Restarting the 302 - Should It Sound Like This?

68Blue302Coupe · Oct 3, 2009

Afternoon all,

So, today was the first time I have started my 302 and really let it idle (only tried to start it one other time the other day). This is a used 1971 302--supposedly rebuilt--that I installed in place of my old 200 I6. Doing the engine and trans swap has been a huge learning curve but the thing actually does start now, amazingly. This engine has sat for nearly 7 years in a garage.

My concern is that the engine sounds, well, rattley and is just plain noisy.

My only comparison was my old six cylinder (which was supper quiet) and modern cars (guess no real comparison there). The engine has long-tube tri-y headers, cheapo steel chrome valve covers, an aluminum Holley intake, a 500 cfm Edelbrock carb, a Jacobs ignition module, and a stock distributor with a Pertronix Gen 1 system. I also installed a new high volume oil pump.

When I ran the engine, the oil pressure gauge (stock gauge) read near the "H" mark, but temp was fine, running on the low side. I didn't notice any colored smoke in the exhaust, either. After running the engine, I pulled both valve covers to see if the rockers were getting oil, and they were, no problem there.

I did notice that the balancer had a very slight wobble, faint, at lower idle.

- Is a 302 with long tube headers normally noisy?

- Is there something I can check? Could it need a valve adjustment (no clue how to do that).

- Will the high-volume oil pump cause the stock gauge to read near the High mark (I assume yes).

I would really appreciate any thoughts. I could try to record the idle sound in a video, but it probably won't translate well.

Thank you!

Tim65GT · Oct 3, 2009

I'm sure some of the noise are because of the headers. They transmit a lot more exhaust noise than cast iron mainfolds. Check and make sure the header bolts are tight and you can sometimes feel a leak with your hand. Just make sure you do it when it's cold.

If it was rebuilt a while ago with the block decked or the heads milled, that would affect the distance for the push rod length, but I think you can adjust the valve rockers on a '71.

The balancer shouldn't have a noticable wobble. You better check that out.
Other than replacing it, I guess you could check runout with a micrometer

The high volume oil pump should be ok. The oil pressure should drop once you drive it and get it warmed up.

jcode68 · Oct 3, 2009

I agree that you should focus on looking for exhaust leaks. If you don't have a good seal, the engine will be very noisy, almost like noisy rockers. Check at the heads and the flange that connects to your H pipe. The other thing that comes to mind since this is an engine that has been sitting a while is bad bearing in the water pump, alternator or PS pump. Bad bearings can make horrible sounds too. Good luck chasing it down.

68Blue302Coupe · Oct 3, 2009

Thanks guys, I appreciate the input. I think you are right about that exhaust leak. I have had to remove my headers several times over the course of this build and the gaskets are likely toast. I went out today and got some of the nicer Felpros for the head/header and the collecter/pipe connections. I am going to put those in tomorrow and make sure everything is tightened down. It did sound like rockers, very rattley although it ideled well.

I had not thought about the water pump or alternator, but as "luck" would have it, my water pump gasket is leaking so the has to come off. I think I'll just replace it since they are pretty cheap. I'll check out the alternator too, since that has to come off to get to the water pump.

Regarding my balancer, I assume the only recourse is replacement? I belive all the bolts are correctly torqued, and I really hope that it is not the crankshaft that is wobbling. If it is I am SOL... Any recommendations for a balancer? I have a 164 tooth flywheel.

woodsnake · Oct 3, 2009

Go ahead and try to post it. My audio links are from my digital camera, they turned out pretty well...
Other wise, I can't "hear" it from here....

68Blue302Coupe · Oct 4, 2009

I pulled both headers off today and I had some serious exhaust leaking on the passenger side header. I could see some nice carbon blow-by all over the bottom of the gasket, so that is definitely part of the problem. Part of the header tube was touching the bell housing and that was preventing everything from sealing properly. I had to slightly dent the pipe in order for everything to fit, but now it is seating correctly.

I also pulled the old water pump (leaking) and will replace that. I'll see this week if the 302 has quieted down any.

Any have recommendations on the balancer? I can't replace mine with a stock balancer because I have a 164 tooth flywheel, right?

Since I have the water pump off now, should I also change the timing cover gasket? How much more work is that?

woodsnake · Oct 4, 2009

If you don't know how old your timing gear set is, replace that now too!!!!!!
Then, you can put a new gasket on after you replace the timing gear, and also put a new front cover seal in it also.
That should resolve all your front end leaks!

kilgorq · Oct 4, 2009

68Blue302Coupe said:
I pulled both headers off today and I had some serious exhaust leaking on the passenger side header. I could see some nice carbon blow-by all over the bottom of the gasket, so that is definitely part of the problem. Part of the header tube was touching the bell housing and that was preventing everything from sealing properly. I had to slightly dent the pipe in order for everything to fit, but now it is seating correctly.

I also pulled the old water pump (leaking) and will replace that. I'll see this week if the 302 has quieted down any.

Any have recommendations on the balancer? I can't replace mine with a stock balancer because I have a 164 tooth flywheel, right?

Since I have the water pump off now, should I also change the timing cover gasket? How much more work is that?

if you still have the noise. Try running it with the belts off. Obviously only for a minute or two. This will eliminate all of the accessories as being the cause of your noise. You can replace the balancer you just need to make sure you get the correct one for the motor. Make sure you have the correct year on the motor and the balancer will be no problem to get. I think I paid 28 for mine.

68Blue302Coupe · Oct 4, 2009

That's a good idea with the belts, I'll give that a try if I still end up having problems. The water pump will be new, and I will presumably have fixed the exhaust leaks. I think I'll run a compression test too before messing with adjusting the valves, although I'd like to figure out how to do that regardless.

Regarding the balancer, the engine is a 1971 302 connected to a 4 speed top loader with a 164 tooth flywheel. I **think** the balancer should be the 28oz. model, at least based on today's Googling. Nothing is stock on this car unfortunately, but from what I could tell the 28oz. was the correct one.

Another thought occurred to me--could the engine be miss firing or something? When I first started it up it sounded like a Harley, but then I bumped up the timing and it sounded OK, other than very rattley.

kilgorq · Oct 4, 2009

68Blue302Coupe said:
That's a good idea with the belts, I'll give that a try if I still end up having problems. The water pump will be new, and I will presumably have fixed the exhaust leaks. I think I'll run a compression test too before messing with adjusting the valves, although I'd like to figure out how to do that regardless.

Regarding the balancer, the engine is a 1971 302 connected to a 4 speed top loader with a 164 tooth flywheel. I **think** the balancer should be the 28oz. model, at least based on today's Googling. Nothing is stock on this car unfortunately, but from what I could tell the 28oz. was the correct one.

Another thought occurred to me--could the engine be miss firing or something? When I first started it up it sounded like a Harley, but then I bumped up the timing and it sounded OK, other than very rattley.

If it sounded like a Harley you have to have an exhaust leak. I have never what a Harley motor sounds like because the exhaust drowns all other sounds out.

Try to find the casting date on the block. That will tell you for sure the year and what balancer to get. The block casting number is under the started usually. Sometime you can see it with a mirror and flashlight. Other times you have to remove the starter.

Restarting the 302 - Should It Sound Like This?

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