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You have some decisions to make on pistons. If you plan to reuse your rods and crank then you need to number the rods so they return to the same holes they came out of - even if your boring the block. Are your reusing the rods as is? Are you reconditioning the rods with new rod bolts? If just reusing the rods make sure they go back in the same holes they came out of.
For pistons you want to have at least one piston pressed off the rod and weight it. You will want to match the original piston weight with the new piston. So lets do some math for you to see how the compressed height works.
Most stock blocks have a 9.025" tall deck. Stock 350 stroke is 3.48" and divided by 2 gives you 1.74 crank throw reach. So 9.025-1.74=7.285" distance to block deck. Now 7.285-5.7" (rod length) = 1.585" remaining from the center of the piston pin to the deck of the block. So your piston with 1.562" compressed height still has 1.585-1.562=0.023" clearance. Most performance machined blocks will get "zero decked" such that the block deck height is 9.00" and those 1.562" compressed height pistons would be 0.001" down the hole - for good quench with a approx 0.040" head gasket.
This is something you need to sort out for yourself as there are soo many options for pistons and compressed heights - dish and valve reliefs too.
Hope this can get you started and good luck.
I'm surprised 0.025" is typically removed when decking the block; not that i don't believe you, but when i surfaced the heads, he said he only had to remove 0.001-0.002".
I didn't even think about the weight difference in the pistons. How does that affect the crankshaft?
I guess that's what is meant by crank balancing?
I tried to mention for performance rebuilds as most rebuild shops may not even shave the deck to clean it up. And it gets more complicated as for aluminum heads you would want a deck roughness of 25Ra to 30Ra but for iron heads 50Ra to 60Ra is good though basic engine shops overlook this. I think you should read up on "quench height" to see if you are interested in that. Just a performance trick but not necessary as nearly all stock block don't utilize good quench.
Trying to save you money for balancing the assembly if you can match piston and rod height. Hopefully you can reuse the crankshaft so all you need there is a polish and press on new pistons.
FWIW the L82 is a forged crankshaft assembly and even the camshaft is a good performer so adding better heads like it sounds you want to do with vortecs should put you well over 350hp maybe 400hp with a simple rebuild. BTW the stock L82 pistons are forged also but it reads like your planning on changing those. How many miles on the engine? If less than 100k mi I would have the bores checked to see if just a hone will be enough to clean them up and reuse everything except the rings, bearings and heads. Talk a budget build for less than a 1000 bucks.
Won't happen with L82 pistons' small dome. Any dome is a mismatch with Vortec's Fast Burn chambers; fast burn designed to pair with flat top/dish while dome interferes with flame propagation.
Would it even fit?
Vortecs w/ dish & L82 cam probably about 325-335 fwhp pump gas (compare with GM crate 350 HO pn 19355660)
Vortecs w/ flattops & L82 cam probably about 335-345 fwhp but hi-compression prone to pre-ignition pump gas
Well I pulled the engine. First time I've ever pulled a car engine.
i really should have gotten the attachment from the hoist to the engine better. Most videos I have seem show hooking up to the cylinder heads or carb plate, so I improvised a little bit on the places to attach the chain.
What do you folks use to support the transmission after removing it from the drive shaft?
Also, whenever I did it the yoke came out of the trans rather than separating from the tail shaft where the u joint is. Did I do something wrong here?
separating from the engine from trans was a real bear as well. I used a table to slowly lower the engine/trans on, partially lower the hoist.
is it fine to have the weight of the trans be supported by the trans flyid pan. Removed the trans with the engine still supported with the hoist. Trans fluid leaked from the torque converter once removed from the input shaft.
does the mean I need a new gasket?
either way, I finally got it on the stand and will be taking all the rest of the goodies out before going to the machine shop.
Last edited by mongoose87; 02-07-2019 at 01:05 PM.
Don't deck unless you NEED to... don't deck unless a deck is Un-level more than 0.003"-0.004" from front to back
Use a dished piston 1.560" - 1.565", with a 0.015" gasket and stock deck makes 0.035"-0.040' quench at about 9.5:1 CR
If you have to cut decks, remove about 0.010"-0.013" then follow above example but use a 0.027"-0.028" gasket readily available.
If you cut deck 0.025" to start with, then if some damage occurs later you have little-to-no wiggle room. Frankly, tighter quench is best, BUT you must ensure piston is fitted TIGHT to bore as loose piston rocks more and when canted to one side it will extend even farther than its speced CD/CH
I cut a "Xmember" from scrap lumber from framerail-to-framerail just under front of bellhousing
No, nothing wrong, but I go ahead & change the tailhousing seal.
No, there's front seal that you should go ahead & replace
Thanks for your reply.
Whenever the trans came off the cross member in the car, the yoke slipped off and is still attached to the driveshaft.
Trans fluid poured like crazy once the yoke came off. What a mess!
What keeps the yoke from coming out of the trans?
The trans also tipped the engine/trans way down, and it even rested on the floor (i think/hope the foam mat under the car prevented any damage) . I think this tipping partly due to my sub par attachment to the hoist, but not sure if something is typically used to support the trans when first pulling it off the trans mount.
When i removed the torque converter from the input shaft, the torque converter also leaked like crazy. several quarts of ATF.
Should I refill the torque converter separately from the trans before reassembly?
How full does it need to be?
nothing holds yoke in except driveshaft
if you take ujoints loose, wrap them in tape so caps don't fall off.
did you pull eng-trans together as one unit?
if so you CAN reinstall same way...regardless, don't install distributor until after BOTH motor&trans bolted in
both my 71 with auto has removeable xmember under tailshaft
Don't deck unless you NEED to... don't deck unless a deck is Un-level more than 0.003"-0.004" from front to back
Use a dished piston 1.560" - 1.565", with a 0.015" gasket and stock deck makes 0.035"-0.040' quench at about 9.5:1 CR
If you have to cut decks, remove about 0.010"-0.013" then follow above example but use a 0.027"-0.028" gasket readily available.
If you cut deck 0.025" to start with, then if some damage occurs later you have little-to-no wiggle room. Frankly, tighter quench is best, BUT you must ensure piston is fitted TIGHT to bore as loose piston rocks more and when canted to one side it will extend even farther than its speced CD/CH
This advice about NOT decking unless you NEED to for a street build is spot on. I was told the same by my builder and did NOT deck the L-82 block since it was not needed. 5 driving seasons since the rebuild all is perfect. The L-82 with forged crank, rods, and 4 bolt mains is a really sturdy foundation for a build and as good as any high performance GM SBC engine of the time. Roller cam and top flowing heads like AFR's with forged pistons and 10:1 compression and the L-82 355 will make an easy 425-450 Gross HP on 89 octane fuel with no detonation, 1 3/4 inch long tube headers needed as well.
So I dropped the block, crank, and pistons off at the machine shop today. They already told me it will likely need to be bored rather than honed, so they will press out the piston wrist pins. Hopefully I can reuse the rods.
Generally, I would say the crank looked pretty good without much scuffing or scratches, but the main and rod bearings show some distress, some more than others.
I would say the main bearings look worse than the rod bearings, overall. When I pulled the main caps off the oil seemed really "sludgey," and looked kind of grey, almost like assembly lube.
Is this bearing particles?
How can i figure out what happened to the bearings so the same thing doesn't happen again?
Could it be just that the oil holes on the crank became clogged with age?
Before I began disassembly, there was good oil pressure, but not sure what else there is to indicate something else.
Last edited by mongoose87; 02-08-2019 at 07:38 PM.
now's the time for a 383 stroker.
sees it must be bored and crank journals worn more than a couple thou.
must have new pistons
buy a stroker crank for not a heluvalot more than grind & chamfer OE crank
but wait until ALL measuring checking completed by shop AND you have had time to ruminate over ALL OPTIONS.
Those bearings look worn somewhat in the pix but I don't see any base metal showing through. And the rod journals look good or at least I can't see any damage there. Since the crank is already out it's to late to measure end play.
I thought all L82's were 4 bolt block but yours is a 2 bolt. What is your casting number and stamped number?
So you want to reuse the rods? I hope your marked them unless you are going to have the big ends resized and if that's the case then new stronger rod bolts should be added (ARP). But resizing the rods with new bolts costs within $20 of new aftermarket rods. Hard to beat the aftermarket rods for price and value.
That block looks like good shape and I bet it has low miles. Your options are many so don't rush to spend money on it until you have what you really want sorted out.
I finally got my block back from the machine shop.
It was not decked
bored 0.030 over
crank was ground to 0.010 under size
new cam bearings
he hasn't measured the rods yet, but visually he thinks they can be just boiled and good to go.
Is it as important to match the rod into its original cylinder if it is ground down and bearings replaced?
I put a little sharpie on the rods, but not sure if it will last through the cleaning.
My plan was to get these rod bearings, which don't look like they have the oiling hole in them, but from what I've heard, they dont really need the hole. That hole is more a ford thing, where oil gets sprayed from the rods.
Does this sound correct?
I know forged is better, but not sure my build is aggressive enough to warrant the extra $. If they were available at a reason able price, I'm leaning toward just hypereutectic pistons with 1.560 compression height and 12-15cc dish. I see some examples on summit for less than $100 with the dish, but the compression height is too low, around 1.540.
If I can't find any I'll probably get the ones above and be happy my quench is as close to 0.40 as possible. (Hopefully exactly 0.40, but maybe the copper cote spray I'm going to use on the head gasket may add a hair)
If anyone knows where I can some like stock, please let me know.
that wiseco piston ring kit is nice … you'll be pleased.
ensure shop also chamfers-dresses edges of journals' oil holes … journal grinding can leave edges SHARP.
sbc rods ok to go into any cylinder
note rods' big end have chamfer on one side and that always faces crank and NOT the adjacent rod.
test fit all 1st & 2nd rings in a specific bore …. push a ring down into bore about an inch using piston to square them ….measure ring gaps w/ feeler gage … record which bore those rings are fitted to. perhaps set up an 8-place grid on some cardboard to keep ring sets indexed.
shop will press piston onto your oe rods.
check bearing oil clearance for each journal position using PlastiGage … clean it off w/ brake clean and repeat check but clocked 90 degrees. … clean PG off w/ brake clean.
double, triple check Ensure 2nd ring goes in 2nd groove … same for top ring & top groove.
double, triple check Ensure rings are in UP orientation.
save some $ on shim 0.015" gaskets . instead of coated FP 1094 … use FP 7733SH-1 with copperkote about 1/3 cost of 1094
if pistons have directional F or Front or dot or dimple or arrow, Ensure it's oriented facing front motor … also Ensure valve reliefs are indexed to valve faces.
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02-01-2019, 12:06 PM
