Stroking a 318 to a 390

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Here’s Chrysler blue with flat black stock valve covers, high temp silver water pump. I like it!
 
This project went backwards today.......So i have this crank....

Mopar Performance Heavy Duty Cast Crankshaft

Put crankshaft in last weekend ...did not have a woodruff key on the crank until today....turns ok...but somewhat tighter than i thought it should....so i read the description at mancini racing

Requires Narrow Bearings: No.......

so had used standard FM full groove main being...
today....i got the pistons in....and using CL77 cb481 rod bearing...I put the even side in...no biggie..
move over to the odd side...number one goes in and the engine will not turn....yeah....it needs narrow rod bearing...so i replace all the rod bearing with narrowed bearing...and as each odd side piston is added...it gets harder to turn...
finally after 7 piston are in...i can not turn it over...lol

so i read the description again...lol

these Mopar Performance special heavy-duty crankshafts feature radiused fillets for the small block engines......and knowing it is SCAT i go to Summit and look at cast crank
Requires Narrow Bearings:No......does not mention the radiused fillets .........

to me it looks like it has radiused fillets.....but i getting older by the day......

put big plastic bag on it and went home....
 
I've gotten in the habit of mocking up all the stroker kits. Of any displacement. Some say they are fine - but when I get them they are not. Be it the tangs on the bearings or rod, the design of the crank, just the Universe working against me... I end up with hard to turn and no side clearance. Usually it's just some chamfering of the bearings are required. No big deal, but much easier to do as you go.
 
70aarcuda said:
This project went backwards today.......So i have this crank....

Mopar Performance Heavy Duty Cast Crankshaft

Put crankshaft in last weekend ...did not have a woodruff key on the crank until today....turns ok...but somewhat tighter than i thought it should....so i read the description at mancini racing

Requires Narrow Bearings: No.......

so had used standard FM full groove main being...
today....i got the pistons in....and using CL77 cb481 rod bearing...I put the even side in...no biggie..
move over to the odd side...number one goes in and the engine will not turn....yeah....it needs narrow rod bearing...so i replace all the rod bearing with narrowed bearing...and as each odd side piston is added...it gets harder to turn...
finally after 7 piston are in...i can not turn it over...lol

so i read the description again...lol

these Mopar Performance special heavy-duty crankshafts feature radiused fillets for the small block engines......and knowing it is SCAT i go to Summit and look at cast crank
Requires Narrow Bearings:No......does not mention the radiused fillets .........

to me it looks like it has radiused fillets.....but i getting older by the day......

put big plastic bag on it and went home....
Click to expand...

Found this out in the late '90s-LOL. Man was I impatient back then too! Had to wait another week to get the radiused Clevite bearings in. THEN it Plastigage'd a little tight, so I had to wait ANOTHER week for some .001" loose radiused bearings. Used 1/2 standard and the other 1/2 shell loose for perfect clearance. Tore down 10yrs later and they were still mint, cleaned 'em up and they went back in after a deglaze re-ring job. The weaker Eagle cast steel shaft needs 'em too! You CAN scrape the bearings, but to me that's ghetto. I did do it once on a friend's 471 with a 440Source crank, on the mains, since the B engine mains aren't readily available narrowed. Found out when IT bound-up on assembly. Knifed the edges, deburred and it worked fine. Now 440Source offers the bearings relieved by them, I don't think the bearing manufacturers are going to offer them like the Hemi/440 ones you can easily get. Here's an example of the 1/2 and 1/2 bearing trick in action:
valiantWheelie.jpg
valiantWheelie.jpg
 
Man, that’s an awesome more door race car! Appreciate the heads up on the clearance issues of the 4 inch cranks.
 
Been searching the internet trying to see what is available for narrow main bearing for 318/340 main bearing size...actually trying to see if anyone has a set on sale...lol

Going to order a set of king xp series main bearings mb 558xp standard size from Summit...with my discount they got same price as most everyone else plus they will be here on Tuesday.....I need a few other small things to add to the order and get the free shipping...
Not going to quit ...just got frustrated Saturday........so mowed the grass today....and have new gas power weed eater...that it alot of fun
 
I've just recently acquired a low mileage '89 roller cam 360 with the stock cast pistons at .125 inch below deck. Since we're talking about going all ghetto, would the stock pistons have enough material to mill off .100 off the top on the valve side and enough off the bottom (if necessary) of the pin boss to fit a 4 inch cast crank?
 
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I'm going to measure them as soon as I get the pistons out. I seriously doubt it, but I'm more morbidly curious than I am serious. However, that can change if there's enough piston left to avoid pinching the top rings or cutting the crowns too thin. But it may be still be possible with a set of vintage TRW 360 forgings witht their average of .300 thick crown, if a person could find a pair...
 
You can build the engine ghetto style, and then we all watch how it goes off ghetto style.

Sorry, no pun intended. :)
 
TRW maybe but stock cast you have to figure on valve notches
were there any trw stock ht pistons?
what do you have to take off for 0 deck .070 or so?
and balance?
stock open chamber heads
how much to run out of the block? e-85, propane?
 
That’s my thoughts, too! But if the deck height is 9.60 (I'm suspecting its taller) they would have to be milled .099 for zero deck. If setting up for a .038 piston to head clearance to achieve some resemblance of quench, the chambers would have to be in the neighborhood of 76 cc's just to get the compression to pump gas level. So if it's even a possibility with the pistons, the bare minimum would be a premium pump/low lead AvGas blend . Half of the 3.13 inch diameter by .05 deep (6.3 cc's), .0705 deep (8.9 cc's), or .100 (12.6 cc's) deep dish (my pistons) would become part of a dome along with the outer edge of piston above the rings outside of the dish. But the 536 gram pistons would be down to a lightweight if there's enough meat for it to be milled off on the valve side. One think I do like about the stock pistons, though. The possibility of reversing the pin offset to help reduce the side loading from the 1.53:1 rod ratio.
 
The steel expansion limiters in those pistons makes them really strong, too, although they were never intended for this level of possible abuse.
 
No, if I attempt to put this together I’ll probably be using some ‘73 340 heads or 1995-1987 HD truck 475A castings, both open chambers, hence the piston being milled into mini dome shape. Even so, cylinder head selection is still variable because I’m into 3 builds with final installations right now so it’s going to be awhile before amassing parts and I’m not sure of what else may come available. I’d really like to have the 308 heads off that engine but they’re going on a grunt torque 360 going into a short wheel base W100 with 31 inch tires, 3.55s and an NP435. To be so much into cars, it seems like I work on an awful lot of trucks...
 
And some more good news on the 390 inch 318 build. New valves, others were bent during extreme valve float and improper geometry, and waiting on a new set of push rods to finish the long bock. Compression came in at 10.6:1 with .90 Intake valve clearance and .128 exhaust valve clearance. Comp XE 275 HL with 1.6:1 rockers for .560 lift installed on 107 ICL from 106 for intake closing of 65 degrees ABDC.
 
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Garrett Ellison said:
And some more good news on the 390 inch 318 build. New valves, others were bent during extreme valve float and improper geometry, and waiting on a new set of push rods to finish the long bock. Compression came in at 10.6:1 with .90 Intake valve clearance and .128 exhaust valve clearance. Comp XE 275 HL with 1.6:1 rockers for .560 lift installed on 107 ICL from 106 for intake closing of 65 degrees ABDC.
Click to expand...

You're gonna love that cam. With pissy ProForm blue shaft 1.5 rockers (customer's cheapness-LOL), we made obscene street power and torque 2500-6500rpm in a '72 Duster back in the early 2000s (04?). We used a (cheap!!) MP 360 shortblock, which was basically a Magnum 5.9L core block, drilled for shaft oiling and bored .020" with 2-eyebrow Speed Pro pistons (near zero deck) and a .508" MoPar cam. We shitcanned the .508 and stuck the XE275HL in at 106* with some OOTB Edelbrock RPM heads and an LD340. With a 2500 stall 11" converter and 3.23 gears, it was an absolute joy to drive and a beast WOT! In your 390, you better multiply that fun factor by 10% at LEAST!!
 
garrett
get some lube saver lifters pm dart19666 or contact Rhodes
and i'd do the dril on breakin with weak springs or just the outers
 
ok,,,,changed out main bearing....sure feels alot better turning it over....all pistons are now back in and rods torqued...

plastic bag going to cover it up for now......have to figure out what to do with it....heads...cam ...
 
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