Vintage b20 just installed, making a noise in neutral

Hi all,
I've just had a Volvo remanufactured b20 installed into my 72 1800e. We think the engine has had about 15,000 miles since being remanned. Then it sat on a shelf in Fidel's shop until the person I got it from bought it.

My shop that did the installation mated it up to my BW AT, and moved the FI stuff from the original engine (with a cracked piston) to the new one (well, new to me). They've gotten it all mated up and ready to be driven away (well not quite).

When the car is in neutral, it makes a sound like a car alarm going off every 2 seconds or so. My mechanic thinks it might be a thrust washer issue, and that the crank may be moving slightly from side to side. It sounds like the sound is coming from the middle of the engine, underneath the exhaust manifold.

When the car is in gear, the honking sound goes away.

Now this engine hasn't been run for a very long time, and the rings don't seem to have seated yet. It's only been run for a few minutes at a time, as it is smoking out the shop if we run it too long.

My mechanic is a Volvo master tech, but this engine came out when he was still in pre-school, so I can't really blame him for not knowing all the tips and tricks for a b20.

So any of you b20 gurus, I'm all ears. (I sure hope it doesn't involve tearing the engine out of the car and tearing it down).

Thanks in advance.
Bruce

I dont think there was a center thrust washer in that engine...

Sounds trans related given that it goes away when in gear. The crank can only move in and out, not side to side. The trust bearing is on main bearing 5, the rear most bearing. Perhaps a youtube video would help the diagnosis.

Excellent suggestion. I'll go make a video tomorrow after work.
And I stand corrected on how a crank could move.
My error in how I described it earlier.

Here's the YouTube link.
Take a watch and listen and weigh in with your opinions.
We're thinking it's a a cracked exhaust manifold, based on using a stethoscope. When we get below the exhaust manifold it gets incredibly loud.

http://youtu.be/4-NWVbF6WaA

Wow

Your video doesn't show the front of the motor. Did you remove the belt to make sure it isn't the alternator or water pump making the noise?

hiperfauto said:

Your video doesn't show the front of the motor. Did you remove the belt to make sure it isn't the alternator or water pump making the noise?

Click to expand...

+1, Remove all of the auxiliary belts and start the car. (only for short period of time, obviously) Then see if the noise persists.

Will try the belt removal tonight. And yes it will be a brief test.
Thanks for the suggestions, especially ones that don't involve tearing the motor down.

Just jumping onto the fan belt bandwagon, before I read those responses that was my first thought as well. It sounds like a dry bearing chattering on and off in the video.

I'm really not thinking that is exhaust manifold related, at idle there shouldn't be any pressure in there that would lead to trumpet noises, at least not if it can otherwise run above an idle.

If it's not a water pump/alternator issue, my next suspicion would be the transmission. Perhaps something is amiss in the torque convertor/bellhousing area?

Looks like John Mc is on the right track...

We've determined that it is coming from the bellhousing, not the exhaust manifold.
We took the accessory belt off, and that didn't change the sound one bit.

The car originally had a b20 with 6 bolt crank and automatic transmission.

The replacement engine had an 8 bolt crank and was from a manual transmission car, so I had to find the plate at the back of the engine for an automatic transmission for an 8 bolt crank. Found it from a friend on Turbobricks.

So perhaps there's something in the way that the new plate and spacers aren't fitting correctly.

If anyone out there has replaced a BW35 into an b20 equipped 140, perhaps you'll have some wisdom on what to be sure to get right inside the bellhousing.

Thanks for playing "Name that Sound".

Bruce, just chiming in for others to see: At the end of the video, the sound becomes consistent, but there is a vibrato to the noise, it's not smooth. Torque converter???

The 8-bolt drive plate has a spacer and different bushing on the crank is all I know, and early BW35 and late differ slightly but I never kept track of all the changes. All I/we ever did when someone needed one was buy a car with a good one in it complete.

Pretty riddled when going 6--->8 bolt if you happen to have an automagic car. Its probably trans related, sounds like a stator bearing or splines spinning on the stator in the converter or pump bushing.

If the converter isn't properly seated far back enough on the trans it will make those noises or if it has stripped stator splines or a bad bearing in the converter.

pity, there wasna ;74 automatic in one of our yards with a converter and the whole mess. I was thinking of pulling all the 8-bolt specific automatic parts, but usually when people pay to stick the later motor in them, they have or want a stick, so I left it all.

I remember BW35 converters having cooling vanes or fins...perhaps the driveplate is pushing the converter too far back and the fins are rubbing the converter housing?

Did you use thread locker with new bolts on the flywheel/flexplate/TC?

Never mind, I just watched the video and that doesn't sound like anything I've heard before.

KJOAP has me thinking: For the converter to be hitting something as it rotates, it would have to be way off center. We assume your mech put in the bushing I sent and that it was right. As to the flex plate spacer, even if there is a difference and the one I sent is too thin, moving the converter forward in the bellhousing shouldn't bring it into contact with anything in the bellhousing--other than the plate. If the trans is working, then it can't be the pump engagement either--that is, the teeth on the converter hitting the input. If the pilot is wrong, then just the converter bolts will center the unit enough to keep it from hitting anything--although the pilot is a must long term. Thus it can't be the converter rotating out of center. It must be in the converter or the trans. Unless--are you sure the starter is disengaging completely? Are we sure that the flexplate and spacer provide the right clearance for when the starter is disengaged?

I did once have a situation on a GM trans where the flex plate to converter bolts were too long (replacements) and bottomed maybe half a thread before tightening, unbeknownst to me. Every time you hit the starter, engaged the trans, or the trans shifted, the flexplate would ring.

The only thing I've ever done with a BW35 is replace it with a manual. I did that in my old 145E, and my first 1800E.

I suspect the spacer or offset of the mounting face of the driveplate has the early model converter pushed back such that the fins are mangled a little and hitting the converter housing listening to and thinking about the noise.

I've heard a noise like this on the SOHC when the upper timing belt pulley seetmetal rubs against the sheetmetal backing on B21/23.

I'm guessing starter is contacting ring gear (sorta does sound like ring gear teeth chewing on a a starter) or converter is contacting bellhousing.

Ahhh.....just the opposite of what I was thinking. Back, not forward. Good possibility, but I would think the input would contact before the converter was allowed to hit the back of the bellhousing. That said, if the spacing was "just right". That is, if the whole thing could be put together such that it fit, but the input was forced together too tightly..... If the entire input is now pre-loaded by bolting it all together, that could wreak havoc inside the gearbox as well as the converter.

I want to say that the spacer plate I sent Bruce with the flex plate was about 5/16" thick, just by memory. If anyone knows that the plate for this installation should have been considerably thinner, then we may have found the culprit.

When it's in neutral, wouldn't the fins be freely spinning, and pretty much at rest with the convertor body? And when put in gear, the fins would stop, and start moving relative to the convertor body.

All of which would seem to indicate that perhaps something inside the trans is howling.

Has it been driven at all? I'd half suspect that it would start making noise again once the drivetrain starts moving.