850 R engine rebuild time - what to be careful about?
 

So it turns up my 850R needs an engine rebuild. Stem seals are bad - it puffs blue from the exhaust after idling and then pressing the pedal (PCV was just cleaned). Crankcase pressure is also pretty high and I was told I'll need to change the head gasket. After picking the car up from my mechanic, he told me to just keep driving it for some time until the rebuild - I found that a bit crazy, given the symptoms, but did drive back home. The morning after, I realised I have a big leak (coolant). Took the car back to mechanic (not the same one). Turns out coolant hose connected to the turbo was pretty worn and plastic and it just gave up.

So, rebuild time it is. This was a part of the plan from the beginning - car is otherwise in great condition with bunch of new parts (including intercooler, turbo, gearbox, overhauled brakes, dressed with new alcantara, overhauled steering column, refurbished wheels etc...), I just hoped it won't be needed right away :)

Anyways, I'm not having the job done by renowned Volvo specialist as first planned. Really didn't like the attitude as the guy kept whining and had a surprisingly negative approach. He told me to keep driving the car which was clearly in no condition to be driven and overtightened (and I mean, REALLY overtightened) the spark plugs. I lost all trust. So, I decided to have the work done by guys that aren't Volvo specialists, but do have the tools, knowledge and experience. They've put together a bunch of engines, including numerous race car projects.

Now, my question is - are there any specifics with Volvo B5234T engines that need special attention? I'd like the job to be done by the book, within correct specs and well documented. I got time to prepare and would love to gather as much info as possible prior to start so any feedback, tips, links and general information is really appreciated.

Thank you in advance!

Frane

My only advice is, if you have a budget double it and double it again, that should get you somewhere near the overall build cost!!!

My estimate is around 4-5K EUR (know of three T5 engine rebuilds done - all pretty much there). Labour alone around here is estimated to be around 1,5K (+/-) to give you some perspective.

Yup, more so if you're paying labour cost too. These projects are rarely viable. Do it because you going in with 'eyes-open' Not to see a return. There's almost always a better way. If you're doing it because it makes sense provided you don't think too hard, think harder.

If you have patience, tools and the time & space I'd say give it a go yourself, or at least do as much as you can - leave any machining work to specialists but do the strip down and assembly yourself if you feel confident? These aren't hugely complex engines but you do need to be scrupulously clean and methodical.

If you're after some guide prices, you could ask Tim Williams (on Facebook), Shem (https://www.facebook.com/shemtekautomotive) or there is an indy in York who is supposed to be very good - https://www.dyrdalsgarageyork.co.uk You could ask any/all of these places for a quote - that would give you a ballpark figure to consider.

The other cheaper alternative, albeit not ideal, is to simply drop in another engine. Get an early S70/V70 B5234T3 engine as this has slightly stronger pistons etc. as shown in the attached technical bulletin. It is otherwise mechanically identical (barring a 16T turbo if its come from a manual car) and you can re-use all your sensors from your existing engine so it will continue to run fine on your Motronic 4.3 ECU. Obviously you'd need to make sure this engine is better than the one you have :)

NB I realise you are in the Netherlands (?) but I can't recommend anyone over there as I have no knowledge of them, hence me suggesting a few that I do know of - and would use myself.

HTH

i wouldnt rebuild an N motor again, they wear heavily: barrelled bores, shorter rod is the culprit for this wear.

best bet would be to get hold of a late 2.3 single VVT engine and just fit your N head after its been skimmed, valves/guides checked and tested / new stem seals. these are short skirt pistons with a 147mm rod, much much better at not wearing its bores out.

the later block has far superior oiling, a vastly lighter crank, windage ports at each cylinder base and can facilitate all your N parts aswell as a better PCV port size. RN oil pumps are 5h1t3, use your 850 one after youve opened it and inspected and cleaned it.

you could use a B5244t5 bottom end also, but they cost more to acquire due to being the more desirable of the 2.


Speak to Sebastien Schutten ;)

If you end up re building it is very important to clean/replace the oil pick up and replace all the relevent oil seals and o rings on the pick up pipe also use the correct volvo spec liquid sump seal as these are a zero tolerance fit . do not use any silicon seal or rtv .

Totally agree !
I love the 850R i have , had it 10 years and have juts spent 5k on engine and I did most of it myself ! Costs just went up and up.

Also that saying .. whilst im here i might as well upgrade.. x y and z

Make sure you REALLY want to keep the car before your spend your hard earned money on it !

And make sure you check the sills before you start !!!!!!!!!!!!!

Thank you all for great feedback!

Oh, I'd do this simply because I want to keep this car for good (read: as long as possible). It's been a fantasy of mine for more than two decades. Gorgeously shaped 5-pot turbo that's immensely practical and great fun to drive - it's really difficult to top this.

No such luxury, I'm afraid. I'd love to, but a lot is missing in this equation. 1500-ish EUR for labour is a very reasonable price for me, given the fact I'm fully occupied with work, nor do I have space or tools. I'm from Slovenia btw, the car was imported from NL though ;)

Was thinking of this option myself but I lean towards keeping as much car as original as possible. Why do you think this option isn't ideal? The problem I see is, getting a really good engine. Only when taken apart, one can tell about its condition. That's the main reason for concern. I do have an option do get a working B5234T3 engine. A guy is selling his scrapped C70T whole for 600 EUR. Engine has the compression and runs well and has 130K miles on the clock. But I'll need to buy a new turbo as the "old" one wont fit. Thing is, my current car already has a fairly new, larger turbo (just 35K miles on the clock).


Thank you! How about overboring the original block + new pistons? As far as proposed alternative goes, let me see if I get this right:

I'm in position to acquire a B5234T3 engine (2001 from C70T).
- complete 850R head is a direct fit?
- 850R oil pump should be kept as it's better?
- all the sensors and original computer will fit?
- no need for new turbo as existing head can be used.

Will make sure this information is passed to mechanics! Thank you!

Thank you! As mentioned - 5K is within my expectations. I do want to keep the car for sure :) As for sills - it's completely rust free.

I just realised you and RollingThunder weren't talking about the same engine as the one he's mentioning is literally the same (but with stronger pistons). What is the engine code of the one you're advising?

Thanx!