precious ponies from that 8 hours of work.

My machinist had a pneumatic spring compressor for installing the valve springs, what a nice piece of equipment that is...all in and ready to go. Used stock valves, retainers and springs.

Tomorrow I am meeting him at the shop and we are going to mount a piston to a rod, install the crank and that one piston and check deck height. I am still shooting for zero deck, so I will report back as to how much I need to take off the block. Then we are going to cc the head and piston dish and really find out how much I need to remove from my pistons to get in the neighborhood of 9.5:1 scr. Because of the MLS Victor head gasket which measures under .040(.038ish), I think I will actually shoot for .002 deck height, putting me in the neighborhood of .042 quench. Any closer to .040 (or possible under) makes me nervous, as this thing needs to be very reliable and not finicky. I really don't want to tap the head under throttle and have to start all over because quench was just a little too close...

I then plan on sending my pistons to oletshot to have some of his custom dishing done on them, then it is on to assy. I was originally shooting for the end of this month as completion/start-up time, but the pistons and machinist are causing some delay.

This weekend, I am returning to the Jeep carcass, which is in Madison, WI. I will probably install the PSC1-003 while the engine is out and I can stand in the engine bay to wire it. I plan on finding a mounting spot under the passenger side dash. I also hope to get my injectors in the intake and the fuel rail mounted. I will re-assemble the throttle body/sensors and mount that on the intake as well. When we finally finish the short block assy in the future, we are planning to install the short block, then mount the head once the short block is bolted to the trans. It will hopefully make it easier to clear the cowling, as we bumped/bent it on the way out.

Currently looking for suggestions on a free flowing but sedate muffler choice. My wife (part time driver of the 'kee) will not accept any drone at highway speeds ( and I don't blame her at all). I think that rules out the 40 series everyone talks about. Anyone got a nice sounding (not loud) muffler that will improve my breathing?

I will get some pics tomorrow and let you all see why the money in my wallet keeps jumping into my machinist's hands...

[Mgardiner1]

I think a turbo style muffler is a good choice. I almost got one myself, but i wanted more rumble, so i went with flowmaster delta flow 50. The FM would be WAY too much for your description...

[bratcop]

Well, just got back from the machine shop...installed a piston to check deck height and found that the piston at TDC sat .110 down in the hole...WTF? The mad search was on for a piston that would fit with a different pin height as we couldn't possibly deck that much. I just couldn't figure out what I had misread or done wrong to be so far off. Started to think maybe I got a stock 4.0 crank instead of the 4.2...then.........

Someone else(I so wish it would have been me, and only me) then noticed that I didn't install the rod bearing, what a dumb ass I am...they concurred that I was indeed a dumb ass and we continued...

All the cylinders vary some and the deck height was anywhere from .030 to .042, the cylinder closest to the flywheel was .042, while all the others were .030 to .037...we decided to deck the block .030. Also, the center cylinders were .030 and .031 deck height. The center bearing cap and the front bearing cap were the only ones installed, just slightly tighter than finger tight. With the block upside down, I imagine the greater deck height at the rear could be from the sag of the crank due to it's unsupported condition at the back?

Anyway, if we deck .030, that should give me a quench at best of .039 and at worst .051(which I believe is a high estimate because the crank sag situation). That is what I am shooting for anyway. So, so far so good...

With the block decked .030 and the head only shaved like .006 to flatten it out, I am hoping to not have to modify my valve train at all? The preload on the lifters after all is a range of .020 to .060. I will measure and hope to fall within that...which reminds me, I need to remember to account for the thinner head gasket, which is like .013 thinner. Therefore my total valve train height modification is somewhere around like .049" Anyone have an opinion as to whether I will need to shim or take a little off the valves? I will still measure, but I am curious...

Bratcop

[dwg86]

It would be great if Speed Pro could leave an extra .030-.035 on the tops of thier pistons when they mill the tops. That would also increase the cc's of the dish in the pistons. I think the speed pro pistons are 15.5cc. That might increase the dish to 18-20cc's.

[SilverXJ]

I would use a .030 shim. That should get your close enough.

[bratcop]

So I finally got started on the actual build thanksgiving weekend...

I had my block zero decked, took .030 off.

I sent my pistons out to Oletshot, whom I must give a shout out to. He was very professional even sending a cad drawing to my phone so I could check out the design prior to him running in in the cnc mill. I sent them out and had them back in less than a week, and talk about a great job...sheesh, this guy is great at what he does...

Anyway, I decided to go with a minimum piston thickness of .195 which got me 21.5cc from the dish. That coupled with the zero deck and .039 gasket gives me desired quench (realistically about .043) and static compression of 9.64:1 and a dynamic of 7.98:1.

We zero decked it to the tallest piston, which gives us a deck height variance across the pistons of .000 to .005, average is about .0025. I attribute this to differences in the rod lengths, and possibly minor differences in the piston heights(?). Anyway, that should put me right in pump gas range. Below are some pics of the pistons and the block during assembly...

[bratcop]

So once we got the crank in, and ringed the pistons, we installed them. After putting 4 in we noticed that the top ring installation was counterintuitive in that the bevel on the inner lip of the ring must go down, not up as we thought. Out came the 4 pistons and reversed the ring...

All the pistons are in, and we put the "girdle" in place. I bought two sets of hardened washers because I couldn't recall the size of the studs...It was a good thing, as a single washer wouldn't let it clear, and two washer were just enough, as you can see in the pics. This of course caused a clearance problem with the pan...man they build that thing close to the girdle...

Jeep Laredo-15.jpg

We used a dremel to relieve the baffle in the pan, and to take the leading edge off the girdle...this allowed us to pull the pan down tight with the pan bolts...it seems tight enought to keep oil in and water out....

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We chose to install the short block to further avoid clearance problems with metal above the firewall (the name escapes me right now, valance?).

Jeep Laredo-18.jpg