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Tahoe Motor Is Blown Up

Same here I havent even had time to install most of the extras I have sitting in the shop. Had to put it back inservice the day I got mine going.
 
Got the cyls honed,and a used cam installed. Also got the crank and reused main bearings installed.
 
I got the pistons installed. Not sure what the problem is,but piston height varies,from .023 in the hole to .045. I guess it must be the rods . They are from two different motors. The pistons were all machined, measuring from the pin. 4 of the cyls vary from .032 to .037, I'm ok with that,but one is .045,and 3 are .023.
 
Both banks in the hole?

I had a few 'out' of the hole a few thou on the 6.2 engine I'm running now. Weird. No noticable core shift either.

Have more rods to sift through?
 
I want them in the hole,but about all the same. I do have 5 more rods. All the rods I used seemed to be straight,but offsets varied a little. I checked them all with a straight edge on both sides.
 
Foutunately for us the 6.2/5 has floating wristpins. As long as the bushings are good now.... Swap in/out as you see fit.
 
I swapped a few rods,but the best I got was .030-042 in the hole ,at least I got rid of the high ones . I think some rods are bent,since they came from a stock comp 40 psi boosted motor. I checked rod lengths by fitting two rods together with a wrist pin. They varied as much as .022. From the factory, is there different sizes,and then they custom fit each cyl,to get the correct piston protrusion ? I noticed some had letter code,like K or L or O. Basically I'm wondering if all 6.5 rods are the same length,when new.
 
6.2 turbo said:
I'm getting the pistons shaved .045 thousands. They are all getting reused,except 2 are from a parts motor . So far I collected 6 straight rods,but will have to pull 2 more from another one of my blown 6.5's. I discovered that 6.5 rods are ofset,the flat sides go against each other. I should be close to 18-1 with stock thicknes head gaskets ,and .010 decked block. Pistons should end up about .030 below the deck. That would give me .075 squish. I didn't break any rings, so I plan on reusing them. Not sure about the rod bearings,I might just flip them. One or two of the main bearings show some slight grooves of copper. I will look into some bi metal bearings,instead of tri metal.
Click to expand...

With decking the block and standard gaskets, the .045" shave should put you at 19:1 CR if you are using 6.5 turbo precups. Thats much better than 22:1 or whatever you were running before and should be good.

What turbo did you have on there, size of turbine housing and wheel? If youre getting 40psi of boost then likely could use a larger turbo or wastegate and let it breath better and not get much over 30psi with no loss in power and more reliable. That would be like having a 20 liter engine after all, 3 times atmospheric pressure/oxygen content. the more turbo drive pressure the more resistance the other cylinders have during the exhaust stroke and the more exhaust gasses left in the cylinder for the next fill.

Do you have some power comparisons at same fueling, the higher boost values provide increased power? Or is the turbo non-wastegated so any increase in fuel causing increased boost?

The O-ring job fixed the weak point in the system and you've found the next! Rooting for you!
 
The turbo is a HX52 ,supposedly a pro 52. The compressor inducer is 2.5 inches. The turbine exducer is a hair smaller than a Hx55,inducer is the same. Not sure what size the turbine inducer diameter is. They all have 12 blades. The exhaust housing is a 16 cm none waste gated. It would light around 2000 rpms . I'm sure it didn't need 40 psi. I think I should get my fuel and boost adjusted so that there is still a fair amount of smoke at full throttle. I know it sounds odd,but I think it was super lean.
 
You must be pushing like 110mm^3 of fuel or so, pretty cool.

Yes, a little lean, just too much boost providing more than necessary oxygen, and too much backpressure. If you can either get a wastegate, or an 18cm^2 housing I think it would be great. Or with the 16cm^2 housing but a 10-blade turbine wheel with a larger exducer if it will fit as its the exhaust side to worry about.

You might drop a little boost with the compression ratio lower too, but not much.
 
I boosted 40 on my first 6.5 stock comp, and the rods didn't bend,I boosted 60 on my 6.2,I don't think they bent either. Maybe the extra .010 closer to the head is what did it. Also most of the injectors leak,but the cyl that threw the rod had a good injector. I do have several different turbos to try ,some are waste gated. I could also install an external waste gate. The HX 55 that I have has a 19 cm housing,but lagged pretty good on the 6.2.
 
I'm with buddy, this is pretty cool.

Sometimes they blow up when we push them past the design limits, but it's fun finding that ragged edge... every modification changes the picture just a bit.

Thanks for sharing the story!

It's something like this, some days...

View attachment 30891
 
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Can't see it either
 
Nice. Well,I got the heads on. We also discovered one lifter was sticking in the bore,so bad that the valve spring couldn't close the valve. Turns out that the broken connecting rod nibbled the lifter bore . I honed out the bore with a wheel cyl hone while the head was still on. Works great now,but I still should check lifter preload on all the lifters .
 
With a mix of good and bad injectors you a have a power balance problem. The good parts are taking the strain of full power and driving the bad stuff. Big iron has serious issues and damage when all 16 cly do not light during starting or very shortly after.

So you were making more power in the cyl with the good injector...
 
I will probably have to lap the pintles,on whatever injector tip I use. I do have some marine tips,but not Bosch. The injectors that I was running,were Delphi. Probably my best option,would be to use some stock Bosch tips ,and cut the pintles to make them marine style.
 
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