List your hardest mechanical challenge and the final Fix for it!

[Kern Dog]

Kern Dog, wow; you had 10 years of frustration from 2005-15. What was the solution, hi octane fuel or?

It was a strange thing. Common sense would have told me that the compression ratio was not to blame. I tried different distributors, ECUs, different timing settings, springs in the distributor and even 100, 104 and 110 octane fuel. Only the 110 completely eliminated the knock. I pulled the heads and found zero evidence of detonation. I was told and I read that detonation leaves sharp impressions in the pistons as if they were poked repeatedly by an ice pick. All my pistons looked fine. no marks but just discoloration from some oil burning due to a poor fitting intake manifold.
Finally, lowering the compression was the fix. I could have pulled the engine and swapped in dished pistons but instead, I had the heads off to be ported and used a .075 head gasket to drop the CR to 10.07 to 1. No problems since.

 

[munger77]

Wow, never heard of that kind of problem of solution before Kern Dog!

 

[mopar 3 B]

That ran ranks right up there with "not too many out there would have figured that one out!"

I guess no one checks friction disk clearances?

 

[Kern Dog]

My pistons before cleaning and after.
No marks at all. I know I heard detonation but there was no evidence of it.

 

[dvw]

When my wife was in High School she went to tune up her VW bug. One of the spark plugs broke the hex off leaving the threaded portion in the head. She pulled the ceramic out and spent 2 days filling the plug from the inside out with a jewelers file. Pulled the halves out installed a new plug. Good to go. I new I was marring the right girl.
Doug

 

[khryslerkid]

When my wife was in High School she went to tune up her VW bug. One of the spark plugs broke the hex off leaving the threaded portion in the head. She pulled the ceramic out and spent 2 days filling the plug from the inside out with a jewelers file. Pulled the halves out installed a new plug. Good to go. I new I was marring the right girl.
Doug

And those plugs weren't that easy to get to. Champion was known to seize in those aluminum heads. We got in the habit of useing Bosch for that reason. We use to find a lot of them cross threaded also.

Nice having a partner in life who enjoys the same things as you do!

 

[Cranky]

It was a strange thing. Common sense would have told me that the compression ratio was not to blame. I tried different distributors, ECUs, different timing settings, springs in the distributor and even 100, 104 and 110 octane fuel. Only the 110 completely eliminated the knock. I pulled the heads and found zero evidence of detonation. I was told and I read that detonation leaves sharp impressions in the pistons as if they were poked repeatedly by an ice pick. All my pistons looked fine. no marks but just discoloration from some oil burning due to a poor fitting intake manifold.
Finally, lowering the compression was the fix. I could have pulled the engine and swapped in dished pistons but instead, I had the heads off to be ported and used a .075 head gasket to drop the CR to 10.07 to 1. No problems since.

Did you ever check what your cranking PSI was? I'm thinking that maybe the oil issue was your part of the problem if not all of it. My last high compression engine to work with on 93 pump was 11.25-1. It did run better on race fuel but it did fine on the street.

My biggest problem is digging into something I've never done before and procrastinating until the issue won't let me anymore. Then I find out how simple it was and there was no reason for putting it off but one that kicked my butt was a TQ carb. After many years of great service on my 71 Cuda, the TQ finally needed to be rebuilt. I've done a few over the years but never bead blasted one and that created my problem. It got a light blasting knowing that the TQ had small passageways so it got a good blowing out before going back together. It ran like crap so it came back apart......3 times! Finally checked exhaust temps and found 4 cold cylinders, two on each side so off it comes again. The 4 cold cylinders all ran off one side of the carb. This time the little passageways were cleaned with a torch tip cleaner and found some bead blasting crap inside. Threw it back on and the world was ok again.

 

[Kern Dog]

Oh boy...cranking compression!
I had a reading average of 210-215....THEN I realized this:
The gauge that I was using started at 30 psi !

 

[Kern Dog]

This was like the man that wore two watches....he was never quite sure of the time.
With the other gauge, I was in the 188 range. The switch to 1.6 rocker arms closed up the spread between the cylinders but did not lower the numbers much, if at all. A switch to a more radical cam made it worse because even with a rougher idle, it apparently had an earlier intake closing point. This was a real learning experience and although it was a real pisser at the time, I do appreciate the lessons that it taught me. I had threads here, on FABO, Moparts, DC.com.....I was reaching for help in all directions.
I had several, I do mean several ....respected people claim that a switch to the thicker head gaskets would not help. They swore that it would eliminate any quench I had and make the situation worse.
Sometimes it can be frustrating when you try to help people and they seem to deviate from your advice and head down what YOU think is a wrong path. I went with the thicker gaskets and the problem was gone instantly. My cranking compression went from 188 average to 160. Idle vacuum dropped a bit too due to the lowered compression. I even tempted trouble afterward by switching to a milder cam, one with an even earlier intake closing to tame the engine down a bit. THis resulted in an increase of the cranking compression to 170 but the idle vacuum went from 9 @ 900 rpms to 16 @ 900 rpms. I was finally able to run the power brakes without a brake booster pump.
If I were to rebuild this engine tomorrow, I would choose dished pistons and standard .039 head gaskets. There is probably some power gains to be had with a little more squeeze and proper quench but for now, it isn't knocking and it runs pretty strong.

****Here is a link to one of my threads here about my engine troubles...***
http://www.forbbodiesonly.com/mopar...-cr-and-a-509-cam-i-guess-i-screwed-up.54949/

 

[Fran Blacker]

Oh boy...cranking compression!
I had a reading average of 210-215....THEN I realized this:
The gauge that I was using started at 30 psi !

View attachment 553818

Always thought that a gauge that started a 30 psi just wouldn't read under that? Am I misinterpreting what your saying?

 

[Cranky]

Always thought that a gauge that started a 30 psi just wouldn't read under that? Am I misinterpreting what your saying?

Looks to me like the gauge starts at 0 but the needle is resting at 30 so it'll most likely be reading 30 psi high....

 

[flypaper]

not a mopar
i had a gmc that had a very fragile fuel system
that went thru 4 tank pumps when i had it
in the end I became a expert with it in the 485k miles i threw on it before i sold it.
one time it had me stumped no start for a few days before i figured it out
when it had about 120k on it
no start,it was getting no fuel,new fuel pump,power was at the injection spider
and i would hear the tank pump come on and off which threw me off
as it seemed like it should all be working and it wasn't
i was starting to look around for a wire schematic looking for a direction
and digging out a meter
i thought maybe it could a fuel pump relay? and that was behind the glove box.
(just guessing at this point as i had a similar problem like that in a ford truck years ago)
so for some reason i grabbed the harness going to the fuel pump relay and I moved it around
as I cranked the engine and bam got lucky it started!
so i knew the problem was in that harness
i peeled back the wrap around the wires going to the relay
and could see that the connector was fried.
went to my junk pile found another connector just like it
from a impala harness and i spliced it in
and never had that problem again.

 

[khryslerkid]

not a mopar
i had a gmc that had a very fragile fuel system
that went thru 4 tank pumps when i had it
in the end I became a expert with it in the 485k miles i threw on it before i sold it.
one time it had me stumped no start for a few days before i figured it out
when it had about 120k on it
no start,it was getting no fuel,new fuel pump,power was at the injection spider
and i would hear the tank pump come on and off which threw me off
as it seemed like it should all be working and it wasn't
i was starting to look around for a wire schematic looking for a direction
and digging out a meter
i thought maybe it could a fuel pump relay? and that was behind the glove box.
(just guessing at this point as i had a similar problem like that in a ford truck years ago)
so for some reason i grabbed the harness going to the fuel pump relay and I moved it around
as I cranked the engine and bam got lucky it started!
so i knew the problem was in that harness
i peeled back the wrap around the wires going to the relay
and could see that the connector was fried.
went to my junk pile found another connector just like it
from a impala harness and i spliced it in
and never had that problem again.

Electrical gremlins can be a real pain!

We had a '80s Toyota in the shop that wouldn't idle. Ran fine other than that. The carb had a electric idle solenoid. Jumped a hot wire to it and it would idle fine. Disconnected and it stalled out. Went to trace the source of that wire and found myself in a sea of all white wires with not even any numbers on them. How the heck are you suppose to find anything in that mess? So I thought to myself let's think of the stupidest thing that a manufacturer would do. Check fuses. Yep one was blown, replaced it and the wire was hot again. The owner had already paid another garage over $200 for a carburetor rebuild, then replaced it with another carb before bringing it to me. I told the owner just give me $20 and go after the last garage to get your money back.

 

[Kern Dog]

Looks to me like the gauge starts at 0 but the needle is resting at 30 so it'll most likely be reading 30 psi high....

That is exactly what was happening. It made me think the numbers were WAY too high.