Time to rebuild, Opinions / Suggestions Options

[Demick]

QUOTE (BPGREER @ Mar 14 2005, 06:42 PM)

Are you running carbs or FI? I'm planning on maintaining my Djet setup. If you're running Djet, how much tweaking did it require to get it dialed in? Thanks.

I'm running d-jet. I did have to do some adjustments to the MPS. I used a wideband O2 sensor to take readings and make adjustments accordingly.

You'll have to split the case to change the cam. If you go that route - use Jake's split duration cam.

Demick

[TheCabinetmaker]

Ok, heres my pennies worth( don't have 2 cents today). 110 and 120 ain't great, but ain't that bad either. Depending on driving habits, frequency of oil change and valve adjustement, proper dwell and timing, and properly tuned d-jet, you could get another 10,000 or another 50,000 miles from your engine. You'll never know till you do it. Your 2 liter should be good for at least 100K!! If you really want a bigger engine, find a 2.0L core, take the time and build it right, while driving and enjoying your car, (after all, thats what they are about). Then take a weekend and swap motors.

That said, The 96mm's is where I go next, with stock d-jet(except with an mps tweak).

There are different opinions about a top end rebuild, Some say ,loose bottom, tight top. Others disagree. If you do a top end only, go from the rod bearings up. It takes very little more time and money to replace rod bearings, when doing a top end.

[Demick]

QUOTE (vsg914 @ Mar 14 2005, 07:51 PM)

Ok, heres my pennies worth( don't have 2 cents today). 110 and 120 ain't great, but ain't that bad either. Depending on driving habits, frequency of oil change and valve adjustement, proper dwell and timing, and properly tuned d-jet, you could get another 10,000 or another 50,000 miles from your engine.

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif)

[McMark]

It just depends on what you tolerance is for "problems". As it ages your engine starts going down on power and starts running a bit "funny". How long you want to live with that depends on the person. I agree that 110 or 120 psi isn't a severe case. But it is about a 25% loss in compression. You can take that engine to it's bloody edge, or you can rebuild it and bring it back to life. Factor into that the increased chance for catastrophic failure as the engine ages and engines at this point are really starting to enter the "rebuilt-it" territory, IMHO.

[Gint]

Just drive the damn thing! (IMG:http://www.914world.com/bbs2/uploads/peelout.gif)

[Triaddave]

to get back to the orginal post, i would do more tests, like a leak down test, the compression is really not that unreasononable, i've have worse. the leak down will tell where the problem is. you said 110/120, what is #1,#2 #3 #4?

[IronHillRestorations]

QUOTE (jd74914 @ Mar 14 2005, 07:06 PM)

Jake (or anybody reading), what is the easiest way to increase compression without increasing displacement (ie: boring out)? I'm kinda confused with this subject.

Flycut the heads. You don't want to go more than 9.5/1 for FI though.

[IronHillRestorations]

QUOTE (Triaddave @ Mar 14 2005, 08:34 PM)

to get back to the orginal post, i would do more tests, like a leak down test, the compression is really not that unreasononable, i've have worse. the leak down will tell where the problem is. you said 110/120, what is #1,#2 #3 #4?

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif)

How does it run and feel?

Another general barometer is oil consumption. If you use more than a quart every six hundred miles, it's rebuild time.

[nebreitling]

dude, drive your car until the engine won't go any more. not driving your car SUCKS. if you can, build another engine while you drive the snot out of that one.

[BPGREER]

QUOTE

How does it run and feel? Another general barometer is oil consumption. If you use more than a quart every six hundred miles, it's rebuild time.

It's difficult to say how it drives, as I have nothing to compare it to. This is the only 914 I have driven. (IMG:http://www.914world.com/bbs2/html/emoticons/sad.gif) I would have guessed the car to have more "pep" than it does. If it leaks any oil, it is a tiny quantity, because I have never seen a drop on the floor where its parked. The oil does however get very dark, very quickly. Like say 500 miles after an oil change. What I am concerned with is letting it go, and setting myself up for an avoidable major failure. I agree with vsg914, that properly rebuilding another one while running this one, would be the best way to go. However, that seems like a much more expensive proposition, if a top end job would be pretty sufficient. Brad drove it a few months back and said "yep, it drives like a stock 2 liter motor with 64,000 miles on it." I'm not sure if that was a positive or negative comment. I didn't give it too much thought at the time, and don't want to bother him now. I will definatly give some thought to all options, they are very much appreciated. If there were only one answer things would be boring.

[BPGREER]

QUOTE

dude, drive your car until the engine won't go any more. not driving your car SUCKS. if you can, build another engine while you drive the snot out of that one.

Maybe you're right. If I spend the time trying to make it perfect, it may never see any of the wonderful windy roads out there. This option is starting to sound good. Wait a minute!...are you the guy that used to talk me into ditching classes? Thanks alot man, I could have been a doctor by now and bought a real porsche. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[newdeal2]

QUOTE (Jake Raby @ Mar 14 2005, 07:00 PM)

I have a split duration version of a web 73 that works very well for stock FI with a stock or 96mm bore and around 8-8.5:1 CR. The straight pattern web 73 works ok, but having a dual pattern cam with the TIV head is the first step at making bigger power with cooler temps. Going to a cam with a tad more duration and lift will cool the heads off (as much as 50 degrees) and will really help with down low and midrange power. I have seen improvements with gas mileage as well.

Interesting point Jake. One of the first things I have noticed is cooler running temps. My gauge barely gets to 1/4 in a half hour of running. It was up to 1/2 prior to the rebuild.

[Jake Raby]

Thats due to increased efficiency... EVERYTHING follows efficiency and the camshaft is the start of the snowball in that category!

You should see what happens to a head temp gauge when just a couple of changes to the combo are made...

FYI- My 3 liter engine runs head temps of 275 degrees and only has FOUR cooling fins on the heads! I finally got the oil to 230 degrees yesterday... With Synthetic oil it won't go over 215...

Thats 195HP at the rear wheels fellas... 230 at the flywhel on pump gas!