Rennlist - Porsche Discussion Forums

Rennlist - Porsche Discussion Forums (https://rennlist.com/forums/)
-   993 Forum (https://rennlist.com/forums/993-forum-58/)
-   -   Strange sound from rebuilt engine... (https://rennlist.com/forums/993-forum/739444-strange-sound-from-rebuilt-engine.html)

Vorsicht 02-05-2013 08:42 PM

Strange sound from rebuilt engine...
 
Just started up my newly rebuilt engine (top end) and am experiencing a very loud rattling sound (louder than it sounds in video). See attached video (please excuse my poor directorial skills). It sounds like a freight train. What do we think is making this noise? It definitely does not sound right. I have eliminated the fan/alternator as the source by testing without the belts attached.


goofballdeluxe 02-05-2013 08:44 PM

Highly recommend you take the car back to the shop that did the top end rebuild and let them figure out what's wrong and fix it :cheers:

vincer77 02-05-2013 08:47 PM

Lifters?

k722070 02-05-2013 09:17 PM

yeh, lifters?
when I replaced the exhaust lifters it took until the thermostat opened for them to quiet down, so call it 8 minutes. it sounded like I left a screwdriver inside.

Pete Debusmann 02-05-2013 09:23 PM

If it isn't the lifters it could be that one of the chain tensioners was installed upside down. Very easy to do.

Pete

Vorsicht 02-05-2013 09:51 PM


Originally Posted by goofballdeluxe (Post 10200355)
Highly recommend you take the car back to the shop that did the top end rebuild and let them figure out what's wrong and fix it :cheers:

LOL. I am both the shop and its first customer


Originally Posted by vincer77 (Post 10200360)
Lifters?

I had a friend over and that was his first thought. His second thought was, "that engine sounds dry - any oil in it?" Ten quarts.


Originally Posted by k722070 (Post 10200435)
yeh, lifters?
when I replaced the exhaust lifters it took until the thermostat opened for them to quiet down, so call it 8 minutes. it sounded like I left a screwdriver inside.

Well, this may be the culprit. I have to say it was so loud I didn't want to go 20 minutes until the first oil change. At 2000 RPM all of my neighbors would lynch me. This is my first time at this so I shut the engine down for fear of doing damage. Now that you mention it it does sound like six crazy monkeys tappin' away with hammers. All brand new lifters.


Originally Posted by Pete Debusmann (Post 10200450)
If it isn't the lifters it could be that one of the chain tensioners was installed upside down. Very easy to do.

Pete

Well, that's possible too although I looked up the german for top, bottom, left and right and was very careful. I think I took pictures so I'll check.

vincer77 02-05-2013 09:58 PM


Originally Posted by Vorsicht (Post 10200543)
I had a friend over and that was his first thought. His second thought was, "that engine sounds dry - any oil in it?" Ten quarts.

Well, it needs 12.

NP993 02-05-2013 10:06 PM

Sounds like lifters to me. And the engine will be fine, just fine, on 10 quarts for now.

Vorsicht 02-05-2013 10:23 PM


Originally Posted by NP993 (Post 10200583)
Sounds like lifters to me. And the engine will be fine, just fine, on 10 quarts for now.


Yes, correct. I should have been more clear. I put ~9-~10 in which is roughly what I drained out of it.

So with the lifters do I proceed with the 20 minutes 2000 RPM as per Wayne's book with the idea that the noise will die down?

Thanks everyone!

Quadcammer 02-05-2013 10:27 PM

I'm assuming you turned the motor over a few times by hand to make sure all was well?

hows it run?

Vorsicht 02-05-2013 10:34 PM


Originally Posted by Quadcammer (Post 10200644)
I'm assuming you turned the motor over a few times by hand to make sure all was well?

hows it run?

Yes, many times during the rebuild process. It seemed to turn over with a little resistance here and there. Harder after plugs.

As for it running - besides the noise it seems very strong. No misfires or anything like that. The throttle has a little slack in it but I will adjust that a little later.

diet97993 02-06-2013 12:10 AM

Lifters, they need to pump themselves up. Sounds like the tech didn"t do them prior to assembly to get out any traped air or they bleed down during the assembly if there was substancial time between assembly and engine start. should be OK.

Quadcammer 02-06-2013 09:43 AM


Originally Posted by Vorsicht (Post 10200671)
Yes, many times during the rebuild process. It seemed to turn over with a little resistance here and there. Harder after plugs.

As for it running - besides the noise it seems very strong. No misfires or anything like that. The throttle has a little slack in it but I will adjust that a little later.

Based on this, I'd say its something like lifters needing some time to pump up.

Oil pressure is good I'm assuming?

trophy 02-06-2013 12:48 PM

This sure does sound like a lack of oil issue. Total capacity if you drained everything is more than 9. Did you drain the oil lines, oil cooler etc?

Had a friend do a WB conversion on a cab recently, so the oil system was completely drained as the oil tank etc had to be removed. The car sat for quite a wile before it was restarted. On first restart there was wuite alot of lifter noise, we checked the oil, it was at the bottom of the dip stick, as soon as we started topping up the oil the noise disappeared.

I would get the noise fixed prior to doing the 20 min 2000 rpm run in.

Vorsicht 02-06-2013 01:26 PM


Originally Posted by diet97993 (Post 10200913)
Lifters, they need to pump themselves up. Sounds like the tech didn"t do them prior to assembly to get out any traped air or they bleed down during the assembly if there was substancial time between assembly and engine start. should be OK.

I soaked in oil overnight and installed in rockers but there were several weeks before startup.


Originally Posted by Quadcammer (Post 10201357)
Based on this, I'd say its something like lifters needing some time to pump up.

Oil pressure is good I'm assuming?

I'm getting 1 on the gauge at idle and increasing pressure with higher rpms into the 4 -5 range. No codes or warning lights.


Originally Posted by trophy (Post 10201791)
This sure does sound like a lack of oil issue. Total capacity if you drained everything is more than 9. Did you drain the oil lines, oil cooler etc?

Had a friend do a WB conversion on a cab recently, so the oil system was completely drained as the oil tank etc had to be removed. The car sat for quite a wile before it was restarted. On first restart there was wuite alot of lifter noise, we checked the oil, it was at the bottom of the dip stick, as soon as we started topping up the oil the noise disappeared.

I would get the noise fixed prior to doing the 20 min 2000 rpm run in.

Did the standard drain as in an oil change along with the oil return line by small filter.

My plan for today is to run the engine at idle and let it warm up to get the oil flowing. If noise continues after 15 - 20 minutes I'll check the dip stick and add some oil as suggested. The adventure continues, will report back later.


All times are GMT -3. The time now is 06:50 PM.


© 2019 MH Sub I, LLC dba Internet Brands