Broke the block today. So, what did I find? grant - 7 years ago |
Re: Broke the block today. So, what did I find? MarcW - 7 years ago |
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grant
Broke down the bottom end today: basically it breaks into two block halves and two crank carrier halves, plus a crank, and IMS, some chains and miscellany, and other small parts. Except for trapped oil int he IMS, all very clean. But some very worn - VERY worn.
A "top 7" list (they are all the rage, eh?) of what i found:
1. Scored cylinders on one side. *something* got in there, maybe before my ownership
2. some really smelly oil in the bearings and inside the IMS. Burnt. Ugly.
3. Burned and worn rod bearings - not good at all!
4. An LN IMS bearing that was in terrible shape, after only 3 years - albeit of track use. Pretty scary.
5. good rings
6. good chain guides and chains
7. The rods are "cracked" - i should have known that, but didn't. Still terrible, with the wear to prove it.
Why top 7? Not 10? I didn't think of ten things that were similarly interesting. I'm sure i forgot three, sorry.
Blocks is now off to Chicago, and I need to think about some decisions re: deep sump, IMS bearing (thinking DOF), X51 baffle in addition to Pedro's deep sump?, etc.
Grant
Answers and comments grant - 7 years ago |
Re: Answers and comments MarcW - 7 years ago |
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grant
Hi Marc,
I'll give you a brief update - i posted the macro plan here some weeks back. I'm rebuilding the motor and tranny at and with the assistance of a top Porsche re builder locally. Very generous of him, and a great learning experience. I'm doing 3.2 --> 3.6 via Nickies (LN) which means a new, stronger liner which is also nikasil rather than locasil is inserted at the LN factory in Chicago, and then they return it, only with matched JE pistons which are metallurgically similar to minimize different expansion and consequent wear. Or that;'s the theory. Most race shops agree this is the best way forward for the bottom end,
I'm sending the tranny to GBOX in Colorado, the go-to re-builder. Synchros (1,2), diff whine, overall check and recon, likely LSD too (especialyl if i can deduct the cost of fixing the diff whine, which is likely).
The rest will be traditional local machining and rebuild- heads, polish crank, carillo rods, blah, blah. As noted, i still have a few detail decisions to make during the long gestation at LN. I believe i will put in the DOF for one - the IMS bearing felt awful. Startling to me. Clearly the LN is not up to this kind of abuse, and I'm more and more convinced by pedro's explanation that lubrication is the real culprit.
Hey, its only money. Gulp.
Now, to your questions:
No pic of the scoring? Does a fingernail when dragged over the scored part catch ridges/grooves?
--> i'll get some. A small number of fairly heavy vertical traces indicating a foreign object. I was pretty much out of time and had to clean up. I cant play too much hookey from work, my boss is a slave driver. (me)
The inside of IMS can accumulate some oil over time and the inside of the IMS doesn't really get washed/flooded with oil and stagnant oil (mixed with combustion byproducts) can develop quite an odor.
Yep, and now i've seen it. and smelt it!!! Like 150000 mile old transmission fluid. Rank.
Good rings is good but it doesn't seem to jive with scoring.
agree. go figure.
Cracked rods are very common. Eliminates a machining step (or two) and the halves fit back together perfectly. No risk in assembling the two halves slightly misaligned which can cause rod bearing grief.
Oh, yes, very familiar with the method. I was just surprised that they went to the trouble (and cost) since the rods and rod bearing are known to be under designed and stretch, then fail rapidly once out of round.
Are you going for more displacement? Or just having the cylinders sleeved or ? and sized back to stock bore?
As noted above - yes, but not by boring - by the LN 3.2-3.6 kit (you can read about it on their website). Seems pretty slick, durable. I'm hoping to pay more for robustness than power, but as you have seen, power would be useful for me :-) Even with all this I'll be in about the slowest car out there in terms of raw power: weight in black or red. I have been advised to be very careful if I was ever to bore out a 3.2 --> 3.somethingbigger because one loses both strength and silica density in the impregnated liner.
Right now I'm trying to ascertain the difference between wise upgrades along the way and good, old-fashioned "scope creep".
Your two cents always welcome. Four even, in this case.
All true, all trade-offs, but from what i hear.... grant - 7 years ago |
On displacement vs. Strength, from LNE grant - 7 years ago |
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MarcW
There is no replacement for displacement, but with these engines bigger equals weaker. With a bigger bore the cylinder walls become thinner. A "stroker" keeps the cylinder bores either the same size or requires they not be machined as much to pick up the desired increase in displacement but a "stroker" brings with it its own problems. Higher piston speed and thus possibly a lower red line. Even so the crank/block experience more stress. The cylinders experience more pressure from the longer rods, too.
One is kind of damned if he does, damned if he doesn't... Stick with the stock engine size and its output. The engine probably lasts longer but the risk is the on track performance has one hoping the engine blows so he has an excuse to do a bigger/more powerful engine. Bump the engine's size and the power's there but the engine goes boom even with good aftermarket hardware installed.
Re: Answers and comments SteveJ (2010 987 base, manual trans) - 7 years ago |
cracked rods frogster - 7 years ago |
"Cracked or Fractured Rods" grant - 7 years ago |
thanks grant frogster - 7 years ago |
Re: Broke the block today. So, what did I find? MikenOH - 7 years ago |
Quote
grant
Broke down the bottom end today: basically it breaks into two block halves and two crank carrier halves, plus a crank, and IMS, some chains and miscellany, and other small parts. Except for trapped oil int he IMS, all very clean. But some very worn - VERY worn.
A "top 7" list (they are all the rage, eh?) of what i found:
1. Scored cylinders on one side. *something* got in there, maybe before my ownership
2. some really smelly oil in the bearings and inside the IMS. Burnt. Ugly.
3. Burned and worn rod bearings - not good at all!
4. An LN IMS bearing that was in terrible shape, after only 3 years - albeit of track use. Pretty scary.
5. good rings
6. good chain guides and chains
7. The rods are "cracked" - i should have known that, but didn't. Still terrible, with the wear to prove it.
Why top 7? Not 10? I didn't think of ten things that were similarly interesting. I'm sure i forgot three, sorry.
Grant
Re: Broke the block today. So, what did I find? grant - 7 years ago |
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MikenOH
Grant
Re: Broke the block today. So, what did I find? MikenOH - 7 years ago |
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grant
The rod issue can be reduced with a) better rods and b) better lubrication. I'm almost certainly using carillo rods.
I have three tricks i want to try for lubrication:
1. now my sump is modified to work properly all the time - there were times it could have starved due to oil trapped above the windage tray - sump doing the opposite of what it was intended to do.
2. DOF - maybe (only helps the IMS, not rods)
3. DIY dry sump (if i can make it work - biggest issue is scavenging reliably)
IMS is another story. I'm really hoping the DOF is the answer. I want to do a bit of sleuthing. Wish there was better field data. Unfortunately much published data on all failures comes from folks with money to be made on other fixes.
Grant