mystery of the stretched timing chain solved

[jerry S]

This topic came up about a year and a half ago.

http://forums.stangnet.com/showthread.php?t=638890&highlight=timing+chain+stretch

I had a new timing chain suddenly develop a lot of stretch in it. My mechanic took the engine down and found that the crank had been improperly balanced by Rombold's in PA. They simply did a half-assed job. My new guy was able to tell that the engine was not balanced just by feeling and listening. A trip to the machine shop confirmed it. The crank has been rebalanced along with the rods and pistons, something the US shop did not do.

In the mean time, I have a Pete Jackson (quiet) gear drive that was installed so no more stretch worries. It is good that the balance problem has been solved or I would have trashed the engine in no time.

 

[C0V3R]

How did he determine it was out of balance from observation only?

 

[jerry S]

How did he determine it was out of balance from observation only?

listening and feeling. It is like the custodian of my old grade school who knew what was wrong with the building's ancient steam boiler just by listening to the noises it made. In this case, the mechanic said that he thought the engine was out of balance by how it felt and this was confirmed when he took it down. The PA shop added heavy metal in a spot where you aren't supposed to add it and when they rotated the crank on the balancer, it showed. I guess if you do this stuff long enough and become expert enough at it, you just kinda know intuitively.

 

[66bluepony]

Chain

My opinion, engine balance does not cause chain wear or stretch. But valve springs and cheap chains do.

 

[10secgoal]

Did they check run-out on the crank, or check to see what the main looked like ?

 

[jerry S]

My opinion, engine balance does not cause chain wear or stretch. But valve springs and cheap chains do.

The valve springs came with the new Edelbrock heads and were more than adequate for the lift of the cam I was running at the time. As for a cheap chain, it was a Cloyes true double roller and I don't recall it being cheap.

Did they check run-out on the crank, or check to see what the main looked like ?

regarding the the run-out, the new mechanic replaced all the main bearings though as they showed a lot of premature wear after only 1K since the initial rebuild. He showed me some grooves on the bearings that should not have been there as they are essentially new.

A previous dyno-tuner took a #10 machine screw and bolted open the vac. secondaries on my carb and left me with a rich condition that was off the charts. My new mechanic said that this caused a lot of accelerated decrepitude on the cam and main bearings as the fuel just washed the coatings right off. I am guessing the out of balance condition might have caused the grooves.

 

[10secgoal]

Wow, I wish you lived here where we have good mechanics. I see this this all the time with you. That really sucks man. Looks like you found a good paint shop though.

 

[jerry S]

Wow, I wish you lived here where we have good mechanics. I see this this all the time with you. That really sucks man. Looks like you found a good paint shop though.

I got as much bad work done in the US as I did here. I finally found a good mechanic who knows his stuff backwards and forwards and is an honest guy too.

The mechanic in PA charged me for parts that were never installed and overcharged me for some that were (e.g., invoice listed $289 for a B-Cool radiator when what I got was a $169 Griffin universal radiator. I have several such examples). Also, when he changed from the Trick Flow to the Edelbrock heads, he never changed out the push rods and left me with push rods that were way too long for the Edelbrocks. He also overcharged me on the push rods by $100, saying they were Comp Cams Hi-Tech push rods when in fact they were plain old Summit brand push rods. He also charged me for Flowmaster mufflers but actually installed $14 Summit mufflers.

The machine shop in PA screwed up the balancing on the crank. They also put on the wrong crank pulley, giving me something for a chevy.

The Amsterdam dyno tuner is a thief and incompetent. No questions about it.

The new Dutch mechanic is a complete pro and an honest guy. He is fixing the errors of the Amsterdam dyno shop as well as the PA machine shop.

The body shop is expensive as hell but very competent. He told me up front that he is one of the most expensive body places in the NL. However, he is also one of the best. You get what you pay for.

There are incompetent bumble ***** both here in Europe and in the US and dishonest guys on both sides too and not just with cars but in everything.

For example, consider my wife's former US dentist. She had all kinds of problems with her teeth. A Chicago dentist gave her an implant after supposedly doing an extraction of a molar. However, he never extracted the molar. He sawed it off at the gum line and screwed a titanium post into the root. Ten years after, it caused all kinds of problems that required extensive oral surgery to correct. The dutch dentist was astonished that a US dentist could do such a thing. He remarked that "Not even 50 years ago in rural India would you find such bad work".

 

[jerry S]

oops

 

[10secgoal]

Wow, that sucks. I did forget about the PA guys. I know you guys have competant folks over there. There are more dishonest over here than honest I think sometimes. I used to work for one.