how about some pics of inline 6 engines

[crispo-71]

i want to keep the inline 250 in my 71, looking foward to rebuilding it, i have never done an inline 6 though and i have no idea how good they are, ive herd they overheat fast especially on highway because they are low rpm but dats all i kno.. any hints or facts??

[Shyguy]

The 250 L6 in my '67 does not have an over-heating problem when setting still or running down the highway, it runs 190 degrees.

My truck has the old style 4 speed.

If a person is running an air conditioner and an automatic transmission a fan shroud and larger radiator may be in order.

Everyone I have talked to that has a L6 says they are reliable and last a long time.

[BMERDOC]

Found out most Chevy I6s (mine) have integral intake manifolds which is an instant no no. Tracked down the block numbers and found that it was a 71(?)-79 250 block, tracked the carb numbers 17057014 and found it is a 77 (5th digit indicates) year. Because its a monojet it probably came outta a 1977 Camaro or Nova because the trucks straight 6 had a two barrel. Nothing but a carb rebuild and a set of plugs and it runs like a champ!! Two pumps on the gas pedal and she fires right up, runs nice and crisp. No smoke and idles all day at 190 degrees without a shroud. Believe me, I've let it idle for a looong time to make sure its not gonna overheat.

[Shyguy]

Oops! L6's in the '67-72 range did not have integral head and the carbs were 1 barrel mono-jets.

Here are a few pictures I have collected over the years from other posts.

[geezer#99]

Some newer sixes where not integral head. Here's a 79 with 1 barrel carb.

[BMERDOC]

Yeah, I did enough reasearch on mine to find out it had the integral head and I just shut down. It'll do for now.

[crispo-71]

ok ok thats good to know ill stick with the inline 6 then.. im tearing it down now im going to send it to the mechine shop.. iave also herd some where that they port the heads a little and it really helps.. anybody agree?

[northerngmc]

Take a look here, 6 pages of Straight six pics!

http://67-72chevytrucks.com/vboard/s...d.php?t=258488

[Matt67C10]

My '67 250cid I6

[bosco200]

Heres mine.....

['68OrangeSunshine]

Originally Posted by crispo-71

ok ok thats good to know ill stick with the inline 6 then.. im tearing it down now im going to send it to the mechine shop.. iave also herd some where that they port the heads a little and it really helps.. anybody agree?

"Twisted 6" is Larry Page in Orlando FL. He puts lump ports in heads. He's a moderator on the Inliners Internatrional website: www.inliners.org. You can also read about lump-porting in Leo Santucci's "Chevrolet Inline Six Cylinder Power Manual." Recommended reading.

[martindc1]

Just got mine back together and it runs like a top. The old pistons were shot because I had several broken rings. Before the rebuild it used over a quart of oil per 100 miles but still ran ok. I can only guess that the engine had around 128k on it by the odometer, but it probably had a lot more use than the odometer shows because the truck has an original PTO output. The crank still measured within spec on the mains and 0.001" under on the rod journals. After the rebuild I calculated the fuel mileage and calculated 15.

I've heard you can bump the compression in the 250s by using 307 pistons and in the 292s by using propane pistons.

I really like the straight 6's. Plus their easy to work on. I often sit in the engine bay on the the fender wells with my feet on the frame.

[bosco200]

I do that to lol its awesome!!!!!

[PanelDeland]

The overheating is usually on the earlier 6 IIRC the 216 and it's sister engines.I think you will find the 6 is a strong reliable engine that lasts way longer than a V8.Whether that is due to the fact people don't hot rod the 6 as much or if it's just designed in a way where it handles use better,i wouldn't know.I just know that people always look at me weird when they ask when I'm swapping to a V8 and I tell them the 6 is staying,I've already seen a bellybutton.(No offense,I think the GM 350 is the best engine design ever)

[GRX]

Cannot tell you how many times I've pulled my '69 stepper into a car show, opened my hood, and & got comments how reliable the 250 is. The inline 6 is a very good design. Why aren't they used in more modern cars? Think about what was happening in the late 70's. Cars were changing to front wheel drive. Engines were turned sideways to make room. The I6 was simply too long. And yes the integral head is utter crap. Gasket issues - crack city. A regular head & set of manifolds can be made to fit if one is so inclined.

[factorystock]

Not only are the straight 6's super reliable ( ask any mechanic who worked at a GM dealership ( 1963 thru 1974 non integral head versions ) they are also very easy to maintain. Just look at the location of the distributor, fuel pump, spark plugs and starter.

[martindc1]

factory stock, do you have the full size version of the pic in your avatar? I have the black and white version but would like the color version as well.

I too get many stories about how good the 250 and 292's are. One time they even got praise from a die hard Ford man.

There are still a few old grain trucks around here with straight 6's. Its kind of funny considering all the hot rodded diesel pickups running around town.

[crispo-71]

thanks guys... very helpful info.. this will be my 1st block i will be taking to a machine shop.. what should i ask for???

[pritch]

Originally Posted by PanelDeland

I think you will find the 6 is a strong reliable engine that lasts way longer than a V8.Whether that is due to the fact people don't hot rod the 6 as much or if it's just designed in a way where it handles use better,i wouldn't know.

I've always heard that it's because the pistons are traveling straight up and down, not laying on their sides like in a V-thingy. Equal wear on the rings and the pistons themselves, as opposed to the slight gravity exerted on the rings and pistons in the V-thingy set up.

[Shaky]

Originally Posted by crispo-71

thanks guys... very helpful info.. this will be my 1st block i will be taking to a machine shop.. what should i ask for???

It depends on how much you want to spend. I just had my 250 done. Here's what they did, some of it necessary, some of it nice to have:

1. They baked the block in a big oven to get rid of the grease/oil/coolant residue. Some shops use a hot tank.

2. Chase threads. This cleans out the threads so there's no junk in there (that falls out later in the build and ends up in your engine) and you get accurate torque readings on critical fasteners.

3. Overbore. Mine needed it.

4. Deck the block. This makes for a nice flat surface for the head to mount to. You want to take the minimum amount of material so it doesn't affect pushrods and whatnot.

5. Align-bore the main bearings. It should at least be checked.

6. Check the cam bearing alignment.

7. New freeze plugs.

8. New main and rod bolts.

That said, I tend to be a little paranoid about this stuff, so others may have different opinions on what is required.

[crispo-71]

thanx alot shaky, i will send it off this weeknd.. around how much did all that cost you???

[Shaky]

Whaddya know? I found the receipt.

I told these guys to do it right, but not spend money on anything stupid. The total, including all the cylinder head work was $1600.00. Keep in mind that I live on the gold coast of CT too.

Here's what the short block got: Clean, pressure test block, plug, cam bearings, bore .040, deck block, grind crank, align hone mains, hone rods & install new bolts, disassemble & assemble long block, hang pistons, clean all parts, resurface flywheel, balance rotating assembly (including flywheel & clutch), re-stud manifolds, remove flapper in exhaust manifold and plug, drill & tap crank for balancer bolt (1967 didn't have this).

Here's what the head got: clean, pressure test, valve job (including hardened valve seats, R&R rocker studs & pin, set-up spring & stem heights, update for positive seals.

You can get away without some of this (like balancing), and save money by doing some stuff yourself (teardown/buildup).

[Autoblueprint]

Originally Posted by crispo-71

i want to keep the inline 250 in my 71, looking foward to rebuilding it, i have never done an inline 6 though and i have no idea how good they are, ive herd they overheat fast especially on highway because they are low rpm but dats all i kno.. any hints or facts??

I like the 6 bangers...there is quite a bit you can do with them.



This photo of 235 c.i.d. engine is from my 1961 Apache...more photos ( with enlargements ) and tech info can be found at my web site:

http://www.autoblueprint.com/1961_pa...html#AUGUST_09

[crispo-71]

Originally Posted by Shaky

Whaddya know? I found the receipt.

I told these guys to do it right, but not spend money on anything stupid. The total, including all the cylinder head work was $1600.00. Keep in mind that I live on the gold coast of CT too.

Here's what the short block got: Clean, pressure test block, plug, cam bearings, bore .040, deck block, grind crank, align hone mains, hone rods & install new bolts, disassemble & assemble long block, hang pistons, clean all parts, resurface flywheel, balance rotating assembly (including flywheel & clutch), re-stud manifolds, remove flapper in exhaust manifold and plug, drill & tap crank for balancer bolt (1967 didn't have this).

Here's what the head got: clean, pressure test, valve job (including hardened valve seats, R&R rocker studs & pin, set-up spring & stem heights, update for positive seals.

You can get away without some of this (like balancing), and save money by doing some stuff yourself (teardown/buildup).

a little pricey but man that thing looks good.. thanks alot now i got an idea of what im going to do...

[crispo-71]

Originally Posted by Autoblueprint

I like the 6 bangers...there is quite a bit you can do with them.



This photo of 235 c.i.d. engine is from my 1961 Apache...more photos ( with enlargements ) and tech info can be found at my web site:

http://www.autoblueprint.com/1961_pa...html#AUGUST_09

wow real nice..