looking for guidelines on S52 refresh

[evandael]

well, I recently discovered that the S52 I picked up came from a car not with 90K miles, but 190K miles (verified with carfax with the donor car's VIN). needless to say I'm a bit flustered, as that was a selling point, but whatever, I'm moving on.


of note: this will be a completely stock motor for a car that will predominately be driven on the street, with some auto-x or HPDE fun stuff (I would say the ratio is 75/25). I am also on a budget but understand the pitfalls of being penny-wise and pound-foolish, especially with engines.


I have the engine on a stand right now and the head is still on, no manifolds, and there is no oil in it. I think I want to perform wet and dry leakdown tests to verify the condition of the rings/valves. I need to buy a leakdown gauge and but have a compressor. I've read that up to 15-20% variance across the cylinders is tolerable with these tests, is that true?


Since I have to remove the oil pan anyway, I guess that gives me a good chance to look at the rod/main bearings. I've heard main bolts are reusable, but rod bolts are not. Is this true? Should bearings be replaced?


I'm also going to install the Beisan VANOS rebuild kit, and most every seal/gasket on the engine.


Are there any other things I should look for, like the timing chains/tensioners/guides/etc? Should I replace the head gasket and install ARP studs? If the leakdown test is favorable, should I leave the head alone? What about other miscellaneous bolts/studs?



Thanks for the help!

[Boise]

I am in the process of rebuilding my s52 right now so here is what I have learned. I don't believe the main bolts are reusable, so plan on replacing those. If it was me, I would replace the bearings. My engine had 246K and the bearings had some good wear, but were not terrible. I like the piece of mind knowing their replaced.

I would examine the chains & tensioners. Also give the chain gears a good look over too. I found one of my gears had a good chunk of a tooth missing.

Unless you are planning on turbo/supercharge someday, I would just use factory head bolts and save the ~$200 and put it towards replacing other worn parts.

Oh, and double check the oil pump nut is tight! Or consider getting a nut you can wire on so it does not back out. Worth $7 in my opinion if you are going to do some HPDE.

On a side not, the s52 flywheel you are selling, does that have 190k on it then and not 90k?

[evandael]

thanks man. i took a look at all the timing components on realOEM. the tensioners are spendy, but it's probably worth it to check them and replace the guides at least, and maybe the chains themselves.

the bearings seem damn pricey, but definitely warrant inspection at least. and I laughed, then sorta winced, when I saw the prices for the main and rod bolts!

good point about the head bolts vs. studs.. I personally won't be going FI.


and yes, that must be the case regarding the flywheel.. some bullshit. i'll update that. the mileage is confusing really because the whole motor and everything seems so clean and new, but maybe the car it came from was a fair-weather kinda thing.

[Farbin Kaiber]

Although some people speak of issues with Victor Reinz gaskets, you can pick up the complete top and bottom set for about $130 or so. It's always nice to have every gasket you might need as opposed to the ones you think you might need. Buy a cam lock set, and pull/replace all the chains/sprockets/guides/tensioners. It's better to spend a little more now, as opposed to having to pull it back out and do something you skimped on. Since you are gonna have it apart, I would do a head/valve job too.

[Adrian_Visser]

Having installed a VR oil pan gasket and promptly had it leak... Like a fucking sieve. I would say if you are going to use that brand smear it with gasket maker, I have heard permatex "right stuff" is quite good, permatex grey is also supposed to be great. The BMW manual calls for Hylomar on the VC gasket, I used it and noticed some seepage after a year, but nothing near what the damn oil pan is leaking. I'm not kidding the oil pan gasket leaks so fucking bad, I used nothing but permatex ultra blue on my eta's oil pan and had no leaks... Then this shit with an OE gasket GRRR!

[evandael]

I don't want to have any oil leaks. I may just pony up for genuine BMW gaskets.


Farbin, when you say head/valve job, what do you mean? Skim the head, new valve guides and seats?

[Farbin Kaiber]

I would have the machine shop check it, surface if needed, new guides, and at minimum, relap the valves, seat and valve angle job if suggested. You are gonna have it so far apart, there is no reason not to, it will cost three times as much to do it later. I would have the block checked, and replace the rings as well.

$200 sets of extra parts now, or downtime, teardown and those parts later anyway.

[Boise]

I would have the machine shop check it, surface if needed, new guides, and at minimum, relap the valves, seat and valve angle job if suggested. You are gonna have it so far apart, there is no reason not to, it will cost three times as much to do it later. I would have the block checked, and replace the rings as well.

$200 sets of extra parts now, or downtime, teardown and those parts later anyway.

+1. This is what I am doing with mine. The block and head are going to the machinist this week.

[Toadleg]

I would get an oil pan baffle with the oil pump nut fix depending on how much racing your planing on doing.

[evandael]

wow.. all good advice, but what it seems is closer to the rebuild end of the spectrum then a refresh.

I'm going to price this all out for sure, and talk to some friends about a good local engine shop. but at some point I'm gonna have to draw the line!

[Farbin Kaiber]

If you are looking at it that way, throw an oil pan gasket on it, toss it in the e30, drive it for 20k miles, then likely blow something, and spend 5g's to rebuild it. I would at least replace the complete exterior cooling system at the bare minimum. It's really about spending it now, or spending it then. It's easier to do all this stuff once when the engine is on a stand than it is to pull it back out and do it later, and either have to deal with head or block damage..

[evandael]

yes, yes. believe me i already have an extensive list of what will be done. i'm prepared for a 6K budget for the whole swap.

i suppose what i'm really doing is weighing the options of spending a ton of money on the s52 (lets say $1500 on top of the $1500 the longblock cost me, in addition to the maintenance items, upgrades and all the supporting changes on the e30 for the swap) or finding a lower-mile s54 longblock for around 3000, spending near the same amount on the required maintenance, and a bit more for the DME flash.


all in all it seems like roughly the same cash expenditure for far more gain. if i could verify the mileage and maintenance history on the s54 (like if i pulled it from the car myself, and had the VIN to check carfax and dealer records), i would much rather go that route and just drop the engine into the e30 as if it were an e46 m3 that just had a 75k mile inspection.


of course, i'm sure there can be stratospheric costs associated with an s54, but that's why i like to discuss with r3v.

[devon.818]

Having installed a VR oil pan gasket and promptly had it leak... Like a fucking sieve. I would say if you are going to use that brand smear it with gasket maker, I have heard permatex "right stuff" is quite good, permatex grey is also supposed to be great. The BMW manual calls for Hylomar on the VC gasket, I used it and noticed some seepage after a year, but nothing near what the damn oil pan is leaking. I'm not kidding the oil pan gasket leaks so fucking bad, I used nothing but permatex ultra blue on my eta's oil pan and had no leaks... Then this shit with an OE gasket GRRR!

was the mateing surfaces clean and flat?
maybe install error.

[evandael]

still looking for a few more opinions, here's my short list to critique:

first the inspection:
leakdown test
check head for flatness/cracks, machine and new valve seats and guides if necessary
check timing chain and sprockets, replace if necessary
check rod and main bearings, replace as necessary
check bores and clean pistons, machine and new rings if necessary

now actual parts:
new head bolts, rod and main bolts
new chain guides and tensioners
beisan single vanos rebuild kit
all new gaskets and seals


of course there are other things like waterpump/thermostat/belts/fluids but i already accounted for all of that. this list is just applicable to the engine internals.

[cormier]

Oil non return valve I have heard can go, screws into the bottom of the head. Just an idea.