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Discussion Starter · #1 ·
I'm thinking of trying to build a cheap backyard 408C stroker motor. I have a 400M crank and a set of 6.03" cleveland rods (aussie 302C rods). The 400M crank has the correct b/e journal size and should only need the main journals turned down to cleveland size. With this stroke/rod/block combo, I calculate a 1.2 inch pin height piston would be the final part of the equasion. These would need to be in dish top design (about 10cc's) to get a streetable compression ratio, or have a slightly shorter pin height to acheive the same result. I'm thinking of running open chamber heads. Now my questions.

Has anybody done this before? Who makes a suitable piston? Any tricks or pitfalls? 2V or 4V heads?

Thanks in advance for any help, experience or insight you may be able to throw on this idea.

Cheers
Tris
 

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It's been done before but it's not done any longer because of the aftermarket cranks that are available now. The 400 crank weighs 13lbs more than the Cleveland crank. The counterweights are massive and have to be cut way down to fit a 6.03 rod" (piston bottom hits the counterweight). Rebalancing the crank requires expensive mallory metal.

The most cost effective way to go is with an aftermarket crank, 6" Chevy rods and a custom piston. Wiseco used to make a couple 1.23" CH pistons for this application.

4Vs all the way. What compression are you after?
 

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Discussion Starter · #3 ·
Thanks for your reply. My target compression is about 9.5:1. Any higher with an open chamber head and they ping.

On the balancing side I hoped it may even itself out. ie. Cut the counterweights down to clear the piston skirt, use a 6.03" rod and short piston. The short piston and short rod (shorter than original 400M rod) would weigh a bunch less than factory 400M rod and piston. This should allow a considerable reduction in the crank counterweights before any heavy metal is added. I planned on using an angle grinder to reduce the counterweights rather than a lathe. This way the cut would not be parallel with the crank centreline. I was thinking of a radius profile to match the piston skirt. Again this would reduce the weight loss.

If mallory metal needs to be added, wouldn't this be identical for an aftermarket crank as well? The stroke, rod and piston is the same (or similar), then the same piston skirt clearance would be needed, hence the same heavy metal rebalancing. Where am I going wrong with this "logic"?

Cheers
Tris
 

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Well, I don't know about you plans. Cutting down your counterweights with a hand grinder will be a HUGH job and not very precise. I can't tell you how the balance will come out but my Scat crank and 6 in. rods balanced with no mallory.

I agree on the 4Vs. The big ports LOVE the added stroke.
 

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You need to cut down about 1/2" around the perimeter of the counterweight. To get an idea what it will look like see,
http://www.bacomatic.org/~dw/430/430.htm

The shorter piston & smaller pin is lighter but the con rod isn't much because the weight reduction is only in the beam area. Yes it's definately somewhat lighter, just not enough to make up for the counterweight reduction.

I'd bet the 430W's rods and pistons are close to what the 302C rod and custom pistons would be. The journals were ground a smaller dia and lightened internally, they switched from a 28oz to a 50oz external balance and heavy metal was still needed to get it balanced right.

Aftermarket cranks can be made with wider and/or additional counterweights and smaller or hollow rod journals to avoid any heavy metal for balancing.
 

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Discussion Starter · #6 ·
1/2 inch sounds like a heap of grinding..... Good link, thanks. Let's me see what I may be in for. Might be more of a project than I anticipated.

I already have 302C rods and a couple of 400M cranks. Rods were free and a couple of cranks were $100, so there may be money for mallory.

Anyone got any info on a piston with 1.17-1.20 pin height to suit? This may be the overall decider whether the project flies or dies.

Cheers
Tris
 

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On 2006-07-22 03:09, xafalcon wrote:
1/2 inch sounds like a heap of grinding..... Good link, thanks. Let's me see what I may be in for. Might be more of a project than I anticipated.

I already have 302C rods and a couple of 400M cranks. Rods were free and a couple of cranks were $100, so there may be money for mallory.

Anyone got any info on a piston with 1.17-1.20 pin height to suit? This may be the overall decider whether the project flies or dies.

Cheers
Tris
If you have money for mallory then you have money to buy a crank that you have to do anything to.
 

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Unfortunately a 302C rod (6.03) is .55 shorter than the 400 rod (6.5
.
The shortest off the shelf piston I know of is 1.25 with a Chevy pin (.927). They're about $500 USD.
I think you'll have a hard time finding a budget piston for this application. Most custom pistons will be in the $6-800 range.
 

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Discussion Starter · #9 ·
The closest piston I have found so far is from Probe. From the Sportsman Racing Series, p/n 14212. This has a 1.2 comp height, but is a flat top design. I could run thicker copper head gaskets to make this work, but I'd prefer a dished piston.

In New Zealand, aftermarket cranks are much more expensive than in USA. If I were to buy an aftermarket crank, I'd also need rods, which will run about $1500 minimum. Yes I could do this, but I'd get more satisfaction from building one myself.

Thanks again for your thoughts

Cheers
Tris
 

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tris,
im in the same position as you when it comes to buying aftermarket parts here,but have you checked these guys http://www.segedin.co.nz/index.htm ,i know youre trying to put a cleveland stroker together but on
crankshaft page in this link they have a couple of 3.85 windsor cranks-the probe crank is just under $600 and the other cast crank is about $380,i havent asked them about any cleveland stuff,might be worth a try.
i was going to use a 400 crank a couple of years ago but after pricing up all the work it was going to need it was easier for me to sell it and look at buying an aftermacket crank thats ready to go.IMO using the 400 crank just isnt something that can be used in a budget build.

_________________
81 aussie ltd-351w,rpm heads,performer rpm airgap intake,10.3 com,angus 1.6 rollers ,1 5/8 long tubes,750 edelbrock,comp xe274h,c4, 2800 stall

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Discussion Starter · #11 ·
Cheers Kiwi Mate - I'm in Hamilton, where are you? Performance Parts Papakura have a 3.85" clevo crank for $600 + tax. Rods for about another $800 + tax. Still needs imported pistons to round it out. The clevo isn't as well supported as the windsor for aftermarket gear. I'm just interested in having a go with the parts I've got, just to see if I can make "my own" engine. The old Kiwi number 8 wire thing. The piston is still my biggest problem. I might try denco, see what they say.

Cheers
Tris
 

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im in palmerston north,thats not a bad price for a cleveland crank,i know what you mean about the cleveland stuff being expensive but there is alot of stuff coming out of aussie now for them.the price of the aftermarket stuff was my reason for going with the windsor,not easy finding the 351w blocks but once you have that the rest is getting easier to find.
pistons shouldnt be too hard to find,id start looking around the australian sites,alot of guys over there building 393c engines.good luck with the build--steve
 

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Is there any reason why you guys have to get a crank and rods locally?
http://flatlanderracing.com/ ships word wide.

I checked this distributor and came across a 1.20CH probe piston with a 16cc dish. 14213-030 $499. Both use a .927 so you'll have ream out the 302C(.912) rod .015"

Assuming I added right, what are you planning to do about the +.024 deck clearance?

With these you won't have to run an open chamber head. A quench head should make 15-20 more HP.

I hear what you're saying about satisfaction but I think this build will mainly cause grief unless you research it 110%. You should make a few inquiries on these forums.

Clevelands Rock
http://autos.groups.yahoo.com/group/351ClevelandsRock302C351C351Boss351HO400/

351C Tech
Pantera Based Forum: Engine Info
http://pantera.infopop.cc/groupee/forums/a/frm/f/5650045562

351 "Cleveland" Series Engine Forum
4,500+ posts, keyword search for archived info Q&A. Mostly 351C info
http://www.network54.com/Hide/Forum/119419

351 Cleveland Maniacs
Here it is Cleveland nutcases!
http://sbftech.com/index.php/board,5.0.html

351 Cleveland Tech
http://www.fordforums.com/forumdisplay.php?s=d914bb28fb7374f0114071bc835e98d7&f=497

351C/Big Block Engine Tech
Not sure why the 335 series is lumped together with the 385s?
http://www.corral.net/forums/forumdisplay.php?f=314

Who's Denco?
What car is this going in?
What cam do plan to use?
 

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shipping and the exchange rate.1nz dollar is only worth 62us cents,that makes a $500 set of piston cost us $800 nz dollar+ shipping.the exchange rates were really good the last couple of years but have taken a dive the last few months so itll be a lot cheaper to score parts locally that were imported at the cheaper rate,in theory anyway.
 

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I AM MAKING A 410 INCH MOTOR WITH DART 9.2 DECK
4.0 STROKE 6.0 ROD 1.200 COMPRESSION HEIGHT.
THE CRANK DROPPED RIGHT IN BUT IT TOOK 6 PCS OF HEAVY METAL TO BALANCE THE THING.ITS A SCAT 4340 CRANK . ITS A VERY NICE PC.

MIKE STEPHENSON
 

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That's strange how one Scat crank requires 6 pieces and another doesn't require any. Was the one requiring heavy metal internally balanced?
 

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Discussion Starter · #17 ·
Thanks again for all this useful information, everyone. Yep, research 110% first. This is what I'm doing, by talking to people like yourselves who have invaluable experience and opinions on clevelands. Sounds like I have some other forums to check into over the next few weeks as well.

The calcs I used for the engine were 9.213 crank centreline to head surface, 2" crank throw from centreline, 6.03" rod length, piston pin height 1.2 (for the probe). So the piston should be 17 thou out the hole. This should be OK with a standard head gasket at 40 thou, although I did think about the feasibility of offset-honing the rod small end to increase this a little (effectively shorten the rod). But I think it will be OK at 17 thou out the hole.

The compression ratio using the dish probe piston you found and an open chamber head (76cc) will come out about 9.61:1. This uses a 40 thou Fel-Pro head gasket (8.8cc volume) compressed thickness. This is almost perfect!!!!

Denco is a NZ based custom piston manufacturer. At US$500 for a set of probe dish top forged slugs, I don't think I need worry.

I haven't really got a car in mind at the moment, but it will probably end up in an Aussie Falcon like my XA. So it will be quite big and definately heavy.

Camshaft choices are a long way off, but most likely a hydraulic flat tappet around 235-240 @ 050. With the 302C rods, I wouldn't want to see it rev past about 6000. Torque should be big though.

Thanks again for your help.

Chers
Tris
 

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wow a lot of good info. im new to stroking motors and am greatly appreciative for all the info in here. ive been trying to find a good aftermarket crank for my 351c for my 408 plans but everywhere i look they are quite expensive. also ive found loads of the aussie c heads. bout $400 a set, wondering where i might find the valve sets for them without having to sell my kidneys for all of this.
 
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