2.7i upgrade questions

[AC_Schnitzel]

I understand this topic has been beaten like a dead horse. I'd like to get definitive answers to some questions though.

Recently bought an 88 super eta w/ 103k original miles. I'd like to source a 325i head (+ other needed parts) to complete the 2.7i "stroker" upgrade.

Just had a few questions I'd like to get clarity on:

- is it best to source a complete 325i head or buy parts individually?
- what work, if any, should be done to the new head before I install?
- what are other considerations or things to do "while i'm in there"?
- what is a reasonable (or average) price to pay for a complete 325i head?

[SkiFree]

1)Depends if you want to run used or new parts. Performance or stock.
2)Tear apart, check springs, check cam, check sprocket, check rockers, check eccentrics, have machinist check for straightness, have machinist skim head, have machinist do a valve job.
3)Consider a hotter cam
4)$100-$500 plus new parts and machinist costs

[AC_Schnitzel]

1)Depends if you want to run used or new parts. Performance or stock.
2)Tear apart, check springs, check cam, check sprocket, check rockers, check eccentrics, have machinist check for straightness, have machinist skim head, have machinist do a valve job.
3)Consider a hotter cam
4)$100-$500 plus new parts and machinist costs

Thanks SkiFree.

I've decided to try and find a complete head. will do valve job, get new valve guides, deck the head, etc.

Is a hotter, more aggressive cam really worth it in terms of power to $? If so, which cam... 272 shrick/ or regrind?

Are new rockers necessary as well?

[SkiFree]

No worries.

1) It's a nice little bump that goes well with your intended setup (272). As for new or regrind, that's up to you.

2) Depends if the used ones are shot. Never a bad idea.

[jeffnhiscars]

OE rockers are hardened all the way through so I had mine refaced for $50 instead of spending 3x as much for Chinese replacements or 5x as much for HDs. Rebuildable cores are getting up in price so you may want to look to,bimmerheads for a turn key head. You'd be surprised how quickly the cost of refurbishing a used head can add up.

[AC_Schnitzel]

OE rockers are hardened all the way through so I had mine refaced for $50 instead of spending 3x as much for Chinese replacements or 5x as much for HDs. Rebuildable cores are getting up in price so you may want to look to,bimmerheads for a turn key head. You'd be surprised how quickly the cost of refurbishing a used head can add up.

Those heads are pretty damn spiffy.

I just got quoted 400 for a 3 angle valve job, and 100 to deck the head...

this doesn't even include new valve guides/seals.

Does this sound expensive?

[e30davie]

For reference it cost me $900 AUD to get my m20 head cleaned, standard valve grind, pressure tested, decked, new valve guides and setup the valves.

Your numbers sound about right. But get a second quote if you have any question.

Engine machining gets veeeerry expensive very fast.

[jeffnhiscars]

Those heads are pretty damn spiffy.

I just got quoted 400 for a 3 angle valve job, and 100 to deck the head...

this doesn't even include new valve guides/seals.

Does this sound expensive?

that's extremely high

[digger]

Yes it is big $$$ for little work with the VJ . Also unless the guides were done pretty recently it's hard to do a proper VJ

[e30sh]

I would reuse my 103k mile SEta head. All you need are inner valve springs and an i cam to make it an i head. You may have to drill the extra oiling holes but that's no biggie.

With that kind of mileage, your guides should be fine and your rockers ok to resurface. You can do it yourself with a sharpening stone.

[AC_Schnitzel]

I would reuse my 103k mile SEta head. All you need are inner valve springs and an i cam to make it an i head. You may have to drill the extra oiling holes but that's no biggie.

With that kind of mileage, your guides should be fine and your rockers ok to resurface. You can do it yourself with a sharpening stone.

Great points, I forgot about that.

I do know the seta head is missing oil holes in cam journals 2 & 6.

I found this on e30tech:

Be carefull, because that is only half true....there were 2 castings made for the super eta. Earlier ones did not have the holes, where as later ones did. If you have the earlier casting, you need to drill the holes.

The way to tell the difference is the raised flat round part near cyl#2 if it is blank, then you have an early casting. If it has "2.5/2.7" stamped on it you have the later casting, which is identical to the m20b25 head.

Looks like I'll be pulling the head to find out!

If not, I'll have to take it to the machinist to drill 4 holes... probably a lot cheaper than buying a complete i head

[e30sh]

Great points, I forgot about that.

I do know the seta head is missing oil holes in cam journals 2 & 6.

I found this on e30tech:


The way to tell the difference is the raised flat round part near cyl#2 if it is blank, then you have an early casting. If it has "2.5/2.7" stamped on it you have the later casting, which is identical to the m20b25 head.


Looks like I'll be pulling the head to find out!

If not, I'll have to take it to the machinist to drill 4 holes... probably a lot cheaper than buying a complete i head

No need to remove the head just to figure out what you have. You can look on the outside for the 2.5/2.7 casting mark or remove the valve cover. If you are on a budget, you can install the springs and cam without removing the head at all.

[AC_Schnitzel]

No need to remove the head just to figure out what you have. You can look on the outside for the 2.5/2.7 casting mark or remove the valve cover. If you are on a budget, you can install the springs and cam without removing the head at all.

That's an option. The car isn't a daily driver so I'd like to do it right the first time. I'm contemplating prepping for turbo (arp hardware, mls hg) so I'd have to remove the head anyway.

I'd like to also replace any hard-to-reach parts while the head/intake manifold is removed... any thoughts on what those parts might be?

[e30sh]

I'd like to also replace any hard-to-reach parts while the head/intake manifold is removed... any thoughts on what those parts might be?

Check the water pipe bolted to the back of the head. They can get pitted to the point of failure due to calcium buildup. Everything else you can reach with the head installed. Change the o rings on your breather tube while you're in there.

[AC_Schnitzel]

No need to remove the head just to figure out what you have. You can look on the outside for the 2.5/2.7 casting mark or remove the valve cover. If you are on a budget, you can install the springs and cam without removing the head at all.

How do you remove the springs with the head installed??