My project...

[no cigar]

Knocking in new engine... Help!

Hey guys just thought I'd share my project. It's a rebuild of the Vortec 5.7 in a 99 2dr Tahoe. This was a budget build and I reused a set of pistons and rods from a grand sport corvette. Pairing that with an LT4 hot cam and ls6 valve springs. All in all its been a fun project with the exception of having to helicoil the crank.



Sent from my SCH-I535 using Tapatalk 2

 

[retorq]

Those sure are short skirted pistons.

 

[saif najd]

Nice, please keep it up

 

[no cigar]

Yes they are short skirted. I'm thinking that the stocker that's still in the truck and broken may become a 383. Picked up some SP hypers for $50 bucks on CL. Just need a good set of Vortec heads and might do an E85 beast.

 

[retorq]

I think I'm gonna go with the bowtie vortecs on my next old school sbc build. Just like the vortecs only more better.

E85 is rare here and costs the same as low grade so its not worth it for the cost savings.

 

[no cigar]

Nah not in it for the cost savings. I want the compression

Sent from my SCH-I535 using Tapatalk 2

 

[retorq]

The block that is in the Tahoe now will come out and be my next race engine, I thought about doing alcohol on that one but .... guess well see.

 

[no cigar]

So we finally got it all together and R&Rd and on first startup purred like a kitten. Idled it around a little bit and let it sit until the next day. Started it up and once the lopey idle subsided and the RPM stabilized it developed a loud, high frequency knock on the bottom end. Not a solid knock like a rod or piston, but a tapping. Very hollow, tinny sound. Almost sound like the crank is striking a baffle or windage tray.

In fact it sounds identical to the sound I had when I accidentally put a jack under the oil pan of my mustang and pushed one of the baffles of the pickup tube about 1/4 of an inch into the path of the crank.

This is the oil pan I am using:
http://www.summitracing.com/parts/sum-g3503/overview/

Windage tray is stock, pan pickup is new OEM unit. Anything come to mind? It's definitely coming from somewhere in the pan/bottom rear of the engine. In fact the mechanic thought it was the torque converter.

 

[99Vortec]

And it's not a connecting rod bearing problem?

Those initially start out very slight sounding.

 

[retorq]

Flywheel is in good shape and not cracked anywhere?

 

[no cigar]

Haven't looked into flywheel. It's an auto. Maybe the flex plate though?

As far as a bearing problem, i m not sure what it could be? I torqued all to spec as in the manual, double triple checked orientation. All were inspected by machine shop and resized etc.

Sent from my SCH-I535 using Tapatalk

 

[no cigar]

Talked to the mechanic today and he's going to drop the pan. He swears it's a clearance issue somewhere. Researched some more into parts I bought and pump and pickup are sealed power units but all for 5.7 vortec engines per Rock Auto. Same for the pan too. Anyone ever hear of windage tray interference?

He seems confused how it doesn't come on until the RPMS stabilize... Usually after about 10 seconds of run time.

 

[SunlitComet]

possibility the oil pick up is getting blocked and your pump may be being starved? have that looked into when pan is removed.

 

[retorq]

Yeah flex plate on an auto.

Yeah your oil pump is starved for oil and you happen to hear a little tick, not a knock or other catastrophic sound, that's most likely it. Hahahaha

 

[no cigar]

Hey guys. This was resolved. Culprit was a cheap summit oil pan.

Now chasing a valve train gremlin. Has a sound that sounds like a spring binding and unloading. Definitely top end.

Has the comp retainers and keepers that allow you more clearance for an LT4 hot cam. Also LS6 Springs and new 1.5RRs

Sent from my d2lte using Tapatalk

 

[retorq]

Who setup the installed height of the springs?? Those LS springs need to be set dead on in these heads ...

 

[SunlitComet]

what was wrong with the oil pan? and its part number please.

 

[99Vortec]

Thanks for sharing resolution.

Could you see where the rotating assembly was contacting the pan?

Or was it blocking the pickup?

Any pics?

 

[no cigar]

Hey guys the offending pan was this one:
http://www.summitracing.com/parts/sum-g3503

The mechanic said that there was nothing 'wrong' with it, however the Doorman we bought as a replacement did have a noticable 1/4" or so of clearence so maybe a mfg oversight or something would have been to blame.

The truck seems to be running fine. Heard it fire up this weekend and sounds great.
Mechanic seems to be apprehensive about the oil flow and functioning of the lifters. I went with the GM LS7 ones mostly due to cost and everything I saw online pointing to them being a replacement for almost all previous GM hyd roller lifters. He is concerned about the oiling. And the fact that at ¾ turn past zero lash adjustment the truck will hardly run. I believe he set them at 3/8 of a turn and that seemed to work fine. No noticeable ticking or knocking at all, and truck was up to temp.
Does anyone have a comparison of the LS7 to std. vortec lifter? Or at minimum a detailed picture of a stock vortec lifter?

Thanks!

 

[no cigar]

Finally got her out of the shop and drove around Saturday. Everything seemed okay except for the timing. Getting infamous P1345 code. Mechanic swears up and down he has the distributor dead on but can't get it timed correctly.

Cam was installed straight up and double/triple checked to have the dots on the gears lined up. Mech performed successful relearn process with a snap on modis and everything completed just fine but the truck still wants to run like a dog.

Also, I did see where the crank was contacting the pan. It was a pretty good sized ding. I'll have pics next weekend.