4.6L Stroker, Help me build it please!

[jeepinwi]

XJoshua-
What's the reason for milling .035" from the block? Why not mill only .020" from the block to keep the quench close to stock? Your CR would drop a little, but you won't lose much power. Your 88 block is identical to any other 4.0 block, regardless of year. You're effectively building an HO since you're using the 7120 head.

For the bolts, If I remember right, it is a standard SAE bolt that attaches at the top of the block. Either a 5/16" or 3/8"...that's just a guess. for the bottom, just take a couple longer bolts that will fit through the holes and attach on the other side with a nut. When I got my complete 4.2L engine for parts, I disassembled it in the back of my YJ because I didn't even have an engine stand at the time!:dunno:

 

[old_man]

The reason is to get the quench height in the sweet spot. I did .020 IIRC but went with the thin performance head gasket on my 4.7L. By getting the quench right, it allows me to run the cheapest gas I can find with no ping, even with the high CR.

 

[XJoshua]

This is my very first engine rebuild so Im just using data from various tutorials and adjusting it. Im very happy I came across the calculator otherwise Id be lost and sound 200% more n00b then I do right now.

Heres the new data I entered in. I could do the thing head gasket idea and get the CR to about ~9.40:1. Running a 0.035 head gasket(not included in the newest calculations).

JeepinWI-
Isnt the only difference between the HO and nonHO is that my block will be metric and the hoe is SAE? Or is that just with the oil filter?

 

[vetteboy]

Isnt the only difference between the HO and nonHO is that my block will be metric and the hoe is SAE? Or is that just with the oil filter?

The oil filter thread changed, yes.

Another difference is that the earlier 4.0's had a knock sensor w/the Renix computer that helps avoid pinging issues a little bit by retarding the timing. This is really only a difference if you're using the pre-HO computer though.

 

[jeepinwi]

JeepinWI-
Isnt the only difference between the HO and nonHO is that my block will be metric and the hoe is SAE? Or is that just with the oil filter?

I wasn't aware of the oil filter being different, but I've never worked with a renix block. I've heard time and time again that all 4.0 blocks are identical dimension-wise. I assumed all the bolt holes would be the same also.

I understand that a tighter quench allows you to run lower octane gas. You can also run the lower fuel by slightly retarding the timing, running the engine cooler, and making sure there are no sharp edges which would induce hot-spots and pinging.

I personally would be VERY happy with your column C in the chart. Had I found the spreadsheet before I installed the pistons into my engine, I probably would have had my dish volumes increased 2 cc's. This would have reduce my CR to 9.32, which would be more tolerant to lower octane fuel.

 

[XJoshua]

So then with how my column C is right now can I still expect to have a kick in the pants when accelerating and still have the power to pull a tree out of the ground? What kind of fuel can I run will I be able to stick to the 87-Octane I currently run or will I still need the 92-Octane I was planning to run with the CR of 9.50:1?

 

[jeepinwi]

I don't think a .27 difference in CR will make too much difference in the amount of power your stroker makes. I think the longer stroke, camshaft, and better breathing engine is what really give you the acceleration and low end torque.

I wish I could help you on what gas to use, but I'm also wondering the same thing. I'll be running premium 91-92 octane in my engine until I have it broken in. I may then try some mid grade 89 octane to see if the engine will run with out pinging.

 

[XJoshua]

Anyone know the Dish Volume of the Federal Mogul Cast Pistons STL-677CP30 on SummitRacing. I sent a tech request to them and all I got back is a "I dont know, maybe same as stock" So stock is 13cc, but does anyone know for sure what the dish volume is?

 

[Israel]

My guess is that it's a Sealed Power 677CP with a 15.1cc dish volume and 1.585" pin height.

 

[jeepinwi]

My guess is that it's a Sealed Power 677CP with a 15.1cc dish volume and 1.585" pin height.

I'd guess the same thing.

 

[XJoshua]

Well the guy who I was getting the crank, rods and '88 Renix from finally pulled the pan two days before he's suppose to bring it down to me. Well the 4.2L engine only has a four counterweight crank. I know the rods will still be of great use to me, but what are the downsides to only having a four counterweight crank? Thanks a million, these quick responses are awesome keep them comming.

 

[XJoshua]

Also if I do get the 4 counterweight will the vibes be so bad that itll keep me from going 75MPH on the interstate This is a major issue since I go this speed to get places and to go work on the jeep at shops in other towns.

 

[Dr. Dyno]

Also if I do get the 4 counterweight will the vibes be so bad that itll keep me from going 75MPH on the interstate?

No. The 4 counterweight crank will do fine. There are many strokers out there running quite happily with it.

 

[jeepinwi]

The 4 counterweight crank will allow the engien to rev up a little quicker, but may not have as good of low end torque. It would be a good idea, regardless of which crank, to have the rotating assembly balanced. I did not have mine balanced, but now I wish I had.

 

[sjkimmel99]

Running a 0.035 head gasket(not included in the newest calculations).

XJoshua, Can you give the brand and part number of the .035 head gasket and maybe where it's available? I've only heard of the stock .051 and the Victor 5713 at .043.

Thanks.

 

[XJoshua]

sjkimmel99-
Im just assumming it would have to be a custom made one. I had a Metal Headgasket made for my old 5M-GE motor and it ran me about $200 including shipping. It was a 0.040. So Since the 2.8L is a little smaller then 4.0L Im assumming a custom would cost maybe $300ish.

DrDyno-
Thank you much on the quick response. I guess Im getting a four counterweight and Ill have it balacned aswell.

 

[sjkimmel99]

Also whats a good kind of bolt to use for securing the block to the engine stand(length, and type, also the type of nut to use)?

did you ever get a response to this question? Here's what I used, grade 5 from Lowes:

top bolts 3/8-16 x 3"
middle block bolts: 7/16-14 x 4"
pack of 7/16" washers. I ended up with 4 washers under the head of each of the two larger bolts - I could see the bolt coming through the hole on the other side and didn't want it to go into that area cause it didn't look like the threads had been cut all the way through. Now that I think about it a washer under the top bolts probably wouldn't hurt, I don't think I checked carefully enough to make sure they are not bottoming out in the holes.
Keep in mind the bolts go through about 2 1/2" of engine stand tube before they engage the block so you may want to measure your stand before getting the bolts.

No nuts needed - the holes in the top of the block are blind and in the bottom even though the hole goes through as long as the bolt is about through the hole and the head of the bolt is bearing on the washers it will be fastened.

 

[XJoshua]

I stopped by the stealership today and the tranny guy said to just pull a bolt from the bell housing take it to napa and ask for larger ones thatll match with the engine stand studs. So Im going to do that tomorrow maybe, should have done that today since I dont have work, but didnt.

So then the middle and top bolts are difference. Well Im going to take your word on those being the exact sizes and just cross my fingers. Thanks

 

[XJoshua]

And the glory shots.

1991-1995 Crate Engine. We arent sure on the acutal year but know its a H.O. by looking up the casting number. This is great news because I was told it was a RENIX since he pulled it from a '88, but the previous owner must have done a swap.

4.2L Crank. I got some mass on my arms today, got bored and started pressing and curling it

4.2L Rods and Pistons. While I have no use for the pistons I got them anyways.

Now the kid I bought it from said the 4.0L crank was knocking. I checked the bearing clearance and it was within specs. The bearing themselves look like over sizes, and the crank looked in perfect condition. So he might have meant it used to knock until someone rebuilt it, not to well in my opinon the oil was about 30% RTV and 70% Syntetics and the oil pan gasket was bearly making contact with the pan or the block. Now my idea is if it does really still knock its the rod bearings, but thats okay since i have a new crank and rods to replace it.

The bolts I used were:
Top block bolts: 3/8-16 x 3"
Middle block bolts: 7/16-14 x 4"
I also used four heat treated washer per every bolt and grade 5 wasnt enough I broke one torquing it down so went back and got a exchange for some grade 8s which torqued down fine. The four washers on everything help alot on the top bolts. Also the middle block taps are threaded all the way through for anyone interested in knowing.

Well I hope to have the engine completed by March 2007. Ill post updates in this thread since there is no point in starting another thread.

-Joshua

 

[XJoshua]

Well today I made a plan to get the block completly torn apart. I did pretty good, but didnt get around to getting the camshaft pulled, or the valvetrain completely disassembled. So far this whole thing has been a big learning experience, and something I believe any n00b with tools can do as far as disassembling. Also Ive been bagging everything according to what they do (ex. lubrication, cam, valve cover, head) and I hope this will help me reassemble it perfectly. Well here's some photos everyone loves photos.

4.0 Pistons & Rods, 4.0 Crank, 4.0 Head Assembled, 4.0 Oil Pan

4.2 Crank, 4.2 Pistons & Rods, 4.0 Valve Cover, 4.0 Bolts and Crap