Max Power NA 7afe ????, Dyno Charts Posted Options

[Bitter]

damn, i wonder what failed? just ****ty machine shop work or an actual part problem?

[94celicadude]

well either the machine shop bored the block out bigger than needed for the pistons, or they incorrectly installed the piston rings, but either way all the probelms that we developed from that are linked to an improper assembly of the bottom end.

it is a real shame too cuse they were highly recommended to us, and it seems like they may have messed up. Hopefully they will be nice enough to help us repair the problems and situation.

[hurley97]

Now on a side note, for those of you that have rebuilt a 7-AFE motor, i am wondering if you have ever had any issues with the motor burning oil.

I just did an all highway trip, the motor having about 4000 miles on it, and it was just a straight 200 mile trip on the highway at approx. 70-75 mph constantly.

I had filled up the oil to the full line before leaving for the trip, and then after coming home and letting the car sit for several hours, i checked the oil level and it was 3/4 of a quart LOW!!!!


Now i know that it burns oil on overrun, if i let the engine slow the car down in a gear, as soon as i step on the gas again, it puffs a cloud of blue/ white smoke.

I also know that that comes from bad valve guide/ seals, and the thing is that both were replaced in the rebuild.

Does anyone know if there is a difference in between the intake valve and exhaust valve seals? and could my head builder have possibly swapped the seals from one side to the other...so having reversed them from where they are supposed to go?...

I would love some insight on this before i decide that i am going to pull the head and replace, once again the valve guides and seals, hoping that this time they will do their job.

I know you've already figured this all out but I thought I'd answer some of your concerns anyway...

First, my rebuild 7A consumes almost no oil at all. I had already changed the oil 3 times within the first 4k miles then again when I needed to swap the head, all those times I hadn't really checked how much was taken out since I did it at work and emptied it right into the waste oil container.
The last oil change (before the turbo install since I changed it then as well) I did right outside the house and emptied the used oil back into a container to find out if there was any consumption. There was about 13k miles on the motor at that point, I took out just under 4qts, when you account for residual oil in the pan and the filter full of oil it was probably a hair over 4qts, which is just what I put in.

Second, blue/white smoke on start up is valve seals, smoke while your driving is an indication for the oil control rings on the pistons.

Third, the valve seals are generally the same sizes but the rubber on the intake and exhaust seals are different. It probably makes no difference but the valve seals with the darker rubber part are the intake seals and the ones with the lighter gray rubber part are for the exhaust side.

[Bitter]

are you burning coolant? i'm sort of wondering if you dont have a head gasket failure!

[94celicadude]

no there is no coolant being burned. The head gasket was intact when i removed the cylinder head.

The problem is truly all with oil consumption, i had a problem with the car burning oil on over run, when u get up to 75 in third and just let the car slow down in third to about 50 and then just step on the gas normally, a big blue puff of smoke would appear...that was caused by the fact that there was too much pressure from the crankcase, and it blew oil back up and was sucked past the valve stem seals on over run, i managed to solve that problem before i even pulled the head.

But there was still an extremely high oil consumption, hence the 1 quart for ever 200 miles driven...NOT NORMAL.

I do understand that there are different types of rubber for the valve stem seals, and i hope the shop assembled it correctly, my guess is that one rubber is slightly more heat resistant than the other, for the exhaust valves.

The only thing that we can assume is that there was a mistake in the assembly of the bottom end, ie the pistons rings were placed incorrectly or the bore on the block was not properly matched to the piston sizes.

Once again, i will be able to tell what the real problem is once i have pulled out the pistons, until then these are only assumptions.

I appreciate the thoughts and inputs from everyone, please keep them coming i am always open to suggestions.

Thanks again

Matt

[7afe_carina]

**Waking up the dead**

And then the thread just ends before he told what the problem was...
Like reading a book where the last pages are ripped out