highboy

OK...I have 300K on my '88 951 - it's time to do a complete motor rebuild!

I have two options: I can pull and rebuild my '88 Turbo motor (and put the car out of service - she's a daily driver) OR pull a '86 Turbo motor (showing 166K on the clock) from a parts car. I prefer the later so I may use the car till the moment comes for the transplant.

Is there any differences in these two motors? My plan is to utilize a Turbo S turbo, a set of chips, MAF, etc... What all is involved with transplanting a '86 motor into a '88 car (changing of electronics, fuel, etc...) - will I need a '86 DME, KLR, etc...

I do not plan to build anything outragous, I want this to still be a daily driver and reliable - but yet proivide a little excitement at DE and autocross evets!

Thanks in advance for all your help, comments and suggestion!
Tom

cruise98

Swap the later wiring harness over, along with the oil pan/baffle, pickup tube and dipstick. The '86 will not have the oil level sensor hole unless it has been updated. The cam belt tensioner is different between the two and a few other minor details. Some claim that the oil passages are different, but I cannot confirm or refute that.

I would freshen up the '86 engine and swap it in. That is the quickest thing to do. You could search around and probably find a late oil pan so you would not have that delay to deal with.

highboy

Cruise98 - thanks for the input! during the rebuild on the '86 - is there anything that should be addressed and/or updated (besides the pan/baffle and such) while i have the motor dis-assembled!

thanks
tom

Mike1982

Do anything you need to on the engine before you put it into the car, such as waterpump/belts, any gaskets, oil pan/baffle, etc. That way you just drop it in ready to go, hopefully.

MichelleJD

The 86 has NO cam belt tesioner, but it can be added if you like.

Chris White

Not really 'no cam belt tensioner' - just a manual one instead of automatic!
I trust the manual one better than the automatic one anyway!

Chris White

Sam Lin

I remove the auto tensioners on all my late engines and put in the stud for the early manual tensioner - like Chris White, I trust it more AND it's far easier to do a belt job. Rebuild the '86 engine, it's a better choice simply for the tensioner hassle it saves you.

Sam

highboy

thanks guys...

i'm sure as this project unravels i will have many more questions...

thanks
tom

cruise98

I'll wager the first question will be..."do these bores look OK?"

JDeitz951

I am pretty sure the '86 has better rods and/or pistons. Forged vs. cast or some such thing. If you keep the "S" turbo, you can keep the "S" chips. If not, you will lose some top end power and add half a second to your 0-60 mph times. When you rebuild the '86, use the later '87+ vacuum diagram and save some plumbing.

pikey7

the early block has a smaller oil pressure relief valve guidebush so you can't use your late 1-piece valve. you get stuck with what's in the '86 block (prob. 3-piece), or spend (I think) around $200 on a new 1-piece. I stuck with the 3-piece and have not had a prob, but you must align the housing spot on..

jns

What's involved in swapping to a manual tensioner? You say just a stud and I guess you need to buy a new manual tensioner. Is it the same as the lower balance belt tensioner(I have a spare one)? I'm doing a belt/wp job and thinking about the easier manual type. Also, I'm getting a new rear t-belt cover so would I need to get one for an 86(mine's an 88)? Thanks.

Olli Snellman

I am doing the swap right now. Have a '88 with badly scored cylinder walls. I bought for parts an '86 951 with 90k miles on it.
I will move some parts from '88 engine to that '86 one, for example oilpan. I will also install new water pump, oil pump etc just to be sure that i don't need to change them soon. Also new piston rings will be changed.
My '86 engine have a rebuilt 26/6, but my plan is install a 28/8 instead.
'88 engine will be a future project, perhaps it will be 3,x liters some day

Here's a pic of my parts car.I bought it from Estonia.Originally a US car.

cruise98

You need the following three parts:


1 each Toothed roller 944.102.216.01
1 each Stud 944.102.216.01
1 each Nut 944.102.243.00

jns

Thanks for the info. Does the toothed roller have a tensioner on it? I see the stud and roller have the same part numbers but I'll look up the number when I order it.