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The 6.5TD Power Project I put together in 1999 had a pretty raucous rattle when cold and when the hood was up. Part of that was the DSG gear drive, which had some timing advance built-in. The 18:1 pistons may have had an effect too. On the highway though at 65-mph, the rattle was only barely detectable from inside the cab. Sarah's Blazer is like that too... the rattle is only barely detectable at 65-mph.
My new engine is a little unusual to me.... it sounds great from inside the cab; sounds nice and healthy at idle with the amount of rattle I would expect; very smooth at all rpm above idle; idles perfect (to me) when cold.
However, if I step OUTSIDE the cab and the engine is warmed up, the idle seems a little rough with not as much rattle as I would expect. However, I'm wondering if it might be my old exhaust system (3.5" exhaust I pieced together years ago). If I pop the hood and stand next to the engine, I think it sounds great; but close the hood and listen to the exhaust, it just sounds... weird... to me anyway. That's why I was thinking maybe the engine timing could be advanced a bit....
Kinda hard to explain in words. But having driven 5.7L/6.2L/6.5L diesels for 27 years, I kinda expect them to sound a certain way. But this is my first 6.5L that I've completely rebuilt.
Come to think of it, the 6.2L I previously built sounded about the same after I rebuilt it. I always thought it had a weird idle when I was finished. Hmmmm.....
Casey
Maybe it's the Casey touch putting in a signature rattle...
Or are you missing any tools?
Kinda like the last 100 miles of a long trip. Everything starts to sound weird.
LOL! Nope, no missing tools. I didn't even have any leftover nuts or bolts! I was pretty proud of that. :DQuote:
Originally Posted by Yukon6.2
Casey
I grew up living on a Highway Lodge in remote Yukon
I spent my free time watching my Dad fix stuff.
In the gas shortage of the 70's VW's became popular.The highway we were on was gravel at the time.The VW's had a area where they dies on the way up from Haines Alaska.They ran fine on pavement without oil in the oil bath air cleaners,but the dust killed them off.
One engine rebuild my Dad did there was a putty knife inside when he split the crankcase
One truck tire fix came with a nice hammer in it,split rim tube type tires.
Tools and where they end up...
Back in the 70s, during my aircraft years, the local SnapOn guy had the ring spanner end of a 9/16 wrench mounted to a board in his truck. Said it was the most expensive wrench ever made. Turns out the whole wrench was left in the intake of a turbine engine. Took out the entire compressor section and a few parts of the hot section. Only the ring spanner end survived.
A 200,000 dollar mistake :mad:
Bill
Hope it didn't have the owner's name engraved on it... ;)
First thing the men I worked with told me right after I got out of A&P school in '74. Do_not_engrave your name on your tools.
With nearly 1200 miles on the the new engine, my son and I decided it was time to test it out under a load. On Saturday, we loaded up our antique John Deere B onto the flatbed and went for a drive. I was quite pleased with the results!
First off, the HX35 turbo with the TurboMaster wastegate set to its lightest setting seems to produce a maximum of 15 psi under full throttle between 2500-3500 rpm. I am comfortable with that pressure. EGT's hovered around 1050 at the same time. This was under relatively short duration pulls on a large hills (about a mile long each), but I was giving her all she had. Longer pulls in hot weather may produce different results.
With the original engine, I was only able to maintain speed (65 mph) on both of these hills; now, I was actually able to accelerate and had to back off the throttle to keep speed in check. That was a nice surprise!
Also, engine coolant temp seems to be much more stable; again, this was cool weather (ambient temp was actually a nice 55* on Saturday), but every time I have ever towed before (no matter the ambient temp), the coolant temp would always climb steadily on hard pulls. I had performed every cooling upgrade possible, but my original engine would ALWAYS run hot when towing. However, I couldn't get the needle to move on this test. I can't wait to test under summer towing conditions.
It was only about a 40 mile round trip test, but initial results were quite promising. I can't wait to hitch up the camper and go for a trip to see how she does in a better, real-world test.
I haven't checked MPG empty yet; I did top off today (about 10 gallons), and with the towing mixed in (with a lot of full-throttle pulls), I achieved 14.5 mpg. I'll try to get an accurate reading on this tank I have now.
Casey
Sounds great.
Having the coolant temps stay steady is a very good thing.....
Looks like a winner.....;)
Sound great! Long pulls at 15-psi could use an intercooler. Otherwise, as you've discovered, a more efficient turbocharger helps with EGT. The HX-35 is a really good choice for a more or less stock engine and fuel injection system - especially when towing.Quote:
Originally Posted by arveetek
An intercooler is definitely on my short list for needed upgrades. I want this engine to last a long time, and I think an intercooler is the most important upgrade I could make next.Quote:
Originally Posted by More Power
Casey
The ol' Tahoe is running great! No issues now after approx. 2,500 miles. Any weird sounds have either disappeared or I've gotten used to them. Seems like she idles smoother now.
I was a bit worried about the fuel mileage at first. After a 1,000 mile break-in period, I started logging the mileage. My first tank came back at 14.5 mpg! That shocked me; I had never seen that low of daily driving mileage before. I usually saw a consistent 17.5 mpg. Best tank I ever had was 18.5 mpg on a road trip one time.
But every tank since then has improved. The next tank was 15.5; then 16.1. Today I recorded 16.85 mpg.
I don't think my driving habits have changed that much; it's quite possible that early on I was really mashing the go pedal and enjoying the turbo spooling up; I may be driving more conservatively now, but it's also possible the engine is still breaking in.
Hoping that soon I'll see the 18 mpg I was getting before.
Casey
Likely all of the above.....
Great to hear!
Good to follow one of these threads that comes to a good end.
As I recall, your Tahoe has 3.42 gearing... My 3.42 geared 1982 GMC K1500, with a fresh 6.2L and Banks turbo and TH700R4, would deliver 24 mpg commuting 50miles/day. I checked dozens of tanks of fuel to get that number. It was super efficient. I suspect some of the fuel mileage we're both seeing (Sarah's Blazer is doing about the same as your Tahoe) is due to the DS4. I'd wager a few bucks that if we were to install a DB2 fuel injection pump, the mileage would be better.Quote:
Originally Posted by arveetek
I've read about the TH700 being a more efficient transmission than the 4L80-E. That may be some of it.
Sarah's Blazer engine is equipped with the small port precups, as it was from the factory. Our 6.5TD Power project truck, with 4L80-E, 4.10 gearing, and a DB2 marine pump would consistently deliver 17-18 mpg. That engine had the large port precups. It delivered 21-mpg once when driving between Lolo MT and Lewiston, ID on US-12. (slow winding road, averaging about 60-mph, slightly downhill - a river valley - most of the way).
Jim
You are correct; I have 3.42 gears and 33" tires (and the speedometer has been corrected). My old '81 C20 2WD project that I had equipped with a 6.2L turbo, 700R4, and 4.10 gears with 31" tires used to consistently average 19 mpg, even though it had a much higher cruising RPM.Quote:
Originally Posted by More Power
The only GM diesel I've had that broke the 20 mpg mark was my old '77 Blazer 2WD project that I had swapped in a 5.7L diesel with 3 speed auto. It would get close to 25 mpg, but couldn't use the passing lane since it was so gutless! :D
Casey
Mileage on these rigs can be all over the map.
We had a 1986 Suburban K2500 4.10 gears Turbo 400 trans
Stock tires and wheels.
On the road it would consistently deliver 26 mpg and on a trip from home to Long Beach California it did 28 mpg on the leg from Sacramento to just before the grapevine (Flat easy running on cruise control)
Around town it ran on average about 22 mpg