GTR Forum banner

1 - 20 of 46 Posts

·
Registered
Joined
·
807 Posts
Discussion Starter #1
R34 Gtr Vspec, Coverd 60000 Miles, Car has approx been 530bhp since the clock was showing 20000.
Engine had hks 1.3mm Head gasket, and uprated Cams profile unsure unless check receipts.

Started wat sounded like a rattle, Thought it was something to do with the head or cams, so i changed oil from millers bk to a 10 40 Mobil 1. No change. The noise got a little deeper, so everyone i asked said it would have spun a shell, as there quite common.
.















Was very surprised to find wat the problem was.



It had also taken the oil squirter out aswell.












Engineer has seen all the engine and is very surprised how little bore wear there is, and how good the crank looks.
so moving along nicely and see wat the next 4 months brings.
 

·
Registered
Joined
·
807 Posts
Discussion Starter #7
Block pistons and crank have been sent away. Thinking of the same really 550bhp i think daz.
 

·
Registered
Joined
·
6,560 Posts
Interesting that after discussing Pro's and Con's of squirters on another thread we now see an exact example of a motor running oil squirters and cast pistons with the releif for the squirter weakening the piston.

R32 Combat will be interested to see this I'm sure.

Do the pistons you have have the releif in the skirt in the piston? I presume they do, but if not, it might be worth considering not re-fitting the oil squirtes, just block off the ports in the oil gallery.

Rob
 

·
Registered
Joined
·
807 Posts
Discussion Starter #10
you will have to explain wat you mean with the piston. i can get more pics soon.

Do you think the piston broke first, must have surely?

piston must have been rattlin like a good un in the bore lol.

 

·
Registered
Joined
·
6,560 Posts
On the bottom of the skirt on the thrust side of the piston there should be a small releif so the piston will clear the oil squirter at BTC.

The top of the pistons you have shown look very unusual for a RB26, thats why I thought I'd ask if the pistons you have are RB26 specific.
 

·
Registered
Joined
·
1,855 Posts
Wouldn't you think that with the skirt breaking like that it would be down to the map??
It's the only time I've ever seen a piston break on the skirt like that?!
You've surely got to get to the bottom of this before rebuilding & running Matt,
How long did it last after the recent re-map? (ie miles)
 

·
Registered
Joined
·
807 Posts
Discussion Starter #15
Nothing to do with abby map. Yes was rich but was all okay. Part throttle was a little jumpy in the tables but not to bad.

Ive allready come to my conclussion how longs a standard piston goin to last at 540bhp? It has done around 30000 at that power.
 

·
Registered
Joined
·
1,855 Posts
(i might be wrong) but...if it did 30000miles on the abbey map, and countless trackdays, then was re-mapped and had 60 or so bhp more and it broke the skirt on the piston in how many miles....? id just wonder if it was the standard piston on ''its limit'' as there have been a few standard internal cars making good power and lasting.. just seems very odd! maybe wrong...
whats the experts view on this...
what mileage did it do after the second re-map, before this happened, around 2-3k or something?! it'll be interesting to see if we can get to the bottom of this :thumbsup:
 

·
Registered
Joined
·
277 Posts
My mates piston did the same and that was down to dett do you not think that abbey can't map a car after all these years, you tend to run them a bit rich for a reason on cast pistons. second pic from the bottom looks like dett to me as well.
 

·
Registered
Joined
·
807 Posts
Discussion Starter #18
There was no dett wats so ever. The map was still rich.
Countless track days??? hardly any.

If you have a set of standard pistons thats had alot of hard use, then to me its not rocket science that its basically worn out.
Yes i pushed a little more power as the map was so retarded it was crazy. The week point showed up.

I have no issues, guy whos looking after it mapped every noble in the country. has mapped for 20 years using every method possible. Maps Time attack cars. So wen we was checking the map, there was no dett, feuling was fine.

540bhp on standard pistons thats covered same horsepower for 30000miles is doin well in my book.
 
1 - 20 of 46 Posts
Top