Found why chain was making noise! + ?s

dlagerstrom · 04-01-2007, 10:58 AM

Well, I quit driving the car when I figured out that the 'rattling' noise was probably the timing chain.

Pulled the engine and removed the timing chain covers. Here is what I found:

The pieces of the broken ramp are big enough that I don't think I have small parts rolling around in the case. But I will check the sump extra closely.

Now onto the question.

I have the tensioner update and new ramps to put in.

Everything I have seen on the ramps says to put the brown ramp in the lower right spot.

As far as I can see, the only ramp in the right chain housing is the one that broke and I wouldn't call that one 'lower.'

Am I missing something? I can't seem to find any images showing exactly where the ramps go.

TIA.

oldE · 04-01-2007, 11:52 AM

Look VERY carefully for chain ramp bits. They will be in there.

On the right side (pictured) just peek into the crankcase half. You should see the ends of the upper and lower ramps next to the chain.
They are held in place by through-bolted studs which are removed from their positions just outside the image you posted. Similar set-up on the other side.

Les

BURN-BROS · 04-01-2007, 12:20 PM

The chips will most likely stay in the timing chain area. Replace all your ramps at this time if you were not thinking of doing so.

dlagerstrom · 04-01-2007, 12:48 PM

So the brown ramp is the lower one that is inside the crankcase?

I am going to replace all ramps. I will do a thourough search for ramp bits.

Thanks for the help.

jmohn · jmohn's Garage

Do you have Wayne's 101 projects book? It gives very clear pictures and description. In your picture, if you follow the lower portion of the chain into the crankcase, just inside the crankcase and below the chain you'll see the ramp in question. This is just from memory, but I think you'll need to support the engine and remove the mount to remove those bolts to remove and reinstall the new ramp. Remember to orient the ramps corectly, I think the ones closest to the crank have the long end pointing at the crank and opposite for the outboard ramps.

Good luck,

Jerry M
'78 SC

911pcars · 04-01-2007, 01:31 PM

I'm sure plastic chain ramps have broken before, but this is the first photo I've seen of such an occurrence. Before the plastic versions, the ramps were made of a rubber/EPDM material that hardened with age/miles and broke with much frequency.

You're fortunate. A piece of ramp could have lodged between the sprocket and chain and caused the chain to skip resulting in a valve-meets-piston situation. It happened to me once upon a time.

I suggest getting some basic Porsche repair manuals to complete this repair as well as many others you'll eventually need to do.

Sherwood

Walter_Middie · Walter_Middie's Garage

Dave,

Quote:

I can't seem to find any images showing exactly where the ramps go.

There is a good picture of the chain ramps - including the brown one - in Wayne's book:

How to Rebuild & Modify Porsche 911 Engines.

Page 138 picture 3-39.

dlagerstrom · 04-02-2007, 05:57 AM

Thanks Rex, that was what I was looking for. I guess I need to finish reading that book as I put the engine back together!

All the other references just said "lower right" and the picture in my mind was more right than the ramps in the case. Usually I read about it before doing but in this case it just confused me.

Thanks to all for the help.