Double knock turning newly rebuilt engine over by hand

[Who.Me?]

1600 dual port built back to stock with new bearings. Case was machined...

I got my engine off the stand tonight and bolted the flywheel up and it's making a double-knock noise.

I'd already checked and fitted the flywheel before fitting the tinware etc. I left it off to make it easier to lift the engine back on to the stand.

The engine is now fully built and flywheel is torqued with the main seal in, but no oil (just the assembly oils).

Initially it was very hard to turn over by hand, but hadn't been while it was on the stand with the flywheel off.

I figured the main seal was tight, so turned it over a couple of times with a long bar on the crank nut. It now turns over freely but it has a distinct double-'clack clack' knock that occurs twice each revolution (180 degrees apart).

My wife listened and thinks it's coming from low down in the case around cylinder 2.

Any ideas before I tear the whole engine apart again?

The only thing I can think is that one of the rods is hitting the case, but it's only doing it now the flywheel is torqued up?

Can that happen? I'm sure I turned the engine over when I was test checking shims and didn't notice it then. It's really obvious now.

Would I be able to see enough to know by removing the oil plate and putting an inspection camera up inside the case?
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Andy


Looking for info on my truck's history. Are you from Campbell California or nearby. Do you recognise it? ... http://www.thesamba.com/vw/forum/viewtopic.php?t=636786

[fl59bug]

Could it be the oil pump body hitting the cam bolts?

[Who.Me?]

[Brian_e]

Do you have the rocker arms on?

You should be able to turn the engine over by hand with no rockers or spark plugs in. No long bars needed.

If you need a wrench to help turn it you have a problem, noise or no noise.

Start taking it apart, and turn it over after each step. That will help narrow down where the problem lies.

Did you check ALL of your bearing clearances?

Endplay?

Did you check ring gaps?

What about skirt clearances?

The clicking does sound like a cam bolt hitting the oil pump.

Brian
Brian
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[GARRICK.CLARK]

Sounds like oil wrong oil pump, pull the oil pump and turn engine over again to check

[mark tucker]

also feel the oil pickup to be sure it isant out of place and the rods are hitting it. usualy just large strokers get close. but I reckon if it get twisted it could contact somethen. does it have all the rod bearing in it?...

[jeffrey8164]

That blows.
I thought I had it bad with a pushrod tube leak.
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[Who.Me?]

Thanks all. To correct my original post, the noise seems to be coming from around No.1 rather than No.2. All the tinware makes it echo though, so it could be a red herring.

The engine is completely assembled now (so all the rocker assembly is in.

The only internal moving parts that were replaced in the rebuild were the bearings and the cam (removed engle W110, replaced with repro stock 4-rivet cam).

I had the engine shop rebuild the crank assembly for me with its bearings. As far as I know it was rebuilt with the rods in the same order, so I'm reconsidering whether the rods could be hitting the case. They weren't before dissassembly.

I'm wondering whether a rod could be hitting the cam with the crankshaft in its 'working' position. The crank shifts rearward relative to the cam when I rotate the crankshaft without the flywheel as the crank/cam gears are helical and the crankshaft end float allows it to ride up the gear.

I'll see if I can see up through the oil drain plate to see whether anything is hitting the oil pickup. Then I'll start taking bits off until I find out what is going on.

<Insert Expletive>
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Andy


Looking for info on my truck's history. Are you from Campbell California or nearby. Do you recognise it? ... http://www.thesamba.com/vw/forum/viewtopic.php?t=636786

[FreeBug]

You changed cams from a 3 -bolt to a 4-rivet, but did you change the oil pump?

[db69]

Do you have the distributor installed? If no, drive gear clunking up and down possibly.
Rods on crank backwards will pull flywheel toward block ( i bought a parts motor assembled this way had no noticeable endplay until i removed p&c’s then it had about 3’ ) .
Maybe push rod out the lifter cup?
Keep diggin you’ll find it!

[Who.Me?]

[andk5591]

we had an issue recently with my engine builder having a problem with the length on a CB pump. I do not know exactly how he fixed it, but I checked with CB and they were not aware of an issue, but said its possible the cam and pump combination may have something to do with it.
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[Bruce Amacker]

Is your endplay still present?

Maxi2 pump clearance (to cam rivets/bolts) has been a problem a long time and must be checked before mating the case. Getting the Maxi 2 pump out without f'ing it up will be a challenge, no tool is made to pull it.

Like others said, pull the rocker shafts and spark plugs. The crank should spin fairly free- both hands on the flywheel should be able to turn it, and at TDC/BDC maybe one hand.
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'66 Deluxe Bus
'65 Standard Bus
Build threads:
'66- http://www.leakoil.net/forum/viewtopic.php?f=23&t=2888&sid=54d8dedfb3822f99c7f2ea430cb4e856
'65- http://leakoil.net/forum/viewtopic.php?f=23&t=4263

[nsracing]

did you do a trial-assembly before you glued this together?

All this headache is mitigated if a trial assembly is done.

As for oil pumps, you check fit while it is still in half-case stage. All you need to do is put the pump against the cam and see how the rivets clear ..if they clear.

My advice is people need to modify their engine building skills and be more thorough. I strongly advice a trial assembly - at least once. So if everything checks out as the engine will be run in all that, all you need is a teardown and a cleanup and a final assembly. Everything goes together easy coz you already check it the first time.

IN your case...pull the pump if you can and see where the knock is. Could be just your pushrods off their seats in the lifters. PUll the rockers off and see if it will turn. if the knock is still there, pull the pump. If it is still there, then you probably forgot a rod bearing.

Or you left a tool inside...

[Who.Me?]

It turns over freely. It was just straight after the flywheel was bolted back up with the oil seal that it was stiff.

Yes, I checked the oil pump clearance before assembly. I couldn't see anywhere that it would clash with the cam rivets... https://www.thesamba.com/vw/forum/viewtopic.php?p=9254787#9254787

One thing I couldn't check was whether the allen bolts that replace the pump studs projected through the case when it was bolted up though.

I'm going to pull the pump tomorrow and see if the noise goes away.

I tried an inspection camera up through the oil drain plate hole, but I couldn't get a clear view.
_________________
Andy


Looking for info on my truck's history. Are you from Campbell California or nearby. Do you recognise it? ... http://www.thesamba.com/vw/forum/viewtopic.php?t=636786

[nsracing]

Long pump bolts? That will explain it. Back off on them and see then...

Sometimes it is best to just leave things be if they are working.

[Bruce Amacker]

It was just straight after the flywheel was bolted back up with the oil seal that it was stiff.

That's kind of concerning. Check your end play, loosen the gland nut and back the flywheel off and see if your noise changes.

Here's the best pic I had handy of a Maxi 2 pump going together. This is an early 3 bolt cam (CB2280) with a stock gear IIRC.
The studs are for mockup, it gets the Allen bolts. I remember checking the length of the Allen bolts and there wasn't a problem. I chase the threads with a tap since it seems like they're cut for interference to lock/seal the studs in place.

There's 2 different lengths of bolts for the cover, could you have mixed those up? You're not going to get the pump out easily, try backing the bolts out and see if your noise changes.

Here's the Gr 8 bolts I use for the gear with Loctite, I ground the heads a bit thinner for pump clearance. Some guys grind the pump body. There's a "knob" on the pump which hits the bolts if you're not careful.

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'66 Deluxe Bus
'65 Standard Bus
Build threads:
'66- http://www.leakoil.net/forum/viewtopic.php?f=23&t=2888&sid=54d8dedfb3822f99c7f2ea430cb4e856
'65- http://leakoil.net/forum/viewtopic.php?f=23&t=4263

[Who.Me?]

It's not the filterpump

Guess I'm going to have to dissassemble it step by step until I find out what's hitting what.

I suspect either rod hitting cam or rod hitting case somewhere. Either that or the crank broke, but I can't see how that could have happened.

Bruce, the noise changes with the flywheel off. It becomes more of a single knock, but the crank is free to move relative to the cam due to their end floats, so the noise changes anyhow. That may be why I didn't notice it during assembl.

Plus the tinware amplifies the noise, particularly the fan shroud (fan belt is off and fan is static - it's not the fan hitting).

I've left the flywheel on again now because it the noise is more distinct.
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Andy


Looking for info on my truck's history. Are you from Campbell California or nearby. Do you recognise it? ... http://www.thesamba.com/vw/forum/viewtopic.php?t=636786

[SBD]

I don't know if it would make this kind of noise or not, but... Do you have the correct fuel pump and pushrod? But 4 times per cam turn, not likely the problem.
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