Is my engine toasted?

[Lee]

Out driving today, just after I shifted down into fourth while slowing for a speed zone, my '78 911 began making a hell of a racket...loud clattering...I'm not certain if it lost power, because I had it over on the shoulder as soon as possible, afraid to give it any more gas. I had it flatbedded home, and haven't done anything. I did start it up once, and it sounds like hell. It's not the chain out of the garbage can noise...it's more like the sound of a small caliber automatic rifle. The tow guy was certain it is a piston going, however it sounded like it was coming from behind the fan housing.

It was running great, I wasn't running it hard, it had plenty of oil, and wasn't overheating. It was in good tune, and has updated tensioners.

My question: is there a way to see what's going on without starting up the engine? I'm afraid I'm going to put a piston through the block, if I'm not careful.

Any help is greatly appreciated...I've been mourning all day long.

[Early_S_Man]

Turn the engine over by 22 mm wrench on the fan pulley nur. If it turns over 2 complete crank turns without any hard resistance spots, then there is nothing loose and hitting the pistons.

Let us know what you find.

------------------
Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

[campbellcj]

Ouch! What a bummer - sorry to hear it.

There are lots of things it might be, but the most likely are probably either a broken rocker or a bent/broken valve.

You didn't happen to over-rev it during that downshift to 4th, did ya?

Good luck,

------------------
Chris C.
73 914 2.0
70 911E Targa
campbell.chris@gte.net

[jabb]

Do like warren said... If it turns OK
remove the valve covers and look for a broken Rocker ar or a possible rocker shaft that may have backe out.

Good Luck

------------------

• Joe A.
• 84 911 Targa
• 75 914/6 3.0

[john walker's workshop]

pull the plugs and see if one is hammered. coulda dropped a valve.

[Lee]

Thank you, I appreciate y'all's replies. I've been too busy over the week-end and today to do much except think about it, but I'm going to turn the crank by hand, first thing in the morning, to see if it's as bad as I think it is.

The thing is, I wasn't really stressing the motor...I didn't miss the shift, and it didn't go over 4000 rpm on the downshift...so I'm hoping for the best. I have to tell you, my heart has ached since this happened Friday...I guess the only way to judge the real beauty of something is by how you feel when it's taken away.

Dan Crockett

[Britwrench]

Sounds like chain tensioner failure.. the "update" tensioner is not perfect and at the beginning of this year we had a box of ten brand new faulty units that we had to send back. I would pull the chain covers off and have a look.

[Jdub]

Is there something other than a valve in your cylinders? Or, is the sound that of a spark plug that is permitting gas to escapte past the threads? Pull the 'plugs then turn the engine over with the 22mm and carefully listen in each spark plug hole (get a nice long piece of tubing to do this). Any clatter should be investigated with a magnetic probe and a flashlight.

Good luck. This is a chance to think through upgrades on your '78. The SC is a fantastic car and even an engine rebuild is not enough reason to sell this model of Porsche.

Jw

[Vipergrün]

Originally posted by Britwrench:
Sounds like chain tensioner failure.. the "update" tensioner is not perfect and at the beginning of this year we had a box of ten brand new faulty units that we had to send back. I would pull the chain covers off and have a look.

What were the symptoms of the failures? When my pressure-fed tensioners were installed by the PO (by Redline), they had two tensioners fail, one from each side. Upon looking further they found it was because they had not *primed* the tensioner and it would not work correctly and appeared to collapse. They were able to work in the tensioner, re-insert the pin and install it. No more problems. I have a bit of chain slap still, so I am trying to figure out if there is indeed a problem with some of the tensioners.

Thanks
-Brad 80SC

[Britwrench]

We had them fail after installation, before installation, after priming etc...

Soon after that, the parts were back order...

We don't fit them anymore unless the customer insists and we certainly don't warranty the labor if they fail.

Yes, the chains rattle like the old tensioner failure noise.....