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View Full Version : Doing a 4.2 buildup in a month or so .... with a twist



DMX
05-29-2006, 10:22 AM
The twist being its a FWD application so dropping in a full f150 engine wont work this time.

The trans took a major dump so while the engine is out now's a good time to take on this project.

I'm trying to keep costs down so for rods I was hoping to use some "off the shelf" 351w pieces >>
http://cgi.ebay.com/Ford-351-Windsor-H-beam-6200-Connecting-Rods-ARP_W0QQitemZ8068096791QQcategoryZ33623QQrdZ1QQcmd ZViewItem
or
http://cgi.ebay.com/ebaymotors/FORD-6-200-CNC-I-BEAM-351w-393-408-RODS-TMD_W0QQcmdZViewItemQQcategoryZ33623QQitemZ8067855 647QQrdZ1QQsspagenameZWDVW

then just get custom pistons to keep the compression ratio at about 8.8-9.1.

That rod isnt too long / too weak is it? Research has shown a longer rod+shorter piston helps reduce side loading on the crank. There may also be benefits of longer dwell time at TDC/BDC (maybe). I dont want the pin to intersect the oil ring though, that seems like its just a headache waiting to happen.

I dont have any crazy 350+ HP goals, i'd be happy with about 280HP and a mountain of torque. Those rods should be strong enough to support that dont you think?


What is the standard deck height by the way? and combustion chamber volume? I have some of the info already but i'm missing a few pieces needed to calculate the final CR.

96+ Windstar block (stronger/lighter than mine)
4.2 f150 crank (should make engine 3.81 x 3.74 bore x stroke)
standard deck height (??)
?? custom pistons

Its just in the planning stages right now, am I overlooking something major?

DMX
05-29-2006, 10:25 AM
There was also talk of having to machine the crank to fit, i'm assuming its just because you guys have that undersized rear main, I dont think that will affect me.

Mickey
05-30-2006, 10:01 AM
DMX, defiantly use the long rod combo with the 4.2 crank. The short rod route was a huge mistake. I'm the one that bought he short rod set up from Jeramie Schall (92Bird/95SE). Give a call to SSM - Tom Yenzer. He is the best source of information for your build. His guys haven’t reported any problems with the short pistons and the oil ring position. The undersize is only in the bearings that are matched to the crank. IE: any block will fit the SC crank with the matching (thicker bearing) as you already know, or correct me if I'm wrong. I finally got my 4.2 crank bolted in an early SC block this weekend with the 4.2 standard bearings. Goto http://www.wallaceracing.com/Calculators.htm for the compression calculator. The crank machining is for the “standard” 351 rods due to the pistons intersecting with the crank counterweights. I went this route; and the final crank, machining (more like butchering) and balancing was over 4 figures. The long rods and “short pistons” clear the counterweights just fine. Even with my short rods & tall pistons, no internal block clearance was needed even at 30 over, as the myth goes. The only concerns we had when planning this for 92Bird's Taurus was the block strength and the oil pan interference with the 4.2 crank, but you may have gotten around this with the Windstar set-up.

DMX
06-02-2006, 12:01 PM
Long rod it is then :-) i'll just have to decide on 7.125 or the 7.200 rods that are on ebay for <$300.

Do you have any insight on this bearing chamfering that needs to be done, I did the search and the results point to it being a simple filing job but I just want to be sure.


Also, one thing i've been wondering about, if this engine has lived its 70,000+ miles as a 3.8, woudlnt the extra stroke pull the piston down into areas of the cylinder without any wear? That wont be an issue will it?

I'll definately get a hold of Tom Y and see what kind of advice he can lend, just wanted to get some more input.

thanks,
Craig

92bird
06-02-2006, 01:44 PM
Craig, you should overbore the block when doing a stroker. Even if you hone farther down the cylinder, it will be tighter at the bottom than at the top.. NOT what you want.

I would go with a bit higher compression and run lower boost. Seeing as how on the taurus, belt slippage is an issue.

Did you bust the new trans you just put in like a year ago?

Good luck with everything.

Jeramie

DMX
06-03-2006, 09:19 PM
That transmission literally exploded underneath me a few weeks ago, i've got a big thread on tcca about it if you wanna check it out. No power braking, no unusual stress, just normal acceleration from a stoplight and BOOOM, it sucked. Since i've got the engine out now and a 2nd set of wheels (04 Duratec) I'd like to turn it up a notch :-)

I didnt figure on needing to overbore things, if I end up going that route I hope I dont end up with weakened walls. Plus figure in the cost of machine work oh man, this could get out of hand quickly.

I've got a plan to combat that belt slip, no more of those tiny 2.5" pulleys, I'm going to see about running a 2.85-3" blower pulley with one of those lightning 8.4" crank pulleys. I've got the pulley ring I just need the hub to get started lining things up. Plus i'd like to leave my options open in case I want to try a turbo setup in the future.

Do you think that 520 special will work well enough for the 4.2?

Remember, I absolutely dont want to spend a ton on this project, maybe a "medium" budget if that makes any sense. Think its doable?

92bird
06-04-2006, 11:14 AM
The .520 cam will work good with a stroker. It will mellow it out a bit.

I'll have to check the thread. Haven't been on TCCA much lately

seawalkersee
06-04-2006, 01:16 PM
Kind of off the subject...but who is Dr. Fred?

Chris

92bird
06-04-2006, 04:37 PM
In a nutshell, Dr. Fred was kind of like the XR7 Dave of the early years of SCCoA and TBSCEC.. He had a falling out with a few members and has sinced pretty much kept to himself and a few of us local guys. He's a Chemical Engineer, and is known for his work on developing Oxy Clean products, by Orange Glow International. He also has a Masters in Metallurgy from the Colorado School of Mines. One smart cookie..

He was one of the first guys to "tune" an SC with the EEC Tuner, and used to do EEC tunes for members. He also used to do pretty good headwork and make some killer cam regrinds. I have his first "prototype" cam, and ported heads with the stock sized valves, which put out a healthy 345.5 rwhp and 399.9 rwhp with all the MP stuff.

Fred also has a Moldex custom cut billet 4.3L "bulletproof" crankshaft. He had one of the first 4.3L SC's, which was developed jointly with Coy Miller. Though the first one was a cut and welded crank which broke. That's why he's running the billet crank now. He's in the process of rebuilding the engine with some lower compression pistons (first 4.3L redition had 10:1 compression). We should have him back on the road this summer.

Jeramie

seawalkersee
06-04-2006, 10:19 PM
Does he still play here? Does he still have an xr7?

Chris