Style_Front

I have been down on power for over a year and never really looked too much into it. I never had any symptoms like oil in my water or water in my oil. I consume a quart of oil every 5000 miles but by then I just do an oil change anyway. None the less, had the E55 apart to replace the MAP sensor, all gaskets on the upper end, cam angle sensor, knock sensors, spark plugs, etc when I did a compression check today and numbers ranged between 55 psi and 165 psi. They were all over the place. Car never misbehaved (apart from being down on power), never threw codes affiliated with a blown head gasket and never consumed fluids at a crazy rate but here we are and the compression tests were UUUUUgly.

I already have the blower and valve covers off for gaskets, how much more work and money does it take to also replace head gaskets?

hayseed

iTrader: (2)

curious why do you believe a head gasket will correct your compression numbers or are you sending your heads out for valve work too ?

Style_Front

Im not convinced of anything really. The heads are coming off whether they need work or not and I don't really know the steps involved with that.

Pieter Schepers

This should help.

Style_Front

I've definitely been watching his videos. They've given me some insight for sure but leave me wondering how different the procedure will be with the engine still in the car.

I saw a different guy working out of the car from his garage tied his timing chains up and suspend them from his roof, he also ziptied the chain to the sprocket to keep everything mostly assembled but his video was short and about another topic.

Ive never been this far into the guts of my car so feeling a little out of my element lol

Pieter Schepers

I took the heads of my engine when it was still in the car. It's possible to remove them without taking the engine out. However a couple of the bottom bolts near the firewall are impossible to take out of the head. But if your careful you can undo the bolts, lift the head slightly and slide it forward with them in it.

My engine is apart as well and I'm also looking for a repair manual.

SICAMG

Honestly those videos 1-6 will cover everything you need to do . Mine will be out this Saturday and those videos will be a big help.
It's nice to "see" it live sometimes than read it.

tw2

Have you done a leak down?

C32owner

Couldn't agree more. They are lifesavers at times.

Style_Front

unfortunately I don't have access to a leak down. Im sooo not a mechanic. Im a fireman being coached by another fireman that knows more than me.

tw2

If the car is still in one piece it might be worth getting it done. I don't do it myself, you need quite a bit of equipment and some expertise, I would rather pay a shop to do it. It will show you whether you have blown HG, leaking valves or piston rings. If HG, it can tell you whether the problem is between cylinders, coolant system, oil channels or just to outside (in the case of a closed deck block). It isn't mandatory but it is nice to know what you are chasing and whether you need a valve grind or a resurfaced block etc.

Style_Front

My car is currently dismantled at my fire department. Should I reassemble, install the supercharger, take the car to a shop to have a test then bring it back and disassemble it again? Or if im going to have to go in anyway, can I not just take the heads off and identify these things once removed?

tw2

Definitely don't put it back together for this purpose. I wasn't sure if you had it apart currently or in the past and now contemplating dismantling again. You can't check valve leaking very easily with the heads off for example. Same with piston rings. However if you are going to replace the piston rings anyway, resurface the block and heads, replace the head gasket and get a valve job then it doesn't matter.

Style_Front

I definitely do not want to go into the block if I don't need to.

Sulaco

no matter what you do, if you leave the piston rings alone and put it back together, there's probably a 50/50 chance it was the piston rings and you just wasted time and money.

there are tests you can do to see if the rings are bad, but it's too late with it apart. excessive crank-case pressure would've been a dead giveaway (exhaust gases escaping around the piston rings and into the crank case)

tw2

If the heads are still on you can still do a leak down. As above, you may miss something and need to do it all over again. It involves taking a spark plug out of a cylinder and attaching an air compressor and measuring how much pressure loss you get in each cylinder and working out where it goes.

Style_Front

I'm soliciting mobile mechanics to see if someone can come do the leakdown. Everything above the heads has been completely removed and the plugs are out, after the compression test **** the bed I just assumed I would start figuring out how to remove the heads.

Style_Front

So one of the mobile mechanics was like yo leak down is sorta pointless. He said just squirt oil into spark plug holes and see if the compression test numbers increase. He said if pressure goes up, bad rings. If pressure stays the same, gasket or valves.

hayseed

iTrader: (2)

that is true but leak down test is more accurate - if you did not touch your head bolts/cams you should be able to do this simple test

Style_Front

Yup, heads are untouched. One dude agreed to do the leak down on Monday but ill still do the wet test as well. Oh motherfather I hope its not the rings.

tw2

Totally disassembling the heads is necessary for a valve job. It may or may not be with a head gasket replacement. The heads need to be hardness tested, precision straight edge tested and maybe skimmed on a mill (which is where they would need to be apart). There is a lot of variance in cost for all that. For example if you have a blown head gasket and 3 leaking valves, you may miss the valves. What if they are on the same cylinder. If you are happy to do a whole rebuild then it isn't an issue.