Rhysin

I can post a video later if it'll help, but I have a semi-loud inconsistent knocking coming from the back of the engine (not sure if it's the engine). THe knock is ONLY at idle. It disappears completely the second the car gets even a little bit of gas. As of now, I am running 10w-30 royal purple due to the heat out here. There are no codes or CE lights on.


It's a 95 lt1 trans am with a 4 speed auto. The trans was rebuilt 30k ago but the engine is stock at 165,000. The only mods I have are intake, elbow, headers, hypercrap tune, 160 thermo, exhaust, and some weight reduction and small stuff.


If you have any ideas or need more info let me know. My shop is about an hour away and I am not sure if I want to drive it out to the shop when it's like this.

defaultexistence

iTrader: (11)

Cracked flexplate? starter and flexplate touching? Did it start post trans repair.?

93 LT1 Vette

Check for a broken motormount. The engine shakes alot more at idle then under a load. Could be the y-pipe or cat hitting the tunnel. Most anything else would be heard above idle. I.E rod, lifter or tranny issue. Could be flexplate or starter as stated above.

96capricemgr

iTrader: (1)

10w-30 is NOT necessarily thicker at operating temps than 5w-30, matter of fact there are some cases of manufacturers making 0w-30 5w-30 and 10w-30 and the 10w-30 being the THINNEST at operating temps by a long shot.

Don't think I have ever seen RP do well on the street either, good results in short interval track cars but not the street.

This is in addition to what the other guys said as they had good info to offer. I just wanted to let you know your belief in RP and your belief that 10W-30 is better for heat are both wrong.

Rhysin

What would you suggest I use for my next change?

Also, so far I've checked the starter and that doesn't appear to be it. The motor mounts are definitely in need of a change so I'm thinking it's that because my headers did knock before.

Rhysin

Alright I put it to the test and it appears to be the reflex plate as someone above mentioned. Any idea how long the replacement process for this would take? I can get a replacement cheap.

96capricemgr

iTrader: (1)

Glad it is a cheap and not too difficult fix, the tranny does need to be slid back, how long that takes depends on who is doing it and how well equipped. Someone with good tools and experienced with this car I would think could do it in a couple hours in the driveway. If you are not that mechanically inclined and the car has never been taken apart and everything fights you a newb could spend a day.
You said 30K on tranny so at least the fasteners should not be too corroded unless some cheap replacement stuff was used on the exhaust.

When an enthusiast works on a particular model a LOT they get to know exactly what size every fastener is and can make a project go very fast, a newb will inevitably ens up trying 3 wrenches and a socket and some combination of extensions and all sorts of stuff before he figures out what works for each fastener and running for tools pushes the amount of time it takes way up.

turtle93

As far as oils go I use good ol Mobil one full synthetic just like the owners manuel says to
Works in a zr1 see no reason it won't work in my old lt1 lol

96capricemgr

iTrader: (1)

The CORVETTE owners manual saying M1 is preferred is due to MARKETING not it being the best oil. For a long time M1 showed consistently elevated iron wear in LT1s, formulas change so I can't say that is current, but to blindly believe M1 is grand is nothing but an expression of ignorance.

warriorcustoms

iTrader: (10)

If you wanna run stnthetic Amsoil is good oil I have a few buddys that used to run RP till I told em about 1 offshore boat that fragged 3 lower units from RP Switched him to Yamalube & it never happened again!!! I wont ever use RP in anything Amsoil, Castrol, or Valvoline are good in my book But so is Mobil 1 LoL Never seen any study that said Mobil 1 is **** LoL We used it in Hummers in the ARMY As long as its changed on a regular basis Theres only so many Oil Refineries in the US LoL most Oil Products are ReLabeled products anyway Like fuel comes from the same tank companies just put their additives in the Bulk Fuel when it hits the tanker Go watch a fuel storage unit

turtle93

Never said its the best just that its worked good for 155,000 miles and 20 or so bottles on a 100 shot. Like I said they still use it in the brand new vette's so I'm not changing any time soon just my 2 cents

96capricemgr

iTrader: (1)

Nobody said M1 is ****. LOTS of ignorant folks believe is it special and perfect for the LT1 and that is bullshit.

People want to see dyno and track numbers for performance mods but never bother to look into Used Oil Analysis which is only $20-25 and can tell you if the oil you choose is actually working well under your circumstances in your application.

The link is dead now but there was a comparison of M1 vs. Amsoil in an LS1 and while neither came out smelling like a rose the M1 fared worse with the oil analysis company recommending changing it before the guys were ready to drain it. No damage done but nowhere near the wonderlube the blind faithful will have you believe.

Realistically with the 3K mile interval most still use about any current API rated oil will do if it is vaguely near the recommended viscosity range, but there are definitely a few expensive oils that do not provide additional performance for their substantial additional cost.

Rhysin

So now that the oil question has been dealt with. Can someone link me to a guide on replacing the reflex plate or at least some guidelines? I have no experience with my trans at all.