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I tore down my '95 6.5 and found unrepairable cracks. I couldn't find a good block locally so I ordered heads and a block from Clearwater.
I also have 18:1 pistons comming from Peninsular. The heads look fine but the decks on the block look a little coarse. When the pistons get here I'm going to have the shop hone to specs and while they are doing that I was thinking of having them deck it .001.
If I had stock pistons I'd have to use the thicker casgets but with the raised wrist pins on the Peninsular units clearance shouldn't be a problem and compression should be a little higher than 18:1.
Does anyone think valve train geometry will be a problem.
I don't think .001 is going to make a difference with hydraulic lifters but I don't know.
Any thoughts are appreciated.
john8662
01-08-2010, 13:47
All bets are off with a Chinese block.
On a factory block you can take .010" without any harm to the valvetrain, the hydraulic lifters have over ~.120" range. No issues with taking up to .010" off a block.
Please update after this engine is running, quite a few of us are keeping tabs on the aftermarket blocks to see if any of them survive.
You'll likely need to take .005" or more off depending how square and flat the block is. My guess is not very.
Might consider having the shop bake the block at 500°f and gradual cool a couple times.
Also check the line bore...
SmithvilleD
01-08-2010, 21:07
Depending on where you're located, the bit of compression gained above 18:1 w/ a 0.010" deck surfacing may also help a bit w/ cold weather starting.
My OEM '95 929 block (truck bought w/ failed head gasket) needed a 0.010" surfacing cut to straighten & square up the decks. With the Mahle 18:1 marine pistons, that winds up in the neighborhood of 19:1.
From comparing notes with others that have built 18:1 6.5's, I get the sense the little bit of extra compression heating (18:1 -> 19:1) makes some significant difference in cold weather startability.
I've also spent some $ for stout batteries, 1-0 batt cables, Powermaster starter, manual glow extension, etc. Last weekend, the truck started after an overnight low of 0 F, with 12-14 seconds manual pre-glow, then the lengthened glow cycle Kennedy's chip provides. Only did this once, just to know if it would start in such conditions; otherwise at low temps, I plug it in, whenever possible.
As this was my first 6.5 build, I'd certainly defer to other's w/ more experience at running 6.5's at different comp ratios. Just thought I'd provide my 19:1 6.5 as one data point - because a number of people told me I'd be unhappy w/ a lower compression IDI 6.5. So far, in the first 7k miles, I haven't noted anything that would make me reconsider building another 6.5 at the same compression. Just have to note how the lower compression will impact starting & compensate if your climate gets cold enough to justify some starting system enhancement.
From what I have seen, the clearwater blocks are damned good.
Yesssss the casting is done in China, but so it the Dodge cummins and other well known items that we used to associate with the good old USA.
The castings are "according to clearwater people" machined here in the States on top notch CNC machines.
As far as the quality of the machine work goes, GM was no saint when it come to perfection either.
I have seen two of these Clearwater blocks put together this past year and both were great.
The first one was absolutely georgous and the second had slightly coarser finish on the decks but is working fine and has about 20K on it now.
If you are at all worried about the deck finish, .005 off the decks will not hurt anything.
NOW
Before you get squirrely and start cutting on things, drop the crank in with two mains (front and back) and set in a stock piston/rod assembly (No rings) with bearings and such.
Do this on both sides and measure the location of the piston in the hole with the piston at TDC
Spec is that the piston should be flush to no more than .005 out of the hole.
Make sure that when things are done that both decks are the same distance from the crank centerline.
If for instance one side sees the pistons at .005" above the deck and the other side is flush or slightly below the deck then the compression ratio will be off from side to side.
NOT GOOD
This is a lesson I learned when building DaHoooley last summer.
The "GOOD USED BLOCK" from the rebuilders service ($350) had been decked on one side .010" and not marked on the deck.
It never crossed my mind that someone would just do one side.
When I got the thing it needed a "cleanup" and so I ordered both sides decked until they just cleaned.
This turned out to be .015".
Now it got interesting. as soon as I started to stuff the thing together I decided to check piston height and found that the pistons came out of the hole .030" on the RH side and .015" on the LH side :eek:
There was a time that I was ready to scrap the block.
Found out about Cometic custom head gaskets and had one made to make the RH side the same as the left.
As far as the main line goes, I would drop the crank in the thing with fresh STD bearings (Lightly oiled) button the mains down and see how it spins.
Spins free OK then just remove the crank wipe off the oil, do a plasti gage on all the mains and see wassup there.
I like to run these engines at around .0025" to .003" clearance on the mains.
The spec says you can go closer but, NAAAAAAAAAAAAAW lets give it a tad more room to be safe.
The rods can do fine at .0025 also.
So many of these engines came with Undersize select fit bearings.
Many times the upper and lower shells are even different.
Use Std bearings in most cases (Unless the crank has been ground)
The practice of going down into the Sub .002 clearance range makes me nervous on these engines.
To sum it up, if your crank spins good and the clearances are good, your set.
The block is gonna move around anyway once it is in service for a while.
You might talk to Bill Heath about his Block stabilizer cement that they use in the lower portion of the water jacket.
They fill the block up to just below the soft plugs with this special block filler.
The idea is to stabilize the thing so that the lower end does not move around as much.
The reports are, that this has no effect on the cooling ability as the hot area is far above the area that is filled.
IMHO, this may actually help increase coolant velocity through the block and eliminate some of the stagnant areas. ???????/
My feeling is that you are going to have a sweet runner when done.
Personally, unless I was looking to boost the hell out of the engine I would not go below 20:1 comp ratio
Not actually sure what I ended up with on DaHoooley.
The actual clearance between the Piston and the heads at TDC ended up being right at .040" IIRC
I just made sure that with the special gasket on the one side that the stack up was the same so both sides were equal.
Engine is the smoothest 6.5 I have ever seen.
Amazing too since I used a set of 6.2 rods I had sent out for a recon and we did not ballance the rotating assembly.
Runs absolutely rock steady at all speeds and at idle it does not even wiggle AT ALL.
Most I have owned (new and used) will have some wiggle to them.
Just the luck of the draw me thinks.
Good luck and have fun.
Missy
SmithvilleD
01-09-2010, 12:10
I've got a turbo fitting/fabrication project a ways into the future that will require both fenders & inner fenders coming off.
As that will allow yanking the GP's fairly quickly, I plan to do both operating temp & then cold engine cranking compression tests, to get some idea what cylinder pressure levels are in my 19:1 engine, at cranking speeds.
Don't know how meaningful the numbers will be, unless there are a significant number of other's 6.5 results out there in the 6.5 forum's archives. Would expect there'd be a reasonably good correlation btwn cold cranking cyl pressure, mechanical comp ratio, & how the engine starts in colder temps.
More Power
01-09-2010, 15:48
I've written about the 18:1 CR many times through the years, but just to reiterate... Back in the late 1990's the folks at Peninsular told me that they developed the 18:1 CR for their marine applications. As I was told, a stock CR engine would run on their engine dyno for ~3 hours before the pistons swelled to a point of grabbing the cylinder walls - thus destroying the engine. All the while simulating a marine load and with a marine cooling system. On the other hand, an 18:1 engine ran for many times that with no ill effect. All the while simulating a marine load and with a marine cooling system. They suggested, at the time, that I try a set of 18:1s in the performance-oriented 6.5 we built in 1999 - which was used in a pickup truck.
For an on-road app, we may not need >3 hours of continuous "stock" rated power durability. But, add additional fuel, add additional boost pressure, add a 10K trailer to the mix, a long steep grade and a stock pickup truck cooling system, and the 18:1 engine will absolutely improve long-term durability. CR has a direct correlation to peak combustion flame temperature.
When someone asks me whether they should install 18:1 CR pistons, I first ask what they'll use the truck for. If it's a light-duty use, I recommend staying with the stock CR for normal all-season start-ability. For a full-time RV'er, who uses his truck to tow his 10K+ trailer more of the time, I indicate the 18:1 pistons might be a good choice - especially if the owner adds power (who doesn't?).
For most 6.5 owners who live along the northern teir of the lower 48, or anyone in Canada or Alaska, I recommend staying with the stock CR - primarily for typical cold weather startability.
That said, we've published several articles that discuss how to extend the glow cycles, and we've talked about the importance of the block heater. Do these two things, and you can get along quite well with an 18:1 6.5TD even here in Montana - we did for several years.... ;)
This is what happens when a stock CR piston is overheated and grabs the cylinder walls.
http://www.thedieselpageforums.com/photopost/data/500/balzer02.jpg
Jim
[quote=Robyn;264482]From what I have seen, the clearwater blocks are damned good.
Yesssss the casting is done in China, but so it the Dodge cummins and other well known items that we used to associate with the good old USA.
The castings are "according to clearwater people" machined here in the States on top notch CNC machines.
As far as the quality of the machine work goes, GM was no saint when it come to perfection either.
The machining may be top notch but I would like to see metalurgical reports showing these blocks to have the right stuff inside them. Untill that happens I'll stick with a 599 block for rebuilding. Just my 2 cents worth.
I'll see if the shop can gather a clean sample when they deck the block. I'm not sure where to have it analyzed buy I'm sure I can find a place on the web. Does anyone know whet mix of alloys we're looking for?
Make no mistake, I really would love to be able to buy a decent 6.5 block at a price that is affordable.
The AMG stuff is just out of reach (Or justification) for many of us.
The Clearwater heads were covered with loads of smack too and they have done real well.
Clearwater gives a 3 year unlimited mileage warranty on the heads.
Frito lay has been using the clearwater heads as replacements in their chip trucks for a long time and with grand results.
The GM Blocks have all had issues.
Even the Blessed RED Block of the 82 vintage will crack the main webs.
I was looking over a 506 Block recently (Pre squirter series with large bolts)
The 3 center mains had some nasty cracks that were outboard of the outer main bolt. Between the hole and the register cut.
These were not just tiny cracks but instead quite well opened up at the part line.
My feelings are starting to lean more towards GREEN castings as beeing more of a factor in the issue rather than operational stresses.
Had these blocks been stress relieved and cured well, they may have had a longer life span.
Seems to hold true that if you find a good block with a lot of miles that is crack free it can get an overhaul and remain crack free.
My DaHoooley Block had some huge nasty cracks in the bottom end of it.
I would bet a sum that the issue is more a casting curing issue rather than metalurgy alone.
Before any machining is done, heat the blocks up to 800F or maybe a tad more and then allow to cool slowly.
Once cold, then machine them.
Good bet they would do fine.
The old method was to take new castings and toss them outside and let them rust real good for a time. Then they were stress relieved (heat/cool) and off to the machine shop.
My father was in the foundry business with his dad years ago and the curing of castings is very important.
A "green" casting (NOT PAINT) :eek: is no good, it must be cured before machining.
My feeling is that the Clearwater Blocks are no worse than the GM blocks and likely a lot better.
The Chinese did not decide to start making 6.5 blocks and selling them.
Some good O'l Boys have set this thing up and are making a killing on it.
BET ME :D
I have a 929 casting in the DaHoooley. It had a lot of miles on it when I bought the bare block.
I had it decked, bored, honed and such as well as I installed the Inserts in the center main outer bolts..
Having been well cured through tons of duty cycles it will likely last a long time.
To date nobody has ever come up with any difinative answers as to why these blocks and heads do what they do.
Is it poor material, poor curing (stress relieving or lack of) bad design structurally or unforseen stresses that occur under certain operating conditions.
I have yet to hear any real good answers.
I have voiced my theories here many many times.
I have had many of these poor little creatures on my morgue slab for a post mortem and seen all sorts of carnage come from within their innards.
Still dont fully understand the whole story.
Some things seem to help or at least not hurt the cause. Forged crank or at least a good scat steel one, Fluid damper, good ballance job ???????
The material seems fine while your machining it. Cuts good, is a bitch to tap!! ask me how I know this :rolleyes:
The cylinders hold up well to long term use and can see 200K and still show hone marks.
Lets not sell out the Clearwater Blocks too soon.
For many folks that want to keep their GM truck on the road for a couple hundred K miles more, these will be the only option, or at least an affordable one.
For the price, if they only go 100,000 miles they are still a good buy.
$1250 will buy a new Clearwater block off ebay
$670 will sit a pair of new clearwater heads at your door ready to bolt on.
$400 will buy a scat 9000 series steel crank
Scavenge all the remaining parts from your dead 6.5 plus a set of rings, gaskets and a set of head bolts and you have for all intents and purposes a new engine.
The factory rods and pistons last well and in most cases can be reinstalled with no more than a good scrubbing, even with 200K on them.
Some judicious shopping could easily build a lovely Six and Half for around the $2500 mark.
Ebay is full of quality name brand parts that are either stock over runs, sell offs or Mil stuff that can be had CHEAP.
I paid $35 for a complete set of military piston rings (Chrome) for DaHoooley
These were GM packaged and numbered along with the MIL numbers too.
I bought all the guy had too :D
Ended up with 3 complete sets at $35 a set (8 sets of rings for the $$)
Bearings were $50 for a mixed bag of Clevite and Mahle. But who cares whos name is on them as those are both good names.
Shopping wisely is the name of the game in my opinion.
The cam and lifters and the the rest of the valvetrain can be reused as long as its good shape.
A Six and half can be built on the cheap and still be a very sound engine all the way.
The little yellow engine in the DaHoooley was a very cheap rebuild overall with all the cost savings along the way.
Best to all.
Missy
john8662
01-10-2010, 01:03
Robyn,
Could you please, please, please organize your thoughts into paragraphs, and shorten your posts to something that just makes the point?
In this thread alone I've seen some stuff that makes a normal person appear to suffer from "A.D.D." if they have to read it all...
This is me asking nicely.
Sorry for the rambling.
Just the way I am when I get into the groove ya know.
I will attempt to curb it a little.
Robyn :)
Robyn
Thanks for your wealth of information. I appreciate your hands on every day real world experiance!
John, I understand that these blocks are largly unknown but with a dwindling supply of good buildable GM blocks ,we have to turn some where . By the way if the GM castings are so great why are so many cracked? I'd guess my chances are about as good as the GM castings. Time will tell.
Reddog
Your very welcome.
Sorry about the very disjointed and lengthly post recently.
There was just so much info running through my head that was worthy and likely useful to you that I got a tad carried away I guess.
My feeling is not a warm and fuzzy one when it comes to the Products from China, but as you have stated, the supply of good buildable GM blocks is not abundant.
I am not worried about IF the China blocks will work or last but rather my issue is that we should be making this stuff here and putting our people to work.
I think that most of the dissent about the Cleawater Blocks and others is the uncertainty and lack of "Proof time".
But as you mentioned, the GM stuff has proven itself to be unreliable so why not give this other Iron a chance.
Best
Robyn
More Power
01-11-2010, 12:21
I think that most of the dissent about the Cleawater Blocks and others is the uncertainty and lack of "Proof time".
Yes, it would be interesting to know all of the details concerning reliability and durability after about 18 years.... That's how long the 6.5 has been on the road. ;)
Jim
What would be very informative and really tell the story would be the total number of actual Block failures that have acured.
Unfortunately there are likely many 6.5's that are still running that if torn down would show cracks.
Many blocks will survive under running conditions for a long time with cracks in the main webs but will be discarded when overhaul time comes.
The true figures are going to be elusive and very hard to calculate.
With the dwindling supply of good usable blocks, what are we to do.
The sources like Ebay, craigs list and other sources will net things to spend $$$ on but what are you going end up with.
Buy a used 6.5 from a wrecking yard ot other seller and its likely going to be AS IS and with all faults.
So you get it home and apart, then find that its JUNK ???????
Been there done that.
We have a rebuilders supplier here locally and they strip engines down and sell the various parts.
Once you take possesion its yours.
They wont do anything after the sale. SOOOOOOO you hot tank the thing and then find the ugly truth, you still own the thing.
Ebay and Craigs are no better.
Even if a China block does not last any longer than the GM stuff did on average, then by my way of crunching the numbers its still a win win scenario.
Would be nice if we could buy a good Bare block from AMG for a price that affordable.
Missy
The truck this motor is going into is 15 years old wit 144k miles on it my other truck is 16 years old with 200k on the clock.
I'd say GM did fine with these units.
Like Robyn said, if I can get another 100k out of this rig it'll be well worth the 7 grand I'll have into it. But like Jim said it will be years, hopefully, before we know the reliability of these after market products.
What I'd like to know is if anyone has any horror stories with any Clearwater products.
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