i wouldnt see a problem with that. not sure what grade bolts ive used before, just was sure to tourque them down, used loctite for "insurance". yes, the pressure plate should be touching the flywheel, any gap and your not getting full clamping of the clutch disc.

 

Got a couple questions at the end of this post. I'm getting ready to put my engine in the truck this last weekend and one of the double checks I was doing was to check the torque on the bolts for my oil pan and LIM. Oil pan bolts were fine, but I found the LIM had 3 or 4 bolts that, were not quite at 11 lb lbs.

When I checked the bolts I made sure I checked them in the proper order. I went ahead and, as I checked each one, re-torqued the ones that were not at proper torque. The position varied on which bolts were not properly torqued anymore. Meaning, they weren't all on one side or one right after the other in the proper order, etc. As a little background, this engine has been on the stand and I initially installed the LIM many months ago. When I installed the LIM, I insured I followed the correct procedure (3 stages of torquing) in the correct order. Once I had completed the final stage, I went back and checked torque on every bolt again (in order) to insure they were definitely torqued to 11 lb ft. They were. Once again, this was many months ago.

So my questions are: Is it OK that I re-torqued the 3 or 4 loose bolts (not literally 'loose', but not quite at 11 lb ft either) as I described? Or, should I loosen all the bolts on the LIM and go back through the prescribed torquing procedure? If I do loosen all the bolts on the LIM and start over...how possible is it that I will break the "seal" between the LIM and heads, as well as the seal between the LIM and block? Just FYI, I went to GM and bought the actual sealants and such as called for by GM in the TSM. Meaning, I didn't use off the shelf RTV.

I feel pretty good that just bringing the loose bolts back to proper torque (following correct order) is good to go. But I want to get some some expert opinions.

Here is something I found very interesting though...two of the bolts that had to be re-torqued were the two at the rear of the engine on the driver's side. You know...the spot where the LIM gasket typically fails most of the time. Made me wonder if I hadn't checked the torque these many months later from initial install...if a few years down the road I would have ended up with that failure. Anyone think this might be the reason the LIM gaskets fails at this spot so often? That even though the LIM is installed correctly initially (even from the factory), that for whatever reason the torque on those two bolts decreases enough to break that seal?

Thanks for any help and opinions.

 

Issue #2 for today.

This one is something I didn't even realize was an issue. As a reminder, this truck has a manual transmission and the reason for the need to replace the engine was because the thrust bearing went and every time I pushed on the clutch, the crank would shift forward a bit creating a rhythmic knocking sound. As another reminder, the PO put in a bone-yard engine and his work left something to be desired. So there is many unknowns throughout the whole drivetrain I have been dealing with.

I'm was getting ready to mount a NEW flywheel and being extremely careful with everything I'm doing on this replacement, I referenced the TM. Something I didn't notice before is it state "If replacing the flywheel with a NEW flywheel insure you place NEW balance weights into the same location as the old flywheel." No if, and(s), or buts(s) about it.

My brand new flywheel has no weights installed at all and I did purchase it specifically for my truck and engine. There is some steel removed near the center of the flywheel where it meets the crank, but I assume that just balances the flywheel itself (not the balance of the engine). There is a balance weight in the old flywheel, but I have no idea if that is in the proper clock position for the engine.

I went online for the last hour and got a pretty good education on "internally balanced" and "externally balanced" engines. This is brand new to me. Apparently 4.3L Vortecs are externally balanced...which probably means (based off the TM) that I need to press in a balance weight (or maybe two). Does anyone know where the clock position for the balance weight(s) are located? These are completely different (and about 35 lbs heavier) than a flexplate for an auto trans.

It's too late to call the dealership today...and I don't even know if they can help with this one or not. The reason I absolutely cannot use the old flywheel as a reference is pictured below. If you look close enough you will see where the old flywheel gouged into the block when I pressed down on the clutch. In the pic with the arrows, the left arrow should be a little more to the left. You can really see the gouge clearly on the starter shield and to the left of that on the close-up pic.

I can't take the chance that the old flywheel (which actually has two indexing locations instead of one) was the whole cause of the reason my thrust bearing failed...due to the balance weight (and/or indexed position) of the flywheel being in the wrong spot. Any help would be enormously appreciated...like always.


EDIT: Just got off the phone with the parts store. I looked at their website and one of the features and benefits listed for the flywheel states "Engineered to properly fit the intended application with no modifications." I asked the question if the statement was accurate to the point of meaning it was already balanced for my engine and did not require a balance weight. Sounded like a decently knowledgeable counter person and after looking on his puter stated that it did not need a balance weight. So I have the TM telling me one thing (put in a new balance weight) and the parts store telling me it's already balanced for a 4.3L Vortec.

Basically, I'm trying to determine if the "...no modifications." means the flywheel was balanced for the engine. Meaning it has a heavier spot for a "lobe" (probably not the correct word) while turning to counteract the "lobe" of the crank (with the piston rods attached) so the SYSTEM together is balanced, OR....is the flywheel only balanced to itself?

 

On the LIM: The bolt threads, and the threads in the heads, all need to be "chased" with a tap and die to remove all of the old sealer. If you don't chase the threads, (wire wheel does not thoroughly clean and repair the threads) the torque value will not be accurate when you torque the bolts. After chasing the threads, apply thread sealer to the bolt threads. Applying the sealer stops oil from leaking past the threads, and due to the low torque, it keeps the bolts from "walking out" caused by engine vibration. Post #33 has the tightening sequence, torque specs, and a warning.

The flywheel should have a locator hole so it can only go on one way. You can see the dowel pin in the second image, 10 o'clock position.

 

All this was done. The threads in the heads were chased and had absolutely no sealer before the NEW LIM bolts were installed. The LIM bolts were brand new from the dealership so they had no old sealer on them. I followed the correct sequence and torque settings completely when I installed the LIM. Then double checked each bolt again (in sequence) to insure they were at 11 lb ft.

The locater is not the issue. There is only one way I can install the new flywheel. I did mis-state when I said the old Flywheel had "two indexing locations instead of one". I realized that as soon as I looked at it again. I was looking at it wrong for some reason. Don't know why... probably because I was more focused on the balance weight.

My question is in regards to a balance weight for the flywheel (pictured). The old one has one, the new one doesn't and I'm being told that the new one doesn't require a balance weight because it is specifically manufactured for my engine with no modifications. GM Tech Manual states "IMPORTANT: If replacing the manual transmission engine flywheel, NEW balance weights must be installed into the NEW engine flywheel in the same location as the old engine flywheel."

So, which way do I go? One of the choices is dead wrong and significant enough to damage the engine. Which is the wrong (or right) answer? The other part of the question is if the correct answer is to add a balance weight...what is the correct location (clock position with the locator at 12 O'clock)?. I'm very hesitant to use the old flywheel for reference based off the damage to the old engine along with the fact I have found several things the PO did when he installed the boneyard drive-train that were dead wrong.

 

IMPORTANT: If replacing the manual transmission engine flywheel, NEW balance weights must be installed into the NEW engine flywheel in the same location as the old engine flywheel."

There's your answer. Transfer the weights from the old flywheel to the new flywheel. Put them in the same locations on the new flywheel, that you removed them from on the old one. That's why the flywheel is keyed, so the weights end up in the right place. This is external balancing, far less expensive than internal balancing. Your 98 has a balance shaft above the camshaft. Its purpose is to decrease engine vibration. The weights in the flywheel "fine tune" it. The weights are not balancing the flywheel, that's not necessary. They are balancing the entire engine assembly. After the engine was assembled, and before the transmission was bolted up to it, the engine was started and balanced using the weights in the old flywheel. Much like balancing a driveshaft: weights are welded to it. If there have been any internal engine parts changed, (pistons, crankshaft, camshaft, connecting rods, etc) or the flywheel was from a different engine, the weight positioning is most likely incorrect. If that's the case, a capable machine shop or speed shop will need to balance it for you.

 

Just for info: Popped out the old balance weight and the thing is only about 5/8" long and hardly has any weight to it at all (maybe 1/2 oz). Considering the weight of the flywheel..about 35 lbs...pretty amazing that little weight could effect the system at all.

Fact is, this is a NEW engine (reman) that I'm putting a NEW flywheel on...so even using the OLD flywheel as a reference (which came off the OLD engine) is worthless because I didn't realize that each engine is individually balanced with the external components. I kind of halfheartedly hoped that all the '98 vin 'W' would be balanced the same. But that isn't the case as Captain Hook cleared up for me. So the placement of the balance weight could be in an entirely different position.

 

That's correct. I wouldn't put any weights on it, doesn't take much to balance it, or throw it out of balance, you just might make it worse. Cross your fingers and hope the reman is balanced close enough.

Just to give you an idea of what 1/2 ounce can do, stick a hose clamp on your driveshaft and go for a ride

 

Well, after over a year of tinkering around, I finally turned the key. She started right up and hummmed right along. No leaks no hisses, no tapping, no loping...everything sounded beautiful. But I need some help on the finer things now. This was only the first runup and I want everything dead-on before I driver her for the first time and do the drive-cycle. Besides, I have to finish the bodywork first.

Here's where I need some help:

1. As the truck was warming up and I was checking everything (wifey was in the driver's seat) I had my computer hooked up outside the truck on a work stand with my new AutoEngunity Scantool (w/GM Family enhancement). After a few minutes, the SES light went on with P0300. I've attached the Freeze Frame data and if anyone can see what might have caused the misfire, I'd apppreciate the knowledge. We didn't hear it, feel it or nothing. The wife was trying to maintain 1,000 rpm for the initial break-in so she did surge the throttle a couple of times.

2. While looking at the live data, B1S3 Fuel Trim was at 99.06%. All the HO2S are brand new AC Delco. Any idea why the fuel trim was so far out of range?

3. Trying to learn OBD II I'm at about the 3rd Grade level . Second attachment is the On-Board Test results while the engine was running. What am I looking at? I see some "fails" and other things that it looks are not right. What do I fix?

I'd really appreciate the help Gents (and Ladies).

Thanks a million

EDIT: Two other things I should mention: 1)catalytic converter is brand new; 2) I ran the truck twice for about 20 minutes each time. I refreshed the the scantool for new DTC's several times...the P0300 only appears to have happened the one time that is listed in the attachment.

 

The freeze frame for P0300 shows coolant temp at 156F, it needs to be ~198F. Possibly not completely warmed up, or the thermostat is stuck partially open. Coolant temp needs to be at operating temp, (~198F) for fuel trims to be accurate. B1S3 doesn't have fuel trim data on your engine, possibly a glich in the Autoenginuity software. At operating temp, B1S3 should be steady around .45 volts. The data with $ is generic OBDII stuff. It is used when the scan tool can't, or doesn't, communicate with the vehicle PCM's protocol. You shouldn't need to use that menu, there should be a menu that shows the actual streaming data. Might take a while to get the hang of the software on your Autoenginuity