Top End Rebuild - can it be done in time?

[the]

Darn. I was one of the few that thought you were going to pull this off.

Not wanting to go over 3K, that seems pretty severe. Maybe make triply sure the cams are in right. My friend many years ago had his S engine rebuilt by a very old time, respected engine builder, but the car ran horribly. It turned out the builder had accidentally put the right hand cam on the left side, and vice versa!

Surprisingly, the car still ran, just not very well.

I'm sure you'll get to the bottom of it fairly quickly. Good luck!

[disfin]

Originally posted by alniki
John,

Wish you correct the issue very soon and enjoy the car again.

Also, did you get a conclusion of what caused the high oil consumption? Is it the valve guide, valve seal, or piston ring?
I'm interested to learn about that, thanks!

Guides were defintely bad, as would be expected. I suspect the guides were a little more than half the problem and the rest was the rings. Visually, the rings were questionable. None were broken but cyl 3's oil ring looked worn which would explain the >5% leakdown on that cyl.

[alniki]

Thank you, John.

If you don't mind, how did your engine run before the top end job?
Mine consumes about the same amount of oil as did yours but the engine is so powerful that I can hardly imagine there is any serious wear in the guides and rings.
And I've driven high-performance cars before.

[disfin]

Worn guides won't really effect performance, but will increase oil consumption. Worn rings can do both as they allow air to escape the combustion chamber and oil to enter the chamber.

In my case the car felt strong and consistent but I anticipate a mild performance increase considering the buildup in the exhaust ports restricting airflow and the lower than desireable compression in #3.

[alniki]

Got it. Worn guides would not decrease performance.

Guess I can probably wait till I have the resources to do the top end job as I only drive my Targa once or twice per week for less than 80 miles.

Thanks again and good luck!

[DaddyGlenn]

John & Donnie,

You guys should be proud. It was quite an undertaking and in my mind you pulled it off.

I'm sure the issue will be minor and easily fixed.

You get my applause.

[disfin]

Originally posted by alniki
Thank you, John.

If you don't mind, how did your engine run before the top end job?
Mine consumes about the same amount of oil as did yours but the engine is so powerful that I can hardly imagine there is any serious wear in the guides and rings.
And I've driven high-performance cars before.

Have someone drive behind you and watch for blue-ish smoke when you decelerate or accellerate. If it smokes when you accellerate it is coming past the rings, but if it smokes when you decelerate its coming past the valve guides. Of course when mine was warmed up there was never any significant oil burn, so this test didn't provide much guidance. It just blew a cloud at startup and then a little as it warmed up. It was hard to believe it burned as much as it did because I really didn't notice it all that much until it was time to add another quart.


Glenn,

Thanks for the kind words. Donnie and I think we know what the problem is so the car will be going back under the knife on Friday and Saturday. Anyone care to join the fun?! Oh and while we have the engine out, i'll be replacing one of the gaskets i just replaced because the back of the engine has developed a new leak that it never had before. Thats what I get for replacing perfectly good gaskets. I just need to figure out which one it is.

John

[DaddyGlenn]

I'll be heading out on a much needed vacation on Friday so, I'll have to pass on the invite.

I am curious about what you suspect the problem to be since you plan on dropping the engine again. Something in the assembly of the heads/cams or just a hard to reach piece? Care to share?

[dweymer]

Cam timing. I set it 180 out of phase, and checked it by verifying that "930" was up, on BOTH cams. Right cam should be down.

[DaddyGlenn]

Man, that bites!

I did something similar on a bug engine rebuild once. Bolted the cam gear on the shaft 33 degrees off. I couldn't get it to start. Double checked everything I could think of and drained the battery trying to start it.

Convinced that there was nothing wrong I rolled it down the drive way and tried to jump start it, pushed it back up and tried again and again and again....

I finally had it towed to a shop and after about three hours of work they told me they thought it was the cam. This was, I think, my third engine rebuild and I couldn't believe I had done that.

[JeremyD]

I did that too - Good for you for getting as much done in the time frame you had - impressive.

[Gunter]

When one cam is 180 deg off, would that not show up with some valves touching the pistons while doing the timing before starting up?
Is there no concern that some valves may be bend since the engine actually run for a while with the wrong timing?
Realizing how important the cam timing is, I check 3 times around with minor adjustments.
Also, remembering the bad experience with new chains on old I-shaft chain sprockets, I again installed new sprockets for the ss 3.2.
I hope you re-used the old chains and not feed new chains onto old sprockets to find all the teeth 20k later on the bottom of your case.
Still opposed to rush-jobs.

[dweymer]

No contact was made either turning it over by hand before re-assembly or while running.

[disfin]

I wondered the same. We turned the engine by hand after installing the heads and there was no contact. Also, when it was running there was nothing audible.

[john walker's workshop]

Originally posted by dweymer
Cam timing. I set it 180 out of phase, and checked it by verifying that "930" was up, on BOTH cams. Right cam should be down.

??? i don't follow you completely. the 930 mark is up on both cams at #1 TDC. not one up and one down.

[dweymer]

Then I read the bentley wrong; i'll re-read today sometime.
JW-
What intakes should be open at the same time? I can verify Friday by a visual.

[john walker's workshop]

TDC #1, adjust #1 intake to .004, set up dial gauge on #1 intake and zero the gauge, turn clockwise 360° to get your cam timing reading on the left cam. at this position, #4 intake will be adjusted to .004 and repeat the procedure for the right cam.
so with #1 intake at it's starting position, #4 intake would be open and both 930 marks are up. after a 360° rotation. #4 intake is closed, and #1 intake is open and both 930 marks are on the bottom.

[dfink]

Nothing would touch, the piston to valve relationship is the same it is just off by a stroke. The intake would be opening on the exhaust stroke and the exhaust would be opening on the intake.

I had mine the same way but as I mentioned I noticed the intake for cylinder 1 was opening at the same time the intake for number 5 was opening and made me go "Huh" . I thought about it for a bit then figured out I was 180 off so. For those trying to do math. 180* off on the cam is 360* off on the crank. So take out pin turn crank 360* put pin back in and now getting close.
Not quite that simple but the general idea.

[edits for spelling]

[DaddyGlenn]

Oh what fun I have to look forward to! I'll be doing my cams later this year.

[Rick Lee]

I just stumbled upon this and must subscribe. My own SC rebuild was done in three wks. I was adjusting the valves about two nights before I was to go to China for three weeks, when out came two head studs. The following night we pulled the engine in my one car garage, put it on a stand and left the car under a cover in the driveway. I left Charlie a credit card and a garage door opener. While in China I was hitting Internet cafes to check my email and see photos of the progress. When I got home, Charlie was timing the cams. We slapped the engine in a few days later and all worked perfectly. Very lucky, cheap and fast. Two weeks would be very tough though.