low compression on built motor..

[plow420]

Hi everyone this is my 3rd built motor that has failed me.... first two spun number 4 rod bearing..

Well anyways the shortblock was built buy a very reputable company and it was broken in right. The controlled aggression way, lots of oil changes. It was tuned on e85 and the max boost it has ran is 18lbs..

Anyways one day i noticed quite a bit of oil coming from the breather, so i did a compression test and here are the results... from left to right.. 150,140,115,140 that is dry... wet it goes up to 190 and 150 in the low cyl...

I also did a leak down test to confirm that it was the rings.... i could hear air coming from dipstick and crankcase

What do you think i should do? drive the piss out of it till the cyl totally gives out, because i've been pretty nice to it so far. I haven't had a running car in the summer since my car was stock 4 years ago..

I don't think they are going to stand behind their work. Their warranty basically covers nothing the way it is. And how could i prove that the ring clearances were bad.. their is no way..

 

[bryanwheat]

Everything that would need to be done is, New rings, new bearings and possibly a hone? what if the cross hatching looks good?

Could the pistons be messed up from the rings not setting?

The pistons likely won't be messed up unless they were installed with either too tight or too loose. I would hone the cylinders with a ball hone regardless of what they look like just to know for sure that the rings are going to seat.

 

[plow420]

The pistons likely won't be messed up unless they were installed with either too tight or too loose. I would hone the cylinders with a ball hone regardless of what they look like just to know for sure that the rings are going to seat.

That is like a last resort. After paying so much money to have a professional shop assemble my shortblock, i want them to fix it. If i wanted to do everything myself i would have. I just want a motor that lasts!!!!!

 

[TopGun8818]

Just take the motor back if they are telling you that they will inspect it and so fourth as part of the warranty. If they screw you over by not standing by their work. Then go ahead and identify the mystery shop here so we all know who not to take our motors to. It's not good to tarnish a shops name but if they screw you over and have already messed up three motors - then it is a clear sign of a bad shop. I remember my buddy had a shop do all his work (fabrication, install, rebuild etc). Anytime something went wrong they would find some reason to blame my friend for the part going out and so fourth being it was a 10 second car and it's prone to break things. I as well had some issues after my full motor rebuild and install but the difference was that I was the annoying squeeky wheel that would come in and show them what they messed up on and demand for it to be fixed. Ex. I had a loose motor mount screw right after the motor got dropped in - they replaced it with an ARP one they had in stock the same day as I waited. I also had a leaking valve cover - they replaced that the same day as well with another one as they knew it was due to over torquing it (Guy got fired as this was like his 5th one in a row along with other things). I haven't said anything bad as they took care of the problems in my car. In your case - their attitude towards addressing the problem is what's going to make or break their reputation with you along with other dsm'ers on here. That's why I suggest for you to take it back to them and see if they stand by their work.

Just realized how old the thread is - can you tell us how it turned out!?

 

[sidewaystsi]

The only issue that i had was i have a 6bolt block with a 2g head and using a 6 bolt cam angle sensor and a 95 eprom ecu and 96 wire harness i got a random multiple misfire code if i would cruse after about 500-600 miles . I was told to disable the cyl misfire check for that because of my 6bolt swap. I did that and the car runs just fine. There is no noticeable vibration, I have the idle turned up to 1000rpms to help with the cams, poly mounts, and lightweight flywheel. Helps for dive ability.

I wonder if this is trying to tell us a story.Is it possible the tripped misfire code was legit, say the "now bad cylinder" was recieving poor/no spark at the cruising times causing excessive fuel to load up in that cylinder and wash her down.Maybe a faulty fuel injector sticking open.Seems a bit out of place to only have one cylinder carbon'd up whith low numbers while the others are happy.

Just realized how old the thread is

Oh yea nevermind