2.7 total rebuild coming will need some help
 

Hi guys.

I posted here a few times, but mostly lurk the 930 forum.

I am helping a buddy with a 2.7 car. He has someone who didn't know jack about the platform rebuild the car. I got it here a while back and did some preliminary digging. The care had no compression on 4-5-6 so I suspected the cam timing was off.

Well we pulled the engine and trans today and there were 5 broken rockers on the (R) side of the engine.

Leak down was about 80-90 on the first cyl we checks so I am assuming all the valves crashed on that bank.

So a top end tear down is coming next weekend.

I will be seeking some advice from this board for sure.

If the valves do crash, what is the chance the pistons are that badly damaged that the bottom end needs a rebuild. I am trying to not split the cases.

Thanks

Brendon

The rockers worked as advertised. They are designed to break like that when valve/piston contact is made. That (hopefully) saves other parts of the valve train from damage.

Usually when the piston tags the valve, breaking the rocker it shows up on the face of the piston by the exhaust.
The bottom end usually goes when the valve head breaks off bending the rod, holing the piston and head and blowing shrapnel through the injection and in the case.
Bruce

I am getting leakdown in the intake and exhaust side so the valve have to be bent. Tear down is happening late this week or weekend


Thanks

Brendon

I hate to say it, but if somebody who didn't understand the motor did the rebuild, then I'm guessing you'll want to tear into the case anyway just for piece-of-mind.

From my understanding, he only did a top end rebuild. The Owner was there a lot and he's not even sure the heads were pulled off. I am treading lightly as this "rebuilder" is my buddy's father inlaw....

I have office work all week, then I am planning some shop time to get into the engine. Once I dig deeper, I will post up the carnage.

I would hope the pistons are save-able but plan for the worst. Father in law, eh?

yeah, it's a touchy subject. I was going to put an offer in on the car and use the parts to build a light weight car to go side by side with my 930... I am glad I didn't..

Once the heads are off, you might have an idea of the damage, but I'd also think that a complete tear down would be appropriate if in doubt.

If you need specifics, Wayne Dempsey's book on rebuilding 911 engines uses a 2.7 as his example and goes through the steps involved very thoroughly.

It's on my book shelf

What's with the trepidation on splitting the case? If the top end looks like that, you could have:
- bad rod bearings
- bad crank bearings
- scored crank
- oval cylinder spigots
- pulled head studs

Read Dempsey's book and do the whole thing.

I have the book and we are planing a total rebuild now. he's ordered a yoke so we're on hold for a few days.

Got my yoke delivered yesterday and pulled the engine number


Looks like I have a 2.7 out of a 75 Sportomatic car

*6459117*

Splitting the case on anything *but* a 2.7 is a just a bit more money.

A 2.7 case is a different animal and will most likely require resizing - sending it to a west coast machine shop for +$1000 worth of work. I'm not saying you shouldn't split the case, just be aware of what you are in for.

Just take careful steps in pulling out the old or damaged head studs, you do not want to take off case material when you remove them. Ask me how I know.

I would let a pro do it and have them clean up the threads or insert CASE Savers if needed.

Funny, I'm just starting on a 2.7 out of a '77 Sportomatic. The crank is on my bench.

thanks for the input guys. I will update as i dig in.

Timely post, a certainly buddy of mine ;) is helping me (alot!) with my 2.7L sportomatic rebuild. Thanks ChrisBennet :)
Looking forward to this 2.7 rebuild to see how best to do mine!

where in New England are you?

Oh too funny! Southern NH too. I wonder if we both know ChrisBennet SmileWavy
PM me and we can see if we have Pfriends in common or have met at a tech session etc.