Refreshing the Engine

lamaker · 12:37 PM

NEED SOME ADVISE: PLEASE READ MY OTHER POST BELOW AS WELL.

I finally got to take the 912 out yesterday for a long drive in nice weather and I feel that the engine is weak....I know they are not the most powerful engines to start with but something is missing.

My garage did a compression test and confirmed that it is "tired".

I am thinking of having my garage rebuild the weber carbs and then replace all the gaskets and seals in the engine.

At a labor rate of $85/hour and an gasket set from Pelican, what total cost am I looking at and what can I expect in terms on a gain in perfomance/feel after this is done...

I am basically bringing this car back from the dead...it was parked in the 80's...engine started to run again in the 90's but never got on the road and now I have it...I already replaced all the floor pans that were rusted, new tires, replaced all the transmission parts, worked on the interior, changed all the fluids and I will eventually get a paint job but I do not want a good looking car that drives like crap.

Opinions and thoughts are appreciated.

sabby · 02-24-2010, 09:49 AM

Rebuilding carbs and replacing seals and gaskets won't resurrect a "tired" motor. At the very least, you are looking at a top end rebuild (heads/valves) and likely pistons/rings/cylinders. Any idea how many miles on the motor? Also likely that even doing the above is throwing good money after bad since the bottom end (crank/bearings) could be worn. A "tired" motor diagnosis usually means a complete rebuild---$8000-12,000 by a reputable shop (ouch!)------regardless, don't waste your money on what you originally propose...Good Luck!

sabby · 02-24-2010, 12:00 PM

BTW--Is this what the shop you took the car to suggested? Curious what the specific results of the compression test were? What area of the country is the car located?

lamaker · 02-24-2010, 12:37 PM

Sabby...I am in Hilton Head Island, SC....the shop is real good (BPC Motorworks) and he just rebuilt a '66 Polo Red 912 that he is currently getting painted.

The engine has about 86,000 miles on it...I am going to drop the car off tomorrow and see what he suggests...I will also then have a chance to drive his '66 to compare to mine...

My motor just does not want to idle properly, jumps out of first and second gear and overall does not sound right.

I found out that the carbs were recently installed in the car without being properly tuned and they might not even have the right valves, etc.

Here is a typical problem I have: The engine will rev really high when in first or neutral for about 1 minute to about 4,000 - 5,000 RPM and then go down to about 1,500 RPM and then shut down....I am thinking maybe the floats are messed up?

Any advise?

sabby · 02-24-2010, 01:59 PM

Jumping out of gear= usually bad synchros in the tranny or transmission mounts. The rev problem could be carb or distributor related--what model # distributor are you running? The shop should be able to diagnose all this stuff. Also log on to/join the 912 registry. Do a search on the 912bbs--lots of very knowledgable 912 owners in your part of the country.... 912 Board

sabby · 02-24-2010, 02:06 PM

...Also, something as routine as a tight valve could wreak havok on motor performance. As I said, a good shop that does a lot of 4 cylinder porsches should have no problem giving you you a comprehensive diagnosis regarding the problems you describe....................

912UK · 912UK's Garage

this all sounds all to much like 912 ownership from new people..

we have all been there and your car sounds like you need to get some work done but doing gaskets is not going to do anything other than sort leaks..

Gearbox problems are gearbox problems and at the end of the day they cost money

Engine wise there is alot of basic stuff you can do before you get carried away, but there comes a time when an engine needs real money and thats in the region of $8000-10000 to do right.. GOOD CARS SELL , bad cars linger if your selling then be realistic if your not save up and do it right mind you there is alot you can do your self!! to save £$1000's

with 616 motors do it once the right way take a short cut or let a turkey work on it it's going to cost you double I know of some on here in the UK that her engine now owes her some thing in the region of £25,000 $40,000 because the first one was a total &*£$ up by a so called expert so much so she needed a new crank!! so like we say do it once do it right $8,000-10,000 that's 912's for you..

Jerry1 · Jerry1's Garage

I just tore down my 67 912 and found worn out pistons and cylinders. for about 700.00 you can get a new big bore set here on Pelican. I was told the original piston were only good for about 80,000. You might be able to get away a top end for under a 1000.00 if all is good with the heads if you do the work your self. The bottom end is probably good for an other 80,000 just my opinion no expert.

912UK · 912UK's Garage

it's all about OIL changes and how it was looked after.. 80k seen more and there are pleanty about to show it..just look at cars that have 105,ooo on the clock and then they stand for 15years or so and then suddenly sprung into life and then on ebay and being sold as ORGINAL CARS

lamaker · 02-25-2010, 05:43 AM

thanks for the advise everyone....I am going to just have an inspection fo the engine done and will go from there...the big bore kit does sound interesting for the price.

Jerry1 · Jerry1's Garage

Any update on the engine. Does it need to be rebuilt if so what are you going to have done.

lamaker · 03-18-2010, 05:31 AM

Hi Jerry...good timing...

I picked up the car yesterday from my mechanic and all he did was adjust the valves and replace some seals. What a difference (remember, my car had not been on the road in 17 years).

Before, the car was stalling, backfiring, and had barely any pick up. With a simple $150 fix, it is a totally different car. While my mechanic and I still believe the engine is tired and will probably need new pistons, I am pretty happy with the way it is running now. It is real nice to come to a stop light and not have the car die on me. It idles great just above 1100 RPM.

I will be doing an oil change this weeked. We did find that my Rear Brake Caliper is now leaking so I need to address that but it is fine for now.

I have now found someone to assist me in stripping and painting the car (on our own, he is very experienced with DIY painting) and I will be starting to install the new headliner this weekend.

Lots to do. Want to get the car ready for this years Conquers here on Hilton Head in November.

Jerry1 · Jerry1's Garage

That's great to hear. We always assume the worst but its great when its not. If the caliper is leaking I rebuilt mine its not that hard it may just be the brake hose. Keep us posted on your progress.
Good Luck

lamaker · 03-19-2010, 05:05 AM

Now may car seems to backfiring a bit...could this be my carbs? We did not adjust them after adjusting the valves....

Monkfish · 03-19-2010, 05:27 AM

I'm no expert either, but I bought a carb synchrometer from our host and balanced the carbs. Huge difference, much less popping. Next thing I did was clean and re-set the idle screws. Now the engine runs better than it ever has (well, it did, I've now taken it apart to fix some oil leaks).

Best of luck