Prudency of rebuilding overreved M52 shortblock

[FredK]

I am interested in a Z3 M52 2.8 shortblock. The engine was overreved, damaging 2 intake valves (on cyl 1 and 5). My question is, is there any danger in reusing the pistons as is? The seller says they were undamaged, but I believe the only way to bend valves is to have metal on metal contact of piston to valve. I think I'd go for an engine refresh anyway (new bearings, gaskets, etc), but If I had to buy new pistons, this would affect the economy of getting this shortblock.

Any ideas out there? Also, can the steel sleeves be honed or are these just a replacement item? Finally, where can I source these sleeves?

Thanks,
Fred

[Stu]

It is strange for the intake valves to hit on a downshift overrev. Are you sure it wasn't the exhaust valves?

You will probably need to remove the pistons and machine the valve-cutouts.

If you want EXPERT advice on this matter, I highly recommend you contact my dad. His name is Pete McHenry, and his number is (336) 761-0643. He can tell you everything you need to do and give you information galore about the aluminum block.

:)

[E30godz]

do the intake valves not have as much lift as the exhaust valves?

[FredK]

Thanks Stu,

I am not actually sure what valves got bent; the seller said the intake valves got bent. I really can't tell what is what from the pictures he furnished because there is a lot of carbon on everything! And the pics are low res. But for sure I will try to get these things clarified.

I wanted to post to this forum first before enlisting the help of professionals, as I wouldn't feel right about asking an expert a billion questions if I don't end up using his services!

I think everyone has aluminum on the brain, looks like lukas wants to get an Al block, and a few months back JRowe wanted one too!

Thanks,
Fred

[FredK]

Well, it turns out the block came from a 98 328, and at my urging the guy selling it tried to stick a magnet on it and it stuck to the block. Cast iron. Ah well.

FredK