Hi guys,

I've been searching for the "right" 993 for the past two years and have yet to find one. However, I've been more diligently searching for one recently and came across one example w/ a complete topend rebuild. The owner sent me his rebuild receipt and I found the following items were replaced:

- Piston rings
- Valve guides
- Valve stem seals
- Main bearings
- Main bearing oil seal
- Connecting rod bearing

Does it sound like a normal topend rebuild? Seems very excessive and makes me question the engine's health prior to the rebuild. From searching this forum, I found that the reason to replace the piston rings is only if the car smokes. (am I right?) What about the main bearings, valve stem seals and CR bearing?

Thank you in advance.

Jack

 

Jack,

There are many on this forum much more qualified to answer your questions than I. That being said, those receipts represent MUCH MORE than a top-end rebuild. Normally, top-end means the heads only... Not the jugs, not the rings, and certainly not the main bearings!

Something BAD happened to that engine... I suspect something very bad!

 

Michael, I have the same gut feeling as you do. Is there a possbility that the owner chose to replace all of the above simple because the head was off the car anyway?

 

Nope... Not a chance! To get to the main bearings, you have to split the crankcase... This was WAY more than a top-end rebuild!

 

I admit that rings are a bit excessive but there is an argument for splitting the case and resealing while everything is off the motor already. How many miles are on the motor?

 

118k, sorry I didn't post that in my original post. Rebuild was done at 105k.

 

Well... at 105K miles, if you're in the engine anyway...

If the car was burning oil and needed rings, they may have seen some minor or moderate scoring on the bearings and went ahead and replaced those too. Who knows? You should ask the seller.

Me, I wouldn't be all that worried. If the engine had some damage and they had to do all of that, well, hey, it's fixed now! No worries about that stuff going bad anytime soon.

Michael

 

If it had sucked a valve, you would see new pistons on that list. Seized because of no oil pressure, I am sure there would be more on that list.

My guess is that the owner was sold on a complete refresh, while they were there, so to speak. I see it happen all of the time. In other words, the owner is told XXX for the top end, and only just XXX more for the bottom end and reseal. Kinda like at the bar "would you like an extra shot for one dollar more"

 

Thanks for the input.

May I ask which bar do you go to?

 

My only input is that I find it odd that at least the six exhaust valves themselves don't appear to have been replaced. I know mine were severely pitted at 40k miles and were replaced during my top end rebuild... seems like due diligence would dictate replacing them at 105k "while you're in there".

 

chris is right. I needed new valve guides, so a top end was necessary. IIRC it was only about $1200 more to do the bottem end also.

 

Hi,

From the receipt, I can see the rebuild prodecure calls for "grind valves", I'm assuming the mechanic did not replace the valves themselves.

 

The owner told me that he planned on keeping the car for a long time, but due to unexpected emergency, he's forced to sell the car.

 

You don't have to replace valves unless they're out of spec. They can sometimes be ground or machined back into spec.

When I had my SC heads done, it turned out 1-3 intake were all cooked because a previous owner had forgotten to reinstall the air dam on the back of the alternator, so the clockwise-spinning fan only cooled the right bank. A few yrs. of driving in TX and FL like that = new valves.

 

I'm guessing I shouldn't worry about it so much as long as there's records, right?