First engine rebuild

[LAC_STS]

Re: First engine rebuild

Just wanted to add something(s).


I have been looking for an inside and outside mic. I have looked locally since it was mentioned for checking the piston clearances. I haven't been able to find any locally so I guess Im gonna have to order a set. (Harbor Freight has some but I don't buy anything from there that is precision and important.)


The guy today at the machine shop measured the pistons in front of me with his mic. He showed me how much they were off.

I still want to check myself. Im either gonna order some mic's or go to Grainger and pay an arm and a leg for one.


Seeing as I know nothing about pistons, what exactly am I looking or not looking for? The pistons I have now only have a single valve relief. I thought they were cast but the guy today said they were forged.

I know I have a 4" bore, and I'll have to look again but I thought when I Googled the casting #s from the block the stroke was a 3.48, or maybe it was 3.750. I dunno Ill have to look again. Or does the stoke not matter when ordering pistons?

A quick search on Summit found these.

http://www.summitracing.com/parts/SUM-17350-00/

Are these some of the cheap ones to stay away from?
They say they are Hypereutectic, Does that matter?

Again, I know nothing about buying pistons so please throw all suggestions my way. Ill start researching it online though. Ill know enough in the next day or two to make a decision.


Sorry for all the newb questions. This community and all you guys are great. Its greatly appreciated. When Im done with this thing it will be nice to fire it up the first time. Ill have went from knowing nothing and never doing any of this to rebuilding my first engine.

All made possible by all you helpful great folks.



Thanks again

 

[proshadetree]

Re: First engine rebuild

Get a digital caliper. Easier to read than a mic and just about as accurate. Those pistons will lower your compression. You have two reliefs and they have 4. Good set of budget pistons though. My buddy has that set in a camaro and twists it to 7000 rmp between gears. Show insides of the piston I really want to know what happened to swell those skirts. Check these slugs http://www.summitracing.com/parts/CNN-BC1045-030/

 

[LAC_STS]

Re: First engine rebuild

Check these slugs

$640 for those. Is that how much I can expect to pay for decent pistons or are those ones top of the line?

Are all of the pistons gonna have the same size ring thickness? 5/64 in. x 5/64 in. x 3/16 in.

Those are the size rings I have now. So it'd be nice to be able to use them still.

So so far I need 4.00" bore, 2 valve relief, ?5/64 5/64 3/16 ring thickness?, what about Wrist Pin Style? I have Press-fit right? I need press fit so I can re use my rods?

 

[dockwrecker]

Re: First engine rebuild

Yeah those are high dollar pistons for sure. I think maybe overkill as Summit lists several hypereutectic piston sets for half of that. I'd expect that price for forged Hepolite pistons. (which you don't need in your boat) Shopping is in order, there were several Keith Black sets I saw there that were $250-280 per set. You have to keep in mind when looking at pistons at Summit, many are designed for forced induction/high compression/high RPM use (as in 7000+) that you don't need. Look carefully at the compression ratios, I don't think you want to exceed 9:1 with pump gas and marine RPM's. If it makes you feel any better, I've paid $235 A PIECE for Lotus 907E Hepolites, and close to $350 each for 930 factory Porsche pistons. Chevy stuff is a bargain!

 

[1kwik72]

Re: First engine rebuild

Here is something to consider. Obviously the machine shop did not hone the cylinders to match the pistons and apparently, somewhere in the process of pressing the wrist pins in or during their work, two of the pistons are now not good.

In my opinion, I would go ahead and have a good machine shop check this block again. Personally, I would have it bored .030 over and get a complete rebuild kit like THIS or something similar but just make sure the freeze plus are brass. Have the machine shop press on the new pistons AND have them hone the block to match each piston. You will also need to check ring gap but we can go into that as you get there...

I've done many rebuilds and trying to save a few bucks here and there has ALWAYS come back to haunt me... FWIW.

 

[proshadetree]

Re: First engine rebuild

You can also check fleebay
http://cgi.ebay.com/ebaymotors/New-...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories
TRW Speedpro, ect stay with a name brand. You machine shop might also just get you two replacement pistons. Use the ones that check and scrap the two that dont.

 

[LAC_STS]

Re: First engine rebuild

I went to the machene shop today with all of the pistons.

The older guy whom I talked to originally was there. He told me that there was no point in checking all of the pistons. He said I need new ones if 2 are that far off.

He also showed me where the rod had been banging or banged against the inside of the piston skirt.

Heres a pic of the #2 piston.


The guy said that I can sit the pistons on theyre face and let the rod rest against the inside of the skirt but they cant be banged back and forth.

I never was rough with them and never banged them around. but I did set them on theyre face with the rod resting on the inside of the skirt.

Then I showed him what the other guy told me about there being wear marks on the outside of the bottom of the skirt. He said that it looks like were run with the skirt rubbing or being too little clearance.



So either way he said get new press fit pin pistons and hell change them out for $40.




I dunno. Either way I guess I just need to get some new ones so I can continue with the build.

 

[LAC_STS]

Re: First engine rebuild

You can also check fleebay
http://cgi.ebay.com/ebaymotors/New-...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories
TRW Speedpro, ect stay with a name brand. You machine shop might also just get you two replacement pistons. Use the ones that check and scrap the two that dont.

Those look good. But then again what do I know.

That set says "This piston set comes complete with 8 matching pistons, 8 pins and 16 locks. "

"Press or floating pin"

I dont have locks right now. Just press fit. Does "press or floating pin" mean thatr theyre either or?

 

[1kwik72]

Re: First engine rebuild

It means you can get them either way.

Getting all new pistons is a better plan anyway.

I'd also talk to the machine shop (the old guy you dealt with today) and ask him about what size piston you need and about having the machine shop hone each bore to each specific piston...this is the correct way to build the motor. Also, make sure they're marked for order and direction so it's less likely to mess up on the installation. Personally, I'd also have them file fit the rings to the manufacturers suggested ring gap. This will save you lots of time and probably money.

 

[1kwik72]

Re: First engine rebuild

Those look good. But then again what do I know.

Those are dome top pistons...you don't want to go dome top for this application.

 

[926bill]

Re: First engine rebuild

Back to your question about ring size. Ring packs come in many sizes depending on the application. Your're size is pretty old school, so you can order pistons with that ring pack.
Make sure the machine shop honed the bores properly for you're type of ring, ie moly, ductile iron, etc.
I'd call summit racing and to their tech line. They'll set you right up. They have a store in Ga. so you'd probably have them in two days
3.48in stroke x 4.00in bore = 3.50 cu in
BC

 

[proshadetree]

Re: First engine rebuild

Point I was making is there are many affordable pistons with good performance besides summit. Check out Northern Automotive.

 

[GLENN M]

Re: First engine rebuild

wanting to learn is what its all about,trying to help you over thi internet is futile.the stage of the game your at is you need to watch and have each step explained,why and what for and shown the differances,before you make every mistake there is.no insult or put down my hats off you are willing to learn ,i wish i could be there to help.nobody with out a teacher can be expected to have a chance,you have to know what to do and know when machine shop has or hasent done right.they make mistake you have to catch,brand new parts can be wrong or screwed up you have to catch this,you have to know witch parts to get and why.you need to no what parts match for given application.without someone there to teach you will make every rookie mistake there is,anyone would,you wont learn much and become disheartened,get basic book how to build chevy.learning is great fun!throwing money away and beingfrustrated will kill your appetite to learn,get help

 

[1kwik72]

Re: First engine rebuild

wanting to learn is what its all about,trying to help you over thi internet is futile.the stage of the game your at is you need to watch and have each step explained,why and what for and shown the differances,before you make every mistake there is.no insult or put down my hats off you are willing to learn ,i wish i could be there to help.nobody with out a teacher can be expected to have a chance,you have to know what to do and know when machine shop has or hasent done right.they make mistake you have to catch,brand new parts can be wrong or screwed up you have to catch this,you have to know witch parts to get and why.you need to no what parts match for given application.without someone there to teach you will make every rookie mistake there is,anyone would,you wont learn much and become disheartened,get basic book how to build chevy.learning is great fun!throwing money away and beingfrustrated will kill your appetite to learn,get help

100% agreement with this post!

My first 3 rebuilds, I had an expert standing there with me every step of the way. The guy across from my shop built a 454 for his first build, read the books, asked some questions...he refused to allow anyone to help hands on. I completely understand that too. That engine litterally lasted for 2 hours in his truck before he developed a bottom end knock.

But once you learn how, building your own engine is a very rewarding experience! Again, Hats off to you for going forward with the rebuild!!!

 

[LAC_STS]

Re: First engine rebuild

I know guys. And thanks still for all the help. I'm not a quitter and am already in this enough not to.

I know Ive made (and prob will make more) rookie mistakes. And every ones gonna cost me, whether it's time, money, or both. I know it's a gamble on my end. If I knew someone who knew how to do this stuff and would take the time to teach me i would watch and learn, but I don't.

So, I know I'm gonna learn alot doing this. I already have.

Hopefully I come out with a good running successful rebuild too.

 

[1kwik72]

Re: First engine rebuild

I know guys. And thanks still for all the help. I'm not a quitter and am already in this enough not to.

I know Ive made (and prob will make more) rookie mistakes. And every ones gonna cost me, whether it's time, money, or both. I know it's a gamble on my end. If I knew someone who knew how to do this stuff and would take the time to teach me i would watch and learn, but I don't.

So, I know I'm gonna learn alot doing this. I already have.

Hopefully I come out with a good running successful rebuild too.

Not much I can say to that other than I like your attitude and persistence! Keep asking LOTS of questions, there are also some great books on blue printing smallblock chevy engines. They will help too. And of course just keep asking questions here.

Best of luck, I'd love to hear this engine running one day too!

 

[GLENN M]

Re: First engine rebuild

you wouldnt need to ask most of these questions if you had a book.you ask 20 people youll get 20 answers,oh well.several kinds of pistons,forged racing pistons,are the strongest there meant for quarter mile at a time.low tension thin rings dont last on street. forged pistons are the the best strongest for street and strip cars,some factory high perf vehicles came stock with them ie;425 hp corvettes,375 hp l-78 chevs.and more.cast piston is what most engines 90% came from factory with.these pistons are fine for under 5500 rpm and 350hp as long as quality brand and are very cheap.hyperuthetic is a cast piston with 14% or so more silican added for strengh.better than cast not as good as forged.95% all factory pistons even of forged type come with pressed pins,unless all out race effort forget them.cast rings are old school forget them,molly filled cast rings are what all factory cars have,chrome rings are again old school dont use them.just tell auto shop you want stock 30 over pistons with molly rings to match[they will be pressed pin] just have rods resized both ends. all rings for street use are of the thicker size so theyl last 300000 ks racing rings maybe 20000. so cast pistons molly rings cheap and good enough for 90% of motors on street and water

 

[honeys money]

Re: First engine rebuild

Well, I gota add my .02, I like to use factory original parts, if the first engine lasted 200,000 miles, the rebuild should do the same, buy Chevy parts for a Chevy, buy Ford parts for a Ford, can't go wrong.

 

[LAC_STS]

Re: First engine rebuild

Well I finally got my caliper and inside mic. Well kinda. I found one of those telescopic bore gauge sets (image attached)

I measured all of the bores. I measures both horizontally and vertically (sitting sideways at the block). And I measured about an inch down from the top of the bore, and I measured a couple of inches from the bottom of the bore.

ALL of the measurements came within .001 of 4.000". Im thinking all of the bores are 4.000" and my measuring is off by .001.

I did measure each and every measurement about 5 times (took me over an hour) until I got a consistent measurement. And I zero'd the digital caliper every time.



Sooooo....... I need to order pistons still. Sometime this weekend Ill go down to NAPA (machene shop) and get some prices and options on pistons from them, but Im pretty sure I should just order them myselft then take them down there and get them put on.


http://www.summitracing.com/parts/UEM-9902HC-STD/

http://www.summitracing.com/parts/UEM-KB120-STD/

http://www.summitracing.com/parts/UEM-KB120-STD/


I have been looking other places besides Summit. Alot of pistons I find have 4 valve reliefs.

 

[LAC_STS]

Re: First engine rebuild

Oh yea. forgot to attach the pic.