TheSamba.com :: View topic - Reassembled the motor

Wed Nov 18, 2009 12:39 pm

I had a stuck valve in my daily driver (1974 standard beetle, stock engine except 009 distributor). I pulled the engine, removed that head, replaced it with a used head I had from a trade. Reinstalled the engine, did a valve adjustment, started it up - it runs, but it's SO weak - it'll only get up to about 35MPH on level ground, though it'll go 60 downhill without difficulty. I didn't change anything about the dizzy. I replaced the intake boots and gaskets for the carburetor, which may have removed my vacuum leak - the car idles now, which it didn't before. Both exhaust tips are warm after the car has run for a short while. I'm going to compression test all the cylinders tonight. I drove it to work today, but it was a painful process. Any ideas of where I should start checking?

Stray

Wed Nov 18, 2009 1:29 pm

Sounds like you need to re-torque that head. Probably very weak compression on half of the motor.

Wed Nov 18, 2009 1:40 pm

It's possible, but I did torque it according to spec, and double-checked each of the stud torques before I installed the engine. I'll check the four I can do without pulling the engine, and if any of them aren't to spec, I'll pull the engine out and re-do all eight.

Stray

Wed Nov 18, 2009 3:00 pm

did you check the new head? It may have needed work or machining prior to installation. Maybe a shim?

It makes sense to me that after the engine gets hot that you would experience more power since things are probably sealing up a little more.

Wed Nov 18, 2009 3:13 pm

Stray Catalyst wrote: It's possible, but I did torque it according to spec, and double-checked each of the stud torques before I installed the engine. I'll check the four I can do without pulling the engine, and if any of them aren't to spec, I'll pull the engine out and re-do all eight.

Stray

Yeah, same thing happened to me twice first engine I built,

until I realized that torque wrenches aren't always right, or even close/

Wed Nov 18, 2009 3:51 pm

did you do a valve adjustment? is it running rough or just no power? could it be possible you have plug wires backwards, slipped push rod, valve out of adjustment or not seating properly?

Wed Nov 18, 2009 4:00 pm

All of those are possible, and I'll check for them.

I did a valve adjustment after installing the replacement head. It was running fairly roughly - part of that may have been that I broke a muffler clamp, and haven't replaced it yet - but it idled, which was something it didn't do before. It had no power - I could struggle it up to about 35 MPH on level ground, crawled up hills in second gear, but downhill would go as fast as I wanted. It could maintain about 45 on a level stretch after gaining speed down the hill, wailing along in third gear.

I don't think it's the plug wires, I checked that three times. I did just replace them with a new set, so it's possible that one of the wires is defective. I'll try reinstalling the old plug wires to check that.

The symptoms aren't like they were with a stuck valve, but I guess a non-working pushrod would leave a valve always closed, not open - I'll also check that. If it weren't seating properly, wouldn't that feel similar to the stuck valve?

Another problem, probably unrelated - I drove it to work, but it wouldn't start after work - not even a click, though the generator light came on, and the headlights were about as bright as usual. A friend tried to jump start me - no change in symptoms, not even a click.

Stray

Wed Nov 18, 2009 4:10 pm

fastinradford wrote: Yeah, same thing happened to me twice first engine I built,

until I realized that torque wrenches aren't always right, or even close/

how do you figure?

Wed Nov 18, 2009 4:13 pm

fastinradford wrote:
Yeah, same thing happened to me twice first engine I built,

until I realized that torque wrenches aren't always right, or even close/

I kn ow these aren't calibrated or anything, but generally new tools (not cheap imports, perhaps) are at least close to correct. I bought this torque wrench from NAPA a couple of weeks ago, and have been gentle with it. Besides, it felt about like I'd expect 23 lbf to feel - I've used torque wrenches at work that are calibrated.

Wed Nov 18, 2009 4:45 pm

Stray Catalyst wrote:

Another problem, probably unrelated - I drove it to work, but it wouldn't start after work - not even a click, though the generator light came on, and the headlights were about as bright as usual. A friend tried to jump start me - no change in symptoms, not even a click.

Stray

dead starter relay or bad ignition switch?

what do you have for a carb?

Wed Nov 18, 2009 4:50 pm

Mexican 34PICT-3.

I'll check those - I checked the wiring in the dash, but only a quick look - the car's still at work, and my ride was leaving, so I didn't have time to dig into it. This car has been my daily driver for several months.

Starter relay - I'm pretty sure it hasn't got one. I know there's the flasher relay, and the headlight relay, but aside from that, there's no other relay on the car. Are you thinking solenoid? It might be the problem, but I would expect a click at that point.... but I'm not all that experienced with VW starter problems, so I might be wrong about that.

Wed Nov 18, 2009 5:15 pm

Stray Catalyst wrote: Mexican 34PICT-3.

I'll check those - I checked the wiring in the dash, but only a quick look - the car's still at work, and my ride was leaving, so I didn't have time to dig into it. This car has been my daily driver for several months.

Starter relay - I'm pretty sure it hasn't got one. I know there's the flasher relay, and the headlight relay, but aside from that, there's no other relay on the car. Are you thinking solenoid? It might be the problem, but I would expect a click at that point.... but I'm not all that experienced with VW starter problems, so I might be wrong about that.

i know there is a solenoid and i think the one your thinking of is the one built onto the starter. if it were just the solenoid, the starter would turn but not engage the flywheel. follow the starter wires and just about under the back seat on the bottom of the body should be a little relay, i think i have a picture of mine i will link you to, but it may be different since i have a Karmann Ghia and not a beetle.

Wed Nov 18, 2009 7:28 pm

I doubt you've got spark-plug trouble. Every hear your engine running on three cyclinders? It'll halfway idle if it's in good shape, but it sounds like garbage, and shakes like crazy--if it'll even stay running at all.

I wonder if the head you aquired is bad--maybe the wrong size for the pistons and barrels, or ill-fitting? I agree with the diagnosis (based on your description) that you've got lousy compression on the new side. I wonder if you burnt your rings up when the valve stuck?

Good luck!

Wed Nov 18, 2009 7:58 pm

connella08 wrote:

i know there is a solenoid and i think the one your thinking of is the one built onto the starter. if it were just the solenoid, the starter would turn but not engage the flywheel. follow the starter wires and just about under the back seat on the bottom of the body should be a little relay, i think i have a picture of mine i will link you to, but it may be different since i have a Karmann Ghia and not a beetle.

There's a wire leading through the body, under the back seat, on the opposite side from the battery (driver's side). There's no relay there, unless it's on the outside of the car near the starter.

Wed Nov 18, 2009 8:01 pm

Fitz. wrote: I doubt you've got spark-plug trouble. Every hear your engine running on three cyclinders? It'll halfway idle if it's in good shape, but it sounds like garbage, and shakes like crazy--if it'll even stay running at all.

I wonder if the head you aquired is bad--maybe the wrong size for the pistons and barrels, or ill-fitting? I agree with the diagnosis (based on your description) that you've got lousy compression on the new side. I wonder if you burnt your rings up when the valve stuck?

Good luck!

I'm bringing my compression tester with me to work, it's possible I toasted the rings on that piston. The head fits tightly over the cylinders - tightly enough that it was a pain in the a$$ to get it installed, but not tight enough to fear I was crushing anything to get it to fit... but it IS a used head, so it might not have been good in the first place. It passed a visual inspection (no cracks, pitting, holes, etc) but I'm not an expert. The valves looked dirty but not damaged. The compression test will give me my answers to the P&C questions.

Wed Nov 18, 2009 8:03 pm

You tuned and timed it I'm sure, right? Timing is everything, you know?

Wed Nov 18, 2009 8:34 pm

Tripple check the firing order 1-4-3-2 (R/F, L/R, F/F, R/R) and be sure the throttle opens all the way with the cable. I'd recheck dwell, timing and everything.

Did you at least check and lap the valves on the used head?

Simplest way to check valves for leaking is pour cola into the combustion chamber and them and them blow compressed air into the intake and exhaust port. Cola bubbles easier than water so it's easier to see a leak.

Wed Nov 18, 2009 8:38 pm

LeviMan2001 wrote: You tuned and timed it I'm sure, right? Timing is everything, you know?

I haven't tried the timing or tune yet - I'd figured (perhaps incorrectly?) that if I didn't adjust them, and treated them as gently as possible, they would still be in adjustment from before. I guess I'll need to tow the car home to work on it - it sounds like there are too many possible causes for me to diagnose all of them in the parking lot at work.

Wed Nov 18, 2009 8:48 pm

Do all the regular tune-up adjustments on it.
I'll bet your compression readings will go up a lot. :)

Wed Nov 18, 2009 8:56 pm

Stray Catalyst wrote: connella08 wrote:

i know there is a solenoid and i think the one your thinking of is the one built onto the starter. if it were just the solenoid, the starter would turn but not engage the flywheel. follow the starter wires and just about under the back seat on the bottom of the body should be a little relay, i think i have a picture of mine i will link you to, but it may be different since i have a Karmann Ghia and not a beetle.

There's a wire leading through the body, under the back seat, on the opposite side from the battery (driver's side). There's no relay there, unless it's on the outside of the car near the starter.

yes, it should be bolted to the bottom of your body, outside of the car.