sludge??

[rockyrunner99]

this may or may not be oil related... But what causes the sludge on the top of the valves in the intake side of the head? I have a rebuilt head I put on about 3500 miles ago, I am having bottom end engine problems now. Anyway, I am tearing it down, and there is quite a bit of sludge and gunk on the top of the intake valves already. I am running e85 too, I thought that was supposed to "clean things"?

 

[Quest]

unless the head hasn't been serviced properly (excessive valve guide clearances, valve stem seal not replaced, etc.) otherwise, if the deposits on the back of the valve is hard and black (crusty), it's most likely due to poor gasoline; if it's soft and oily, it's motor oil.

Even though there's federal mandates on the bare minimum requirements on consumer automotive grade pump gas detergency and such, no 2 brands/formula of gasoline are created equal (thus the "top tier gasoline").

Q.

 

[JayhawkRoy]

Do you have a flex fuel vehicle? E85 (85% ethanol blend) should not be run in normal gas vehicles without conversion. Do you mean E10 (10% ethanol blend)?

 

[OilGuy]

E85 is harsh on oil - breaks is down faster.

 

[rockyrunner99]

It is not a flex fuel vehicle. It is an E*% vehicle now. I installed 40% larger injectors and a fuel controller to tune with. It was not tuned exactly right at first. It was rich as [censored] for a while.

I had the head completely rebuilt 3500 miles ago, new valve seals. valve job, and resurfaced.

 

[Drivebelt]

What type and weight of oil are you using?

 

[mpersell]

Possibly recirculating some blowby or ventilating stuff out of the crankcase? Thermostat too cold? Look on the bottom of the pistons to see if you have a lot build up there too.

 

[Rodmiser]

A tank of E85 then Reg gas, then E85, then Reg gas. read your book.

 

[Gary Allan]

Quote:
I am having bottom end engine problems now.


Do you mean bearings ..or "other than the head" issues? I've seen more than a few heads replaced where the blowby increased just due to the valves doing their job.

This would (probably) explain your relatively heavy deposits on the refreshed valves.