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Basic rebuild questions (406sbc)


Guest Russ240z

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Guest Russ240z

I'm sure by now you have all figured out I am rebuilding my engine. This is my first engine rebuild so any help is appreciated. I have completely disassembled the engine and cleaned everything. Here's the next question: Can I reuse the rings after honing the cylinder walls? The rings only have about 500 miles on them, mostly from the strip. My budget is limited, so every $100 counts.

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I suppose you could, but if these are not 'special' zero gap rings, please invest in new ones. To me, this is like using lifters over again--you can do it, but why??? :confused:

 

I am on a very tight budget at the moment, but rings, lifters, even cams! are things I would get new for a rebuild. Hopefully someone else will chime in.

 

Davy

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Guest Russ240z

Common sense has kicked in bonk.gif New rings are cheap insurance for the rebuild. Why take the chance of putting it all back together and not get a good seal. Now, I still need some tips on installing rings and which type or brand to buy. This is my first go 'round so help me out... cheers.gif

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Guest Anonymous

Call Cliff at Barnett Performance (Atlanta)...800-533-1320. Ask him about the Childs and Albert Rings...they have some very good rings that are reasonably priced. Barnett is a well kept secret, BTW...they're cheaper than Summit or Jeg's. flamedevil.gif

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a friend of mine knows where you can purchase a re-ring kit and gasket set complete for 115 bucks. thats everything bearings, rings, gaskets, and assembley lube. the rings are also moly. about the only other things you would need is a timing set, cam and lifters. i think most of your mail order houses such as jegs and summit offer that as a kit aswell. if you intrested i'll get you thier phone # and you can call them

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Guest Russ240z

Thanks for the help. I've already bought the cam(Comp xe274), lifters, gaskets and bearings. Here are the specs of the motor so far:

 

406sbc (stock rods, arp bolts)

Forged pistons, .083 dish (TRW # L2352F30)

GM 461 heads 64cc (1.94/1.5)

Performer RPM

Edelbrock 600cfm

Comp XE274 cam/lifters/springs

Note: I wanted to buy new aluminum heads but keeping the stock heads will get me on the road sooner since money is tight.

 

:confused: By the way, Can someone compute this setup on the desktop dyno...thanks. hail.gif

 

Russ

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Im assumeing your running 1 5/8" headers, you will be close to 365hp/451tq

btw the heads you have give you close to 11.4:1 cpr (look here)

 

http://www.smokemup.com/utilities/calc/compression_ratio.cfm

 

so 87 octane regular pump gas will not be an option! and those heads are killing your hp,

look here, summitracing.com

for part # PAM-223260035A

those heads cost $969 ready to run and flow 318cfm intake/205 exhaust

when you get bucks up a change to heads like these and 1 3/4" headers will get you to about 425hp/465tq

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Guest Russ240z

The part number on my pistons is TRW-L2352F30 (Speed Pro). These pistons are .083 dish with .030 oversize.

 

Summit's catalog says the compression ratio with 64cc heads is 9.16:1

 

This ratio is different than Grumpy's calculation (11.4:1)

 

Now I'm confused. I really don't want to run octane booster in a sreet car.

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I found some info on those pistons here:

http://www.herbertperformance.com/Catalog/Pistons/Speed-Pro_Pistons/speed-pro_pistons.html

 

12.5cc dish

 

I put your info into the Compression ratio calculator at http://www.smokemup.com/utilities/calc/compression_ratio.cfm and came up with the following:

 

code:

  Bore - 4.155 inches

Stroke - 3.75 inches

Cyl head volume - 64 cc

Deck height - 0.010 inches

Head gasket bore - 4.2 inches

Head gasket thickness - .039 inches

Piston dish volume - 12.5 cc

 

Compression Ratio is:

10.518 : 1

Note that I assumed a deck height of .010" (typical) and used a .039" thick gasket, with a 4.200" bore (typical for a 400 head gasket like the Felpro 1014).

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Guest Anonymous

Ring Problem,

I was wondering why you found it necessary

to hone the cylinders with only 500 miles on

the engine. If low compression was found, new

rings may not solve the problem. You'll have

to check cylinder taper, out of roundness,

cylinder diameter, etc. This is common problem

with thin walls on sbc 400 engine.

 

Sunny

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yes, cc = cubic centimeter

 

I guess it comes down to history. The US has used Cubic Inches for displacement until the last 10 years or so. And when you go to measure head combustion chamber volumes or the volume above a piston on a motor during the building stages, you use a graduated cylinder. The overwhelming majority of graduated cylinders that are available are in cc's.

 

BTW,

2.54 centimeter = 1 inch (exactly)

16.387064 cc = 1 cubic inch (exactly)

1 cc = 0.0610237441 cubic inches (rounded off)

1000 cc = 1 liter = 61.0237441 cubic inches (rounded off)

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Guest Russ240z

Sunny, I decided to rebuild for a couple of reasons. The main one was curiosity. :D I need to know how things work! One of the others is that when I bought the engine a couple of years ago I broke a valve spring. I was lucky that a friend was there when it happened and we replaced it with no other damage. But I knew there was the posibility a piece of spring may be somewhere in the engine. :( Might as well check everything out while its out of the car. I will be putting it in my 240z (260z is race only). I was told by the seller the heads were drilled for steam, not true. :mad: He said the cam was a comp 305 and I still had stock diameter springs... one had broke so it made sense to swap cams. Cam turned out to be Elgin. :mad: He also said it was 4 bolt... it's a 2 bolt. smile.gif That's okay, 2 bolts are better from what I hear. And to top it off, when I pulled the motor 2 of the 3 torque converter bolts were loose. fmad.gif

 

Everything looks good in the motor so far. I've read and heard to replace the rings no matter what. With new rings comes a hone job. Needless to say my sense of curiosity is getting expensive! :rolleyes: But its all part of the experience. rockon.gif

 

Thanks again.

 

Russ

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lt1240z, nice plug on Barnett's!! it is definately a well-kept (and pretty well-hidden) secret and they can be cheaper than summit or jegs. plus, they usually have what you need in stock. i have joked with those guys before about how jegs will at least send you an ugly new hat with an order. rolleyesg.gif

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the reason I thought you would have about 11:1 plus cpr is I was asumeing a flat top piston because nothing was said about dished/domed/pop-up piston shapes so flat top pistons being the most common type by far and what chevy uses thats what I used in the calc. now of course pparaska is correct if the new data is used. :D

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