Jump to content
  • When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

engine help


wess02

Recommended Posts

69 2002 32/36 weber

121 ti head

flat top pistons

stock cam

took the car out for a spin yesterday. it was funtastic! ...untill the gas pedal stuck and the engine over revved between 5-6000 rpm's. i shut off the engine as fast as i could but damage had already been done. pulled off to the side of the road. unstuck the pedal. went to start and the engine instantly revved to 3000 rpm, killed it. wait a few minutes while i double checked linkages. then tried again, same thing.

a friend drove past to lend a helping hand. i caught him up on my situation and we went to try again. it idled about 14-1500 rpm and drove it back home 3 blocks away. noticed a knocking sound and lack of power.

compression test right away. and got these numbers

after taking a drive____________before taking a drive

#1----135____________________#1----135

#2----120____________________#2----145

#3----145____________________#3----145

#4----125____________________#4----145

took the valve cover off and checked the rocker arms. noticed a few were WAY out of spec (loose). grabbed my .007 feeler gauge and checked ALL the rockers. that addressed the knocking.

compression test again.

after checking rockers

#1----120

#2----115

#3----120

#4----120

have not checked timing

have not checked for vacuum leaks

started the car today.

notice a rough idle

and a fumey cloud out of the tail pipe.(might be burning oil?)

shut the car off to answer my phone, havent been able to start it again.

when i was out driving. i heard a loud BANG, but cant remember if it happened while the engine revved or after i shut it off. it def. came from the engine.

hoping a few of you could point me in the right direction (C.D, Mike and any others i forget to mention.)

this was a new engine <100 hours on it. built by a reputable shop in the area. and ran BEAUTIFULLY until this happened.

stock used crankshaft (within spec)

first overbore flat top pistons bought new from bav

new rod and main bearings

brand new stock cam bought from bav.

new water pump

new oil pump and chain

new timing chain and guides/tensioner

list goes on.

i feel like shit.

thanks for the help guys.

how she ran before the drive. will post one of how she runs now, soon

Link to comment
Share on other sites

If it only went to 6000 I doubt you have any serious problems. Even if it went to 7500 as long as you did not bust a rocker arm I can't believe you did any damage. You need to check everything, the fact that the idle was way up makes me think you have a throttle linkage problem. Look for vacumme leakes and make sure the engine did not move a lot on the mounts (broken?) and maybe hit the dist cap on the coil (seen it done) and crack the cap.

Did you check the compression with the throttle open?

1970 1602 (purchased 12/1974)

1974 2002 Turbo

1988 M5

1986 Euro 325iC

Link to comment
Share on other sites

Update:

checked the timing. thats still good.

checked for vacuum leaks with starter fluid, sprayed around the base of the carb intake ports on the head, and the deck where the head and the block meet(as best i could) with no affect, on the brake booster and hoses too. nothing.

pulled spark plug wires 1 at a time and the engine would stumble when each was pulled.

incredibly difficult to get a warm start out of it and i have not touched mixture screws on the carb. the engine REALLY moves around in the bay when cranking.

Link to comment
Share on other sites

Why is your compression so low on a fresh rebuild? Did you adjust the valves with the engine dead cold (sitting overnight)? Get a hold of a vacuum gauge, that will be better indicator of vacuum leaks as well as timing, carb, or valve train issues.

And just to confirm, was the noise you heard a slow knocking, or fast tapping? I will assume fast tapping because the valve adjustment took care of it. Just for kicks, pull the valve cover again and check for broken springs. You'd have a misfire if that were the case, but it won't hurt to check.

If you can, post up your vacuum reading and what the needle does when it's idling, holding at 3500rpm, and when you snap it open to WOT and back closed quickly. Also give us an oil pressure reading.

1971 BMW 2002

38/38 DGAS

292 cam

TEP 4-1 header

Ansa Sport muffler

Bilstein Sports

H/R Sports

Full Urethane

Bavaria Control Arms/02 Tension Rods

IE adjustable sways

15x7 König Rewind

Link to comment
Share on other sites

im going to pull the head, i got a few opinions saying i might have floated/slapped a valve. the valve springs were one of the items NOT replaced. and i heard a loud BANG from the engine before the knocking. wen i get some more time i will dive into it. il be busy for the next day or so.

Link to comment
Share on other sites

Jimminy Christmas! Pulling the head because of what you heard?

Do some more looking. I bet there is something simpler.

John

Fresh squeezed horseshoes and hand grenades

1665778

 

Link to comment
Share on other sites

The knocking is your parts salesman at your door. He is persistant and you might as well take it apart.

A radiator shop is a good place to take a leak.

 

I have no idea what I'm doing but I know I'm really good at it.

Link to comment
Share on other sites

Take it slowly. Don't make a rash decision to tear it down yet. Check the cam and crank and see if both are at TDC at the same time. If they are, you're probably not too bad.

How about pulling the coil wire from the dizzy and taking out the plugs, then turning the engine over with the starter? Watch and see how quick your oil pressure light goes out and listen for strange noises.

Then start it for real and listen. Run in up to 3000 and listen.

I feel your pain. Last summer I decided to replace all of the hoses and water pump on my e46. The little metal clips that BMW uses to hold the hoses on the E46 are total shit. They look like they're engaged in their little slots, and it felt tight, but my lower radiator hose backed off of the radiator on the Interstate at 70 mph after 3 days of driving. The temp gage went to full hot before I saw it and shut it down (who stares at their temp gage driving down the highway?).

It wouldn't restart when it cooled off (with new water) I love the car, and it was nearly paid off, so I bought the bullet and replaced the engine. I probably should have parted it out and bought an E30 or 02, but I SPENT $8,000 INSTEAD. So don't feel too bad. The M10 is like a tank; the M52 is like a house of cards.

John in the Columbia River Gorge

1976 2002 Chamonix/Navy - SOLD

2001 330i

Link to comment
Share on other sites

iirc the old spring was reused, but new chain guides were installed. with the head pulled, im having a very difficult time finding damage on pistons and valves. leaving me to also suspect the chain may have jumped.

can the lower timing chain cover be removed without draining the oil?

head is pulled. found a small divet in #1 piston. #1 and #2 exhaust valves have small pieces missing from the edge of the valve face ( away from where the valve seats). timing chain didnt move but i marked it and will double check when i reinstall. new head gasket, check compression and pray i didnt blow piston rings.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Upcoming Events

  • Supporting Vendors

×
×
  • Create New...