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Newer stroker Oil analysis
Posted: December 5th, 2014, 3:24 pm
by Yjwes
Built a mini stroker for my yj. 4.0 block 3.8 crank sealed Power Pistons, comp cam,roller rockers....... All the basic stuff. Put engine together got running broke in cam as per instructions with break in oil .changed oil filter ran the engine hard about an hour then change oil and filter again using 15w-40 with zddp zinc additive. Engine runs awesome makes great power but the the other day I thought I smelt fuel in the oil I did a few simple viscosity tests and it dident seem thin but thought I would send it out any ways. So I got the results back today and all tho there is A little fuel in the oil I'm attributing it to starting it with out it getting up to temp a few times...... My main concern is the amount of Metals In the oil. Is this normal for a freshly broken in stroker jeep motor? Engine only has about six hours on it total also engine runs on 50/50 of 93 and vp 101. What do you guys think?
Re: Newer stroker Oil analysis
Posted: December 5th, 2014, 5:06 pm
by SilverXJ
With only six hours of run time metal content should be high, but yours look a bit higher than I would expect. Silicon level is alarming. Why are you running race gas?
I also would suggest that you remove your personal information from the oil analysis attachment.
Re: Newer stroker Oil analysis
Posted: December 5th, 2014, 6:06 pm
by Yjwes
The 50/50 race gas is because I'm
Running around a 11.1 cr I hear ya with the silicon level but there's no way it's getting dirt past the air filter
Re: Newer stroker Oil analysis
Posted: December 5th, 2014, 8:02 pm
by SilverXJ
Silicon could also come from gaskets and RTV. Dirt during assembly and the machining process is also a source. Sandblasted parts not thoroughly cleaned can be a source as well.
Re: Newer stroker Oil analysis
Posted: December 6th, 2014, 5:07 am
by Yjwes
I played over the Machining process in my head and it's very possible that the head was port and polished after being cleaned..... I'm sure they blew it out and brake cleaned it but that deff could still leave some silicon in there from
The stones and/or sand paper rolles.As for removing my contact info on that pic can I edit my post if not can you as a mod just delete the pic and I'll repost it without the contact info
Re: Newer stroker Oil analysis
Posted: December 6th, 2014, 9:25 am
by Retlaw01XJ
What do you guys think of the high Tin, Lead and Copper levels?
That could be bearing material. Shouldn't be a wear item, especially the copper which is base material.
Silicon is also part of the piston composition... both the aluminum and silicon levels are comparatively high....silicon is 18 times higher than normal, and aluminum is 25 times higher. Maybe piston wear accounts for some of the silicon. Are they hyper pistons (higher Si content)?
And is Silicon used in the cylinder hone stones?
I'm not an expert on oil analysis, just throwing some ideas out for your consideration.
Re: Newer stroker Oil analysis
Posted: December 7th, 2014, 3:42 pm
by SilverXJ
Silicon is used in cylinder hone stones. What is your AFR like?
Re: Newer stroker Oil analysis
Posted: December 8th, 2014, 4:02 pm
by Yjwes
Running about 13-1 WOT
Re: Newer stroker Oil analysis
Posted: December 8th, 2014, 4:07 pm
by SilverXJ
Thats good. What about idle?
Re: Newer stroker Oil analysis
Posted: December 8th, 2014, 4:44 pm
by Yjwes
I would have to go out and start it but it's prob in the 14s
Re: Newer stroker Oil analysis
Posted: December 8th, 2014, 5:09 pm
by Yjwes
I would think a cylinder washdown condition would put more fuel in the oil ....I guess my pan of attack is to drop the pan pull a few caps rods/mains look over the bearings pull the pump look that over and look up from
The bottom at the cam lobes ...might need to use a inspection camera for that. If all looks good change the oil run it some and retest the oil