Have the crank checked to make sure its still straight for sure.

 

sorry dude, good luck with it

 

sorry about your engine.

In my own experience, engine disasters almost always involved top end failures. The late Smokey Yunick allegedly said that the small block chevy lower end could be made to turn 10,000 rpm, it was all that monkey motion on top that limited it's performance.

 

So sorry to hear about your motor. From first impressions the chambers look very rich.

What kind of timing #s were you running at those rpms? What ecm/tune etc do you have? Are those SRP Pistons?

 

I have heard stories of titanium retainers failing. Did you have a lot of miles on them.

 

I have low miles on retainers, maybe 5k. They all look OK, but
I still have to disassemble the heads to be sure.


Pistons are stock. Complete lower end is stock, I have never opened
it before (by lower end I mean block, crank, rods and pistons).

Here are timing maps. It's custom tune by PCMForLess. I've been driving
the car with this tune for approx. 3 years now.




Will do. I'll have to have it rebalanced for new rods and pistons also.
I'll probably have it micropolished also.

 

What software is that?

 

TunerPro

 

Hi
I used to have another car with a 351 cleveland engine , 8,500 rpm no probs with anti pum up hydraulic lifters .. the only problem was dropping valves as you have had ... that was solved by replacing the valve stem collets they wear realy badly at over 6000 rpm so i used to replace them every 2 months. So look at the valve stem and collets for wear
I had that engine reving to 8500 rpm a lot was a nascar spec engine and the valve collets are a weak point ....
By the way my vette doesnt have to rev to 6500 rpm with the supercharger as it has so much torque at lower rpm

 

Why not just use a solid if you want to twist it up that high, 8500 with a hydraulic ? THey are so much more dependable up top, no parts in the lifter to go bad, pump up, etc. Dont know why people are so scared of them.

 

With 383 I'll go with solid roller cause I plan to rev it close to 7500.
For repairing this engine, I allready have LS-x lifters.
They are supposed to be better and should be good up to 6500
what will be my redline.

 

Red coating coloration on plugs or valves is a typical result from the use of additives in unleaded fuels......or it could be rust from getting wet after the grenade went off.
Sorry to hear about the big bang

 

How would you prevent this? I thought that the revolution limiter was enough and it would cut off engine power to avoid this.

Would it be a good idea to change the valve springs at certain mile intervals??

 

I know you did not ask but if this is your total WOT spark advance it is too conservitive and you could pick up good power with more advance. Typical SBC like 30 (fastburn heads) to 36 (Standard combustion chanbers) degrees of advance at WOT.

 

Actually, I'm glad that you mentioned it. I also had feeling that
I gained too little with SR install. Maybe this was where the
power was hidden.

But it won't matter too much now, I'll go with a different cam
with this rebuild.

 

I would have that block magnafluxed before you put any money into it. That wrist pin banging around in the bore probally cracked the cylinder wall. It will probally need a sleeve. If it isnt cracked your hell of alot luckier then I was when my 86 grenaded a piston.

 

It'll definately need a sleeve. I'll have the block checked, but I can
already tell by the look that 0.020" overbore ( I allready have that size pistons ) won't be enough.

 

Nothing wrong with sleeving a block, done properly.

 

My 86 standard bore block with a hole blown. I had to go thirty on all the holes because of the disruption of the sleeve install. It all worked out great and made great power with the build. 6 inch rod 355 moderate 200cc heads with light pistons je. Though my machinist hans fuestel racing engines recomended moderate power levels. I stayed well within with a tpis tpi intake system.

 

I've disassembled the heads and tested the valve springs.
I did it for two reasons:
1. to check if weak spring was a problem
2. to check if I could reuse springs with new cam.

However, I got some strange readings.

1.900" - 112 lbs
1.800" - 157
1.700" - 199
1.600" - 242
1.500" - 288
1.400" - 334
1.300" - 390
1.200" - 456

It's a little bit hard to be really precise with valve spring tester that I
used (see link below), but all springs were very similar.
The weakest one was 364@1.300" and stronest 392@1.300".

Link for the spring tester:
http://www.streetperformance.com/par...760-66834.html

The scale is by 10 lbs, so my numbers could be 1-2 lbs off, but even
if they are 10l bs off, it still looks like those are a lot of
springs for small #219 cam.


I'm about to install XR-288HR cam that has alot more duration than
LPE #219 cam, similar lift and it needs less springs than what I've got.

This are springs that are recomended for XR-288 cam:

Comp Cams #249-986-16
Dual Valve Springs
Outer inside diameter: 1.070"
Inner inside diameter: .697"
Seat load: 132lbs @1.750''
Open load: 293lbs @1.250''
Coil bind: 1.150''
Rate: 322lbs/in


OR


Comp Cams #249-987-16
Dual Valve Springs
Outer inside diameter: 1.070"
Inner inside diameter: .697"
Seat load: 121lbs @1.800''
Open load: 343lbs @1.200''
Coil bind: 1.150''
Rate: 370lbs/in


What is your opinion on this? How is it possible that from 1.900" to 1.800" is 45 lbs and from 1.300" to 1.200" is 65+ difference? Is that valve tester any good at all, can it be that much off? Can it be that springs that came with from LPE are ~450lbs/inch rate???