Valves on new rebuild, When to re-adjust Options

[jeffdon]

Been driving with the new engine, and probably have all of an hour and a half behind the wheel. The engine has quite the clattering noise that I notice at idle, which I assume is the valves. I set (and re-set) them three times before it went in the car. My webcam 494 spec card showed to set both valves to .006. I went with .007, based on the common thinking that its better to be a little loose. I am running stock push rods.

Just climbed under the car thinking to check the valves, and am really not looking forward to this. I have set them with the engine in the car in the past, and cannot recall it being such a crappy job.

I guess my question boils down to this:

Should I put more road time on the car before adjusting the valves? Or am I better off letting things break in more before doing the adjust. I am thinking if the valves are making noise, they may be loose, which is way better than too tight, allthough the performance would be down.

Whats all ya'lls consensus?

[Cap'n Krusty]

First off, loose is safer, but NOT better, as it can cause wear on the valve tips and the adjusters. Not likely on break in, or over a short time, but the possibility is there. Next, we always adjust the valves after the engine has been run at 1500-2000 RPM for 30 minutes and the dwell and timing has been checked (in that order). After that, we do it again at 300 miles, then 1500 and 3000. After that, every 3000 miles, along with the oil change service. We've been doing engine break-ins here for close to 40 years, and it works for us. The initial hot run-in is extremely important for cam and lifter life! During that time, you shouldn't allow the engine to return to idle. We've found the valve adjustments are often all over the place at the first adjustment, but not always.

The Cap'n

[jeffdon]

First off, loose is safer, but NOT better, as it can cause wear on the valve tips and the adjusters. Not likely on break in, or over a short time, but the possibility is there. Next, we always adjust the valves after the engine has been run at 1500-2000 RPM for 30 minutes and the dwell and timing has been checked (in that order). After that, we do it again at 300 miles, then 1500 and 3000. After that, every 3000 miles, along with the oil change service. We've been doing engine break-ins here for close to 40 years, and it works for us. The initial hot run-in is extremely important for cam and lifter life! During that time, you shouldn't allow the engine to return to idle. We've found the valve adjustments are often all over the place at the first adjustment, but not always.

The Cap'n

Safer is probably a better word for what I meant.

I did the cam break as proscribed, and after that, went through the valves, and checked and rechecked them prior to install. Sounds like I ought to put a few more miles on the engine to allow things to break in more before my next adjust. Between fiddling with different jet combos and what I assume to be the rings seating, the car is running stronger. But I keep thinking I should get more of a kick in the butt when I hit the gas. Perhaps I am too used to the power of my 92 325i.

[sean_v8_914]

Krusty knows best.
what pistons are you running? size? brand?

[jeffdon]

Krusty knows best.
what pistons are you running? size? brand?

AA p and c. 96mm.

[jeffdon]

[quote name='jeffdon' date='Aug 21 2010, 11:52 AM' post='1359232']
[quote name='sean_v8_914' post='1359225' date='Aug 21 2010, 11:18 AM']
Krusty knows best.
what pistons are you running? size? brand?

AA p and c. 96mm. Since I did the cam break in, followed with an adjust, I am assuming that i could put off the valve adjust a little more.

Also suspect a bit of an exhaust leak. A little popping when the using the engine to brake on a downhill. But then, isn't a little popping on downshifting to slow down normal?

[Jake Raby]

The web recommendations do not consider the pushrods material you'll be using. Do some searches. We run chromoly pushrods and web cams with zero lash cold. Look at the 160k mile teardown of my 912e engine I built in 2002. It went over 120k of that with zero Valve adjustments. That cam has a 494 intake lobe.

Lash is determined by expansion, expansion is heavily impacted by material.

[jeffdon]

The web recommendations do not consider the pushrods material you'll be using. Do some searches. We run chromoly pushrods and web cams with zero lash cold. Look at the 160k mile teardown of my 912e engine I built in 2002. It went over 120k of that with zero Valve adjustments. That cam has a 494 intake lobe.

Lash is determined by expansion, expansion is heavily impacted by material.

Totally understand that. I am running stock pushrods, so I know they are expanding, and so, need to run some lash. Just wonder if the adjustment will be more effective after a few hundred miles, or if I should do them now.

[Mark Henry]

Stock PR so run them at the .006
It's not going to have the power of a 6cyl BMW

Lack of power when hot could be lean, not good for the engine, do a plug check.

[jeffdon]

Stock PR so run them at the .006
It's not going to have the power of a 6cyl BMW

Lack of power when hot could be lean, not good for the engine, do a plug check.

Plugs might look a little lean. Kinda yellow. A buddy loaned me a colortune yesterday. Anyone ever used these?

[Mark Henry]

You might not have enough miles on it to check, lean plugs usually have a white electrode (the ceramic part). You need to drive for about 20min, turn off the key and coast to a stop and then check plugs. Do a Google search for the full instructions.

I now use a wideband to tune and jet, instant results and no pulling plugs.

[jeffdon]

You might not have enough miles on it to check, lean plugs usually have a white electrode (the ceramic part). You need to drive for about 20min, turn off the key and coast to a stop and then check plugs. Do a Google search for the full instructions.

I now use a wideband to tune and jet, instant results and no pulling plugs.

I am really leaning towards getting a wideband also. Just keeping an eye open for deals.

[jeffdon]

You might not have enough miles on it to check, lean plugs usually have a white electrode (the ceramic part). You need to drive for about 20min, turn off the key and coast to a stop and then check plugs. Do a Google search for the full instructions.

I now use a wideband to tune and jet, instant results and no pulling plugs.

I am really leaning towards getting a wideband also. Just keeping an eye open for deals.

Reset the valves (some had opened, some had tightened). One of the adjusters was hitting the valve cover too! Dimpled the cover a little.

Runs much better....strong enough to really feel the hesitation and dead spot in my webers! LOL!!