How to do a Head/HG (Blown) change RIGHT any tips

[HangerHarley]

Well, IF i have to take my older car and pull the Head off and put a new Head Gasket on it, id like to know if there are any Tips! I used to take it to a cut-rate mechanic and ive had heads changed for as little as $200. They ALWAYS put RTV Silicone (Ultra Black) OR used Gasketmaker in lieu OF a gasket (I think they put it ON a gasket) and followed it up with some "Block Sealer" and .. well once it worked OK and two times it didnt on various cars. I have a car i like more now, and im going to pressure-test the Cooling system to see what the rust-colored Oil was about. if it "Fails" the pressure test, i think no more sealers (Blue Devil, etc., its never went on this car, other cars it has) a Head and Gasket job is in order.

Now, in reality a Head job should cost closer to $1200 than "$300 or $400" to be DONE CORRECTLY, right? And ideally, the heads are pressure-tested too? (We used to just put a "New Head" back on the old block with new gasket if we could find a used head from junkyard car. If i had to get a new head for my car, rebuilt and guaranteed it would likely cost about $2000. Not against it and no we dont want to "Open the block up" but maybe do the cam/crankshaft (camshaft and crankshaft) if it shows wear, and of course clean up what we see, then run Oil for 30 minutes then change to specified grade, no more cleaners and stuff.

However, in shopping for a shop since i can change my own Oil and thats about it, getting to wrenchin' a Head Job is WAY BEYOND my tools, time, and everything.. what do I look for in selecting a shop?

Oh, and this car has been sitting so time is of no importance, just to get it right, assume its just a Head Gasket leak, if Pressure Test confirms, i think it may, to be honest, idk but when/if that result comes in.

FTR: My last car "Dropped a Valve" a month and a half after the $200 Head Gasket job was done, and the Cylinder walls were "Washed" and rusty and a globule of K&W Block Seal was in there too. Trying to NEVER HAVE THIS HAPPEN AGAIN Ill PAY $$$$ for a HG job done RIGHT, but what do i look for? OR any tips, so i am familiar with what they will actually be DOING when they TAKE a few days to DO it?

 

[-Clayton-]

What kind of car are we talking about?

 

[HangerHarley]

Originally Posted By: -Clayton-
What kind of car are we talking about?


1988 BMW 735i.

197,000 miles, noticed possible HG symptoms and want to correct it and if its the Head, i see a lot of original parts so im needing tips.

Those were older pics, the car is "far away" from me and i may return to it in 2011, i will have to see and give it a few months but for when i do... hence, the thread.

 

[Eddie]

The biggest problem I've seen repeatedly that causes HG replacements to fall is NOT checking the head & block for flatness. I found it not uncommon to find rises around the head bolt threads. Another is people ignore the proper torquing sequence which in some cases may require three go-around to achieve the final value. This from my experience. In addition; one does not go cheap on the gasket or torque wrench. Ed

 

[-Clayton-]

Don't know much about those cars, But you definitely need to find a good mechanic.

 

[HangerHarley]

Originally Posted By: -Clayton-
Don't know much about those cars, But you definitely need to find a good mechanic.


Right. That is what im saying. They see "BMW" and they are like, "Ohhh well see thats extra." ??? Surely you know what im talking about.

I want to make sure i can take it to a shop where if the cost is $1500, they will do it RIGHT and MAYBE even pressure-test the Head to inform me if it is straight and doesnt have a crack, and it it doesnt have a crack but is warped, can be milled to spec, maybe even "Overbore."

btw, what is "Overbore?" can a competent Engine shop that knows what they are doing do an "Overbore" if there is maybe a cylinder imperfection for like $3000 to $5000 of course the HG is included there?

And it goes back to, what do i look for in a shop?

Think the Backyard mechanic was ok in previous years. Now im ready to step up to REAL work.

Quote:
The biggest problem I've seen repeatedly that causes HG replacements to fall is NOT checking the head & block for flatness. I found it not uncommon to find rises around the head bolt threads. Another is people ignore the proper torquing sequence which in some cases may require three go-around to achieve the final value. This from my experience. In addition; one does not go cheap on the gasket or torque wrench. Ed


This is why ill be "shopping for a shop" in 2011 and i know not how to present myself in that im "Looking for the best shop." I dont know what to look for, nor what to say.

Any good engine shops that can get me right in or around Jacksonville, FL? Dont know where Cape Coral is but im new here and in 2011 i want to give some attention to this ride. Will be great for Summer if i get enough $$$$$, and beats walkin

BTW: Yes, NOT checking Heads AT ALL likely was why it didnt work right on the smaller engines. Seems its a key point. As to Gaskets, ill have to look for the "Best" one.

I wonder if they have MLS (Multi-Layer Steel) gaskets for this one. I know if you do the job right, the engine will run like Day One.

And if not you will eventually need a new engine.........

 

[eljefino]

Sweet car.

I'd find a beemer forum and the typical failure mode of those cars. If its gaskets what replacement is the best. If it's heads cracking where do they crack. If they warp does shaving fix the warp for good.

In short get as much info on YOUR car as you can. For example a saturn s series you can do a ring job without boring the block or even removing it from the car. Boring is smoothing out the cylinder walls if they were damaged somehow, and you put bigger pistons & rings in when you're done. However SOHC head gasket problems are almost always head problems on MY car.

The best mechanic would be enthusiastic about YOUR car, maybe find an enthusiast website and a guy with a bunch of BMWs in your area you feel you can trust and pay cash for work. Someone who's always taking cars apart for grins, posting pictures, etc but also one who's hesitant to work on a stranger's car, not coming across as money grubbing, has a day job, etc.

 

[Kestas]

If you can't find a decent shop nearby, perhaps you could take it to this shop in Gainesville.

http://www.continentalimports.com/

I also agree with eljefino. You should make yourself busy on the specific BMW enthuisiast sites to find out what common issues come from the root cause of head gasket failure as well as repair for your model.

 

[Food Scientist]

Another option that you could also do is X-Ray the cylinder head to look for cracks. I know they do this on large diesel cylinder heads when rebuilding engines (or should anyways).

 

[SteveSRT8]

Go online and locate the actual factory service manual for that model. Knowledge is power.

BMW's are very intolerant of shade tree mechanics and even experienced pros are sometimes unable to apply regular rules of thumb to the special procedures required.

Very simplified: the head comes off and is sent to a machinist who cleans it and checks for cracks/warp. May also need a valve job at that mileage. Then the engine is reassembled with extreme attention to detail using EXACT factory recommended procedures. Typically VERY expensive.

There will be an import specialist, hopefully a BMW expert, in your area. The one around here has a waiting list!

 

[HangerHarley]

Originally Posted By: SteveSRT8
Go online and locate the actual factory service manual for that model. Knowledge is power.

BMW's are very intolerant of shade tree mechanics and even experienced pros are sometimes unable to apply regular rules of thumb to the special procedures required.

Very simplified: the head comes off and is sent to a machinist who cleans it and checks for cracks/warp. May also need a valve job at that mileage. Then the engine is reassembled with extreme attention to detail using EXACT factory recommended procedures. Typically VERY expensive.

There will be an import specialist, hopefully a BMW expert, in your area. The one around here has a waiting list!


eljefino: Thanks!

This is pretty much what i wanted to know. Im busy on unofficialbmw.com and other "Enthusiast" sites, and the typical "Rebuild vs get another one" applies. i like rebuild myself.

The graduation from a few HUNDRED dollars to a few THOUSAND means im movin on up. Nice car for me. I earned it!

Pretty sure its SOHC too. Want to keep it nice. its survived pretty well, needs a few things though, being original and.. "Sitting." They say using it is its own kind of fixing it, for things that have sat. Maybe Fuel system is all gummed up too, Sour gas and whatnot. 100% replacement needed. ?

And SteveSRT8: Waiting list? Man, that sucks. Well i have to "Get it here" anyways so Jacksonville/Gainesville? Hmmm. Thanks man!

 

[Torino]

All of the above plus--use ARP studs and nuts/washers. Install them per ARP instructions. John--Las Vegas.

 

[PhillyJoe]

bimmerfest.com may be helpful to you. There's a forum for every series.

 

[PandaBear]

Originally Posted By: Eddie
The biggest problem I've seen repeatedly that causes HG replacements to fall is NOT checking the head & block for flatness. I found it not uncommon to find rises around the head bolt threads. Another is people ignore the proper torquing sequence which in some cases may require three go-around to achieve the final value. This from my experience. In addition; one does not go cheap on the gasket or torque wrench. Ed


Yup, a well build head and block usually don't blow its gasket randomly. Every time a HG is replaced, the block and head must be checked and machined if it is not flat. Using sealant instead of a real gasket (i.e. 3 layer metal that Honda uses) means the mechanic is just lazy and trying to get you out the door.

Find someone else to do the job. My friend refer me to his mechanic for a HG job, a guy that send my head out for machining, check all the valves, check the block flatness, use all OEM gasket and seals, replace plugs, filters, and new oil, for only $1000, in SF Bay Area, California. If you look around you can find someone that can do at least this in your area.

 

[meep]

Be careful. I walked away from a 740 (?) that was beautiful at a decent cost after discovering that they were known for having serious head issues for that period of production. maybe it was an 01? I don't know if the 35 used the same design or not, but from what I recall they were susceptible to warping.... not sure if it was head or block... obviously, if the block is warped, gasket jobs are only a short fix--- block would need to be milled.

If you like the car, may be worth it... but I suspect you want to get *real* educated on this.

Mike

 

[brelandt]

I know this wasn't smart of me but I have changed HG on both AL block and head and engines with iron block and AL head and iron and iron. I think I was lucky...but I never had anything machined for straightness and they all came out fine. Not recommending it, but if I got away with it on 4 different cars then I think warping isn't a huge issue.

 

[RH+G]

I didnt even know u can change a headgasket without using a headgasket??

If u take the head off u should send it to a machine shop and let them check for straightness. Its rare that the block gets warped. And if u didnt overheat really bad think u should be fine.

 

[rslifkin]

Brelandt - That just means that all the ones you took care of were just a simple blown gasket, and didn't also have another issue along with it.

 

[HangerHarley]

Originally Posted By: brelandt
I know this wasn't smart of me but I have changed HG on both AL block and head and engines with iron block and AL head and iron and iron. I think I was lucky...but I never had anything machined for straightness and they all came out fine. Not recommending it, but if I got away with it on 4 different cars then I think warping isn't a huge issue.


In my experience, if anything is warped, you an hear it (if not feel it) in the engine after it is all put back together. The mechanics (they have that title, omg) I am LEAVING can get the head off, and on, in about 6 hours if they were doing nothing else.

Thing is, sometimes you can hear this muted weird sound in the engine that might be the by-product of Gasketmaker seals (and pistons slapping against warped heads that are no good, oh well....), and if you experience hesitation, it might mean it didnt seal back up, especially when you "Just pull a head off a junkyard car" and "hope for the best" ..

Yes Mike I AM trying to hear The Ugly Truth I appreciate it i know some engines/cars are all but guaranteed to go out a certain way and a repair of some kind is documented I DO know some of these cars have issues so its basically about taking pretty ms BMW out of its nice little garage home and get its Engine checked out and if it is indeed exhibiting the classic symptoms of Head/HG issues goodness and i go the route of "Get the Head 100% redone and done open up the Block" .. Oh what fun i have in store.

And yes this time im not trying to take "Shortcuts" hopefully if there IS an issue i can get by with about $2000 to $2500 being spent to do it right.

Until then, Mrs. [censored] sits.

No more cheap labor. I once had a Head Gasket done for $200. Lasted a whole 2 months... before i had a HOLE in my piston!

And that was an ordeal to get back home. THREE DAYS... No more.

 

[Steve S]

I would suggest for you to bring the car to a well qualified shop and have them do the job.