CamaroRS385hp

how difficult is it to replace the rings on an engine? a guy around here is selling a 400 short block for $175, and said all that really needs to be fixed is to replace the rings. i was planning on rebuilding it anyway cause it hasn't been used for a while....are rings a normal part of a rebuild? is this engine worth getting??

z28monster

iTrader: (1)

for that price and in soem what running condition for a 400 id say it is worth it.
puttign new rings in it i wouldnt no i havent yet rebuilt a motor my self, lots of snowmobiles, dirtbikes, 4 wheelers and stuff like that but havent taken on the adventure of a small block v8 yet

CaddiBird

Yes rings are part of a proper rebuild. A rebuilt shortblock should have the crank ground, rings replaced, rod main and cam bearings replaced, the motor should be cleaned/checked for cracks, rods should atleast have the bolts replaced it's best to have them reconditioned, depending on the condition of the bores they might have to be bored if not they should be honed to "brake the glaze" so the rings will seat properly, depending on the condition of the deck(where the head sits) it might have to be machined back true and thats what a good machine shop will do when they rebuild a short block. There are several books out there that will be able to tell you how to replace the rings and so forth a hella lot better than I ever could. If you have common sense, the tools and the will to do it it's not that hard though. Make sure it's a 400 though it could be a 305 or 350 and the guy is trying to pass it off as a 400. To tell first most but not all 400 have 3 freeze plugs on the side of the block all 305's and 350's have 2, second a 400 has a 4.125" bore where as a 350 is 4.0 and a 305 is about 3.750 and third a 400 is externally balanced so the flexplate and balancer will have balance weights on them.

wesilva

iTrader: (35)

And....the oldest scam in the motor world is "it just needs rings". Anyone who has spent time at swap meets hears that quite often. Ask the seller if you can take the block to a machine shop to check it out at your expense. 400 blocks can really only be bored .040" oversize and they can crack in unique areas that most experienced machinists can look for. If the block is bad or if it needs more than just rings and needs to be bored, you'll know about it. Personally, even if it did need to be bored, I think the price is good. Good luck.

JHens

an easy way to tell a 400 is the siamesed bores and the steamholes between the bores.

wesilva

iTrader: (35)

Another easy way to tell is that the surface of the block a little ahead and behind the motor mounts will be slightly bulged. This is to accomodate the larger bore. On any other small block this surface is flat.

DTL504

iTrader: (1)

here is a picture of my 400 block

408TA

take the 400, if its not cracked its worth 250 all day long(stock bore)! the 400 blocks are getting harder to find every day. just tell the guy you want to have it magnafluxed(checked for cracks) and if its cracked you want your money back. if it passes DONT forget to drill steam holes in your heads that you put on the motor. if you forget you'll have overheating problems, this is where the old wives tale come from about chevy 400s over heating. ive got a 400+ hp 408(.040" over) that never over heats. im now transplanting it into a 88 TA; i had it in a 69 4X4. the torque a 400 generates in unbeleivable if built with proper componants. ENJOY

CamaroRS385hp

could you tell me what cam/heads/etc. that you used? did you use parts from a 350 or did you get better performance parts made for a 400? i'm buying a rebuild kit, but i don't have a clue what size other parts i should put on it that dont come in the kit. also, where on the heads do i drill the steam holes? do you have a pic of yours? can i drill it myself or should i get a machine shop to do it? thanks

JHens

here is a little explanation of the 400 steam holes, it's one page from Chevy Hi Performance, it's from the February '03 issue, the article is called "The 400 Drill" you might be able to find the article on their website, or be able to find the issue somewhere.

CamaroRS385hp

thanks alot, i'll go try to find that article...man what would i do without TGO?

JHens

I looked on their website, but I couldn't find the article, sometimes they sell back issues of magazines, as I said it's the february '03 issue.

wesilva

iTrader: (35)

Most automotive machine shops will charge $30 to $40 dollars to drill the heads for you.

Air_Adam

Just get a good set of bits made for drilling steel, a drill with some *****, and you should be fine on your own.

408TA

i'll do my best to list what i did but your combo will probably be different considering MONEY.
short block goes like this: block was decked to ZERO(9.00"), studs installed on the mains,rear main was massaged around the oil hole, also used a stud for the oil pump(i HIGHLY recomend buying a stud for the pump, it gets torqued to 65 lbs and i've seen threads get pulled here and a replacement cap for a 400 is scarce or exspensive.)clevite bearings, its bored .040" over(only bore enough to get it straight again), ZGTF childs and albert zero gap rings,pistons are forged TRW with small dish, cam was a special grind from COMP: 224@ .050", lobe seperation is 106, lift is .470", its installed at 102 intake centerline. cloyes hex-a-just timming chain, melling high volume oil pump.stock rods with ARP wavelock bolts. recipricating unit has been balanced. that does it for the short block.
heads are world products SR torquer 2.02/1.60, 3 angle valve job, valves radioused and backcut and faced, good pocket porting, chamber ONLY polished.comp cams magnum roller TIP rockers, 1.6 on the intake 1.5 on the exhaust.
intake is a performer RPM, HEI distributer with MSD 6a box and blaster coil. carb is a street avenger 770 cfm with the proflow body.
that about does it. i had hooker super comp headers on it also. i will post another message after this one to give you a little insight on some "trick" stuff for the 400 and other motors.

408TA

now the 400 chevy likes a tight lobe seperation for most heads that we can afford, but the tight lobe seperation ONLY works IF you have a great exhaust system..... NO BACK PRESSURE!!!! the 400 is under headed;lack of CFM. the tight lobe seperation creates a scavaging afect which gets more fresh charge into the chamber for more power, more or less. im not going to go into total detail on this. but a 400 for the street likes 106-105 lobe seperation. nobody makes "streetable cams" that tight so you have to special order it $180 from comp. but isky grinds a bunch on 108 which is better then 110 or 112. the 400 will twist reliably up too 5500 RPM all day with a few 6000-6500 once in awhile. for the street stay under 232 advertised duration, run 1.6 COMP rollertip rockers on the INTAKE(if your springs will alow) and 1.5 on the EXHAUST. i would use the vortech heads with dished pistons and matching RPM intake. the tighter lobe seperation will make more torque in the mid range rate where you want it. if you cant use the vortech heads use 461 or 462 heads. there are many more things to do but this general combo using the isky cam is worth around 470 lbs of torque and 390-420 hp( depending on duration of cam). this would make first gear useless(tremendous tire smoke) and require tire replacement frequently, plus the GRIN factor is VERY high!!!!!

wesilva

iTrader: (35)

408TA,
I am currently running 6" rods on my 400 and it really likes the 110 lobe seperation. Longer rods do tend to like wider lobe seperations. Do you have any solid experience with motors running standard type rings versus zero gaps? Do you feel they are worth the money? I am considering Blok Filler for the next build up. Do you have any experience with this stuff with regards to long term street use? I will only do a street fill which consists of filling just a portion of the water jackets. I currently am running a Griffin Aluminum radiator and can barely get enough heat to run the heater in the winter despite the 190 degree thermostat. With that, I think I should get away with the block filler.

408TA

did you try an exact cam with 106 lobe seperation? your most likely losing around 30-40 lbs of torque in the mid to upper rpm range. yes i agree with using blok filler up to the bottom of the freeze plug hole. it keeps the oil hotter while being able to get the water temp cooler. and yes a 5.7-6.0" rod is better than the 5.565" stock rod. even though your using 6.0" rods your are still under valved; its physically impossible to put a valve large enough into a 400 CHEVY sm blk. so a tighter lobe seperation on your motor would show improvements as long as you have next to nothing for back pressure in the exhaust. another trick that works great on the 400 and 305 is to have a 30* intake valve seat installed and then blended by a VERY GOOD machine shop. this is worth another 20-40 lbs of torque if done properly. this 30* seat works good for the street or street/strip car, but wont show huge gains on a drag race car because the gains aren't really noticeable after .510" lift. its also worth noting that a 305 and 400 share the same lobe seperation requirements. also worth noting the DESK TOP DYNO wont show you the difference like a real motor on the dyno would.
PS the rings are only worth it if your trying to get the most out of your motor,yes they make a difference but the cost is questionable. i would use them again for the main difference that the blow by will remain low even after a motor has been driven hard for alot of miles.

Drastius

Why do you suggest running 1.5 roller rockers on the exhaust rather than 1.6's like the intake? Worried about interference?

408TA

when you install 1.6 on the exhaust with a with a cam sized correctly to the components of the engine you lose too much low end torque up to 4500 rpm. between 4500-5000 you'll see gains by adding 1.6 on the exhaust, and since most 400s are more of a low to mid range power maker it doesnt make sence too trade off 15 lbs of torque from idle to 4500 rpm to gaine 10 hp at 5500-6000 rpm where most 400s are out of breath because of the heads, not to mention the long stroke is really becoming an issue at 5500 rpm+ because of centriffical forces. its just matching ALL the components together even the one that dont "make" the power like rods and cranks, theres no sense in over stressing the engine by over reving it just to get those few extra HP that 1.6 added at 5500 rpm. remeber its torque you feel on the street not HP. all this goes for STOCK componants, rods and crank. if you added a nice SCAT crank and rods then you can really gear your motor to make top end HP(400 sm blk). the longer the stroke the less RPM you can "safely" get out of a small block. concentrate on making gobbs of torque with a 400 in the 3000-4500 rpm range and it'll make peak hp between 5000-5500; this is with "stock style heads" 165-180 cc intake volume. to get more RPMs out of a 400 you'll have to increase the intake volume to 200-230 of course you'll want added flow to go hand in hand too. anyway 1.6s open the valve sooner at .050"(ofcourse) and also let some of the trapped charge in the cylinder out before it could finish pushing on the piston at lower engine speeds, this is where the lost torque comes from. now if your cam is too small for the engine to begine with then yes you can see a difference sooner and sometimes all across the board. TIP: stock 305s love 1.6 on the intake side. i chose COMP magnum roller tip because they measure exactly 1.52 or 1.6(most stamped steel units measure 1.4-1.5 ),where as others dont always. the roller tip doesn't make a huge difference. and the price is rite for them. i wouldnt use full rollers until lift exceeded .525" or the engine was used for en endurance race, theres not much beenifit form a power stand point unless your winding it up too 7000 rpm( this is what most advertisers forget to tell you when they say you gan gain UP to 15-30HP!) hope this helped!