1986 2.5L turbo engine rebuild/swap

1SickWS6 · 08-27-2006, 11:54 PM

I have a engine that has coolant mixing with the oil. I believe it has a blown head gasket, but I am afraid of anything else that I may run into. The car I was told has been sitting for close to a year after experiencing water loss and over heating. It does not seem like there is a lot of water in the oil, but it is milky. Do you think a simple headgasket swap could solve the problem? I am a little worried about the bottom end having slight rust, but I dont think there is enough water in there to do any real damage. What should I look at before taking the engine apart? I am also considering doing an engine swap. Is it possible to put a newer 3.0L in this car and have everything mate up to it? Would I be safest to find another 2.5 turbo motor out of another car? How much would I be looking at to get all the gaskets I would need to fix my engine and hopefully it all be right compared to finding another used engine to throw in there? Any and all help is greatly appreciated as I am new to these porsches. Thanks!

ae1969 · 08-28-2006, 09:00 AM

Uhmmmm if it has been sitting with mixed oil/water in the block for a year.......... it is not of a question of will it fail......... its more a question of when.

I would pull the engine.......... an minimally I would replace the rod bearings. Although the mains are quite tough on these cars. No bearing enjoys moisture.

Uhmmmm if you do the work and all the engine tolerances are in spec........ and you do the work.... ~1000 in parts to clean things up nicely...but then you will probably want to switch the water pump, belts, rollers.........all the seals for the turbo. etc etc etc.... $$$$

1SickWS6 · 08-28-2006, 10:23 AM

Hmm.. Do you know where I can possibly just find another 2.5 turbo engine? I dont really want to risk it, I'm going to end up pulling this engine out I see. So while it is out I can either swap gaskets, and rod bearings, etc and it might come out ok but it is still a 140K mile engine. Or I can get another engine for possibly not to much more that I know runs without the risk of water damage. (the water pump is new and the belts look to have been replaced not to long ago) What do you think?? Thanks for you help!

1SickWS6 · 08-28-2006, 10:55 AM

What exactly are rollers? I am trying to learn as much as I can about this car since this is all new to me. Do you know of any other online porsche forums that I can take a look through? I am thinking about maybe a shortblock.. Thanks!

nynor · 08-28-2006, 04:08 PM

timing/balance belt rollers. even if you get a short block, you will probably want NEW rollers. ask me how i know...

1SickWS6 · 08-28-2006, 04:14 PM

umm how do you know?? lol Do you know of any other informational forums that I can do some more research on? Thanks

1SickWS6 · 08-28-2006, 05:02 PM

After looking around some more on the net, do you guys think the oil cooler gasket could be the cause of my problems? I know the head gasket was replaced about 3 yrs ago and it was sitting for one of those years.. The car is practically stock with some stage 2 chips and a mass air flow conversion, I dont see why it would blow.. hmmm......

nize · nize's Garage

a buddy's car had the o-ring seal on the pressure relief valve in the oil filter housing go bad, and the result was coolant in the oil.

it's possible this is also your issue.

for more info, you can check the rennlist forums and clarks garage. all of that info can be easily found by searching through this forum.

if you're new to porsches, do some research and legwork. most of the questions you're going to ask in the beginning have already been answered many times, and are all available via some simple searching and digging.

Cory9584 · 08-30-2006, 05:00 PM

sorry for the ot but I want to hear more about the t/a in your sig.

nynor · 08-30-2006, 05:59 PM

Quote:

Originally posted by 1SickWS6
umm how do you know?? lol Do you know of any other informational forums that I can do some more research on? Thanks

well...

i retensioned belts after buying my '83 944, but ignored the fact that the rollers all basically spun like metal roller skate wheels. all was good for almost two years (believe it or not). then, one day, just a block from my house, the engine just died. yep, the rollers and the water pump ate the timing belt. the rest was $1200 in parts and such, even though i did all the labor.

do a search, you'll find my posts regarding the heartbreak.

1SickWS6 · 08-30-2006, 08:57 PM

Cool, I will look into the pressure relief valve seal. I understand now that these questions have been answered many times. At first this was the only forum I knew about then after finding rennlist I have a lot more of my questions answered. I am not new to the car game as I have taken my transam all apart, basically down to the frame and have put it all back together. (with MANY upgrades) So hopefully this porsche won't be to much harder.

Cory: what do you want to know about it?

HWgeek · 09-16-2006, 07:29 PM

Gee,
I just did that July 4th weekend and the week following. I got lucky and bought a beautiful guards red 86 951. Just beautiful, except for the scoring on cyl wall #3. You can't hone these blocks, the aluminum/silica mix doesn't like that. So took my other engine (yea I had a spare engine) and had two 951 in the garage at once. bad engine out, good engine in. 5 days with friend helping.
3 days solid (8hr +) for pulling and moving, 2 days for connect and oh forgot this wire stuff.
Nice running car now. Still sorting out little gremlins. argh.

Like mentioned - rollers and timing belt - very critical, basically say bye-bye to the engine if you neglect those items.

Get the 951 turbo manual or check out clarks-garage.com lots of good stuff.

you can do compression and leakdown tests, might shed some light on possible blow headgasket issues.

Good luck!

1SickWS6 · 09-16-2006, 09:42 PM

Cool, I am just finishing up my rod bearing and oil pan and cooler gasket swap. I will look into these other items also. Thanks!

nize · nize's Garage

awesome. got pics?

HWgeek · 09-22-2006, 05:32 AM

Here are pix from the engine swap, you can see the donor in the background, (going to be hot track car

sooner or later)
Will take a pic of the finished car, hadn't had time, too busy driving it

74goldtarga · 09-25-2006, 02:11 PM

One reason I bought the 951 is that I thought the engine would be easier to work on than my 911. The engine is really packed in there and I found out today (as the above picture shows), the dumb thing goes in through the bottom!!, just like my 911. I say if you have the tools and the know how to do the engine yourself it is probably worth the effort in that the knowledge will save you repair costs in the future, even better if you have a nice engine you can put in in the meantime.

HWgeek · 09-25-2006, 08:34 PM

ROTFLMAO!! Thanks 74goldtarga, you made my day! I got into 951's without knowing better (the background one was my first one before the paint started scabbing off of it) Having now done two 911 engine pulls, I now know better. BUT, still love 951's . Bang for the buck, they just can't be beat. Plus I have a 2.5L modified block (2.9L) just asking to be loaded up with the parts from the bad 2.5L engine. :-) Say winter project. hehehehe
951's definintely are very know-how oriented, otherwise can hurt repair costwise! Local shop wants about $1000 give or take for timebelt,roller and waterpump replacement! ouch.

nize · nize's Garage

$1000 is cheap for that job.