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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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#3 ·
ive been there man...sorry to hear it...
 
#7 ·
The car itself ran ok. Had power. But I burned a quart in 500 miles and my plugs were fouling if I didn't get on it often enough.

Motor has to come out. Motivation going down the shitter....

So hard to find a good machinist.
 
#5 ·
Willl there be another Northeast Cannonball to your place then, for an engine block coffee table ? That sucks, mchicia1.

I'm a dufus on this but there are stories on the 'webz and overbore pistons available out to 4.002 for use on iron blocks. But moreover junkyard iron LQ9 blocks are el-cheapo and might be an option.

Good luck however it works out :(
 
#10 ·
i just seen one for $200 i think it was on here. but cant remember could of been craigs list. use adhuntr.com and you search all of cl at once.
 
#12 ·
I totally forgot you can take a 5.3 aluminum block and bore that out. I will have them buy me one of those. They are about $200.

Thanks for the brainstorming guys. I want to stay with aluminum though. Good thing the 5.3s are cheap either way.
 
#15 · (Edited)
#13 · (Edited)
You can't bore out a 5.3 aluminum block, they are sleeved just like a 5.7 aluminum block. You can have a 5.3 resleeved and make it into a 427 though. But, it's not cheap.

Thompson sells assembled aluminum LS1 short blocks too.
 
#22 ·
Why does Texas Speed use new 5.3 blocks for their ls1 builds then? Something I am missing?

http://www.texas-speed.com/p-3537-tsp-347-cid-street-racer-assembled-short-block.aspx


As for the idea of throwing a 5.3 in, I have $3400 into this motor already. What happens to that? I need to try to salvage this as I am already heavily invested. I am meeting with the builder tomorrow morning to give him the news, I am crossing my fingers he stands by his work.
 
#16 ·
That sucks. I'd check on resleeving those two cylinders first.
 
#18 ·
#19 ·
Jesus Mike, this sucks. Maybe you should take up knitting..... I hear it's much cheaper hobby.
 
#20 ·
Sorry to hear that, Mike.

Maybe consider just sticking a 5.3 or a 4.8 in there? You can get a very nice build within your power goals with one of those motors. They're also kind of throw-away motors in the sense that if you blow it up, you can buy a complete long block for less than it would cost to fix the damaged one.

Especially with the longer rods of the 4.8, you can have a very stout bottom end with just ARP rod bolts being the only upgrade. My sister's boyfriend has a 5.3-swapped Chevelle that had about 130,000 miles on it BEFORE he started pushing 8 PSI through it. Motor is still going strong. He has another one sitting on a stand ready to go in when that one blows up.
 
#21 ·
That's not a bad idea. You wanted to boost your car eventually anyway right? Grab a 5.3 block, build it and boost the hell out of it. Certainly much cheaper to replace the block in case the next engine builder sucks too.

I know of a good shop but it's sort of far away from you. It's a one man show up in boyertown, pa.
 
#23 ·
Knitting is a great idea LOL. I already retired from drag racing...the only times my cars have ever had issues either broke directly at the track, or shortly after. The GTO was 10,000 miles on the cam with no signs of any issues. Broke the rear then shortly after it had lifter issues. The vette had almost 25k miles with zero issues. Took it to the track, popped the piston then shortly after popped the tranny.

I am retiring my daily drivers from ever seeing the track. If I ever want to go again, I am building a dedicated car for it.
 
#24 ·
I see what you are talking about. Texas Speed does say this:

The TSP Street Racer 347 short-block will use a new GM Gen-III, LS1-style 5.3L aluminum block that is bored to 3.903".
Presumably, that's a mistake, because I found numerous other references to state otherwise:

5.3L truck: The cast iron blocks have thick walls so they can be bored up from the 4.8L/5.3L standard bore of 3.779" to 3.893" to make them into a 5.7L standard bore block if the additional weight of the iron block isn't an issue, but the aluminum blocks shouldn't be bored over .010" according to GM.
There seems to be conflicting info on LS1 Tech, although a couple people over there claim to have done it.
 
#27 ·
Wth would cause that in such a short time. Possible the ring gaps are to tight?
 
#28 ·
either something was inside that motor or the skirt clearance was was way to tight...
 
#30 ·
Sorry to see all that nasty damage OP!

Any word or thoughts on what might have caused this to happen? I see a few members have mentioned rings being an issue?
 
#32 · (Edited)
Just talked to machine shop. He was very accommodating and said he would take care of it.

His first suggestion was to see if the cylinders can be simply honed and cleaned up and still have the correct clearance. If not, he suggested resleeving those two cylinders. He also suggested we use different rings....I don't agree with that, I am not even sure you can mix and match rings with Wiseco pistons.

I have two options.

1) Get all 8 cylinders torque plated
2) Just try to save these 2 cylinders and only replace rings there.

I was leaning towards #1, but since those other 6 cylinders are fine, I am not sure I wan't to take that risk again.
 
#34 ·
Wow, I am silently raging at my desk thinking of all the money I am about to lose on this motor.

No way this shop will fix it correctly. They want to bore it out more and knurl the pistons. Da fuck??????????????? Sounds like a bandaid fix.

I would gladly lose another thousand if a sponsor bailed me out and built me a motor based on my current pistons/rods/crank. I already contacted TSP. If they are on board and the machine shop refunds me the labor, I am doing it.
 
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