Rebuilding a 305 L69

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Jul 17, 2010 | 02:43 AM
  #1  
After pulling my spark plugs to hunt down an obnoxious oil burn on my new project camaro, I find that all my plugs have heavily baked on oil. Some more than others, but still at least over a millimeter of caked on crud that scraped off of each. I know my brother put new plugs in a couple months ago before trading it to me so this isn't a good sign to say the least. I did a compression test and got between 110 and 120 on all driver side cylinders. I got less than 90 on the three front passenger side cylinders, and I wasn't able to get to the one in the back but at that point it didn't matter anyway. Every plug I pulled out was caked on with oil and half the engine has real low compression. Makes me wonder how it possibly could have taken a gt mustang in this condition, but whatever.

I was planning on replacing the valve seals, but with this new info from the compression test I think I need to just rebuild the whole engine.

Now to the main point. I am new to the sbc scene and have never rebuilt any engine before. I was looking for a write up or general walk through of it. If anyone can help me out that'd be awesome. Also if there is any advice or specific thing I should be know please do tell.
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Jul 17, 2010 | 02:56 AM
  #2  
Re: Rebuilding a 305 L69
Also, I wanted to know if a can use any 305 rebuild kit, or if I need a particular one for the l69... I also need to know how to check if its bored. Since its got so much power for such a messed up engine I want to check to see if its bored before ordering a kit.
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Jul 17, 2010 | 04:34 AM
  #3  
Re: Rebuilding a 305 L69
HERE IS THE BEST THING YOU CAN DO. PICK YOURSELF UP THE BOOK CALLED HOW TO REBUILD A SMALL BLOCK CHEVY ENGINE. THIS BOOK WILL WALK YOU THROUGH STEP BY STEP IN LAYMAN TERMS AND HAS GREAT PHOTO'S. THIS BOOK IS WORTH EVERY PENNY. GOOD LUCK AND DON'T GIVE UP WITH A LITTLE TIME & MONEY INVESTED YOUR BROTHER WILL WISH HE NEVER TRADED YOU HIS CAMARO.
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Jul 17, 2010 | 05:08 AM
  #4  
Re: Rebuilding a 305 L69
Since it's a 305, just be sure to order a kit with 60-over flat-top pistons. Most 305s used dished pistons, so that's what most kits have, and you don't want that.
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Jul 17, 2010 | 02:46 PM
  #5  
Re: Rebuilding a 305 L69
60-over?

And I've got a Haynes book thats called Chevy engine overhaul Manuel. Is that good?
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Jul 17, 2010 | 03:01 PM
  #6  
Re: Rebuilding a 305 L69
This thread has been up for 12 hours and no one's said it.. wow.

As much as it pains me to be "the guy" you know it cost the same if not less to rebuild a 350. And doing a 305 to 350 swap on a CCC Qjet car is about as easy as it gets for 3rd gens.

I'm all for building what you got but when it comes down to full rebuilding why not go for more power for the same cost?
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Jul 17, 2010 | 03:14 PM
  #7  
Re: Rebuilding a 305 L69
"No" go spend the money on this book. Again the title of the book is HOW TO REBUILD A SMALL BLOCK CHEVY ENGINE. You will thank me. Just google the title find a online store and have it sent to your home.
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Jul 17, 2010 | 03:16 PM
  #8  
Re: Rebuilding a 305 L69
If this Camaro is a true 305 L69 Z28. IT will be worth more down the road with the correct motor and matching numbers.
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Jul 17, 2010 | 03:39 PM
  #9  
Re: Rebuilding a 305 L69
Quote: If this Camaro is a true 305 L69 Z28. IT will be worth more down the road with the correct motor and matching numbers.
Yeah if he plans on garaging it and preserving what's left of the car. It doesn't sound like that is what he has in mind though.
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Jul 17, 2010 | 04:10 PM
  #10  
Re: Rebuilding a 305 L69
Quote: If this Camaro is a true 305 L69 Z28. IT will be worth more down the road with the correct motor and matching numbers.
Camaros from the 80s will never have the kind of valve placed on the 60s ones. So don't base your decisions on future value that may never materialize. At the same time don't hack up the car.

The haynes book on rebuilding the sb chevy is good enough to get you through the project.

The thing to think about right now is the rebuilding cost and what you can afford. Rebuild kits are cheap enough. Its the other stuff you will need to buy that runs up the cost. What will the machine work to the block, crank, rods and heads cost locally? Try and get some figures before you take anything apart. I would not rule out the 350 long block as a possibility. Depending of how much the 305 would cost to rebuild correctly it may be equal to or more than a basic 350.
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Jul 17, 2010 | 04:28 PM
  #11  
Re: Rebuilding a 305 L69
I disagree, early 3rd Gen 82-84 L69 305HO unmolested are priced at $12,000 to $24,000 for a #1 or #2 condition camaro depending on the options the car came with and if it has the correct paper work for the car. NOS parts are very hard to find for these Camaros and half the time Kids purchase these cars that were'nt even born when these cars were new and chop them all up. Enough said
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Jul 17, 2010 | 04:47 PM
  #12  
Re: Rebuilding a 305 L69
Quote: I disagree, early 3rd Gen 82-84 L69 305HO unmolested are priced at $12,000 to $24,000 for a #1 or #2 condition camaro depending on the options the car came with and if it has the correct paper work for the car. NOS parts are very hard to find for these Camaros and half the time Kids purchase these cars that were'nt even born when these cars were new and chop them all up. Enough said
Right and those cars are not raced like his project camaro is. They are kept in climate controlled garages and taken out rarely if ever for a drive.

I would search around for a long block if I were you. Personally if you are going to swap long blocks I would look for a 400sbc. You can find them easy enough.
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Jul 17, 2010 | 05:11 PM
  #13  
Re: Rebuilding a 305 L69
Do the 350. But if not, then do go 60 over. It's not like you're gonna put another 150,000 miles on it, and it's not like there's any risks created by going 60 over. You get better breathing, you get more torque, it's all good.
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Jul 18, 2010 | 12:43 AM
  #14  
Re: Rebuilding a 305 L69
Well Do I even have to machine everything? I mainly what to restore the compression and stop the smoking. Could I not just replace all the seals, rings, and gaskets? Do I actually have to machine the heads and block and all that?
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Jul 18, 2010 | 01:38 AM
  #15  
Re: Rebuilding a 305 L69
That is the most likely situation considering the age and problems with the engine.
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Jul 18, 2010 | 05:16 AM
  #16  
Re: Rebuilding a 305 L69
I have tried to help you. Please go invest in purchasing the book HOW TO REBUILD A SMALL BLOCK CHEVY ENGINE. This book will answer all your questions correctly the what if's, how come's, what inter changes, trouble shooting guide, what kind of gaskets should I use, does the engine need machining, can I use my old parts over. This book is writen in the 8th grade level and anybody can understand it's contents. Do yourself a favor listen to me. If you can't afford the money for the book then you can't afford to repair your Camaro. This will be my last post on this subject. Good luck

Remember: Those who ask for help to seek the answer but fail to follow are destine to fail.
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Jul 18, 2010 | 05:20 AM
  #17  
Re: Rebuilding a 305 L69
To determine what must be done, the engine must come apart. If the valvestems and guides are worn, then new valveseals won't last long. Likewise with the cylinders, if the bores are worn, then new rings won't do any good.
You need to do something. Check the local salvage yards until you find an '87-up 350 shortblock, and then rebuild that with dished pistons, then rebuild your 305 heads and put those on it.
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Jul 18, 2010 | 01:26 PM
  #18  
Re: Rebuilding a 305 L69
I think I'll go ahead and check out that book and see if its any better than the one I have. I don't need an 8th grade level to understand things, and this book has all that you mentioned as well. I was just trying to get some advice from people whom have already done this before I pull the engine and get into everything.

As for the 350 options. I was also thinking about that as well. But If I would have to tear down and machine the block regardless of which one I used, how much extra would it be to bore mine out?
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Jul 18, 2010 | 02:13 PM
  #19  
Re: Rebuilding a 305 L69
Only your machinist will know how much it will cost to bore it. It doesn't cost any more to bore a 305 then any other v8 motor, they charge by the cylinder. The pistons may be cheaper for the 350 though.

If you buy a 350 core they vary in price where you get them. Anywhere from 75-150$+ from a junkyard. Check out craigslist in your area too I see a lot of SBC's on there.

The roller 87+ block idea is great IMO. They make notably more power on the top end and wear less on their parts. I'm actually junking a 4 bolt main 350 flat tappet bottom end (just hauled it out to my truck last night) because if I build a 350 it's going to be roller. Mine needed completely rebuilt and if I'm going to invest that kind of money into a bottom end it's going to be exactly what I want.

Get some budget performance (1.94 intake, 1.6 exhaust) valves for your 305 heads and have the machinist do a 3 angle valve job on them. With this alone you'll pick up a bit of flow, more so on the exhaust, but nothing like porting would. These will set you back about 70$ but are well worth it IMO. RacersOutlet on Ebay is a good guy to deal with on this.

Also I recommend using a melling m55 oil pump with a high pressure spring, I think the common spring is mrgasket #26.

The good news is that you can keep your CCC Qjet easily with a little tuning of the Idle air bleed and/or mixture control. It won't have any problem at all unless you go too radical with the camshaft.
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Jul 18, 2010 | 03:51 PM
  #20  
Re: Rebuilding a 305 L69
What is your budget for the rebuild?
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Jul 18, 2010 | 11:02 PM
  #21  
Re: Rebuilding a 305 L69
ccc QJET? What is that?


And my budget is Dependant on how long I plan to wait to do it. If i do it next month it won't be more than $200-250 unless I get this better job I've been shooting for. Thats why I was wondering if I can do it cheaply by just replacing the worn out rings and seals. If I do manage to get the better job I'll have enough to do a decent rebuild with maybe a few performance parts like a new cam. But if not, i need to do it as cheap as possible.
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Jul 19, 2010 | 02:54 PM
  #22  
Re: Rebuilding a 305 L69
The amount you can spend right now changes how I would deal with the issue. Changing the valve seals might help with some of the oil entering the cylinders so I would do that first. Then I would use some seafoam to clean out the chambers and swap plugs. Finally change the oil to a thicker weight and possibly add some lucas to thicken it up some more. This should give you some time to get funds together to address the problems with a permanent solution.
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Jul 19, 2010 | 04:30 PM
  #23  
Re: Rebuilding a 305 L69
I think I picked up on a question. The 305 and 350 differ by .25 bore. You cant bore a 305 to a 350. You can bore it .060 as Atilla said , though that is pushing the cylinder wall thickness envelope. 350 gets you bigger bore for more power potential. And aside from the pistons, it will take all the same parts.
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Jul 20, 2010 | 03:03 AM
  #24  
Re: Rebuilding a 305 L69
Ok, So I can do a 30 or 40 over and have more power than a stock 350?

Does anyone know what I can expect in general a machine shop to charge?
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Jul 20, 2010 | 12:52 PM
  #25  
Re: Rebuilding a 305 L69
I take it youre still talking about doing the 305. Many members run 305s and like them. The key difference you run into is allowable valve size and flow. At levels below 400hp that really wont make much difference.

When you consider that the stock 350TPI makes 230hp, its not too hard to out-do it. Your 305 can easily make 300hp using stock intake parts, some worked over heads, and a med size cam. That will definitely outrun a stock 350. That said, I want to reiterate what Atilla said earlier. Your 305HO heads on a 350 will make a tire burning beasty. I had one in an 84 Z28. Very fun car. The 1.94/1.60 valves may limit top end power just a bit but with the right cam, you can expect solid mid range torque. More than youll get from your 305 built to the same level. The extra cost would only be a good 350 core, about $100-150. A small price for the added fun factor.

As far as cost is concerned, it depends on how far you go. For a thorough bottom end prep which includes machining crank, resizing rods, magnaflux, checking crank centerline, boring with deck plates, balance rotating assy, new cam bearings and clearancing, youll spend about $750 or so. Just machining crank, boring cyls and resizing rods will run you about $250 or so. The difference is durability. An engine thats properly balanced and clearanced will run alot longer. Especially under the duress of hard driving.
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Jul 21, 2010 | 04:23 AM
  #26  
Re: Rebuilding a 305 L69
Well I honestly don't need a super long lasting engine, nor do I need a crap ton of power. Like I said, even with real low compression on 4 cylinders it has plenty of power for me. It still spins both tires if I power shift in 2nd and 3rd gear. Its got plenty of torque, I just want it to stop smoking lol. One day I plan on doing a good engine build and swapping the t5 for the t56 or building the t5 up itself. But that is probably a year or two away of saving.

I just want to fix up the engine to run good and strong for then next year or two without having to add oil every week. And I want to do it as cheap as possible.
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Oct 12, 2010 | 12:01 PM
  #27  
Re: Rebuilding a 305 L69
Quote: Only your machinist will know how much it will cost to bore it. It doesn't cost any more to bore a 305 then any other v8 motor, they charge by the cylinder. The pistons may be cheaper for the 350 though.
No they are not cheaper, a set for a 350 runs about $560 a set for a 305 runs about $500 this is the same no matter who makes them. A set of speedpro for a 305 is about 200.00 for a 350 about the same in fact about 20 more. So no it is not cheaper to build a 350. Parts are no harder to get for a 305 than for a 350.
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Oct 12, 2010 | 12:05 PM
  #28  
Re: Rebuilding a 305 L69
Quote: Well I honestly don't need a super long lasting engine, nor do I need a crap ton of power. Like I said, even with real low compression on 4 cylinders it has plenty of power for me. It still spins both tires if I power shift in 2nd and 3rd gear. Its got plenty of torque, I just want it to stop smoking lol. One day I plan on doing a good engine build and swapping the t5 for the t56 or building the t5 up itself. But that is probably a year or two away of saving.

I just want to fix up the engine to run good and strong for then next year or two without having to add oil every week. And I want to do it as cheap as possible.
Oh hell, thats easy. If thats as long as you want the engine to last get a set of 30 over pistons and rings, new main and rod bearings, re-gasket the engine and you are done and all for under 400.00 dollars. Hell it may even last longer than you think, this will giver more than enough time to save and build sosmething mean and hateful.
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Oct 12, 2010 | 12:13 PM
  #29  
Re: Rebuilding a 305 L69
Quote: When you consider that the stock 350TPI makes 230hp, its not too hard to out-do it. Your 305 can easily make 300hp using stock intake parts, some worked over heads, and a med size cam. That will definitely outrun a stock 350. That said, I want to reiterate what Atilla said earlier. Your 305HO heads on a 350 will make a tire burning beasty. I had one in an 84 Z28. Very fun car. The 1.94/1.60 valves may limit top end power just a bit but with the right cam, you can expect solid mid range torque. More than youll get from your 305 built to the same level. The extra cost would only be a good 350 core, about $100-150. A small price for the added fun factor.
This is true, in fact if he were to look for the info he will see that a 305 can be built to get 375hp out of it.Many have done it.Yes a 350 can be built up for more money, but what is a small price to you may be over the top to others.
WAY to many people seem to forget that a REAL street car will live it's life under 4000rpm. There is no need to build some engine that has to do 6500 plus rpm to do any good.Thats if he plans on driving it daily.
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Oct 12, 2010 | 12:36 PM
  #30  
Re: Rebuilding a 305 L69
305 pistons aren't hard to find per se, but there's a much greater selection for a 350. A quick search on Summit turns up 197 listings for 305 pistons, and 1,428 for 350 pistons.

The same search also shows a 350's SpeedPro ZH345NP30 costs $11.95 per slug, while a 305's ZH534CP30 is $19.95, so I don't really know where the idea that a 305 is cheaper comes from.

Yes, you can build a 375 HP 305, but it's more likely that you'll have to spin it at 6500 RPM to do so.
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Oct 12, 2010 | 12:50 PM
  #31  
Re: Rebuilding a 305 L69
Quote: 305 pistons aren't hard to find per se, but there's a much greater selection for a 350. A quick search on Summit turns up 197 listings for 305 pistons, and 1,428 for 350 pistons.

The same search also shows a 350's SpeedPro ZH345NP30 costs $11.95 per slug, while a 305's ZH534CP30 is $19.95, so I don't really know where the idea that a 305 is cheaper comes from.

Yes, you can build a 375 HP 305, but it's more likely that you'll have to spin it at 6500 RPM to do so.
The key to me on what you said was "per slug" thats fine if he only get's 1 piston. the same search I did on summit was for a set of 8 with rings. So while I agree on larger selection I disagree on price. Now when I look at the selection of 350 slugs what are we taliking about? we have, dome top, dish, flat top, either 2 or 4 valve relef. cast , forged, hypereuretic. the same for a 305 can be found. But I was talking about was for a basic build,as that is what the op was talking about not some 6500plus rpm monster at 600 plus hp. Another point I was and am tring to make is this.
Way to many people go right for some super high output engine, and seem to forget that as a daily driver it will live it's life at or around 3500-400rpm max daily. Not everybody goes to the track not everybody has a point to prove. Yes a 375hp 305 will have to spin like that, I was going for the fact that yes it can and has been done.
Oh and by the way, I like the banter with you, it had happened a few times and to me it is fun.Because it is always about getting info to those that dont know any better. I just think more of the so called "experts" need to get back to basics when helping new comers. There is no need to go to the advanced stuff. A solid foundation is the key to any build. Wouldnt you agree?
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Oct 12, 2010 | 01:03 PM
  #32  
Re: Rebuilding a 305 L69
Don't look for a set then, take 8 ZH345NP30 @ $11.95 each for $95.60 and add a ZE251K30 ring set @ $37.95 for a total of $133.55. That's less than the cheapest 305 ring and piston set, Z8K454NP30 at $141.99. (Sticking with FM parts, anyway)

Part selection is key for controlling costs.

I agree though, the vast majority of the engines most people here are going to build are for street applications, in which case crazy parts aren't needed. Most people do like to make upgrades and improvements down the road though, so it's better to start with a foundation which will allow you to do more down the road.
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Oct 12, 2010 | 01:32 PM
  #33  
Re: Rebuilding a 305 L69
Quote: Don't look for a set then, take 8 ZH345NP30 @ $11.95 each for $95.60 and add a ZE251K30 ring set @ $37.95 for a total of $133.55. That's less than the cheapest 305 ring and piston set, Z8K454NP30 at $141.99. (Sticking with FM parts, anyway)

Part selection is key for controlling costs.

I agree though, the vast majority of the engines most people here are going to build are for street applications, in which case crazy parts aren't needed. Most people do like to make upgrades and improvements down the road though, so it's better to start with a foundation which will allow you to do more down the road.
See we are eye to eye on that. But down the road could be many years, and if this is his first build this will be a giant learning curve for him. The basics, start small and move up,learn. I have said many many times, dont be stupid and go out and get 1000 dollar heads because somebody says they are good, yeah for his setup, but on your engine it could hurt, not help at all. This apply's to everybody and every engine. K.I.S.S keep it simple stupid. not you apeiron, just in general.
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Oct 12, 2010 | 02:10 PM
  #34  
Re: Rebuilding a 305 L69
The basics of the shortblock are the same, regardless of whether it's a 305 or a 350, they're equally simple.

On a first build with a steep learning curve then, you could argue it's even better to get a 350 and take as long as it takes to feel comfortable in putting it all together and doing all the checks, without suffering through downtime. Although that would apply equally to getting another 305 block as well.

If you want to tear it down, hone it, put maybe $200 of rings, bearings and gaskets into it and then run it as long as it lives, that's not a bad idea, and a good learning experience. As soon as any machining is involved, which there almost certainly will be when changing pistons, then the money is better spent on a 350.
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Oct 12, 2010 | 02:36 PM
  #35  
Re: Rebuilding a 305 L69
Quote: 305 pistons aren't hard to find per se, but there's a much greater selection for a 350. A quick search on Summit turns up 197 listings for 305 pistons, and 1,428 for 350 pistons.

The same search also shows a 350's SpeedPro ZH345NP30 costs $11.95 per slug, while a 305's ZH534CP30 is $19.95, so I don't really know where the idea that a 305 is cheaper comes from.

Yes, you can build a 375 HP 305, but it's more likely that you'll have to spin it at 6500 RPM to do so.


Supply and demand says it all here. People don't usually rebuild 305's so the pistons cost more.

This is all out the window given this guys goals and plans though. $250 won't even get your overbore block out the door at the machine shop unfortunetly.

You're limited to basic things with that budget but it should be able to "fix" the problem. Re-ring it and go. You may be able to squeeze a cam and valve train upgrade in that budget. Or you could forgo that idea and have the machinist do a 3-agle valve job on your heads with 30' back-cuts. The head work would cost $175 around here if you use stock size valves. Personally given the option I would do the heads for many reasons.
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Oct 12, 2010 | 04:42 PM
  #36  
Re: Rebuilding a 305 L69
I remember the build on my IROCZ. Of course Ive built many engines, most of them SBCs. I was planning on going mild, at first that is. By the time I got to ordering parts I was building something closer to one of my NASCAR motors than a mild street motor. Then, after waiting 9 months for my heads from Trick Flow, it was finally time to start. I pulled what I thought was a 350 out of my 5.7 IROC, only to find it was in fact a 305 repl;acement. $150 later I had a rebuildable 350 core in the back of my truck on its way to Archie Somers for machining. In the total cost of building a solid bottom end, $150 was really pocket change. My ARP stud kit cost more than the block.
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Oct 12, 2010 | 05:01 PM
  #37  
Re: Rebuilding a 305 L69
Quote: The basics of the shortblock are the same, regardless of whether it's a 305 or a 350, they're equally simple.

On a first build with a steep learning curve then, you could argue it's even better to get a 350 and take as long as it takes to feel comfortable in putting it all together and doing all the checks, without suffering through downtime. Although that would apply equally to getting another 305 block as well.

If you want to tear it down, hone it, put maybe $200 of rings, bearings and gaskets into it and then run it as long as it lives, that's not a bad idea, and a good learning experience. As soon as any machining is involved, which there almost certainly will be when changing pistons, then the money is better spent on a 350.
Bingo

the guy is looking to get more life from the engine, not restore it to like new condition. Honing, new pistons, rings, bearings, seals and gasket kit. Heck, get the kits that come with cams, bearings and timing sets from Ebay, pay a machine shop for a hot tank cleaning, honing and cam bearing installation and he might be at around $600 total including the kit(give or take).

He can then clean the heads himself and while at it, clean up the runners and get them flowing a little better. He'll have a decent running engine and probably get at least another 50k out of her (pending anything major with the crank)

I'm on the fence with my budget restoration myself. I have a 95Z and 07 Stang if i want power. I've been looking for decent 350's and anything that doesn't require my tearing it down to confirm condition is over $1500 so a budget rebuild of the 305 is attractive to me.
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Nov 23, 2010 | 06:02 PM
  #38  
Re: Rebuilding a 305 L69
quadrajet carb this is what the factory put on it. probably the E4ME computer controlled carb.
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Nov 24, 2010 | 02:36 AM
  #39  
Re: Rebuilding a 305 L69
My 2 cents:
Pull the 305 and mothball it.
Buy a used motor.
Take the time to learn, if by then you still want to build the 305 you'll have the money and the knowledge to do it the way you want it.
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Nov 24, 2010 | 01:15 PM
  #40  
Re: Rebuilding a 305 L69
Quote: Well I honestly don't need a super long lasting engine, nor do I need a crap ton of power. Like I said, even with real low compression on 4 cylinders it has plenty of power for me. It still spins both tires if I power shift in 2nd and 3rd gear. Its got plenty of torque, I just want it to stop smoking lol. One day I plan on doing a good engine build and swapping the t5 for the t56 or building the t5 up itself. But that is probably a year or two away of saving.

I just want to fix up the engine to run good and strong for then next year or two without having to add oil every week. And I want to do it as cheap as possible.
You'll probably never see this but... Based on everything you've posted, I'd do the valve guide seals and see how far it gets you. I did some in 2004 on an engine that was fouling plugs and I still drive it.
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