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92 buildup and questions

vdb11

vdb11

Halfmoon Detroit #2
Messages
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Location
Stormstown, PA
OK guys here goes.

I willing be rebuilding/building up my 92 6.5 this summer (hopefully). I have already begun to assemble some parts for the job. From my testing, it seems as if I have one dead cylinder and it burns some oil so the motor needs a rebuild, and I wanna build it up :)

Here is the list, most of this stuff I am sure about, but I do have some questions on a few items:

New rings and bearings all around (bought)
Main girdle
Block hardener (Moroso or Hard-blok?)
Ported lower intake, heads, and pre-cups (by me)
All gaskets necessary for rebuild
New water pump
New HB and pulley
Holset HE351 VGT turbo (already have)
Remanufactured head and rotor and modified DB2
Possibly intercooler (have)
FTB mod
Oil cooler lines fixed

Ok so like I said, I have much of this stuff figured out, but I still am unsure on some things. Keep in mind I am on a tight budget.

Main girdle I am still on the fence about, I don't trust myself to do it right but we will see. As for the main bolts, what do you think? Could I possibly get a grade 8 bolt, run a nut and washer up it, lop the head off (enough to get a socket on nut) and essentially have a stud??

Block filler. This may seem really dumb, but in our application, does it still go in the water jackets? Does that actually make the bottom end of the block stronger for us? How much should I do, and what kind of machining other than running a hone through the cylinders will I need??

Head bolts. I don't plan on running much more than 15-16 psi even with this set up, and studs are too expensive for me, would regular head bolts from Advance or somewhere be fine?

Water pump. What year should I get? I will be getting a reman most likely and I noticed there is a good size price difference between like 97 pumps and 2000 pumps. I just want one that will flow reasonably more than my 92 pump.

Also when I take out my IP, do I need to score the gears to maintain timing? I ask because I will have the IP apart anyways for the machine work.

Feel free to comment on anything on the list. As for the IP and turbo, I am pretty well set with that, but the bottom end stuff I will take suggestions. If you see anything I should add let me know. Thank you!

Also, I hope to get a dyno run in here this weekend or next for a base run to see how much power I can add after all this is said and done. I am sure I forgot some questions.

Thanks!

Vance
 
vdb11 said:
Head bolts. I don't plan on running much more than 15-16 psi even with this set up, and studs are too expensive for me, would regular head bolts from Advance or somewhere be fine?

Water pump. What year should I get? I will be getting a reman most likely and I noticed there is a good size price difference between like 97 pumps and 2000 pumps. I just want one that will flow reasonably more than my 92 pump.
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The head bolts aren't exactly cheap, but like a third of what the studs cost. The little things add up, but if this will be used for any hard work then I would go with the studs. $200 or a little more for the set. A lot of people would say 15/16psi of boost is too much boost for the heads/gaskets. I and I know others run that much or more boost, I have stock stuff, and some have studs. $6 per stud w/ hardware is steep, especially in a hole kit, but buying a few here and there I've paid $3 a piece for grade 8 bolts for different stuff, and the studs are harder.

The 2000 year water pump is said to have better flow balance between heads. It also has a thread on fan clutch, so you would need a new clutch if using this model pump. I would use the 2000 pump if building a work truck that tows. The stock fan is not very good anyway, and clutches lose fluid engagement capability over time, so a new HD clutch and plastic DMax fan or steel 9-blade fan may be a good idea anyway.
 
I tried 12.9 metric which converts to grade 9 in standard bolts,but they stretched at anything over 120 ft lbs.
 
If you're on a tight budget, I recommend you strip it make sure you have a good block to build on before spending any more money on parts.

A thorough visual inspection and/or magnaflux inspection of the mains is required. Check the heads for cracks between the intake and exhaust valves also.

Block filler doesn't do much to stabilize the mains in these blocks, it mainly stabilizes the bores. It also can lead to higher oil temps in the lower end...
 
ak diesel driver said:
grade 8 fasteners don't even come close to the strength of studs at least good name brand ones
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Yes, thats why if you pay $3 for a grade 8 bolt the studs would be somewhat more expensive each. For 34 studs, nuts, washers, ect.....$6 a piece is a little steep for buying in a pre-made kit, but I'm just saying we get raped on hardware like this all year long, and might not be a bad investment in this instance.
 
ARP 130-4062 from summit racing $173. Worth every penny. How can you buy rings when you don't have a finished bore dimension? I would strongly suggest reading the ring to bore fitting process in a GM service manual. All the ring gaps aren't the same spec. With as many cracked blocks as I've seen I wouldn't count on any block not being cracked unless I saw it with my own eyes.
 
bk95td said:
ARP 130-4062 from summit racing $173. Worth every penny. How can you buy rings when you don't have a finished bore dimension? I would strongly suggest reading the ring to bore fitting process in a GM service manual. All the ring gaps aren't the same spec. With as many cracked blocks as I've seen I wouldn't count on any block not being cracked unless I saw it with my own eyes.
Click to expand...

^^ Sound advice.
 
OK so it seems that the head studs should be added to my list then, thanks bk95td! What about the mains? It seems as if stud kits for the mains are very expensive, the main bolts are reusable right?

great white, thats kinda what I thought about the filler, that's why I was asking about where it went since it didn't make sense to me that filling the water jackets would stabilize the mains. If I was going to run crazy power, then it might be worth it, but not for me.

That is a good point bk95td, I know I probably should know the finish bore first, I guess I am crossing my fingers that the bores are not out of round enough to warrant needing bored out. Wouldn't I need new pistons though if I need to get the block bored out? I guess I should probably get a GM service manual ha, where would I find one?

Also, when you said all the ring gaps aren't the same spec, do you mean along one piston or ?? Sorry I was just a little confused

The reason I have started to assemble parts is because this is my DD and I was hoping this process wouldn't take long. If I don't do the block filler (which I don't think I will now) I will inspect the block myself for cracks, and probably have the girdle made ahead of time. I know this will sound stupid but to be honest with you guys if the block has some hairline cracks in it, I will probably still put it back in the truck. As long as the cracks aren't on the mains (which I guess is probably where they will be if there is any) I will probably just have to deal with it. Now that the block filler is out of the question, pretty much all the money I will be putting into it (less than $1000) will be bolt on stuff that I can transfer if I do decide to replace the block.

About the water pump, I probably will do the 2000 pump and fan at some point since the truck does tow some. Is that the only year that had a better performing pump? Would one from like a 97 flow more than mine or not?

Thanks a ton guys you are a HUGE help! This is why I am asking now so that I can get ALL the details ironed out when it comes time to start.
 
I got a water pump for a 97 with dual thermostats and it has a bigger impeller than the 95 with one thermostat,and still uses a bolt on fan. Was close to $80 though.
 
The piston to bore clearances are different on the rear bores for shure and maybe others. I haven't reread the manuals lately. I've bought the GM manuals on ebay. Do a 6.5 diesel search and then on the left there will be a refine your search for manuals and literature. Books are a very good investment . Check Amazon too. There is usually some on there too. THe genuine GM manuals are the best in my opinion.
Your engine may not even need a rebuild. I have heard of rings sticking from carbon build up. The bottom ends will go over 300,000 miles if the oil has been changed and not run hot.
 
Alright thanks! I will have to get a book before the project begins. I see what you mean about not needing the rebuild, that is very possible. Unfortunately, I think my truck was not treated well when it was young, there are many signs that point to a bad past. I kinda wanted to do some bottom end stiffening anyway.

So are you saying that the rings for rear bores are different size than the others?

6.2 turbo, so a 97 pump will bolt right on to my truck w/ the factory fan clutch?

Thanks again guys!
 
The 97-99.5 High Output water pumps pump more volume than earlier versions and uses same bolt on fan clutch, it just does not have as good of balance between the heads as the 2000 year water pump, so the passenger head could be 20F higher than drivers and since temp sender is in drivers side you just see that. I prefer the single Tstat with it though, the one you already have.
 
I believe the ring gap may be slightly larger and the piston fit looser on the rear cylinders because they run hotter than the rest because of coolant circulation problems. When a 6.5 melts down it's the rear cylinders that go first. I have a parts engine that was severely overheated. The #7 and #8 pistons were melted down to the top rings. I have 2 other parts engines that had been rebuilt within 5000 miles and had broke the #8 pistons.
 
thanks buddy! I agree, I will be keeping the single t-stat. I appreciate the info. I thought the 97 and up to 99.5 were a little better, thanks!

bk95td, luckily my engine seems to run surprisingly cool. The PO replaced the radiator at one point, but the t-stat wasn't working so what it was running temp wise at that point I don't know. However when I got the truck, I replaced the t-stat and now it warms up nice and fast to 180 and literally stays glued there, almost no matter what I do. I don't think I have ever seen it over 200. I see what you mean about the ring gap now. So the piston is the same size as the rest but the bore is a hair larger with larger rings? That's interesting, maybe that explains why those two cylinders lose compression first.

How did those rebuilt motors break the #8 pistons? Were they melted or cracked?
 
The whole unbalanced water pump flow I was explaining is part of the reason the #8 cylinders get beat up. Because the temp sender is in the front drivers side head. But because the pumps are unbalanced temps vary widely from there to the back of the passenger side. If you have a 180 Tstat and are getting low MPG I would put in a 195 Tstat.

Does your egine have much blowby when it warmed up, take oil filler cap off, and check to see if it looks like steam engine blowing out of its stack. If not then it may not have seen much abuse like you thought.
 
The t-stat I bought is actually a 195 t-stat. It was just the cheapo from advance, stant it think is the brand name. I figured if it opened at 195, thats what it should be running right? But I hardly ever see it near the 200 mark. Maybe when I start this project I will buy a good ACDelco 195 t-stat to use. You pretty much have me convinced to get the 2000 year water pump haha, but aren't the fan clutches kind of expensive? Of course if I am going to be running high HP its probably good insurance, I want this motor to last forever when I am done with it.

The reason I want to tear into the motor (besides bottom end strengthening) is that my #8 cylinder shows very little compression (about 150 psi) which from what I have been told, won't even ignite the fuel so I have a dead cylinder. It may be bad rings, maybe a stuck valve or broken valvespring, or maybe worse like a melted/broken piston or block issue. I won't know until I tear into it. Also, I have never taken the cap off when it is running but I noticed it pushes a fair amount of oil vapor and steam out of the dipstick tube (with the dipstick in), enough to keep the outside of the dipstick tube and handle wet with oil. It certainly uses oil, but it also leaks some from the cooler lines. Oil also pools in the turbo intlet. I know all of this is somewhat normal, but I believe I have more than what is "normal" blowby for these motors.

Thanks again guys, my list of parts is being edited and critiqued and added to and thats what I wanted, unfortunately somewhat in the wrong direction for my budget haha :)
 
If the low compression is past the rings or valve seats, it would improve with oiling and higher RPMs where there would be better sealing and less time for pressure to escape. So it wouldnt be totally dead. The compression is way more when idling even over cranking. So although we want to see 400psi when cranking, at idle it should be double that. Its called the dynamic compression ratio. At 3000rpms the dynamic CR may start to converge with the static CR depending on valve timing of the engine. With the stock camshaft in the 6.5 the valve closes very near the bottom part of the compression stroke so it doenst affect the dynamic CR but like 1%.

The main reason I recommend the 2000 year water pump, is that you should also ditch the 6-blade steel fan, and clutches dont engage as good over time. So if its all original, its a good time to replace the pump, clutch and fan. Each of these factor into why the #8 cylinder is probably scuffed/scratched. That makes swallowing the extra on the newer pump a little more reasonable, whereas people that already got an updated clutch and fan for thier older pump, wouldnt want to spend the money to replace the clutch and fan again.

That said, several people run with the 97 year high output pump and Dmax or 9-blade steel fans and do fine. The temps may not be as balanced, but the high flow pump is able to get more cooling to the back of the passenger side than the low flow pump.
 
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