marc_w

I put in the TR220 in my truck this weekend. I'm getting a lot (up to 9*) of KR at low rpm's. (from 900-1,800 rpm).

Is it a problem with overlap and/or the fact I'm running manifolds - exhaust gas is geting reverted back into the cylinders at low rpm?

I have a decent amount of 'sewing machine' valvetrain noise. Enough to be heard echoing under bridges and cement walls and stuff when I'm off the throttle. Could it be that?

I hear aftermarket pulleys can cause KR. I noticed that my stock pulley has the **SLIGHTEST** "shimmy" to it after I reinstalled it here. Should I pull and remount it? (It could have done it before - I just never paid any attention to it.)

Everything else on the exterior of the motor is buttoned down good. I'm pretty sure the internals are holding up okay.

Here is a link to a log...

If it's not mechanical, what tuning parameters can I change to help get rid of this?

Thanks

HumpinSS

iTrader: (1)

To really see if it is false or not rule it out by getting some higher octane gas. I have this issue after a cam install also but mine is no where as high as 9.0 its only 2* @2K

marc_w

Sounds good! What's the deal with high octane gas?

I'm running cats and a full set of 02's. I hear something about some HO gas choking things up?

2xLS1

iTrader: (25)

Just make sure it's unleaded and your O2s will be OK. We can buy 100 U/L around here. Try a 50/50 mix with premium. I would think that you would have less cylinder pressure with that cam over your stock one though. If it doesn't go away with that, it's probably false.

HumpinSS

iTrader: (1)

High octane meaning 94 or 100 preferably of UNLEADED gas. It wont choke anything up and will supress detonation if in fact you have true KR. You o2 and cats wont be bothered as long as you are running high octane UNLEADED gasoline

marc_w

Thanks gus. I run 93/94 as it is (this table here is with 93), so I'll have to track down a place that sells the HO unleaded stuff.

I just ran through the engine bay again, and found a few bolts for my manifold heat shields were on the loose side. Hopefully it's something as stupid as that. I've got to get that order in for headers.

HumpinSS

iTrader: (1)

Any vacuum leaks will cause that also. Make sure yo have them squared away

WS6HUMMER

iTrader: (19)

This is very interesting, I didn't know this. I like everyone else with an aftermarket cam and no tuning have a little KR at low RPM on occasion. I'll get to spraying some WD40 and see if I might have a vaccum leak somewhere. I did have a freind whose 98 SS ran a little on the crappy side for a while finally the vaccum leak got so loud you could hear it and it ran a lot better after that.

Predator

That's been my observation, not with a new cam, but an intake.

Same problem.

marc_w

Everything is tight, as far as I know... The only two vacuum sources I monkeyed around with were the valvecover breathers. They're both well connected.

Could the 112lsa be "interpreted" as a vacuum leak?

MyLS1Hauls

iTrader: (2)

Several LQ9 motors I've driven had a lot of tip-in knock...and they were stock. The cam lowers the dynamic compression of the engine at low rpm and therefore should reduce the knock tendency. Not sure whats going on there with your motor.

marc_w

The motor DID have KR before, but it was always when rolling into the throttle on the highway, and it was 4* at the most. Not once did I ever have it way down low like this.

What I find weird is that it's not consistant. I'll log KR like, one out of every four stop n' go's. I occasionally get it just cruising down the road while locked up in OD.

I can rev the engine in P/N all day and it'll never log anything, so I don't believe it's false...

I can't help but wonder if the O2's are getting confused while I idle (with some of the unburned mixture making it out into the exhaust), and the engine leaning itself out a bit... and when I tip into it, I'm lean?? I should notice the 02's shoot up into the 900's if that's the case, right? ....not to mention the fact that this is a small cam, and I'm sure the big duration people out there would have similar problems.

marc_w

A couple more logs. Maybe someone will spot something...

marc_w

Also... I know cams are supposed to lope, and a lope is type of missfire, but I noticed the truck making a few "puff.... putt.... puff puff" sounds out of the tailpipes, on top of the lope.

I've had this problem with a bad plug wire a while back. These TV50's are fragile so it's possible one's bad.

Is the noise normal?

ataylors

iTrader: (2)

Mine makes the same noise, It could be that the KR rate is pretty high on trucks, and that is why it goes so high, sometimes taking out 1* of timing in the right spot can kill 5-6* of kr

marc_w

I was about to ask that / look into that, next... (How many degrees do I need to remove to kill X-amount of KR). Thanks.

I was previously running a stock crank pulley bolt. I got my new bolt today. After I snugged it down, I swear the pulley moved a CH further in on the crank snout.

I started the engine, and I don't see that slight shimmy anymore. My AC belt was running a lot more "tame" now too - it was erratic before. I'm REALLY hoping the pulley just wasn't completely seated, and I was experiencing the KR that some aftermarket pulley people get. I'll find out tomorrow.

I also pulled and ohmed out all my plug wires. They're good.

HumpinSS

iTrader: (1)

YOu prolly didnt install the pulley all the wya the first time.....

What were your procedures for installing it

marc_w

Well, I'm bummed out. It wasn't the pulley.

To install it - I used a longer crank bolt with a home-made washer... I snugged that down until I could get a few healthy turns using my stock bolt. From there, I just tightened the hell out of it until it felt like I was going to bust the breaker or socket. I was using the handle off a Hi-Lift jack as a cheater bar.

I snugged the new one down right around 100-degree's after the initial 37ft/lb spec. It felt the same as the old bolt.

I drove around with the windows up this morning hoping to hear any KR. There were a few times I could have swore I heard it, but nothing was logged. Other times, I see a burst of 9*, and i never heard a peep. I'm pretty sure 9* should be audible... it is in my girlfriends V6.

I haven't been able to find a place that sells unleaded race gas yet.

Right now I'm rechecking everything under the hood. From the way the dipstick tube vibrates at idle, to the tranny lines again. I had them tied down and out of the way pretty good before the cam install - but when I slid my radiator up to swap cams - I could have screwed with the way the lines were positioned. (I kept the lines connected to the radiator). There is a black plastic clip that helps secure the lines - there is a black plastic "soot" around the clip, so that leads me to believe the lines are moving around.

Short of securing them better (and getting race gas) the only other thing I can think of is copying the LO timing table to the HO table.

marc_w

Does the timing table look abnormally high to any TR220/224 users?

marc_w

I zip-tied everything that could move under the hood. I pulled 4* or more out of the knocking areas of my HO timing table.

I still got the KR monkey on my back.

I'm starting to believe it's valvetrain noise. I have the sewing machine noise, but it's not just that 'scissor-like noise'. It's also got a light 'tap tap tap' mixed in that was never there before the cam. To me, it sounds like an individual, maybe a pair of lifters, PR's, rockers, or valves making the noise.

I think the valvecovers will have to come off for me to get any sleep tonight.