'97 GMC 1500 5.7 L31 Vortec With a Knock

[KDXSR5]

Yes I searched... it just confused me more.

Ok, first off, I am a Toyota guy. This is my first non-Toyota truck. I bought a 1997 GMC ext. cab short bed 1500 with about 167,000 miles on a 5.7 L31 Vortec engine. I have built older GM engines before, but I have never touched an L31, or any Vortec engine for that matter. Long story short, it has what I believe to be lifter knock, so I was going to go on Summit or the like and buy a cam kit to replace the lifters, cam, etc. Well it turns out that Summit does not offer a cam kit for it. This confuses me because in the past, I have just bought cam kits, but those were all non-Vortec engines. So...

Where do I get a set of lifters and associated parts for this engine?

Is there anything I should know before diving in and replacing the lifters and such?

Why is there like no aftermarket support for the top end on this engine?

This all confuses the hell out of me because older GM engines have TONS of aftermarket support. Toyota engines have quite a bit as well, but there is like NOTHING for this engine. Do I need to go through GM and use all stock parts when I do this?

What kind of price range am I looking at to do this?


Thanks in advance for answers.

[trkklr77]

any parts place or gm will have it



any change in lift, center lines and duration is going to seriously fawk with the computer and it will take heavy reprograming to adjust for it.

for a cam and lifter and all gakets probaly 5-700$

[KDXSR5]

Originally Posted by trkklr77

any parts place or gm will have it



any change in lift, center lines and duration is going to seriously fawk with the computer and it will take heavy reprograming to adjust for it.

for a cam and lifter and all gakets probaly 5-700$

Ah now I see. Would you suggest I replace all lifters and the cam? Or can I replace just lifters? I have always just replaced both. Should I do a new timing set while I am in there? I am tempted to do this cheaply, but I have never half-assed an engine before and I do not intend to start now. I wish I could just drop in a new lifter and call it good, haha. I will not have $$ for a couple more weeks so I guess I am back to driving the Yota.

Is that 5-700 estimated for GM parts? Or parts store parts? I will probably go GM with this.

[Bo185]

If I remember you can put a new small cam and not have to many problems, with the PCM. Just google it. Some ave swaped to the 411 PCM that ae like the Gen III PCM and are more tunable. Its been a while since I messed with the ole Vortec 350 though. It's a roller cam BTW.



I would try swapping oils first. What brand are you using as well as oil filter. I ran Mobile 1 10/30 in mine and ac filter. It would tick on start up and them go away.

[ESPEED]

With the roller cam you can replace just the lifter if the cam is still good.

Check the adjustment first it may be a loose nut.

[KDXSR5]

Originally Posted by Bo185

If I remember you can put a new small cam and not have to many problems, with the PCM. Just google it. Some ave swaped to the 411 PCM that ae like the Gen III PCM and are more tunable. Its been a while since I messed with the ole Vortec 350 though. It's a roller cam BTW.



I would try swapping oils first. What brand are you using as well as oil filter. I ran Mobile 1 10/30 in mine and ac filter. It would tick on start up and them go away.

I read about swapping in the LT4 cam, but I think I will just stick with the stock cam.

I just bought the truck a week or so ago, and the oil sticker that is on the windshield says M530. I am guessing that is Mobil 1 5/30, but I really have no idea. The filter is a Powerflo filter, which I have never heard of. I do not have the money to change the oil and filter right now. The oil is not terribly dirty, it still has an amber tinge to it.

The engine always ticks on start up until the oil pressure comes up and sometimes a little bit afterward. It intermittently ticks while running; sometimes it wont stop ticking after start up and sometimes it does. That is why I was thinking a collapsing lifter that doesn't always collapse.

Originally Posted by ESPEED

With the roller cam you can replace just the lifter if the cam is still good.

Check the adjustment first it may be a loose nut.

That is some good info to know! If I just have to replace lifters, that will be cheaper. I will have to open up the engine and see how everything looks, but that is not going to happen for a while.

[thedog]

Try to sea foam the top end and put in good oil & a filter. May take about 75 miles but normally the top end noise will be gone.

[KDXSR5]

Originally Posted by thedog

Try to sea foam the top end and put in good oil & a filter. May take about 75 miles but normally the top end noise will be gone.

I may try this, but I probably will not. I like to replace problem parts, not throw stuff at the problem part to make it (maybe) work again.



On a side note, it is now throwing a P0430 Catalyst System Efficiency Below Threshold (Bank 2) code, so I guess it is getting new cats thrown on it.

[brooks294x4]

if your not looking to spend alot of money, hook it up to a good scanner and look at a misfire graph, will determine what # cylinder is missing and get away with replacing 1 or 2 lifters and not 16

[Grumpy_old_fart]

www.pistonslap.com

[Bo185]

Originally Posted by Grumpy_old_fart

www.pistonslap.com

I don't think its pistion slap thats happens with the Gen III motors for the most part.




If you already have the intake off to replace the lifters might as well do all of them. I would also look at doing the MPFI injector upgrade which moves the poppet injectors from the CSFI to the ports. The upgrade is 300 bucks though.

Read this
http://members.shaw.ca/betterthanyou...g%20Poppet.htm

[BigBlocksRule]

My GF's son bought a '96 with a lifter tick. It would go away fairly quickly, but got to the point where it never stopped, even with the truck warmed up. We got some replacement lifters off of sleazebay for about $100 and installed 'em, problem solved. 3 of the lifters we took out rattled like castanets, they were worn out. Don't drive it too far before you get it fixed, slack in a hydraulic roller cam setup can take the rollers out in a hurry and then you'll have a real problem.
You'll need to pull the dizzy, intake and valve covers. You should be able to pull the bolts out of the front brackets but leave the studs in, that'll let you slide the brackets forward and out of the way. Get the FelPro replacement gaskets for the intake, O'Reilley's has 'em, follow the torque specs to keep from screwing up the new gaskets and introducing water/antifreeze into the crankcase.
It's about a day's job. At this mileage, it was about time to swap out the intake manifold gaskets anyway, it's not that much of a bigger deal to go ahead and swap lifters.

[KDXSR5]

Ok... I replaced lifters, got it all back together, and it no longer ticks. The problem is that it is now throwing a P1406 code: EGR Valve Pintle Position Circuit Fault. What can I do to fix this problem before throwing any more parts at it? Also, anytime this truck sets the MIL (or as some call it the CEL) it causes the transmission to shift like crap. This then throws a transmission slipping code. I have no idea what is up with that.

Anyways... any ideas on fixing the P1406 code? I read about a recall on it, and I read about resetting the pintle or something like that, but it was all pretty vague.

[Bo185]

Originally Posted by KDXSR5

Ok... I replaced lifters, got it all back together, and it no longer ticks. The problem is that it is now throwing a P1406 code: EGR Valve Pintle Position Circuit Fault. What can I do to fix this problem before throwing any more parts at it? Also, anytime this truck sets the MIL (or as some call it the CEL) it causes the transmission to shift like crap. This then throws a transmission slipping code. I have no idea what is up with that.

Anyways... any ideas on fixing the P1406 code? I read about a recall on it, and I read about resetting the pintle or something like that, but it was all pretty vague.

Clean the EGR valve an under the intake. Should fix it, if not might need a new EGR valve. The transmission might not be related to it that's weird, may just happened on its own.

Did check the timing after removing the distributor?

[brooks294x4]

Originally Posted by Bo185

Clean the EGR valve an under the intake. Should fix it, if not might need a new EGR valve. The transmission might not be related to it that's weird, may just happened on its own.

Did check the timing after removing the distributor?

x2, i bet EGR is carbon'd up, best way ive found to clean them is brakeclean with a rag for the light stuff then a little bit of valve gringing compound and just work the shit out of the pintle and clean excess away. ive fixed numerous gm cars by doing that.

[KDXSR5]

Originally Posted by Bo185

Clean the EGR valve an under the intake. Should fix it, if not might need a new EGR valve. The transmission might not be related to it that's weird, may just happened on its own.

Did check the timing after removing the distributor?

I cleaned the crap out of the intake while I had it off. I guess I will find the EGR and try to clean it up.

The transmission only slips if I keep driving the truck with the MIL on. I have no idea what is up with that, but it has done it before.

Timing on the Vortec engines is set by the computer. All I can do is line up the two timing marks. Turning the distributor changes the cam timing, but I need a good scan tool to do that.

Originally Posted by brooks294x4

x2, i bet EGR is carbon'd up, best way ive found to clean them is brakeclean with a rag for the light stuff then a little bit of valve gringing compound and just work the shit out of the pintle and clean excess away. ive fixed numerous gm cars by doing that.

Ok. I will just need to find the dang EGR valve first, lol. It is a very different setup from any EGR systems I have worked on.

[KDXSR5]

So I went to the high school because the shop teacher there owed me for some work I did and I used their scan tool to set the cam retard correctly and to clear the codes. So far no codes have come back. I did manage to hit a pole pulling out of the auto shop though





After removing bumper and doing some clean up. Needs a new bumper and a couple trim pieces and the fender work done.

[Bo185]

The EGR valve is mount on the front of the intake.


Bummer on the carnage!