pressure from tank vent

[quattrorunner]

This is a video of the pressure from the vent on the oil tank. Some pressure, not sure if it's normal. Not lots if you ask me but it builds up. Newer engine rebuild with new rings and new valve guides with 4500 miles or so. Also, the noise. I think it's that the rockers were not rebushed. Can't seem to adjust the noise out. Quiet when cold and noisy warm.
Ideas from those in the know?
Noisy engine - YouTube

[timmy2]

Tank is being lightly pressurized from the crankcase vent hose that feeds in below where your hand is.
Normally the hose from where your hand is goes to the back of the air intake rubber boot and the pressure is dissipated in the intake air supply.
What happens when the hose is hooked up correctly and you remove the oil cap?
Do the RPM's drop? (Assuming CIS)

For the rocker noise...Mine sounds about the same.... Same with sobamaflyer here: Any data I need to collect for the gurus before dropping?
Take a look at how the rocker shafts wiggle!

I just had a spare set of rockers I bought in the classifieds refurbished and ordered all new shafts, nuts, bolts, rsr seals etc. as I have the same condition.... Totally my fault as I had to replace both camshafts last fall for pitting, and did not do the rockers at the same time. (tried to save a few $)
Dropping the motor soon to swap them all out. (Camshafts too!)

[quattrorunner]

Thanks for the input. My cis system isn't connected to the tank correctly as I don't use an air box. Thought about adding a filter on it but never got around to it yet. Makes no change to remove the oil cap at all. But it passes smog so I don't care. It would look better with a filter though I guess.
My rockers will be rebushed at some point just cause the sound Buggs me.

[KTL]

A lot of people choose to connect that tank vent hose to a catch can instead of plumbing into the intake as per the factory design. Upside to the catch is that you don't introduce oil vapor (or purely oil if your tank is a bit full) into your air-fuel mix.

That's a good bit of valvetrain noise. How are your valve guides? I had a similar problem with my '87. Couldn't quiet down the clatter. Turned out I needed new valve guides. When I did replace the guides I also had the rockers rebushed. Nice & quiet nowadays. cgarr is a good guy to have your rockers rebushed.

[quattrorunner]

My guides are new(4500 miles). I have narrowed the noise to rockers needing rebushed by way of Internet searching. I need to do that and then if still noisy ill take a shotgun to it.

[Spenny_b]

Originally Posted by quattrorunner

....and then if still noisy ill take a shotgun to it.

Lol ...ah, my tried and tested laptop repair method..

[KTL]

Yep there's only so many sources of the sewing machine sound. Valve guides, loose valve adjustment, rocker shafts. Make sure your valve adjustment is good.

When I first started wrenching on these, I took the "light drag on the feeler gauge" too literally. My experience is light drag gives you a loose setting. Reason being is because of how the feeler needs to be bent to get into the cam housing to get in the gap btwn the valve tip and rocker foot. I set my lash so there's considerable drag on the feeler but no so much that it requires a lot of effort to move it under the foot. Valves seem to be quieter.

[Steve@Rennsport]

Have you performed a leakdown test to make sure the rings have seated?

[quattrorunner]

Originally Posted by Steve@Rennsport

Have you performed a leakdown test to make sure the rings have seated?

No. And I didn't scuff the cylinders either. How likely is this to be an issue? Thanks.

[quattrorunner]

Originally Posted by KTL

Yep there's only so many sources of the sewing machine sound. Valve guides, loose valve adjustment, rocker shafts. Make sure your valve adjustment is good.

When I first started wrenching on these, I took the "light drag on the feeler gauge" too literally. My experience is light drag gives you a loose setting. Reason being is because of how the feeler needs to be bent to get into the cam housing to get in the gap btwn the valve tip and rocker foot. I set my lash so there's considerable drag on the feeler but no so much that it requires a lot of effort to move it under the foot. Valves seem to be quieter.

Last time I did it, was 600 miles ago and I did a tight adjustmant. The engine is quiet cold and noisy wonce warm. It's better since I adjusted it though. Still same as video.
Heads were done at a machine shop and new guids installed.

[Steve@Rennsport]

Originally Posted by quattrorunner

No. And I didn't scuff the cylinders either. How likely is this to be an issue? Thanks.

Huge.

Blowby accounts for what you have observed and that's why its imperative that a leakdown is done to determine whether the rings have seated or not.

[quattrorunner]

How would I seat them?

[AlfonsoR]

Originally Posted by Steve@Rennsport

Huge.

Blowby accounts for what you have observed and that's why its imperative that a leakdown is done to determine whether the rings have seated or not.

Steve, would you recommend re-honing the cylinders if they have several thousand miles on them but are dimensionally in spec?

[fredmeister]

Originally Posted by Steve@Rennsport

Huge.

Blowby accounts for what you have observed and that's why its imperative that a leakdown is done to determine whether the rings have seated or not.

How does someone scuff the cylinders during the rebuild on slightly used liners when installing new rings? I assume the idea is to break the glaze on the cylinder walls.

Can you comment on the correct procedure.

Also whats the best way to break in the engine and seat the rings once the engine is ready to be started?

Appreciate your time and experience, it makes this forum invaluable.

[Steve@Rennsport]

Originally Posted by AlfonsoR

Steve, would you recommend re-honing the cylinders if they have several thousand miles on them but are dimensionally in spec?

I would not re-hone them, however I'd certainly de-glaze them. If the cylinders were never properly prepared after re-ringing and have been in service for a few thousand miles, it may be difficult to get them properly seated without doing so.

[fredmeister]

Originally Posted by Steve@Rennsport

I would not re-hone them, however I'd certainly de-glaze them. If the cylinders were never properly prepared after re-ringing and have been in service for a few thousand miles, it may be difficult to get them properly seated without doing so.

How does someone scuff the cylinders during the rebuild on slightly used liners when installing new rings? I assume the idea is to break the glaze on the cylinder walls.

Can you comment on the correct procedure.

Also whats the best way to break in the engine and seat the rings once the engine is ready to be started?

Appreciate your time and experience, it makes this forum invaluable.

[Steve@Rennsport]

Originally Posted by fredmeister

How does someone scuff the cylinders during the rebuild on slightly used liners when installing new rings? I assume the idea is to break the glaze on the cylinder walls.

Can you comment on the correct procedure.

I use a red Scotchbrite pad and LOTS of very hot soapy water, scrubbing back & forth along the honing lines.

Also whats the best way to break in the engine and seat the rings once the engine is ready to be started?

Appreciate your time and experience, it makes this forum invaluable.

I do this on the engine dyno so I have full control of RPM, load, oil temperature and cylinder head temperature.

Simply put, drive the car with high load and low RPM. Accelerate hard (full throttle) in 3rd or 4th gear from 2K to 5K RPM, then immediately release the throttle and coast down to 2K again. Drive it nice for a mile or two and repeat the process many times, cooling it off well between passes.

When leakdowns are in the 2-4% range, your rings will be mostly seated.

[KTL]

On my last rebuild I re-ringed my nikasils exactly how Steve described. I used red scotchbrite to clean up the cylinder walls and thoroughly washed them with hot soapy water (Dawn soap is a good choice IMO) several times.

Its hard to know just how much rubbing you need to do on them. So just try to be somewhat uniform in covering the whole cylinder surface. Because you won't get any visual indication of your work. Meaning, you can't see a color or brightness improvement by scotchbriting them. Nikasil is very hard so you're not going to damage the surface with the scotchbrite. In fact, it'll feel like you aren't accomplishing anything.

The new rings seated very nice and I had no problems with oil blowby. My catch can had virtually no oil in it each time i'd check it. I was really pleased with how well the re-ringed cylinders worked. Too bad I smoked the engine shortly after the rebuild.......

[KTL]

BTW this is a good topic/discussion on honing (lack thereof) with scotchbrite

duh......... forgot to paste the link

do I need to hone this?