Enigine Rebuild Questions

[Rudeboy42]

So long story short my 87 NA has a lot of miles and I want to rebuild the engine eventually. The only problem is that it's my daily driver and I don't want to have to be without it for that long. So I decided that I'd be better off buying another engine and rebuilding that one and putting it in my car when I'm done. This way I can take my time and get everything done right. My question is how much do you think this will cost me? Including how much I should pay for a used engine. I've never rebuilt an engine before but I'm more than willing to learn how and I may just need a little guidance on how to go about it. So any suggestions you may have will be appreciated.

[Rasta Monsta]

Used 2.5s are pretty cheap these days. . .you should be able to get one in need of a rebuild for a couple hundred. Just make sure there is no valve damage.

What is wrong with your motor? You may want to do a compression check before committing to an overhaul. If compression is good, you can spend a weekend changing the rod bearings with the engine in the car, and keep on drivin' her.

[HondaDustR]

I spent around $2K after all was said and done, including some extra tools and such, some clutch parts that needed replacement WYIT, and a full bottom end balancing (not necessary...added $260). It was a pretty thorough job with all new bearings, piston rings, and gaskets, although I only cleaned the head and re-lapped the valves, since it looked like it had been rebuilt semi-recently and the valve guides didn't feel too loose. From getting the car towed home to driving down the street for the first test it was about 3 months, but I had some delays sourcing a good motor and waiting for machine work.
Here's the project thread. Project 924 S engine replacement

[Rudeboy42]

$2000 sounds like what I was expecting to pay maybe more I might be a little more thorough with it. Did you get the cylinders machined? What special tools do you need for a rebuild?

I found an engine from an '87 parts car (same year as mine) and the guy says he wants $500 for it. I think I'll offer him $300, does that sound too high?

[HondaDustR]

I did not get the cylinders machined. They looked to be in pretty good shape, so I developed a DIY de-glazing and re-lapping with Sunnen AN-30 silicon paste to prep the walls to break in new rings. It seemed to work really well. I should have had them measured, but I didn't get that fancy. The pistons measured out fine, as did the crank, rods, and pins when they were at the shop. Check out the project thread link for the lapping details.

Tools amounted to a few random things such as an $50 engine stand, a $30 craftsman flexable beam torque wrench, $30 for an early OPRV alignment tool, $25 for the spring hone, $30 for the AN-30 paste, probably another 30 or 40 for all the other random things like razor blades, shop towels, felt, brush for the locktite 574, 6mm thread chaser, a new set of metric feeler guages since my other one disappeared, dremel wire wheels for some parts cleaning, scotchbrite pads, PVC pipe connector to install the RMS...you get the idea. The supplies really do add up, as do the hours! The parts and the motor is often only half the story. It would have been a bit easier to have sprung for an engine hoist, but I was sick of spending money and figured out a way to get it done without one...plus I didn't have a good place to store it. I already had access to a pretty nicely stocked mechanics tool set that I've been adding to over the years, so the basics were already covered.

$500 for a complete known good running motor is a good deal, especially if it's below 100K miles. How many miles on it?. You could talk him down a $100 or more depending on what's unknown about it and how much use it's seen. Mine (the second motor...long story. details in the link) was from a running wrecked car, but I never heard it run, I never got the actual mileage, we took the head off before I claimed it so I could see the cylinders, which looked pretty good. Only a few minor scratches. I got that for $400 plus $100 for delivery from richmond VA.

[Rudeboy42]

Well I'm in good shape since I have most of those tools already. My brother bought an engine stand about ten years ago when he bought a '67 camero and completely rebuilt the engine. And I can just borrow my uncle's engine hoist, he doesn't use it that often.

I'm gonna get the cylinders machined and probably get new pistons just cause I want to do a really thorough job while I have the chance. The way I figure it if I spend some extra money and time now the engine won't need to be rebuilt for another 23 years as long as I keep up with the maintenance.

The engine has 140k on it. He says it's still in good shape but I don't care cause I'm not gonna spend the time and effort to swap an engine for one that doesn't have much lower mileage than mine. Maybe I'll tell him that when I go look at it. If I have to end up walking away from it I'm sure he'll come crawling back with a lower price cause there aren't many other potential buyers for a 944 engine around here. My other idea is to see how much he wants for the whole car so I have extra parts to use/sell or trade.

That thread is gonna be really helpful when I get the engine and start tearing into it. The 924s had the same engine as a 944 in it, correct?

[Aslet]

It can add up fast. It all depends on what a "rebuild" is... To get a long block that is not in horrible shape, $500 sounds like a good deal. Parts add up though. New belts/roller and water pump are $500 right there. It depends what you want to do further than that. If it is just a daily driver and will never see track, you don't have to do as much. Trust me though, I had a newly built motor and was on track, the mechanic reused the connecting rod bolts, one failed and destroyed the motor. For street use I'm sure it would have been fine though. Its all about keeping the, "while I'm in there" under control. I know Lindsey Racing sells a rebuild kit that has everything you need basically. It may give you some ideas of needed parts, and costs to get everything. I think when I played with it and optioned it out, getting almost everything you could possibly need, it was around $1500. Keep in mind machine work adds up fast too. New valve guides grinded properly is around $500...

Good luck

[porsche4life]

Originally Posted by Rudeboy42

Maybe I'll tell him that when I go look at it. If I have to end up walking away from it I'm sure he'll come crawling back with a lower price cause there aren't many other potential buyers for a 944 engine around here. My other idea is to see how much he wants for the whole car so I have extra parts to use/sell or trade.

Not a bad idea but be careful... You are already lowballing the guy.... Sound like too much of a prick and he might just tell you to stick your $300 where the sun don't shine.... I've come close to doing that.....

[HondaDustR]

If you're going to get new pistons and the cylinders machined, you should get JE or someone to machine some euro style flat top pistons for it. That alone will add about 15 hp, especially since you could put the DME into euro mode with the correct coding plug to get the correct fuel and timing settings. Four DMEs in One Box

[TeenerTim]

Originally Posted by porsche4life

Not a bad idea but be careful... You are already lowballing the guy.... Sound like too much of a prick and he might just tell you to stick your $300 where the sun don't shine.... I've come close to doing that.....

I don't think that's a low ball price. I paid $100 for a complete engine.

[Rudeboy42]

I'm gonna try to get him down low without sounding like a prick. I can see how I would though. I can tell he's just saying 500 as a high starting price so I'll be less likely to get him down real low. He said that 500 was what he would want ideally so I figure he's expecting to get less. I'm usually good at not sounding like too much of a jerk while I'm haggling so I'm not too worried.

As for higher compression pistons, I was planning on getting those anyways. The J&E's are actually cheaper than OEM pistons I've found. Someone from 944online already suggested that I get Euro pistons too. I was actually wondering how it would effect the DME and I didn't want it to cause any problems especially for only 15-20hp. Thanks for showing me that link. Which one would I have to set it too though?

[Rasta Monsta]

You may also want to give Diamond Racing a call. . .found out about them after plunking for the JEs for my 931, but they seem to have a quality product that is cheaper.

[HondaDustR]

Originally Posted by Rudeboy42

. I was actually wondering how it would effect the DME and I didn't want it to cause any problems especially for only 15-20hp. Thanks for showing me that link. Which one would I have to set it too though?

I wouldn't say "only" 15-20 hp as it's a pretty healthy bump for a NA, but I'm not sure which one is correct, since there's 2 that fall under ROW.

[Rudeboy42]

True 15-20hp is a lot for an NA but I just meant it wouldn't be worth doing if it's gonna be a lot of trouble. All of the ROW settings say they're used without a cat or O2 sensor, so do I even have to change it for new pistons? I imagine that I would but what would I set it to since I do have an O2 sensor and a cat? I'll have to look into it more to figure out how to set it.

You may also want to give Diamond Racing a call. . .found out about them after plunking for the JEs for my 931, but they seem to have a quality product that is cheaper.
Yesterday 06:50 PM

I don't know they seem more like an American muscle car company, I don't know how well they'd do with a Porsche.

[HondaDustR]

Originally Posted by Rudeboy42

I don't know they seem more like an American muscle car company, I don't know how well they'd do with a Porsche.

Well, seeing as newer Vette motors are alusil/nikasil, seems like they'll do just fine as long as they can make a piston compatible with an Alusil bore.

[cvriv.charles]

I say you spend the money and get another daily driver, a honda or a toyota. Then rebuild the engine you have. this would be the safer route to go. Sounds like your going to take your time rebuilding the engine. Either way you go you would be taking your time but atleast this way you'll have another vehicle as a back up. Just in case your 44 should break down. You can probably assure yourself that it will too. It is an old car as we all know.

Better to rebuild your engine seeing that you know your engine. Better that then taking a chance with an engine you know nothing about. Bent valves, gouged cylinder walls etc,... the price of the rebuild can sky rocket depending on the condition of the engine. Your engine is runnning and sounds like its running pretty good too considering your talking about a slow rebuild of another engine.

Even if you took the other route and the engine rebuild went great. Thats just the engine too. there are many other things that could fail, leaving you with no vehicle.

So my advice is buy another used reliable DD and rebuild what you got. If you did buy another engine and rebuild it and drop it in. What would you do with your current engine? Sell it as is? REbuild and then sell it? Keep it as a back up? You would have to decide on that too. I dont know about you but that would be a hard question for me to answer.

[962porsche]

as you know all water cooled porsche motors have nickeled walled cylinders so boring is out unless you are planing to have them replated . and there is only one type of hone that can be used stone hones are out . i have an extra block at the machine shop right now getting resleeved . its 200 bucks each sleeve ,cross drilling crank $150 , new pistons $1660 new oil pump $500 , water pump $400 , all new gaskets and seals $250 , belts $200 , stud kit 150, barings 250 .and on and on you get my piont ! yep it adds up fast right now in parts its over 4200 just to do the block . i did the head over the summer at a cost of 2300 dollars . this is the 6th 944 motor i have built or rebuilt . can you get more HP and Tork yes but not much . there is only one optsion if you want a 944 NA motor to get big HP and that cost me allot of money to do . and the sad thing is i don't even drive that car .

[HondaDustR]

Originally Posted by 962porsche

as you know all water cooled porsche motors have nickeled walled cylinders .

Negative. Most if not all of the 944 motors are Alusil. Totally different animal, and can be bored out to the next oversize with the correct cutting stones and methods. Then it needs to be polished and lapped with Sunnen AN-30 paste correctly to leave a very fine surface with the suspended silicon particles exposed for durability and to break in the new rings. Actually, now it looks like they have more modernised stones with flexible substrate and the right abrasive to do what the paste does.

It probably would be easier in the long run to rebuild what you have, since there is some crap out there that is hard to tell for sure until you start taking it apart. If it were me and I had the money, I would hunt down a good 16v motor, go through that, and swap it in keeping your old one as a backup. The cheap civic is a good idea as well. I almost went that way, but the car I was looking at had a few problems already that I didn't want to deal with (pay for, mostly) in addition to the mess I already had on my hands. It would have been a fun little car, though...1500 motor, manual everything, they weigh next to nothing, and gets 30-40mpg.

[962porsche]

yes your right its only the motors built after 1984 that porsche had mahle Nicom the cylinders . as stated in the porsche books i have from the factory . 2 and a 4th pages about it .i will try to post them but on this sigh i don't have much luck doing so . there was also a sigh about the same thing 928 motor sport i think it was ? but that was some years ago .

[944 Ecology]

Originally Posted by 962porsche

yes your right its only the motors built after 1984 that porsche had mahle Nicom the cylinders . as stated in the porsche books i have from the factory . 2 and a 4th pages about it .i will try to post them but on this sigh i don't have much luck doing so . there was also a sigh about the same thing 928 motor sport i think it was ? but that was some years ago .

buncha crap. All 944 motors were nikasil, not nickeled walls. The entire block was composed of the same metal, not sleeves.

Do your research before you type any more misinformation about the 944 motor.