GermanEnthus

Hello. I'm new to the forums, and am looking to revive my sleeping beast from it's sad resting place. Hoping I can gain some valuable information, as well as provide some assistance to others as my knowledge base increases.

To start, I'm 27, have been a German auto enthusiast (hense the login name...) ever since getting into my first car, a 1987 BMW 325i. I've owned many older BMW's and made many friends in the German auto community. In July of 2003, my father and I acquired a low mileage 1974 Porsche 911, with quite a few tasteful mod's, a dream come true. When we picked it up, it had roughly 114k on the chasis, and about 9k on a fully overhauled motor, S suspension (F&R sway bars, turbo torsion bars), koni shocks, lowered and bump steered, and 7 & 8 inch wide 16" Fuch's . It needed (and still needs) a paint job, interior work, and brakes. We've since put roughly 4-5k on the clock since purchase and done minor work in the interest of restoring it to a street/track weekend car. Brakes have been fully overhauled with upgraded to the early 80's brake calipers, since the aluminum club race calipers were failing due to rust.

The car sat for a couple years while we priced and pieced together the brake upgrade, and unfortunately, had not thought to drain fluids from the motor because we were not planning on it sitting as long as it did. Before starting the motor for the first time in at least 18 months, we changed out the oil and filter with fresh Valvoline synthetic race blend and turned it over. The motor hesitated at first and made a startling rattle noise. Now comes the part where I confess my temporary ignorance... When hearing the rattle sound, we shut it off immediately, thought about the sound for a moment, couldn't identify it due to our minimal knowledge of the boxer motor, and started it back up to gather further data. When hearing the sporadic rattle, we tried to identify where in the motor it was coming from, which seemed to be around the upper valve cover area, , gave it a few low RPM rev's, checked the fan, which seemed to be moving freely and normal, and shut it off after 2-3 minutes. The car has not moved since, as we did not have the time or money to invest in shop research or revival.

I'm tired of seeing her sit and have thought about pulling the motor myself, opening it up and checking the pistons, cylinders, valves, etc. to see if I find anything out of the ordinary, like scoring or any damage. I can't think of anything small that would cause such a noise, and am terrified to start it up again. I'm concerned that if I take it to a shop that I'll get charged a ton to identify the issue, and if I end up having to replace the motor, I'd be stuck with a R&R bill and back to square one. I don't have the $5-7k necessary for a 3.2 swap, which I'd eventually like to do... it's just not feasible at the moment.

The motor was rebuilt by a reputable local shop with some great internals such as higher compression Mahle S spec pistons/cylinders, bumping compression from 8.0:1 to 8.5:1, new valves, rod & main bearings, chains and turbo tensioners, new clutch disk, SS heat manifold exchangers, and a front wheel well oil cooler. The mileage since the rebuild (about 14k) to my knowledge was pretty light, with regular maintenance for the first 11k miles. In my opinion, there's a lot of money invested in the motor, and feel like it shouldn't be having these issues with so little miles.

I can imagine this may be difficult to identify the root cause of the noise, just hoping to get some suggestions on what road I should take. I can potentially spend $2-3k to get it running now, and of course budget more money for a 3.2 swap in the future.

Thanks for reading!
Jason

DWalker

Need a better definition that "rattle". If its in the head I would first check the valve adjustment as I would wager its long overdue. If I may humbly make a suggestion- spend some quality time with the car or sell it- dont let it sit and become a lawn ornament that you will "one day" get around to. So start by doing a bit of research on how to check and adjust the valves (lots of info out there) and then we can go from there.

GermanEnthus

The car's not going anywhere. So no worries about it becoming a lawn ornament...

Thanks for the suggestion. As for a better description of the rattle, it's been a couple years since it's started, so I unfortunately can't recall the exact noise, which makes this even more difficult to identify. Even if I adjust the valves, finding that they're way off, what other things should I do before cranking it up, to minimize further potential damage?

I've started doing some research on Pelican Parts site, looking at tech articles and will look further at valve adjustments.

I appreciate the feedback.

Steve Weiner-Rennsport Systems

Hi Jason,

Welcome to Porsche ownership,...its a great community,...

Without hearing the engine, I'd guess that you may have chain tensioner failure and they may not have installed tensioner guards which prevent total collapse in the event they lose their charge of oil.

I would remove the muffler and chain covers to inspect each chain and tensioner to see what you have. Do NOT run the engine until this is resolved.

I love the '74 911's for their light weight, simplicity and performance.

GermanEnthus

Thanks, Steve! I appreciate the warm welcome and helpful advice. I'll look into the chains/tensioners as well.

MUSSBERGER

Steve's forgot more than I'll ever know and chain tensioner was my first thought

theiceman

oh yeah rattle .. chain tensioners would be the first place to look , The really good news it is "relatively" inexpensive to fix and it is something you would do with that age of a car anyway given the circumstances. So it is all good.
It can be domne in the car or you can spend a couple of hours taking the engine out and do it at your leisure... Have fun with it ...

MUSSBERGER

I was think'n yesterday when I was looking at some paint charts that you never see any brown 911s anymore.

theiceman

new ones or old ones ?

dshepp806

noise source..where? VC's? Valves would sound a bit tonally different (tapping) than tensioner (rattle), as having a different source location..

As Steve stated, you sure don't want to start her without knowing all is well with the tensioners...I hear that could be big bucks (if it is, in fact, tensioner related).

I've always been intrigued with the pro's abilities (EXPERIENCE) to corrolate (accurately) noises related to the mechanical side,..having done it for so long......I'm an audio engineer and think this is the coolest sheeit when you get a chance to really sit down with a good P-wrench.

Best of luck..

Doyle

GermanEnthus

Thanks all. Planning to open her up this coming weekend and will let you what I find. Hoping it's just a stuck tensioner(s). Yea, the brown 911's do seem kinda rare these days. I have the original rear hood panel, in near perfect condition and it's kind of a cool color, for being brown. Friends always call her the uber-pooper though, so eventually the brown will need to go.

pjc

Brown is cool - it was THE colour in the mid '70's. If you want a red car BUY a red car, why buy the brown in te first place? The colour is part of the history of the car and the marque.

Oh ya - sounds like tensioners - don't think you mentioned having the oil fed type as part of the rebuild?

DON'T try to start the engine again!

PJC

rusnak

A rattle could be loose or worn chain tensioners, possibly also chain wear (stretch), but you said it was recently rebuilt. That stuff except for the idler arms would be replaced right?

I had a chain tensioner fail in the 914-6. It was not a rattle so much as a sound like a large chain being dragged out of a trash can. Sort of a half grinding, half banging sound. I shut it down and pushed it to my mechanic friend's house. He undertook the huge job of replacing everything including re-timing the cams for about $800 parts included.

theiceman

Hey someone has to defend us

GermanEnthus

Nice! Yes... that WAS the color of the car, many moons ago...

As for PJC's question... I'm not sure I understand the question about the oil fed as part of the rebuild? Nothing was changed with oil delivery during the rebuild. The car was given the upgraded oil cooler prior to the rebuild.