Um, yeah. tap, tap?

[Supra]

I have a wierd situation...

I was driving my built up silver 87T around Monday night, boosting to my normal street levels (16psi) every once in a while. I stopped at a park to take a walk for a few before heading home. I turned the key off so the car was running on the turbo timer.

Inside the car, I could hear the motor purring like it always does. As soon as I stepped foot outside the car, I could hear a dreaded "tap, tap, tap". I thought "hells no"! It was consistent like rod knock, but more of a thud than a metallic tap. Anyways...

Checked oil pressure and all gauges - nothing out of the normal. I gave it a light rev & the tapping went away. As the car came back to idle, the tapping came back. I could feel the "tap" in the shifter. I shut it off, did a quick visual of everything. Started it up and gingerly drove it home watching the gauges and listening for any further signs of problems. I heard nothing wrong. Five minutes later, I got home. It was no longer tapping or making any bad sounds. I let it sit over night. Started it cold in the morning, no more tapping.

The only recent changes are that I changed from 10W30 non-synthetic Castrol to 5W30 Royal Purple about 500miles ago. Oil pressure has been great with the shimmed oil pump.

I don't know what to do with it. I wanted to drive it for the rest of the summer and fall then pull the motor to install eagle rods. I'm thinking about sending an oil sample to Blackstone Labs for an oil analysis. If it's knocking, I obviously don't want to drive it. But if I'm just being paranoid, then I'd like to get off my butt and tune it further. Any comments?

 

[againstdawall06]

If it was a tap at idle, it is not rod knock. Rod knock is a loud knock at around 2500RPM ussually. It doesnt necesarly have to be an engine sound, it could be the alternater, PS pump, and alot of other moving parts outside of the engine block. I would check all that first.

 

[starscream5000]

If you didn't say you felt it in the shifter I would have either guessed noisy injectors (doubt it) or valves needing to be shimmed. I'm thinking maybe the RP oil is bringing out a little more valvetrain noise than the other stuff did, but jdub would really know if the RP is thinner at operating temps than the other kind. You may want to take a look at jdub's SME section on oils to see what weights those two oils you were using are at op. temps. to see if my guess is valid...

 

[jetjock]

Me thinks you're worried about nothing but if you want to do analysis you have to leave the oil in there at least 1K miles. That said I'll never understand why people pay a premium for so-so oil like RP when there are better out there.

 

[starscream5000]

Red line and German Castrol for example?

 

[Supra]

Me thinks you're worried about nothing but if you want to do analysis you have to leave the oil in there at least 1K miles. That said I'll never understand why people pay a premium for so-so oil like RP when there are better out there.

I've always been a Castrol non-synthetic guy and even tried to find the elusive German Castrol that JDUB recommended highly. I was under the impression that RP was a decent oil, albeit over priced. I switched to synth because my turbo is now oil only.

To be honest, when you start talking about differences between GC, Red Line, and RP oils...you start splitting hairs with a razor

At least I learned to use WIX filter. :icon_razz

 

[dbsupra90]

rich-

id pull the plug wires one at a time and see if the noise goes away. if it does, you know its motor related. if it doesnt, it could be something like the water pump, flywheel, etc.

 

[Supra]

rich-

id pull the plug wires one at a time and see if the noise goes away. if it does, you know its motor related. if it doesnt, it could be something like the water pump, flywheel, etc.

The only problem with that plan is that the noise has already gone away... :icon_razz

 

[Wills7MGTE]

umm can you get german castrol in the states, I have AMSOIL 10w30 on just a basic tuned 7MGTE auto and it does excellent since I got it in 25k ago. So I odubt I'd switch.

 

[jetjock]

I've always been a Castrol non-synthetic guy and even tried to find the elusive German Castrol that JDUB recommended highly. I was under the impression that RP was a decent oil, albeit over priced. I switched to synth because my turbo is now oil only.

I don't want to open the oil can of worms again but there are differences. If I had to rate 'em RP would be at the bottom with RL on top. RP is a decent oil, just somewhat of a lousy value. As you said, it's overpriced. Besides, basestock does not an oil make. I've never been impressed with their add pack.

Not that your engine requires a Grp 4 or 5. A modern Group 3 will not coke your turbo. These days the razor line is between them and true syns. Since GC went away I've switched to Grp 3 and won't be going back because there's too much evidence showing the differences are nil. That said if you like how it makes you feel by all means use Group 4 or 5. Not spending money on boutique oils the engine doesn't need is what makes me feel better.

 

[starscream5000]

umm can you get german castrol in the states, I have AMSOIL 10w30 on just a basic tuned 7MGTE auto and it does excellent since I got it in 25k ago. So I odubt I'd switch.

Yes, it's only sold at Autozones to my knowledge, but there may be a hidden store out there selling also. Whatever AZ has on the shelf of the GC is it, no more, unless they have some boxes in the back that is .

Like I was saying the other day to someone else. I tried 4 different AZ's, the first didn't have any, the next had like 6 qts. the next had like 17 qts. and the other had 6 qts. I bought every one of them .

 

[jetjock]

Try AZs in, err, economically depressed neighborhoods. It's an old trick I used to use back in the days before most people ever heard of the stuff. It usually sits on the shelf collecting dust because people who live in such areas won't pay it's price. Not that many middle class folks bought it either because well, it's way too thin you know

 

[starscream5000]

And that's exactly what the stuff that got looked like. In the very back, top shelf, most dust covered quart there (had one of the highest prices too) .

 

[Supra]

Not that your engine requires a Grp 4 or 5. A modern Group 3 will not coke your turbo.

- German Castrol is a true synthetic oil…no Group I, II, or III base stock at all. IMO this is important for a turbo car considering the heat produced by the turbo. I did not want any problems keeping my SP61 turbo cool (it’s oil cooled only) and avoid any chance of the oil coking on engine shutdown.

I'm a bit confused. Am I mis-reading JDUB's information? I have an oil only cooled turbo, so I thought I should be running a synth oil? I can't find redline or green castrol here, so what's the next best option? What are some quality Group 3 oils by name?

FYI - I'm pulling these quotes from here: Oil thread

 

[starscream5000]

Penzoile Platinum 5W-30 is on the top of my list as a good group III, that's what I run in my DD and has very good properties for a hydrocracked oil. It sounds like jdub is erring on the safe side of things by going for a syn oil in his oil cooled only turbo for peace of mind .

BTW, Green German Castrol is damn near impossible to find anymore. The newer Gold colored German Castrol is almost as good as it's predecessor .

 

[Supra]

Penzoile Platinum 5W-30 is on the top of my list as a good group III, that's what I run in my DD and has very good properties for a hydrocracked oil. It sounds like jdub is erring on the safe side of things by going for a syn oil in his oil cooled only turbo for peace of mind .

BTW, Green German Castrol is damn near impossible to find anymore. The newer Gold colored German Castrol is almost as good as it's predecessor .

Nice. Before reading JDUB's thread I bought 6 quarts of Penzoil Platnium and then put it on my shelf and bought 6 quarts of RP. :icon_conf I'm going to do a bit more troubleshooting tonight. If I find nothing, I'll change the oil to penzoil since I already have it and keep my fingers crossed. Maybe I'll cut the filter open to set my mind at ease...

There's nothing wrong with 'peace of mind'. :icon_bigg

Thanks for all the advice, even if we're off topic a bit. :naughty:

 

[jetjock]

No, you're not reading dub wrong. Just that I'm not as locked into that belief as he is. I used to feel that way too but no longer. He's just being conservative. As mentioned PP is good. It's what I'm currently using in a 5-20. These days I buy oil based on sales and promotions. That way I get it cheaper than usual and don't lock myself into to using one particular brand. Anyone who tells you that's bad doesn't know much about oil.

SS: GC gold is what's been discontinued at AZ. The green should be long gone although I've heard of people still stumbling upon it. I haven't found any in years. GC gold is still stocked in Canadian Walmarts though. Appears the folks up north know something about oil and cold weather many Americans never cared to learn.

 

[starscream5000]

Yeah, jdub stumbled upon the Green GC and found an easy way to see if it's the Green or Gold, if the production date on the bottom of the qt is '04 or older, then it's the Green. If it's newer than that, then it's Gold. All of mine were made in '06. That's why I said they were damn near impossible to find, but just like you said JJ, there's probably some hidden in a dark, dusty corner at the local AZ in BFE .

 

[Supra]

So a little update... I made short drives to and from my house last night with no problems. (Tuned Vf to 2.5v in the lower/middle range on the MAFTPRO too.) Parked it for the night. Drove it to work and the sound is back.

The sound is definitely not rod knock although it's a tapping in sync with the motor. It is only audible from the lower sides of the car. If I pop the hood - I can't hear it. When it's making the sound, the engine feels out of balance but it's not misfiring. I can still feel the 'tap' in the shifter.

I think it's the clutch, or maybe more damage to the tranny. I've read about RPS PP having 3 rivets now to fix some sort of problem, and someone else posting that they had done a pass at the track and the car felt out of balance afterwards. Mine has no rivets. I'll have to dig up those threads and see what that was about.

I just walked back out to the car to see if the problem goes away when I depress the clutch... Car started and it's not tapping anymore. Arrgh I hate not being able to reproduce a problem... :3d_frown:

 

[starscream5000]

You may want to try placing a stethescope (sp?) up to the bell housing to see if it's coming from in there. How fast of a tap is it? How many times do you hear the tap in one second?