Tune & Log. Gen VI CBB 1999 Vortec 7400

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Originally Posted by SiriusC1024

So what's the next step?

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Well considering how deep I am already in, I don't see how I can light the match without serious marital consequences.... I have been looking for a 4 bolt gen vi block. I see some on Hollanderparts.com. I will need to get the new one redecked (the pushrods I got will need this) and bored out 0.060 over (the pistons/rings I have) and line honed/checked AFTER I get the thing... Looks like between $450 and $800 I am thinking for the block, then the work on top... ugh.

crazy
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Originally Posted by oldpartsnrust

crazy
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The Good news is that my rod journals and rods check out at 0.0025 clearance. Across the board.

Yeah that is good, but it'll change with a new block :(

I can already see scoring on the bore, and it's supposed to be a freshly machined block. That machine shop screwed up a lot of things.

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Originally Posted by SiriusC1024

Yeah that is good, but it'll change with a new block :(

I can already see scoring on the bore, and it's supposed to be a freshly machined block. That machine shop screwed up a lot of things.

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Well, at least right now I have my 'spare' car running so I am not pressed for having redundancy like I was. I hate not having a spare car when I have 3 kids that need to be at three different places all the time. Like you said, I am taking my time and making sure everything is 100% this time. Factory clearances, and none of the 'advice' I got from the machinist this time. I know the components work together, i.e. the new cam/springs/rockers, the stroker 4.25" crank, the -3cc pistons, the 0.010 decking on the block and the 0.060 overbore and the bigger injectors. When it ran, it seemed to have the extra power I was looking for. Pretty sure that when I get this together finally that I will be happy. I just need to be able to tow my boat and trailer without the thing struggling and blowing up like last time. :)

Thank you for your patience with this/me. If it weren't for bad luck, I wouldn't have any luck! Although some of the bad luck I brought on myself like dropping that bolt and not making sure to retrieve it before I forgot and it fell into the head. Blessing in disguise as I wouldn't have necessarily seen the bearing wear and cylinder scoring if I didn't have to tear it down again.

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Originally Posted by SiriusC1024

Yeah that is good, but it'll change with a new block :(

I can already see scoring on the bore, and it's supposed to be a freshly machined block. That machine shop screwed up a lot of things.

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That looks like a flex hone job at best.

Which is unacceptable from a machine shop. I got +/-0.0001 bore and +/-0.0002 taper with a Sunnen hone and handheld drill. Yes, ten-thousandths of an inch.

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Originally Posted by SiriusC1024

Which is unacceptable from a machine shop. I got +/-0.0001 bore and +/-0.0002 taper with a Sunnen hone and handheld drill. Yes, ten-thousandths of an inch.

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Block is on the way here, then will send to different machine shop... There aren't many choices around here! Going to have bored 0.060" over and decked 0.010" to 9.790" and line honed/checked. Sound about right?

Just went through most of the thread. Sad to see the damage. I have been working on my build since last year trying to get the tune and the exhaust/intake adjustments. High IAT on mine as well, it just gets hot with a built motor under the hood of gmt400. I am planning to put vents on the hood to help. Wrapping exhaust helped a lot on my build, but I did not try to insulate intake path.

I ended up changing the intake. I don't know for sure if it was exhaust or intake, but my maf curve would flop after about 3200 rpm. I have changed both intake manifold and exhaust since then, and that let it run up to 5800 rpm. (Cam power band tops out at about 5800).

edit: I have swapped to e38 ecu and over on gen 4 side trying to get idle to calm down and steady. Was looking at your logs for some comparison and to also get some ideas.

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Originally Posted by yevgenievich

Just went through most of the thread. Sad to see the damage. I have been working on my build since last year trying to get the tune and the exhaust/intake adjustments. High IAT on mine as well, it just gets hot with a built motor under the hood of gmt400. I am planning to put vents on the hood to help. Wrapping exhaust helped a lot on my build, but I did not try to insulate intake path.

I ended up changing the intake. I don't know for sure if it was exhaust or intake, but my maf curve would flop after about 3200 rpm. I have changed both intake manifold and exhaust since then, and that let it run up to 5800 rpm. (Cam power band tops out at about 5800).

edit: I have swapped to e38 ecu and over on gen 4 side trying to get idle to calm down and steady. Was looking at your logs for some comparison and to also get some ideas.

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I am too far in to back out now! Wrapping the intake seemed to help, but it was on the road briefly due to the lifter noise, which turned out to be low oil pressure after all. To think this all started with the Brake and A/C lines... Then the tank, then I saw the frame was rotted out and now I am here. Honestly I don't think I could have replaced with anything comparable for under like $35-45K, and even that would probably need work! Good luck with yours. I hope to have a happy ending for this in the not too distant future... I got a lot of practice and gained a ton of knowledge on the domestic engines. All my previous experience was with imports and all stock stuff pretty much. Has been a trip. Great bunch of people here too!

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Originally Posted by oldpartsnrust

Block is on the way here, then will send to different machine shop... There aren't many choices around here! Going to have bored 0.060" over and decked 0.010" to 9.790" and line honed/checked. Sound about right?

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Given the cracking I'd shy away from that 0.060 overbore. You have to consider core shift when it was cast, and some places are thinner. A good shop will know to test for thickness and voids with ultrasound. Really, I'd tell them take the minimum amount out as possible to correct the cylinder bore. The shop will have an idea of how much that will be when they inspect the block. Then you can match the pistons. The power comes from the stroker kit. Bore nah.

One thing I've noticed is the bigger is better crowd tend to end up in a mess. Take LS people. They get a 4 inch stroke kit instead of 3.9 just to be able to tell people "It's a 408 stroker". Yeah that's nice, but they end up rebuilding at about 15k miles because of the way the piston skirt comes out of the bore at the bottom of the stroke. Then there's the people who get these .600+ lift donkey dick cams on factory setups and waller out their valve guides because it's only meant for .551 lift on factory rockers.

There are other ways to make power. I've outrun a few of those .600+ lift guys with my baby .525 hot cam. Coming up on 90k miles on the build trouble-free. It's all in the details. If I remember right your intake setup, tb or manifold, was a pretty big restriction. Also, definitely invest in a nice windage tray. Think about a good modern style coated skirt piston that takes a thinner ring pack (Might require a longer con rod though, so maybe not. Budget considerations, too.). If you're using MLS gaskets specify the correct RA for the deck and heads. We've been over setting the valvetrain up for the valve tip wipe pattern https://forum.hptuners.com/images/smilies/wink.png

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Originally Posted by oldpartsnrust

Wrapping the intake seemed to help

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Which was a hilarious picture btw haha

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Originally Posted by SiriusC1024

Given the cracking I'd shy away from that 0.060 overbore. You have to consider core shift when it was cast, and some places are thinner. A good shop will know to test for thickness and voids with ultrasound. Really, I'd tell them take the minimum amount out as possible to correct the cylinder bore. The shop will have an idea of how much that will be when they inspect the block. Then you can match the pistons. The power comes from the stroker kit. Bore nah.

One thing I've noticed is the bigger is better crowd tend to end up in a mess. Take LS people. They get a 4 inch stroke kit instead of 3.9 just to be able to tell people "It's a 408 stroker". Yeah that's nice, but they end up rebuilding at about 15k miles because of the way the piston skirt comes out of the bore at the bottom of the stroke. Then there's the people who get these .600+ lift donkey dick cams on factory setups and waller out their valve guides because it's only meant for .551 lift on factory rockers.

There are other ways to make power. I've outrun a few of those .600+ lift guys with my baby .525 hot cam. Coming up on 90k miles on the build trouble-free. It's all in the details. If I remember right your intake setup, tb or manifold, was a pretty big restriction. Also, definitely invest in a nice windage tray. Think about a good modern style coated skirt piston that takes a thinner ring pack (Might require a longer con rod though, so maybe not. Budget considerations, too.). If you're using MLS gaskets specify the correct RA for the deck and heads. We've been over setting the valvetrain up for the valve tip wipe pattern ;)



Which was a hilarious picture btw haha

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I agree. It reminded me of "Ultraman" for some reason. It did make a difference, but the fact that it was incredibly not aesthetic on its own is enough to not really plan on having that be the end result it was really just a 'proof of concept' because the unwrapped temps seemed untenable for running it. WHEN I get this back together, I will potentially revisit some sort of cold air intake scenario.

BTW, the cracked cylinder was #3 which is where I dropped the bolt in. I didn't see any evidence of impact though. Maybe someone with better eyes can see it and then that would put the 0.060" bore to rest? That would save me another bunch of money on pistons/rings.

Oh you want to reuse? So have them check it with ultrasound before machining. If they can't then you're at the wrong shop.

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Originally Posted by SiriusC1024

Oh you want to reuse? So have them check it with ultrasound before machining. If they can't then you're at the wrong shop.

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Yeah, I do want to try to reuse the pistons. They are Keith Black -3cc that came with the stroker kit. The compression ratio, cam lift, and overall power seemed to be a decent combination once you turned off the knock sensors (assuming the valvetrain noise/lack of oil noises was triggering it?).

Yeah we had them off to diagnose, but I'd prefer not to run that way.

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Originally Posted by SiriusC1024

Yeah we had them off to diagnose, but I'd prefer not to run that way.

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100% agree. I am speculating that the valvetrain and other 'low oil pressure' noises were causing them to trigger.

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Originally Posted by oldpartsnrust

100% agree. I am speculating that the valvetrain and other 'low oil pressure' noises were causing them to trigger.

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New Block showed up today. It is like 100 degrees out so I am waiting till the sun goes down before eyeing it up.

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Originally Posted by oldpartsnrust

New Block showed up today. It is like 100 degrees out so I am waiting till the sun goes down before eyeing it up.

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So far so good. Only bothering to post to give timeline for when we can hopefully finish up the tune! Block is stripped down, looks good. There is barely any casting flash in the return holes even. Gonna try to get it to the machine shop this coming week. I need to clean it first because they cannot hot tank anymore around here.

Glad you keep posting. I like hearing about how it's going. I think there's quite a few other people interested in this project as well.

Latest update, got the block stripped down and cleaned. Looks good. Now I just have to get it over to the machine shop.

Darn, they're booked up till after the holiday... Well, HAPPY 4th. EVERYONE!!!

OMG I read all of this a wtf.... I have a 1999 BBC suburban. 411 pcm with a mild cam. I had a shop rebuild it after it had a crack in the crank. Everything is new all the way through the motor and sensors. I am hunting it running rich but it runs and pulls well. I use it as a response vehicle where I volunteer as a firefighter/EMT. 6mpg isn't great but it is fun lol. One day I'll go through the tune more. Now I am just reading and figuring things out on how. Thank you so much for this awesome thread! Can't wait to read more!!!!!

Well, one thing I learned is that you should not 'set the bearings loose' even if someone tells you to. I was told to order 'extra clearance bearings' for the rods and mains which seems to have led to low oil distribution even though the pressure showed 60PSI at the gauge. There was the valve train noise and then after stripping it down the bearing wear and cylinder scuffing became apparent. So, my catastrophic mistake of leaving the EGR bolt where it could (and did) fall into the intake when swapping lifters, was almost a blessing in disguise. I do know that the 454 to 496 stroker DOES absolutely work with the Comp Cams upgrade, injector upgrade and roller rockers all with completely stock vortec appearance. Well, besides my Scooby Doo Mystery machine paint choices.

Shooting for tomorrow to drop off the block for the machining. My visual inspection has it as better than my original block! Just overall with the lack of casting flash around the oil return holes and such, but the line hone/check will tell the true story.

Dropped off.... drum roll...

Should show before/after pics for the fans.

Crap, I forgot to get pics before. It really looked just like the old block before. Here are some pics of that.
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Fans? Everyone likes destruction right!? :)

I keep alternating between "lighting a match" and "finishing this thing up". At this point, if I do it right it will seriously outlast me! I guess I will keep pushing onward. I only wish I was retired and this could be my 'hobby' but I need this bad boy to tow some stuff around and haul all of us to and from our place in NY.

Shouldn't be long now till I can start putting this back together again...

Machine work complete. Block is solid. Should be picking it up this week! Decked 0.020" to 9.780", bored 0.060" over to 4.310", line checked OK. I'll post picks once I pick it up. Side note: Spent 3 days in the hospital from a freaking tick bite!

Quick question. One of the things I noticed on the old block is that there was some significant scoring on the piston skirts and cylinder walls. I am thinking that when I had first slapped this together if I recall, it was running really rich. I believe this may have caused that scoring as the walls are splash lubed no? There was also some pretty significant carbon build up on the piston tops when I took it all apart. I also believe that during the tuning process, one of the first things you noticed was that there was a lot of leaning that had to be done as it was running rich. Does this sound correct? I am asking because I think you had gotten pretty ball-parkish with the tune and that I should worry too much about this recurring with where we currently are with the tune? Is that a pretty fair assessment? Thanks. Starting to get pretty psyched now that time has dulled the impact of my f'ups. I think I am now able to categorize it as a different project mentally! ;)

Yes, that's a fair assessment. Low oil pressure was also a contributing factor. Bores are splash lubed in a way, but not from the crank throws getting into the oil in the pan. Windage is something to be avoided. That heavy oil you were forced to use doesn't mist too well, either.

We'll go double check the tune and build sheet when you're ready. The tune we have won't have such a fueling issue. Couple that with a correctly built bottom end and there's the recipe for success.

Yo I got a tick bite earlier in the summer while mountain biking. Little bastard was only about the size of a strawberry seed. Not like a normal size one. I picked it off then put it in rubbing alcohol. It was still alive even after 15 minutes of marinating, so I lit it on fire. Might as well have been a spider bite. Spread in red streaks up my neck over the course of a few days after. I don't remember ticks being like this growing up.

Knock can cause the marks you describe on the cylinder walls.

I have a couple of days off after my unplanned excursion to the hospital and I will try to get some pics of the pistons that I had taken out. If I don't have to move too much stuff, I will try to get some pics of the cylinder walls too. This time I also sent the pistons out with the block so they can measure and fit each one. Thanks guys.

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First batch of calcs don't take into account the gasket bore.... BUT show the other details. The second set were run on a different calculator, with the gasket bore, but don't show the details, but the rest are the same as the first batch. I tried to make it that if I wanted to boost it later for some insane reason, I could add a different head gasket, and lower into the range to take a modest boost from a supercharger (NO TURBO). That was my logic anyway,,,, see how far that got me! Back to square one.

We were seeing the knock sensor going nuts the whole time I believe. I was attributing it to the valve noise, but that might not be the case. I put 0.030" thick head gaskets with a tight bore to actual, thinking I may be able to make a slight lowering if necessary by going to a thicker, larger bore gasket if needed.... HOPEFULLY setting the correct clearances will allow the proper oiling and lower the valve noise thus leaving any knock to be actual knock. I calculated the actual compression to be between 9.5:1 and 10:1 with my intro-level expertise with big blocks (domestic V-8s in general).

Will the casting #s on the heads indicate whether they are 100CC or 110CC? I think I was calculating on 110CC.

Currently trying to run again (unless the Combustion Chamber CCs are 110):
Bore: 4.310"
Stroke: 4.25"
Combustion Chamber (Casting#10141279) : 100CC/120CC not sure? Any input?
Piston Dish: 3CC
Gasket Bore: 4.370"
Gasket Thickness: 0.030"
Deck Clearance (Decked -0.020" for absolute 9.780"): 0.00"


IF my heads are 100CC, that means I am at about 10.2:1 compression.... I believe I can lower it by using the following:
I was shooting for like 9.5:1, but if the heads are 100CC, I may be at 10.2:1
100CC
9.005 - C5634-092
9.294 - C5634-075
9.568 - C5634-060
9.859 - C5634-045
10.172 - C5634-030 <-- Current

This is going to be a tow vehicle, do you guys think I should use the gasket that would provide the lower compression ratio?

I ordered a set of these: C5634-075 which should yield a 9.294 compression ratio, considering the high IAT readings and the fact that I plan to tow through the mountains. I always run premium gas, which is usually 91+ octane. I have run across 89 as premium in our travels, but don't mind running octane boost for a fill here and there. This is really a vacation and tow vehicle only. This is all assuming 100CC heads. Anyone have an authoritative source to verify the castings?

Everything I have read in the last 20 years states: your much better off to adjust the compression ratio with combustion chamber volume and/or pison top shape/volume rather than change the quench depth via gasket thickness or leaving the piston recessed in the bore. With that being said, do what you have to to get the comp. in check, will be much better than dealing with knock.

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Originally Posted by oldpartsnrust

Quick question. One of the things I noticed on the old block is that there was some significant scoring on the piston skirts and cylinder walls. I am thinking that when I had first slapped this together if I recall, it was running really rich. I believe this may have caused that scoring as the walls are splash lubed no? There was also some pretty significant carbon build up on the piston tops when I took it all apart. I also believe that during the tuning process, one of the first things you noticed was that there was a lot of leaning that had to be done as it was running rich. Does this sound correct? I am asking because I think you had gotten pretty ball-parkish with the tune and that I should worry too much about this recurring with where we currently are with the tune? Is that a pretty fair assessment? Thanks. Starting to get pretty psyched now that time has dulled the impact of my f'ups. I think I am now able to categorize it as a different project mentally! ;)

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The way this sounds, you rebuilt this engine and then took it apart again at some point? And the cylinders had significant scoring? Depending on the mileage my first reaction would be it's a less than sterile rebuild. But I'd have to see/know more to know for sure. That would be the most common cause. If there's any debris floating around the cylinder walls and piston skirts are the first to show signs.

SUMMARY TO DATE

Fair enough assessment given the length of this thread so far! I will give a quick summary:
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1. 180,000 miles on stock 1999 L29 Vortec 7400, spun 4 rod bearings seemingly at once while towing through the Appalachian mountains. Still running, towed home, torn down.
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2. Decided to rebuild and upgrade. Sent block out for boring to 0.060" over, decking to 9.780, line hone/check. All clean and good. Followed engine builder's recommendations on what bearings (extra clearance), boring sizes (4.315"), etc. to put together ("these big blocks like it loose" - engine builder).

a. Eagle 496 stroker kit
b. F.A.S.T. injectors
c. Comp Cams towing cam for 7400 Vortec
d. Roller tip Comp Cams rockers (fit under stock Vortec Valve Covers)
e. Couldn't find any local tuners as they "don't work on that old chit". So I bought HPTuners
f. Adjustable rocker studs
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3. Assembled all, programmed in the new injector flow rate and it started! Oil pressure 60PSI, but apparent lifter noise from the get go. Running very rich, but running. Knock sensor all over the place, but so was lifter / rocker noise.
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4. Tried all kinds of things to quiet the lifter noise all while getting tuning assistance (Thanks SiriusC1024!) to back off the richness and get closer to final tune. This is all complicated by noise in valvetrain and Knock sensor.
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5. Oil pressure still 60PSI on start and 18-20PSI after hot. Lifter noise no matter what I did. Decided to get lifters that had additional oiling at the top end. Took apart intake to swap lifters, knew I dropped a 10MM EGR bolt and planned to retrieve it later. Promptly forgot about dropped bolt, even searched for a new one when I couldn't find it. Was re-assembling and using a starter button to bump the engine over to adjust the valves when I heard a lockup, and then a ping, and then a crack. Sat for a second wondering what I just heard... then bumped it again and it spun freely. Decided something not so good happened so I got out a borescope and saw that a piston met its demise. #3 hole.
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6. Tearing down motor revealed the following:

a. coolant in oil, didn't register initially as I pulled intake and coolant migrated, but it was A LOT
b. broken piston
c. rod bearings had some scoring as well as rod journals had a touch of scoring, (was able to be polished out)
d. mains looked pretty good, slight (less than rods) scoring and journal scratches
e. Piston skirts and cylinder walls had vertical lines/scratches/scoring, cannot catch a nail, but obvious sight wise.
f. CRACKED cylinder on #3 when went to hone cylinders for re-ring!
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At this point, with some lessons learned (and probably a few more to come!) new used block, fresh line hone/check, fresh 9.780" decking, fresh 0.060" bore, NEW pistons/rings and polished crank (scoring was superficial and polished out), going to re-assemble. The more research I do, the more I am thinking that the knock readings could be valid as I think these heads have a 100CC chamber instead of a 110CC chamber which is what I used to calculate everything. IF 100CC, the new head gasket should give me 9.4:1, which is where I wanted to be and thought I was initially.

Corrective actions from first swing:

1. Thicker head gasket
2. Factory clearance specs for mains/rods
3. straight 0.060" bore, rather than 0.065" that engine guy recommended
4. Thinking rich issue is mostly gone thanks to SiriusC1024 getting it close to "Ship it!" tune.

Still researching the head casting # unless someone can definitively tell me the CCs of the heads I am going with 100CC this time instead of 110CC.
Casting #10141279