Shot peening engine block question
 

The engine out of our Yenko is just too crusty with surface rust and 50 year old paint that thermal cleaning will not do it justice. Our local machine shop (Tim Wilkerson FC owner/driver) owns the shop. Their tech suggested I use their Ampro shot peening machine to clean the engine. I will admit that all the blocks they had in house looked great though none were Chevy blocks. I was concerned about loosing the stamps of the front pad as well as broach marks though they insisted this would not be an issue. The pad on this engine is not in the best of shape and I would like to try and bring it back best I can. Before I make a $20k error has anyone here used this or a similar system to clean their blocks and what were your pros and cons. It has also been suggested that I make a steel bracket that protects the pad area so I will likely be doing that anyway but before I ruin anything I wanted to check. From all that I have talked to there is no issues with cylinders, bearing saddles or anything such as those areas.

Hi Rick, while I've never used such a proposed service, I do echo the sentiment that the engine pad surface (stamp + broach marks), cast date, and cast # need complete protection. Is shot peening like media blasting? You also want to ensure the residual media is not inside the block post cleaning process and reassembly.

Good luck.

Dan

I have has great success using glass beading on blocks and heads like this.If you want to be safe, cover it up, but I really dont think the glass beads would damage the stamping or broach marks.

It looks like the broach marks are already gone. I would glass bead the stamp area then plate it before its cleaned. Are you shot peening or shot vibrating?

just took a block to get shot peened and magved. we use silicone or a magnet that covers the deck ares for vin and letters. hope this helps.

The engine shop I use has what I would assume is the same machine. It rotates cylinder heads or whatever they put in it in the top and then there's some device in the bottom that throws shot up and cleans the block or heads. I've had heads done in it and they come out looking like new. This guy does mostly race engines and seems to like the machine real well

shot peening and shot blasting are 2 diff procedures..

shot peening changes the surface and adds strength and promotes stress relieving..they shot peen Z28 rods for strength and stress relief..makes the rods perform better..you can actually see what shot peening does on a pink rod..its dramatic

shot blasting removes debris and surface scale....it doesnt change it deeply on a molecular level like shot peen..

shot peen gets a a specific media and air pressure changes the characteristics of how the "grain" aligns in the structure..its actually calibrated, by shooting beads at a metal gauge, and the distortion is measured and that determines what it does..it really changes the surface look and texture....the ole.."lemme roll it around in the shot peen thing" does not work as intended..theres science to it..metallurgy

thermal cleaning goes a long long way to restore the surface to original...the beads are pretty soft...it breaks the bond scale has to the metal..it also boils all the grease out of the pores..so its nice and clean and can oxidize immediately

the ampro machine does not peen it, if thats what you are afraid of...its the best system ive ever seen or used..i recommend it...i would think youd notice a 50-75% improvement over whats there right now..i use it on pulleys and things like that, it doesnt distort or change the machine marks, etc..i really like it for resto stuff...BUT..ive never had a Yenko block either..i understand the worry..ive seen it bring broach marks up better...with out it changing the readability..if that makes sense

find the worst block you have..send it thru..judge yourself..thats exactly what i would do...

Thanks all for the input and yes Mark, I misworded that as it is NOT shot peening but rather shot blasting. HUGE difference!

I can see broach marks on some of the deck but not in the area that the stamping was done as it was just too pitted. I am hoping that it shows up better once blasted. I am not as concerned about the broach marks as I am the VIN stamping but will likely put a plate on it regardless just to make sure. I was also told by someone else that the rocker studs should be removed as the blasting tends to round the threads.

----Just spitballing here but how about soda blasting?.......Bill S

I live in the capital of Illinois, population 170,000 people (and no it is not Chicago :) ). I am lucky to find a hardware store let alone someone who does soda blasting. Ditto for plastic media as I have to go to Decatur for that. Good suggestion however.