3.2 knocking TDC 2 and 5

[MikeMorgan]

Hi from Dallas, Everyone. Could use some advice, please.

Recently rebuilt the engine myself and all seemed well except I could detect a slight rattling at 2500 RPM, which seemed to be coming from the right-hand-side of engine. I foolishly put it down to fan noise!!!

Fast forward, while driving one day, huge loss of power and really loud knocking developed. I pulled over and had AAA tow me home.

Engine now out of car and on stand. Slowly rotated engine by hand and there is a knock and medium resistance to rotation at or just before TDC 2 and 5.

Started to tear-down the right-hand-side (RHS), removed rocker arm, plugs and the knock is still there in same places. I looked in the ports and also in the plug holes (fiber camera) but nothing obvious. Now that the tension is off the valves on the RHS, I dont think it's a valve issue, so possibly piston.

I'm not sure what to do next! Should I keep tearing down the RHS and remove heads or should I start on the LHS and get it to the same point and see if there's anything visually wrong on the LHS valves?

I wonder if anyone has had a similar symptom or has any advice how I should proceed from here. Obviously I would like to minimize the effort as much as possible.

Also, anyone know a good divorce lawyer in Dallas

Thanks

Mike

[MikeMorgan]

On further inspection, found these, what appear to be burn marks on #2 Exaust valve

[smokintr6]

Run a leak down if you haven't taken the heads off. That should tell you where you lost your power. After the leak down I would go ahead and remove the heads and they cylinders and see what there is to learn.

[VFR750]

Leak down before you go any further makes good sense.

Need more data before you go into a tear down to the short block on both sides.

[MikeMorgan]

Thanks Guys. Will give that a try and post the results

Regards

[VFR750]

Rattling can be a bad hydraulic chain tensioner. Had that and pulled the engine apart at 30 miles and replaced it.

Rattling went away

Did you verify cam timing on the right hand side of the engine?

Very easy to mess this up and cause the exhaust valves to strike the pistons.

[Trackrash]

Sure sounds like a chain tensioner issue. Pull the chain covers off and check if the tensioners are still firm.

A leak down is in order, if there was any valve to piston hits now is the time to find out.

[MikeMorgan]

Thanks again for the additional comments and help. I did the leak test cold and got following:
#1 5%
#2 2%
#3 2%
#4 2%
#5 5%
#6 8%

Most of what I could hear was hissing was exhaust ports but #6 was also blowing by the piston more than the others. Will double-check rings and orientation there.

From other postings, sounds like I should repeat warm but seemed OK to me at this point.

I also suspected the chain tensioners but they were nice and tight, went ahead and tore down some more, cams out, heads off, pistons off all around.

Huge amount of side-to-side play on #3 rod to crank, so I suspect the rod bearing is shot. I poked around inside case with fiber camera and saw some small bits of metal laying around.

Seems like I will need to split case, remove crank and replace bearing for #3 conrod. Will post again after I get inside.

More to follow

Regards from Dallas

[Walt Fricke]

Mike - So far it would seem you haven't found a cause for the "huge loss of power," and probably not the knocking. Did the pistons show any sign of contact with the valves? Those leakdowns aren't going to give you a sudden loss of power. I don't think ring orientation is going to cause that extra 3-6% - guys report finding their orientations all over the place after running an engine for a while. Good to follow the instructions on assembly, to be sure, but they can move around.

On your recent rebuild, did you do the valve mating surfaces?

You haven't estimated the hours/miles on this engine since you rebuilt it, nor what was replaced or done during that rebuild.

Can we assume that the cams seemed set where they were supposed to be when you took the chain wheel off? Nut/bolt nice and tight?

[gwag]

Sounds exactly like what happened to me......spun a bearing.

I started a thread......turning lemons into twin plug.

I thought the same things about the ticking......fan housing. But then it got louder and power gone.

[al lkosmal]

Mike,
I also think that those are decent cold leak-down numbers. Your rings and valves seem to be holding pressure. I do not think they are the issue here. If your valves made contact with the piston, it would likely bend the valve and result in very high leak-down numbers.

regards,
al