I have an 01 galant that is a race car. I did an oil change and used 20w50 and a quart of Lucas (at the recomendation of a friend) and now there is a loud knock in the top of the motor which is quite loud under startup and idle but quiets down under acceleration. Any ideas what to do so my motor dont blow up?
Dan, I See You’re Into “Web Racing”. Is This A “Virtual” Race Car Or A Plastic And Steel Race Car ?
What kind of racing do you do ?
CSA
I race 4 cylinder cars at a local race track…I just drive them though I dont know much when it comes to fixing them…obviously.
Was it knocking at all before the oil change?
There was a slight knock but not as loud as it is no…nothing that worried us when we bought it.
And your mechanic did not think that a knocking engine was a bad sign for a car that will be driven at high RPMs???
There was more than one person present when we bought the car…we paid $150 for it…and everyone there agreed that the motor was still strong…I only race 20 laps against other 4 cylinder cars its an automatic so I dont get really high RPMs its a short dirt track…Like I said i just drive them.
You are using too heavy an oil for this engine. The lucas thickens it up even more I think. I’m not that familiar with the lucas product. The engine was built for lighter oil, likely 20-30 weight range, probably 20 weight. Probably not enough lubrication getting to the top end at lower rpm because of the increased viscosity.
I was thinking that but I was told that since the higher temps thins the oil it wouldnt matter. Should I do another oil change without the lucas? If so what oil should I use? It was only run for a short time…5 laps and load and unload off the trailer so Im hoping I can avoid major damage.
Well, my opinion is that it’s just too heavy an oil. I looked at the lucas product and I assume it’s their racing oil at 20w-50 as well. You can reason that racing runs higher temps thinning the oil, but I don’t think that’s the case. If your cooling system is working as it should, you are not going to be running much higher temps if they are any higher at all. The final number is the oil weight at operating temps. You should stick with the weight the engine was designed for. Not sure what the spec is for that motor but probably a 30 weight, 5w-30 or 5w-20. I’d go with a 5w-30. Go for synthetic if you want the extra protection. If you aren’t sure about it, drain the oil into a clean container so you can re-use it later if you want.
If the noise is in the valve train then I would suspect a faulty valve lash adjuster. Faulty adjusters are not that rare.
Remove the valve cover and note if you can feel any excessive looseness in any of them.
As I said I just drive them and usually if its an expensive repair we just run it til it blows and look for a new car. Are valave lash adjusters an easy fix if thats what it is? also since i dont know what im doing is it easy to check? If it helps me diagnose the issue I started the car today and for a few minutes there was no noise at all.
A valve lash adjuster can be a fine one minute, noisy the next thing. The valve cover must be removed and the camshaft at least loosened quite a bit to change these out. It’s recommended they be changed in sets and (ouch) this gets pricy at probably 10-15 bucks a pop. This is what they look like.
Both the 4 and 6 cylinders uses these; just like a lot of other vehicles out there.
If it’s not noisy and appears to run fine then you can probably skip over this for now.
They usually fail in one of 2 ways. Either they collapse (and possibly resurrect themselves as what may have happened with yours) or the end of the adjuster will disentegrate. With the latter they will be noisy all of the time.
Another way of checking for valve train problems is to connect a vacuum gauge to an intake manifold vacuum port and watch the gauge reading. A problem in the valve train will usually show up on the gauge as a shaky needle.