C20let rattle

[pepper]

Hi I have a c20let nova that I've just rebuilt with wossner pistons , steel rods, kent cams, double valve springs, garrett gt3071r etc, it was running fine but now it has got a rattle,not sure if its top end or bottom end. someone told me that it sounds like the top end because the rattle goes away over 2500 revs so got some gm lifters and that still was not the problem, can anyone help or who has had the same problem.

Thanks
Ian

[Plug]

did you fill the lifters with oil before fitting?

or at least sit them in a tube of fresh oil an hour or so before fitting?

[John]

Vid?

[pepper]

Yes, they were full of oil and were in oil for 3 days
the oil pressuse is good aswell.

[pepper]

The only thing I can think of is when I mapped it was running really rich and the oil was thin it might of damaged the bearings
Don't know if that's it tho
http://www.pngclub.com/forum/showthread.php?199527-C20let-rattle&p=2151794#post2151794

[philip]

Problem I've found with wossners is they run a larger piston-bore clearance. Personally won't use them in builds because of the alloy there made from(I know specky ran 600+ on wossners before someone says) could be pistons slap........does the rattle go when engines warm or rattles no matter how long be run?

Another possibility is bore wash, contaminated oil + possible bearing pick up. Do you know what clearences big ends + crank were on assembly?

Also how come your on double springs? I've seen lifters burst between using double springs + an aggressive cam.

What spec are the cams? Just on your build I'd of gone for solid lifters, which then would of expected a rattling sound which would be normal

[pepper]

Hi the cams were a fast road cam and was told that they were good with hydrolic lifters, not to sure about the bearings but the engine was running sweet, thencouple of weeks later it started to tap, I had them cheap eBay lifters in there so I change them to gm ones but the rattle is still there. I have heard about the piston slap on wossners because my mates got them but when it gets hot I can't hear it anymore. The rattle goes away over 2500revs, do you think I should use a thicker oil then a 15 40 ? Have you got what's app so I can send you the vid of it.
Thanks

[philip]

07807 040522 + yeah got what's app. Ebay lifters are crap, but as you have said you've bought gm/ina lifters and still taps. Usualy if goes above /2.5k and shut throttle and hear it knock, that idicates big ends. Otherwise lifters will tap with the revs if makes sense and usually still tap higher then 2.5k.the normal 10/40 semi syn gm oil should be more than upto the job.......unless it is 15/40 now.

[meritlover]

taps are hard to source on the internet.
take the sump off and remove a couple of bearing caps. that's the only way to know and its not hard. the last thing id want is a mis diagnosis assuming its just a lifter and then wrecking a crank and rod because it turned out to be a big end shell.

what is the oil pressure at idle?

if you have doubts about the oil being contaminated, change it and see if theres any white metal flakes that come out with it.

[pepper]

Oil pressure is 25-30psi on idle and goes up when reved.
Gonna take the sump off tonight, I just can't see that it will be them because the crank was polished and are brand new bearings from sbd Motorsport

[philip]

Daft question but was your rocker cover blasted?

Tbf it only takes a split second or a tiny bit of debris to cause an engine to knock bearing out. Even mapping wrong I've seen mates evo's throw rods. If it was massively over fuelling then chances are you've washed bores and may need another strip/build.

[pepper]

Just took off the sump and took off some of the caps, bearing look good so took the head off because oil is getting in to cylinder 3 and found that the piston rings have worn the bores right down and so that's what the knocking was piston slap does anyone know why that's happend? The rings and bore was new
And another thing in the sump is full of metal