Here is the story:

After one hard start and revving the engine to almost 7k rpm, valves on the piston nr.8 broke (or probably first hit the piston and then broke) and destroyed the piston, bent the rod, destroyed cylinder wall.........

This is what I first saw after removing SR lid


This are pics of destroyed head and broken piston




After seeing this, only thing left to do was to pull the engine and check for other damage and see what could be reused.



Here is the damage to the cylinder wall


First i was thinking about "sleeving" a block, but after closer inspection I've discovered cracks on cylinder wall that go all the way from the bottom to the top of cylinder. This means a different block is a must.
I allready have a block that I planned to use for my 383 build, but I think that I'll use it for this engine now and wait for another block to come along for 383.

And this is where I am now. I need to prepare all the parts that I bought (I'll post that later on) and take
everything to the machine shop. While the block will be machined, I'll port the heads and the intake.
Also I'll have to have crank checked if it's good to go
with polishing only or if it'll need to be machined for oversized bearings. Crank will also need to be balanced because I'll use new rods and pistons.


Update 11/07/2009


I haven't done much, but I spend as much time as i can on this. I've cleaned the "new" block, applied anti-corosion layer, painted with primer and with orange metal enamel.
I did'n clean the block inside thoroughly, I'll do that after the machining.

Here are a few pics:







While I'm waiting for the torque plate to be machined, I'm cleaning and preping the pistons.








Update 12/05/2009

Update:

The torque plate that I had fabricated was finally done,
so I took the block to the machinist.

He will do next operations:
- boring/honing 0.020" over
- milling the decks to 9.000" deck height
- installing new cam bearings
- installing new freeze plugs
- polishing the crankshaft
- check the crank if it's in tolerances (I'll double check
that myself)

Here are a few pics:





While the block will be at the machinist, I will do some
work on the heads and intake. As you know, one of my heads
had some serious damage, so I gathered a new one. Only
difference is that this head is completelly stock. So now
I have one fully ported head (by myself) and one stock.

I've cleaned one of the ports just to take some pics for
comparison. I will do some more porting on both heads, as
there is still some room for improvement but I'll do that
later, after I'll have seats for new 2.02/1.60 valves
installed.












And this is where I am now. I'll post as I'll progress.



Here is a short description of combo:

- 2-bolt block
- stock/repolished crank
- clevite bearings
- SCAT forged I-bem 5.7" rods
- SRP forged .020" overbore pistons
- #113 ported heads
- 10.8:1 SCR
- 8.2 - 8.4 DCR (I'll do some work on chambers so I'm not 100% sure in final chamber cc)
- 0.039" piston to head clearance
- 2.02/1.60" valves
- CompCams XR288-10 cam
288/294 adv.
236/242@0.050"
LSA 110
- new matching valve springs
- Ti retainers
- LS lifters
- Superram with some mild porting
- Hooker 1 5/8" headers

I'm really not sure what to expect, but I'd like to see ~400 chp with 6500 redline. What do you think?

 

 

I'd pick up Lingenfelter's book If I were you, and check through it to see tht you haven't missed any tricks.

 

Making good progress. Good pictures. Set your rev limiter for 6700 and be careful starting.

 

Thanks guys! I've been through both Lingenfelters book and a few from
David Vizard, Graham Hansen.....

To 383 vett: i was thinking about 6500 rev limit, but I'll see where
it'll make power. You think that I should be safe up to 6700?

 

If you get flow #s on both heads that will tell you if you cna hit the target.

 

Finally I did some progress.

I was finished with rough porting so I took the heads to the machinist for new, larger valve seats to be installed.

Here are pics before:





While he installed new seats I also asked him to add some material on the
lower side of intake ports. I had some problems with leaks here bacause
gaskets didn't have to much material to seat on.


On the pics below you can see how much is gained in intake and exhaust
ports with new seats installed. Also, you can see where material was added
for better gasket sealing.









After removing extra material that was gained with larger seats, I went to work
on chambers. Deshrouding valves is very important as new valves are
significantly larger than stock and are much closer to chamber walls.
First I roughly removed some material and then polished the chambers.

Here are a few pics of work and the final result:

















Next, I have to take the heads back to machinist to have new guides installed
and valve job done.

 

Thanks for the pics. and info.

 

Very nice!

 

That port you have done is beautiful. I have done some porting on my own heads on past motors but they never looked anything like that. Thanks for the detailed photos, its a pleasure to see that work.

 

Betting you were around 220-230cfm int/180 exh before the larger valves .You going to have them flowed?

The pistons...are those the original cast ones youre reusing?

 

Unfortunatelly, my flowbench is down at the moment. If I get it fixed
before I assemble the engine, I'll post the numbers.

Pistons are SRP 4032 forged.

 

WOW!!

What piston to valve clearance were you running prior to the damage?

Jake

 

What is the welding all about on one of your heads? Just curious.
93cruiser

 

Welding is for adding material to the lower part of intake runners. When port matching to 1205 gaskets, material on that spot becomes really thin and problems with gaskets sealing may occur.
Both heads are welded.

Jake, I really don't remember what was the clearance. But I know that it was way on the safe side. It was basically stock bottom end with #219 cam installed straight up and 1.6 RR's. It ran like that for more that 5 years.

 

Because we can see the piston pin, I believe you broke a piston, which then broke the valve. I've seen this happen on the Chevy dyno. A broken piston trashes everything except the opposite bank's cylinder head.

 

It's really hard to tell vhat happened first, but either way, it wasn't nice.

 

Sorry for your loss and thanks for posting all the photos and info.

Many guys like flirting with those wonderous "R"s with a stock bottom end. Maybe your terrible experience will give them pause to reflect.

Best of luck on the rebuild.

Jake

 

Looks like you have no problems getting parts and the machine work is top notch! Do you get all your parts from the US?

 

Thanks guys!

Sidney; unfortunately, yes. There are parts available in Europe, but even with
extra shipping, form US is still cheaper. Especially performance parts.