What else can you expect from used motors...

[rbsileighty]

You'd think I'd be more upset, but really... not like an importer is going to pull the head on a motor

I thought I'd take a break from working on the house and spin some wrenches... check out what I found when I was pulling the head on my spare motor:



Time for a rebuild... to bad it will be after the bathrooms are finished in the house. I might pull the one in the car to see how it looks inside, but I'm thinking I'll just rebuild both... my feelings on running used motors is changing the more I dig into them. One if not both motors might end up as 2.2L's... so keep your eyes open!

[Carl H]

perhaps im not seeing it but whats wrong?

[audtatious]

Valves dug into the piston top?

[wild_maxx]

stock pistons don't have valve relief cuts in them?

[Coolwhip]

detonating = pits on dome of piston.

As well, I'm not familiar with RB20 pistons so if they don't have valve reliefs than the problem is appearent.

[rbsileighty]

The arrow is pointing to it in this picture... there is a pit in the piston... probably 1-1.5mm deep

[Coolwhip]

Yup.

I wonder what else was done to the motor to start detonating? Maybe some wack a** timing. or poor fuel, bad plugs, high boost. Probably poor mantainace throughout.

[Darius]

I've never seen stock RB20 pistons, but I know the RB25/26 pistons do not have valve reliefs like that. Is that normal? What is the condition of the valves?

[rbsileighty]

I'll take more pics tonight... pistons are normal... cyls were rather black, so maybe they had a lot of buildup which lead to detonation w/ concentration on some deposits => localized explosion => pitting... maybe... just a guess
Modified by rbsileighty at 10:32 AM 10/10/2007

[rbsileighty]

Haven't had time like I thought I would to take pics... but hopefully I will by the weekend.

Might go ahead and pull the head on the one in the car as well... just have to figure out where to put it in the garage (that will be 3 motors sitting on stands (2 RB20's and 1 5.0L... ha... don't ask...)

If there are things people want to see while I have the heads of these motors off... let me know
Modified by rbsileighty at 4:10 PM 10/10/2007

[blurrbosi]

Is the one in the car running badly or do you just have an itch.???

[rbsileighty]

headgasket blew last year when I was on the track... not sure what else might have been damaged, so I'll find out soon I guess

[DriftX]

Are you building a fox body mustang? You said you had a 5.0L in the garage!

[rbsileighty]

Are you building a fox body mustang? You said you had a 5.0L in the garage!

No... thought about putting it in my 85Z, but we'll see... I have a header design I want to try on a V8 and this one was $200... only time and money right?!?!

[ripracer]

I just picked up two 2 rb20's, 1 de, 1det, and also have one det running in a sil80. I plan to run 80mm pistons in my "race" motor, I think that is 2.2L. Then build another with maybe the pistons from tophateperformance they say 78.5 and don't seem like a bad price.

Cheap way to do it would be gasket kit and new rings, might as well do bearings too.

My rebuilds will probably take up the next year or so, that is just for one to be completed. I love buying RB parts. Who knows might even try to do the infamous 24det with the other block.

[craz4240]

RB22 is with 82mm pistons,rb20 rods and crank.

[ripracer]

isn't hat quite a bit to go up in size? stock bore is only 78mm

[themadscientist]

looks like an NA motor. My CA18DE pistons look exactly like that.

[Adrian gt]

The arrow is pointing to it in this picture... there is a pit in the piston... probably 1-1.5mm deep

that's to lower your compression to run more boost, trust me it will be fine

[craz4240]

Thats he size though my friend.....