Compression test results

[super diesel]

Yes. Compressions testers can be had from Harbor Freight. When you see the pressure drop to around 300+-, It's time to tear into it. Mine ran quite well at 290-310psi (all rods bent pretty good) for quite some time, but not recommended though. In my experiences, I've always noticed that the studs are needed about the same time as rods.

 

[JoshH]

I compression tested mine and was seeing around from a high of 320 to a low of 280 with "unbent" rods (15:1 compression ratio). Once they got really bent, the highest was around 290 and the low was something like 170

I wouldn't worry about your numbers.

 

[KEVINL]

Mine were all between 345-375

 

[super diesel]

My #s was with stock pistons (nothing else commonly available at the time). These #s will change of course with cut and aftermarket pistons. This is why it is good to compression test a new built motor just to reference later if needed.This will tell you of pending problems or even divert disasters if caught in time.

 

[ecc_33]

After numerous drag races and about 28 truck pulls with the stock charger and then about 6-8 pulls with the bigger charger and super diesel fuel regulator. i decided to do a compression test.
I only got to do the left bank today after getting back from the hospital

Test as follows:

piston PSI Todays test
1 425 340
3 415 320
5 430 360
7 427 340

right bank test was
today
2- 440 320
4- 415 305
6- 420 310
8- 420 295

I bent the rods....Thats what i have came up with. The wierd thing is it ran fine coming off the track the last pass. I noticed the tranny was hot so i shut it off. Then turned it on and let it idle for about 5 minutes twice. Than when i started it up for the last time is when it started smoking white and got worse as i drove it home even know i babied it home. I don't know if the water meth really killed it or what. It would only pull 38 pounds of boost with the gears in it. I was leaving at 8psi. Another thing that was really wierd is there was coolant around the pass side last glow plug and i thought oh a blown head gasket....But it was dry inside. coolant was coming from the far back side and lower part of the lower valve cover were it seals to the top of the head. There also wasn't any coolant in the oil...Everything else was dry. The coolant resivor did have pressure still in it.

 

[TheBac]

Yep...rods. Your numbers look just like mine did. I bet you'll be able to see the bend in 4, 6 and 8 when you pull them.

 

[paint94979]

Eric were you running a non detorqued tune? I bet you were making some good power. What did your turbo see for max psi? I see 50psi with mine

 

[ecc_33]

Paint, I ran the shift points last year at 4200rpms but floated the valves everytime it would shift so this year i bumped them down to 3600. I ran good but not for long. Can't say it was just that. Everything comes in heavy fueling at 2800rpms. Timing is maxed out at 40* When I dynoed in 08 i made 1174 torque and 604hp only making 29psi with the 4088r. So moving 7000 pounds with a 1.86 sixty at 11.94 at 113 is making more power than 604 It was a long time coming and can't bash the truck one bit. Been a damn good one. I also ran water meth this year and don't really know how much more cylinder pressure that caused. it was fifty fifty mix

 

[ecc_33]

turbo boost was 8psi launching when i made my first pass wed night and i went 1.67 After that i didn't log but went 2.02 and 1.86. The run i logged i seen a max psi of 38psi imho boost is way down cause of the 4.56 gears

 

[Kat]

Paint, I ran the shift points last year at 4200rpms but floated the valves everytime it would shift so this year i bumped them down to 3600. I ran good but not for long. Can't say it was just that. Everything comes in heavy fueling at 2800rpms. Timing is maxed out at 40* When I dynoed in 08 i made 1174 torque and 604hp only making 29psi with the 4088r. So moving 7000 pounds with a 1.86 sixty at 11.94 at 113 is making more power than 604 It was a long time coming and can't bash the truck one bit. Been a damn good one. I also ran water meth this year and don't really know how much more cylinder pressure that caused. it was fifty fifty mix

Sorry about the rods But, the 11 is new isn't it? Congrats :woott:

 

[ecc_33]

Yes kat, The 11's is a new best :woott: No need to be sorry about the rods. It sucks I can't drive the truck to the wedding but it is to be expected from 4 years of abuse with a bigger turbo, dual fuelers, It made it 3 thousand miles with dual fulers LMAO The antifreeze thing is what I can't figure out???? I will have to pull it apart to see what that is.

 

[x MadMAX DIESEL]

4 years and only 3,000 miles?? Whats the deal with the antifreeze?

 

[ecc_33]

4 years and only 3,000 miles?? Whats the deal with the antifreeze?

Yep, 4 years and 3,000 miles. In my sig very small i put the milage when I installed the dual fuelers. It now has 49,250 miles. I hardly EVER drive the truck hint the low miles. Not sure about the antifreeze. I figured it was a injector cup but there was no fuel, antifreeze in the oil Im not sure what some of the signs of pushed out injectors are but i will know more when the engine gets disassembled

 

[Schwinn68]

are you going aftermarket rods and full build this time? Congrats! 11's is moving for a big truck!

 

[ecc_33]

Yes, I will have aftermarket rods, headstuds, ATI dampner, Possibly bigger injector tips, and BES will be doing the machine work. I am hoping the pistons are fine but if not i will prob go with forged pistons as well.

 

[duramax3388]

Sorry to about your rods but Congrats on the up coming build. PS does this mean it might make it's way back to the pulling track? Good luck.

 

[bullfrogjohnson]

Mine were in the low 400's high 300's and I just pulled mine down yesterday and all 8 were bent

I guess Todd is the only one left in the club.

 

[LarryJewell]

Mine were in the low 400's high 300's and I just pulled mine down yesterday and all 8 were bent

I guess Todd is the only one left in the club.

NOT........Duel fuelers and twin turbos for over a year & half

 

[bullfrogjohnson]

NOT........Duel fuelers and twin turbos for over a year & half

Sorry Larry, I forgot about you:hug:

 

[ecc_33]

I think this is the reason for my rough idle, surge if you will everyonce in a while. I think they have been bent for a year or so but the last 3 passes at the strip finished it off. No, I don't think I will truck pull for a long long time