Cylinder Head rebuild, what could go wrong?

Tiny
PHILIPEMAD
  • MEMBER
  • 1991 TOYOTA CROWN
Last year my dad made a mistake be sending our Toyota Crown 1991 5M carburated engine for a cylinder head rebuild to an unexperienced mechanic just because he charged cheaper.
The thing is after the job the car was:
-Noisier, sounded a liitle bit dirtier (Fixed by replacing exhaust manifold gasket)
-Car stalled when left running for about 20 min (Fixed by replacing the fuel pump)
-Now is the main part, the torque is lost and acceleration is very weak compared to prior the rebuild
My question is what could've gone wrong?
What did he do or didnt do that caused a severe loss in engine power
Valve lash adjustments?
Timing chain postion?
IDK but I would be grateful if you could predict what might have happened to cause this
Thank you
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Monday, May 6th, 2013 AT 1:55 AM

3 Replies

Tiny
CARADIODOC
  • EXPERT
The logical suspect would be the camshaft timing is off by one tooth. Any mechanic, inexperienced or previously inexperienced, should be given the chance to recheck his work. The guy who did the work could become one of the best mechanics around if people give him the opportunity to sharpen his skills. We all started out with no experience.
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Monday, May 6th, 2013 AT 3:03 AM
Tiny
PHILIPEMAD
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Thanks for your reply
So can this be a DIY job?
I live in Saudi Arabia, Mechanics here arent what you think, I mean if I go to him for a fault he made it he is not gonna take responsibility and will simply charge you extra for fixing it. They dont Warranty their Job
The camshaft timing belt is on the inside of the engine so any idea how to free it and which position should it go onto?
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Monday, May 6th, 2013 AT 4:26 AM
Tiny
CARADIODOC
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I'm in the U.S. And mechanics here have an undeserved bad reputation because of a small percentage that are dishonest, just like any other profession, but all the good shops warranty their work. The trouble is you often don't know for sure if a new problem is caused by the recent repair or if it's just coincidence. No one likes to be blamed, and when it's not something the mechanic caused, it can be hard to convince owners of that.

It sounds like you could build a thriving business if you gave customers good service and warrantied your work. The strongest businesses here are those that put the needs and best interest of their customers first. The profits come shortly after that from happy repeat customers who spread word-of-mouth advertising.

Some people seem to think it's a character flaw to admit you did something wrong, especially when it affects something as expensive as a car, but in reality it takes a strong and confident person to own up to their mistakes and correct them. Those are the people I respect. Consider going into that line of work.

The best I can suggest is to get a copy of the manufacturer's service manual. There will be diagrams showing the timing marks and instructions on how to take apart what is necessary to set that timing. You can also buy a subscription to online service manuals but I don't like them as much as paper books. Mitchell is one. We have links to them on this web site. All Data is another one that is real popular. You might even ask your mechanic if he subscribes to one of them and will print the relevant pages for you. Here we spend over a thousand dollars a year for access to the information. For individuals like you they offer access to one car for a year for around $30.00. You might try bribing your mechanic with a box of cookies. (Chocolate chip)!

My community college also had subscriptions to both services for five computers. One of them was in the library to make it available to the general public. That was because those schools are funded in large part by the tax payers and that was one way to give back to them. We have to pay for the printouts but that is real cheap.
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Monday, May 6th, 2013 AT 8:58 PM

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