options for engine rebuild or partial rebuild

[dyermullet]

Car is a 87 WE4, with TA49 injectors and tune.

I am about 6 months away from getting back to working on my car, I need to buy a house first.  This question is more thinking out loud and looking to hear the options from everyone who has been there before.

The car has been parked for over 2 years due to a bad trans, I have drove it a few times recently after swapping the trans but right now the car is in the garage with a cover over it. From sitting for so long the car has developed some leaks from the engine.  Once I get a place to work on the car I am going to pull the engine so that way I can replace all the gaskets, cleanup under the hood, paint, etc.  My wiring harness is falling apart so I will need to replace it also. 

My engine has ~119,000 original miles all stock, still has the original head gaskets, but has had the timing chain and valve springs replaced, and has the wearplate deal installed in the oil pump.  It runs strong but it gets significant gas dilution in the oil.  This car has been ran hard taken to the track plenty of times, but it has always had the oil changed and been taken care of, careful with the tune etc.  It consumes a little bit of oil, and also a tiny amount of coolant.  The coolant and oil consumption is very slight after a month of driving the car 3 or 4 times a week I will notice the coolant level somewhat low and ~ 1/2 quart low on oil (this was before it developed the leaks the engine used to be done dry). 

When I get the engine out and on a stand I will know more of its internal condition.  I will inspect all the bottom end bearings.  I know I will be able to see the bottom side of the cylinders, but since I have this small coolant consumption I think I might as well just break the factory head gasket seal and replace them (I am assuming they are letting a small amount of coolant by, nothing is showing on any plugs but the loss is so slow it wouldn't show). 

Here is where the questions start:
Should I break the sacred factory head gasket seal? 

How well do these engines wear, is there a good chance that when I open it up that I will be able install new rings on the stock pistons?  Or am i more likely to find that I will need to bore the engine? 

How about the bottom end with this many miles what should I be expecting?  The car does not have an oil pressure gauge so I don't know how many pounds it holds currently. 

I don't really care to go any faster with this car and don't have any plans for more mods(I have a stick shift car with a blue oval for that), I just want a solid street car that I could drive everyday if i wanted to.  Before the car got parked it used to be dead reliable, I just plan to get it back to that condition and enjoy it. 


Thanks ahead of time for any replies.  I have some pictures of my trans cooler install from a question I asked a few months ago I need to dig them out and post them up to that thread.

Scott

[Steve Wood]

Sacred factory head gasket seal?    Did they bless the machines that installed the heads?

The only thing I would do would be pull the injectors and have them cleaned if you have some proof that they are leaking fuel into the cylinders...Pr oof would be a fast loss of fuel pressure that still occurs when you clamp off the supply line below the front of the car where it goes up to the fuel rail.

Otherwise, I would be sure I had a modern chip in the car and tune it so it was not overly rich at idle. 

I would not worry about a rebuild for another 50,000 miles or so as long as it has compression and oil pressure.

Unless you just like to pull engines, there is no real need to pull the engine to fix oil leaks unless you want to paint the engine compartment or such.

[earlbrown]

Sounds like you need to buy a leak down tester and/or cooling system pressure tester and go from there.  If that engine hasn't been harmed you've got another 125,000 left in it.

New injectors and a modern chip is never a bad idea.  (that oil pump plate on the other hand...)
 

[dyermullet]

Sacred factory head gasket seal?    Did they bless the machines that installed the heads?

The only thing I would do would be pull the injectors and have them cleaned if you have some proof that they are leaking fuel into the cylinders...Pr oof would be a fast loss of fuel pressure that still occurs when you clamp off the supply line below the front of the car where it goes up to the fuel rail.

Otherwise, I would be sure I had a modern chip in the car and tune it so it was not overly rich at idle. 

I would not worry about a rebuild for another 50,000 miles or so as long as it has compression and oil pressure.

Unless you just like to pull engines, there is no real need to pull the engine to fix oil leaks unless you want to paint the engine compartment or such.

That was sarcasm about the factory head gaskets.  You don't remember back in the day when guys used to swear "You could never get them sealed as well as the original".

I guess I left out the prereq to making a post on a turbo buick board.  I have a scan tool (power logger), 231 regulator, walbro fuel pump, hot wired fuel pump, a turbo tweek chip matched to my injectors, the injectors were purchased new when I upgraded the turbo three years ago.    The oil dilution happened with both the stock injectors which I had flowed and cleaned and with my current setup. 

The car will hold fuel pressure in the rails with the engine off for well over 24 hours.  My pump check valve, injectors and regulator are all in good condition.  Measured with a real gauge not the kind you leave installed on the rail. 


Yes the engine compartment is in desperate need of cleaning and paint.  The trans has to come back out anyways so that is why the engine is coming out.  I am going to seal it back up on the stand which will be much easier than in the car. 


I have a wideband O2 sensor installed but like I said the car has been sitting for almost 3 years so I need to start over (Don't remember off the top of my head anymore) with checking out the tune and how rich at idle.  But I don't feel it runs very rich at idle, I think it is leaner than some of my other cars, and the plugs never look dark. 


The car has always gotten terrible fuel economy ever since I have had it.  I have never gotten better than 15mpg that was with AC off flat ground cruse control on never getting into the boost trying to get good economy.  That includes with the stock injector stock chip.  It has never been out of line on BLM readings.


I had done a compression test but that was 2 years ago so all I remember is that all the cylinders were even but I don't remember the psi.  I need to pull the valve covers and rocker shafts and perform a leakdown test on the car.  I have a new radiator, heater core, and hoses with no leaks so the coolant has to be going into the engine.  It is a very very slow coolant leak so it isn't what bothers me the oil compumption and dilluition is the problem.

[dyermullet]

Also I forgot to mention, i really think it is blow by past the rings because I will get a slight amount of oil all over my breathers.  It is more than any of my friends turbo regals show.  I have been around turbo and super charged cars where the blow by was excessive and also ones that have none.  Mine falls in the middle. 

Sorry about leaving out details like that, it has been so long since I worked on the car I have to remember the details and how I reached the conclusions on its current condition.

[Steve Wood]

I don't see anything that would make me want to do a rebuild.  Most of them have a little vapor coming out...some of that may be because we screw up the stock pcv system with breathers, block offs, etc.

Do a leak down and go from there.

A modern chip with decent injectors should be close to 20 or better on the road on a near stock engine.  I have done close to 25 on one of my cars.  The other one with a roller cam, etc. gets 19-20 on cruise with the ac blowing.

That assumes the maf is giving the right numbers to the ecm, etc.

[dyermullet]

Thanks guys, this is what I needed to brain storm on this.