Sonic check opinions

This is some info I got re Mega Block test. Bore 4.565...will be short trip street use, and up to 6300rpm race use, 1/4 mile. But what are your thoughts on more serious drag race use as the motor is very mild currently and only 10:1, max power is@5600, max torque@4400. Motor is built and going into car and will not come apart now.

#7 is a bit thin at the rear. I would probably sleeve that hole and run it.
Brian

Yes I know that but your opinions on what you see and the use we plan to put it through with more serious use later.
thanks

Well I just got word yesterday that my 2001 mega block (I bought it new) is a bit thin also. But this thing will go 7500 rpm+ and make up to 1100 hp.

I have 2 cylinders that are in the 0.135" range - I believe that he said it was the bottom readings. My bore is 4.504 so our blocks are almost identical in original thickness - disappointing. Tony Bischoff (BES) is building the motor and I have utmost trust in what he tells me. But the engineer in me also worries............

I wanted to sleeve them and he told me no. He wants to do a short hard block fill in the water jacket. He said that would help and that a sleeve is only 0.125 wall thickness so I am not gaining anything with the sleeve.

What is a stock block wall thickness?

I will take Tony's advice, have it filled and not look back..............

Also - the one good thing in your case is that the thinnest spot is not on a thrust surface. My thinnest parts are on the thrust surfaces. That makes a big difference.

We shot for .150” min back in the 70’s. You have it together and said it’s not coming apart.

Drive it and race it, once broke in do your leak down and keep an eye on it.

If you cut the bore another 1/4-inch in diameter (1/8" wall thickness), and then
put in a 1/8" wall sleeve, what have you gained ?

do you know where they did there measurements at? Top, bottom or middle of the cylinders?
I sonic test all my blocks in all three locations, top, middle and bottom on all four sides
If the measurement for #1 cylinder on the cam side is at the middle or top I might be a little bit concerned, if it is at the bottom I wouldn't worry at all
I do have to move the sonic tester around at the top of the cylinders on the cam side due to that head bolt boss being there also, you can find some blocks that will have a tiny area that is really thin, say the size of a half dollar, a two inch diameter circle, and be really good around the rest of that small area

Looks magnificent except for the back of #7. Run it.

If you did that it would be the same exact thickness and weaker.

Have to remember sleeves are ductile iron and centrifugal cast. Much stronger than the poured block. To the OP's question, I would sleeve 7 and 8.

Thanks guys, not an easy question really to answer I know, It will be run as is now, engine was built earlier this year with all new internals, was built by good reputable builder here, (ex racer). We'll keep an eye on things as suggested, I think the most we would do with it is to increase lift using r/ratio (doubt if it has 1.7's) but thats expensive with Jesel stuff, a carb change is likely as its currently small but that won't work wonders either, the 2 together may help. As its a brkt car only it will be a personal goal to get in the 9's@3850lbs which we should only be 3>4 tenths away as it is. My mate didn't pay a fortune for the motor and it was perfect for him for dual purpose use and will do what he wanted which was to run 10.50's and cruise on the street.

Here’s what I find “interesting” about the numbers at the front/rear of the adjoining cylinders.

How do those areas between the cylinders not agree with each other?
Particularly between 4&6 and 3&5.
Is it not a Siamese block?

The only thing I don't know yet is block no., he forgot to write it down, he did say it had a shield type logo on it, could be an MC block?......but here's the original sheet I got for test, I wrote it out to be more clearer but may have got some numbers you refer to a bit off>


upload

The other thing is...... with the BBM bore spacing of 4.800, if the bore size is as you say......4.565...... then there could only be .235 thickness between the bores.
No way those numbers near .300 between bores are correct........ which then makes you wonder how accurate the other numbers are.

Well it is what it is, but I see what your saying is correct. I'm the crew for next year and my mate isn't really a hard core racer tbh, too laid back, so I'm just trying to get as much info on it as poss to have an idea of just how hard we should push things with it in the future once he gets fed up running mid>low 10's and it all stays ok. We'll get it run in down the 1/4 and keep an eye on it. Are these blocks good for cooling or do they have any issues is another thing that would be good to know, we'll find out of course but a heads up would be good, that no.7 is thin if any of these numbers are correct.