B210 A-14 Rebuild

[Vethraxx]

Problem:

 

Oh okay. I have rebuilt my first A-14 motor. Everything has been fine up until now. The motor never purred. It had a klak-klak dieseling sound (that was NOT spark timing) It ran nicely. It had plenty of speed.

 

NOW,that slight klak-klak has become very loud. You can barley feel it in the gear shift, and not in the pedal. It's loudest at idle, and when you rev the motor is all but goes away. The engine runs fine, except for that noise.

 

The latest development is that the engine has started to backfire, and lost some of it's pep, like it was out of time (no power on hills).

 

What I have done or thought"

 

I thought that it perhaps was sloppy pushrods, I rechecked the head bolt torque, then re-gaped all the valve-tappet clearences to their cold measuremnts. No luck. The sound is still there.

To me it sounds like it's upper block only. I don't think it's related to the crank/rocker arms. (They would have blown out the side of the block by now with how loud this klak-klak is. Whatever it is, it makes my car sound like a diesel. (but not because of spark).

 

Any suggestions on things to check or how to properly isolate a knock? I'd hate to have to pull the motor and taking it apart. If noting else, I can swap a head with one of my spare A-14s I have laying around

 

THanks

[datzenmike]

Run with the valve cover off. Use a piece of wooden dowel or broom handle and push down on each rocker arm where it meets the valve spring. Takes a bit of practice and you have to push down so it doesn't flick you off. Compare all the rockers. Excessive noise or something damaged on that valve will transmit up the dowel as a harshness like a sharp hammer tap. This may locate the sound source.

 

As a rule a damaged part or excess clearance does not usually get quieter when revved.

 

Try pulling each plug wire one at a time and see it the sound stops or is reduced. This could point to one cylinder.

 

Pull the plugs and 'read' them. Is one black and sooty but dry? Is it black and oily wet. Does one have a BRIGHT white insulator? Any damaged?

[Vethraxx]

Thanks for the input. I will see that what I hear with the dowel. The spark plugs look like a picture in a book. No oil, no carbon fouling.

[Vethraxx]

Update. On a cold start, there is no clak noise, within minutes of running, it comes back. With the valve cover off, watching the motion of the tappets and push rods. The clacking is in perfect time with the motion.

 

While cold , before the noise reappeared. I pulled plug wires 1 and 3. Each time the noise came on strong, 2 and 4 had no effect other than causing the motor to miss. So... what I am seeing. I am not quite putting it all together...

[Vethraxx]

Thanks for all your advise, but I am tossing in the towel. The list of parts that move in an engine are pretty finite. After eliminating the rods, tappers, valves That leave the cam/crank/timing chain. I have a feeling it's the cam. It was the only thing that I did not replace because I had no press. SO. I shall drive it untill it pukes, and rebuilt one of the other A-14s I have in the garage. *sigh*. Unless someone likes close to Lynnwood and wants to give it a listen too.

[Vethraxx]

Doah. The engine died very softly yesterday coming home from the store. Just a little squeal, a hesitation then a muted thud. The engine reciprocates with the starter. I will take it all apart and see what's what.

 

Does anyone know who sells A14 crate motors anymore? I used to get them from Nix 99 in mukelteo for $250.00. That was in the early 90s. so.... anyone got any ideas?

[datsunaholic]

Wild guess is the timing chain or camshaft broke, but heck the noise could have been the fuel pump arm and maybe that broke (it was timed in with the cam). But it will take disassembly to find out.

 

Crate engines... maybe 20 years ago.

[Vethraxx]

Yeah, 20 years ago... that's about the last time I bought one. I just don't feel that much time slipping by.

 

The timing chain was new when I put it in 5 years ago. I hope it was not that. I have others. I had my hand on the fuel pump with the engine running. I did not feel the knock there. I will let ya'll know what it was when I pull the engine. Just a hassle. If I did not think the B210 Coupe was dead sexy, it'd abandon it on a lone mountain road somewhere.

[Master-O-Turbonics]

. If I did not think the B210 Coupe was dead sexy, it'd abandon it on a lone mountain road somewhere.

 

ROFL! I like mine