head rebuild shopping list

#1

after making 133hp on the dyno i’ve decided to pull the head and have it refreshed at my local machine shop. having never done this before i want to make sure i order all of the necessary parts. plan is to reuse my cam and rockers since they’re supposedly not very old. if i’ve missed anything please chime in, i’ll probably snag everything from pelicanparts.

  • head gasket kit (victor reinz or elring klinger?)
  • head gasket (goetze)
  • 14 head bolts (victor raeinz)
  • 12 valve stem seals
  • exhaust valves? kinda pricey at $25 each
  • some sort of camshaft seal?
  • timing belt
#2

you spelled goatse wrong

#3

The cam seals and valve stem seals will be in the head gasket kit.

The machine shop will tell you if any valves need replacing. Tell them to take a hard look at your rockers and see if any of them are worn. Also have them carefully inspect the cam for wear on the leading edge of the lobes.

When you replace the tbelt folks often also replace the tbelt tensioner and waterpump. Both are cheap. Is also a good time to change ignition rotor and cap if they are >2yrs old.

#4

133? I don’t think a head is going to do much for you. There must be something else wrong. Your car looked super strong in those VIR vids not that long ago, what happened? Was that 133 on a dynojet?

#5

I recently did a leakdown test and pulled the head. With the engine cold it tested 17 on 1, 37 on 2 and 87 on 3. I didn’t bother with the last 3. I thought I had bent exhaust valves. When I pulled the head and lapped the valves I found the head to be in great condition. The center cylinder walls however are gouged horrifically. If your head looks good up top theres a good chance that its not the problem.

#6

133? I don’t think a head is going to do much for you. There must be something else wrong. Your car looked super strong in those VIR vids not that long ago, what happened? Was that 133 on a dynojet?[/quote]
Jason, you did dry and wet leakdown tests, correct?

#7

133? I don’t think a head is going to do much for you. There must be something else wrong. Your car looked super strong in those VIR vids not that long ago, what happened? Was that 133 on a dynojet?[/quote]
Jason, you did dry and wet leakdown tests, correct?[/quote]

did them? yes. did them correctly with good gauges? no.

but at this point it doesn’t really matter, there’s nothing obviously wrong that i can spot. motor seems to run well, doesn’t hesitate or cut out or sputter, dyno says a/f is right on, etc. will redoing the head make the world right again? maybe, maybe not, but i’m out of things to try and nationals is in three weeks so i gotta start somewhere. in 2010 i did nearly 30 track events, not all were in the e30 but quite a few were so that’s probably 50 hours right there. bottom end seems solid, OP is always excellent and nothing leaks (badly) and no funny noises so i’m not touching it without a damn good reason.

#8

What is the history of the bottom end? I had the same problem a while ago although not as low on HP just not much area under the curve. I had a head rebuilt and put it on and was very disappointed with the outcome. I have read and it has been my experience that with high mileage engines when you tighten up the top end the bottom end goes next. So after the install of my new head the rings seemed to let go and had more leaking from them. This has also seemed to happen to another racer in our region as well. I ended up getting another engine rebuilt top and bottom and still have the one with the new head sitting on a stand as a back up. I plan to have a bottom end build someday when needed and just use the head on it.

BTW, there are lots of places to get parts. Bimmerparts.com gave me a smoken deal on some pistons and bearings. Not much over cost.

Oh, I forgot, the engine with the new head ran fine and in a street car would have been no problem but so would have the engine before I replaced the head. Racing is different. Sometimes they just get tired.

#9

the entire motor was freshly built by a reputable shop before i bought the car in 2009 (it only had break-in miles when i acquired it). ran great and was quite strong until fairly recently.

#10

That engine shouldn’t be down on power yet.

I’d keep at the dry and wet leakdown tests until you’re able to get repeatable results and can say for certain that you have valve leakage.

If you do decide to pull the head, I’d do a drip test to double-check that the valves aren’t sealing before the head goes to a shop. You to this by inverting the head and pouring a little gas into the chamber. Then you watch for drips past the valves. 3drips/min or less is good. Wipe the valve seats so you know there’s no debris preventing a seal and give the rocker a little bonk to make sure it’s seating all the way.

#11

Well my rebuilt engine is older then that and still going strong as ever. So, I would guess you have an actual problem not just a tired engine. Maybe bent valves. Maybe AFM restriction, TPS, bad O2 sensor, etc. The compression and leak down will tell the story on the mechanicals of the engine.