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My block is screwed isn't it....

16K views 284 replies 35 participants last post by  Jaime Lannister 
#1 ·
Many of you have been following along my previous threads discussing the issues I have been having with my built 347.

To sum up, it was burning oil from 2 cylinders. The plugs in those cylinders would foul within 30 miles.

I got to the bottom of it tonight. Ran a compression check...was perfectly fine. Did a quick leak down test by spraying air into the chamber and did not hear it in the pan. I was actually happy at this point and was hoping it was something in the head.

NOPE

Got the head off, and those cylinders have DEEP gouges running vertically the entire bore. When you feel the bore, it feels like you are reading brail. The other 6 cylinders feel great by comparison. I am already running slightly overbored at 3.905. The max you can bore an LS1 is for 3.908 pistons so I am pretty sure this block is screwed and cannot be saved but maybe you guys have a better idea.

Looks like I am smurfed. Andrew gave me a deal on that block since he is a friend at only $300. No way I will find another that cheap. I know the machine shop will try to avoid liability since it is now more than just a simple rehone and rering (they said they would cover that on their dime based on our previous discussion before we knew exactly what was wrong).

It is now a $600-800 dollar mistake....I only paid them $1800 for this job.

In b4 Mike ends up paying over 5Gs for a simple forged 347.


CURSE ME FOR NOT DRIVING THE 200 MILES TO ANDY. That would have been a minor inconvenience but it would have been done right. Yay I am now a cautionary tale. Learn from my mistake...go to only people you know and trust.
 
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#120 ·
Nope, these were the same heads that I got from AI that I was running for 20,000 miles. I had one head repaired by AI since a valve was burned from blowing my piston, but that head was on the opposite bank of this one. AI does great work.
 
#123 ·
I defer to the experts on that one. To me it looks more carbon fouled than oil fouled. It looks dry and baked on, but I trust you when you say it was oily. What if those two injectors were stuck open, pissing fuel the whole time and washing the oil off of the cylinder walls, thereby allowing the rings to scratch them due to lack of lubrication?

Then the scratches let excessive oil blow by and...well you get the idea.
 
#124 ·
Eh, I would notice that on 2 cylinders. The car ran too smooth for that to be happening. Plus nothing was wonky about my wideband readings either. My wideband was on this bank BTW. The tune was pretty much dead on from before.
 
#130 ·
I would never do something like that outside in the dirt (unless it was at the dirt track) and my HOA would have my ass for even trying.
 
#139 ·
Got the replacement block and the bad block at the machine shop. They are honing it with arp head studs in place and I gave them specs this time.

.023" top ring
.027" 2nd ring

.005" piston to wall clearance.

I came up with these clearances with boost in mind.


I hope it doesn't get screwed up again :(. Ironically, I purchased the replacement block from a guy who also used this machine shop and his motor is going strong.
 
#144 ·
Stopped over there today.

The block is prepped and ready to be assembled, just waiting on rings and a line bore for the main studs I am putting in now.

The culprit of the scored cylinder walls was from the oil rings shattering. I guess there wasn't enough gap and they butted together. The weird thing is Wiseco says right in their documentation that you don't have to gap the oil rings, you can just put them in. Maybe it is not the machine shops fault after all?
 
#145 ·
If that's what Wiseco says, then per their rules, the rings were faulty.
 
#147 ·
Kind of a catch-22 there. You want to trust the manufacturer's instructions, but experience dictates that you should never trust the manufacturer's instructions.

However, I agree that if Wiseco states that the rings do not need to be gapped and to just slap 'em on and go, and this whole mess is a result of a faulty ring, then I would be calling Wiseco and letting them know what they owe you.
 
#148 ·
Well, the shop is already doing the work again on their dime, so looks like I can avoid that would-be-mess.

Agree on the catch-22...the shopowner admitted he didn't check the oil ring gap based on that documentation. But we are definitely checking it this time and adding a bit more to it, like .015.
 
#149 ·
How far are you from Quakertown?

I live up by that area and work at the Lehigh Valley Mall. I can always stop by and give a hand after work.
 
#150 ·
About an hour. I appreciate the offer though :). I am really only working on it on weekends anyway. I refuse to get under the car in the dark outside and alone when it is 29 degrees. I don't mind working in the engine bay in the dark though. So the plan is to get the tranny and motor back up into the car next weekend. Then I can work on the accessories after work during the week with my spotlight. This thing should be running again before XMAS. All I want for XMAS is some fucking luck with this build. Is that too much to ask????
 
#153 ·
Thanks man. If the block is determined to be a good build this time, I am going to spend a week detailing it, then I am going to cover it and never drive it again. That's the only way to not break LOL. I am so tired of turning wrenches. I need at least a year off.
 
#157 ·
I've never not seen a specification for oil control ring gaps contained in the ring manufacturers literature or published by the OEM. Regardless, the omission of a specification does not mean that it does not need to be checked, that's the difference between an engine builder who has the ability to take a pile of parts from different manufacturers and machine them to fit properly vs. an engine assembler that just throws the parts together and hopes for the best....a monkey or a five year old could be trained to do the latter.
 
#160 ·
There was no mention of gapping oil control rings in any of those instructions, only a minimum gap of 0.015" from all manufactures. You obviously don't want ring end gaps to butt, but there was never any mention of correcting the gap like there is with the first and second rings.

They mention gapping the rings in the bore they will be used in, as a bore difference of 0.001" will change gap by 0.003". If you bunch up half of the oil rings and gap them in one bore, you are not gapping them properly to each individual bore.

I still stand by my statement that there is no "gapping" of oil control rings. You can verify they have a minimum end gap, but there generally isn't a need like with the top two ring packs. I'm not saying it can't be done, or doing it is wrong, it's just something that isn't normally done. The gap isn't as critical as with the top two rings, and heat expansion is less as the oil ring is further down the skirt. The oil rings don't seal compression, they only scrape and drain the excess oil from the cylinder walls.
 
#164 ·
There was no mention of gapping oil control rings in any of those instructions, only a minimum gap of 0.015" from all manufactures. You obviously don't want ring end gaps to butt, but there was never any mention of correcting the gap like there is with the first and second rings.
They give you a minimum specification, that means you are expected to check it, as I said, any builder worth his salt is going to check everything, and leave nothing to chance....again, the difference between a garage assembler, and an engine builder is the ability to make proper and precise corrections to parts in order to put them within specification. So you tell me, since you're so adamant that there is no "gapping" of those rings, then what do you do if they're out of spec?

They mention gapping the rings in the bore they will be used in, as a bore difference of 0.001" will change gap by 0.003". If you bunch up half of the oil rings and gap them in one bore, you are not gapping them properly to each individual bore.
If someone is honing cylinders with a spread of .001" you need to find a new machinist, mine never go over .0002" spread from top to bottom and O/R...regardless, as you already pointed out, gapping oil control rings is not that important - you just need to make sure they're open more than the minimum spec which is exactly what you're doing when you group them together in order to get an accurate measurement.

I still stand by my statement that there is no "gapping" of oil control rings. You can verify they have a minimum end gap, but there generally isn't a need like with the top two ring packs. I'm not saying it can't be done, or doing it is wrong, it's just something that isn't normally done. The gap isn't as critical as with the top two rings, and heat expansion is less as the oil ring is further down the skirt. The oil rings don't seal compression, they only scrape and drain the excess oil from the cylinder walls.
Uh, is that any different than what I said? Yes, in 95% of cases you will not need to adjust the oil control ring end gap....BUT, that does not mean that you can just skip the step of checking it, there is a minimum specification for a reason.
 
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