Engine knocks after starting, thoughts?
 

It's chris here again with my many questions about my SVX. So I've noticed that when I start my car in the morning, it's smooth at first and then about 10 seconds in, it starts to knock. I can hear a "tok tok tok tok". Kinda sounds similar to my XR350R Valves sounds. Less of a tap, and more a knuckley knock. It does that for about a minute or 2 and then it stops knocking and sound normal. Another issue, and they may be related, you tell me. Is that when the car is in drive or reverse and it is not rolling or moving it vibrates. And it's not a subtle vibrate it's a pretty good vibration that even makes a buzzing sound in the interior. When it's rolling or driving it doesn't vibrate like that. I'm more concerned about the knock but I would like to adress both. I recently sold my other car and am now at the point where I have some money to spend on it. I want to fix the body damage but Idk how serious this is and it may be better to address this first. Not sure. Just looking for some thoughts or suggestions. Also highly interested in some "Do it yourself" work.

Also important to note:
Recently changed the fuel filter
Previous owner used regular gas like a blockhead
Bought denso platinum spark plugs. Will change them soon.
New tranny mount on it, retro fitted from a legacy tyranny mount. (Done at a shop)
Recently cleaned the throttle body and the MAF sensor.
(While doing that job, I found a lot of brown oil in the intake tube past the MAF sensor, but before the throttle body.) Throttle body was pretty gunky but after I cleaned it, it didn't seem to affect anything.

Thanks guys, cheers.

Re: Engine knocks after starting, thoughts?
 

Timing belt tensioner maybe, when I put my engine back together mine **** the bed and made a pretty hard tok while running.

Re: Engine knocks after starting, thoughts?
 

Possibly but wouldn't that be consistent? It only knocks when it's cold and it goes away in a bout minutes. I feel like if the timing belt tensioner was off, it would be knocking constantly

Re: Engine knocks after starting, thoughts?
 

Piston slap?

My #6 cylider is slightyly oval at the bottom..... out fo spec, but the wall still has all the cross hatch visible.

The piston skirt slap can be heard for a few minutes - then it quiets down totally.

I did not think this would justify reboring and piston replacement - everything else was still within new engine spec.

Just a thought.

/T

PS Maybe a leak / crack in the exhaust?

Re: Engine knocks after starting, thoughts?
 

Piston slap. Sounds viable. It only has 77k on it so I can't imagine what has happened to it that would have created that issue. Could it have been caused by not running the right octane fuel? Previous owner used regular.

Re: Engine knocks after starting, thoughts?
 

Try giving it an oil change and new OEM filter. Can't hurt.

Re: Engine knocks after starting, thoughts?
 

Might be worth trying SeaFoam in the engine before your change. There are a few results in Google that show success with SeaFoam quieting their engines.

Re: Engine knocks after starting, thoughts?
 

Oil just changed. Almost a thousand miles ago. Plan on changing it every 3 thousand. I've used Lucas oil fuel injector cleaner. I will try seafoam, can't hurt. I also have Lucasoil oil stabilizer. Might use that. My dad suggested marvel mystery oil. Did not put an OEM oil filter in it, I used a K and N.

One thing want to address is the air filter I put in it. I've read that your not supposed to use oil based air filters for the sake of not ruining the MAF sensor. So the only dry filter I found for the car is some shifty 11 dollar off brand that may also contribute to the engine not running at 100%

Re: Engine knocks after starting, thoughts?
 

That noise could possibly be the valve lash (for lack of the right word) lifters, our cars use oil filled "lifters" normally they fill with oil and they stay full even after shutting down but after long sitting they do drain.

I have used seafoam many times I think it is wonderful stuff, put a few ounces in the oil and run it no more then 50 miles is my personal recommendation, it will clean dirty gunky oil passages. Also be sure to use it in the vac system to clean the tops of the valves and the intake track from any and all oilly gunk. then put a small amount in the fuel tank it acts as both an injector cleaner and additional carbon deposit remover.
The problem with oil type air filters is too much oil (user error) will allow some of that oil to coat the maf sensor as its pulled through the system.
I believe I mentioned this before but the gunk in the air intake is from the pcv system not much you can do about it other then to make catch cans or just let it vent to atmosphere.

When was the last oil change before your oil change 1k miles ago? it may need a shorter oil change interval while it "cleans" up the engine.

Re: Engine knocks after starting, thoughts?
 

Speaking of the MAF sensor, I clean my MAF every oil change with some spray cleaner.

Re: Engine knocks after starting, thoughts?
 

Thank you for the advice. I already went out and bought a bottle of seafoam. The last oil changed was supposedly done right before I bought the car, but I didn't trust it, and sure enough when I changed the oil it was not great. It still had a decent consistency but it was pretty dark and I wanted it out. I Put in full synth 10w30 I believe. Don't remember the brand but I want to say valvoline. It's color is still very nice and I'm about 1500 miles in on it. It is draining slowly tho, so I'm keeping an eye on the levels. I'm not sure but it looks like the valve cover gaskets might be leaking. But there's definitely a considerable amount of oil leaking. The pan gets greased up real fast. I'm really unsure of where to take the car because I want someone who knows the SVX to work on it and if possible to have me there to observe and learn. That thing about oil lifters also seems like that could be the case. I'll have look into that. I'd like to adress the issue with the pcv but I have to worry about the trans and the engine Leaking first.

Re: Engine knocks after starting, thoughts?
 

Its more than likely piston slap. Although typically that is heard during very cold starts in the winter but hey, its been years and many heat cycles on the engine you could have an oval cylinder, they are pretty common on these engines. Nothing to freak out over though so long as you give it time to warm up before putting the engine under a heavy load.

Tom

Re: Engine knocks after starting, thoughts?
 

Okay thanks Tom. I always let the car warm up and let the idle lower before I drive it and I won't accelerate hard until the car is up in the operating temperature range.