Aluminum cylinder block

By Lawrence (*****)

Date 01-22-2009 17:17

I'm unclear about your problem.

When you say "oval form" are you referring to a depression or concave weld termination?

If this is in fact your problem the most simple soluton is to slowly decrease your welding current via remote control foot pedal while at the same time adding a small amount of filler metal when you terminate your GTAW aluminum weld.

Using larger diameter filler wire will also aid in controlling heat input during GTAW buildup operations. The larger diameter filler wire acts as a heat sink of sorts when it is dipped into the puddle.

In combination, you should be able to see the size of the weld pool shrink while at the same time the depression at the weld termination is filled.

If I misinterpreted your problem please give us more detailed information and somebody is sure to have a helpful suggestion.

By labib

Date 01-22-2009 19:54

Thanks lawrence for your suggestion to apply large diameter of filler wire- but what is the largest diameter could be used for Aluminum TIG welding.

Attachment: bottomalum.cylinderhead.jpg (0B)

By aevald

Date 01-22-2009 20:11

Hello labib, I'm with Lawrence with regards to describing what you are trying to accomplish in a bit more detail. I can take a stab at your situation and guess that you have an engine block that has some corrosion issues where the liners fit to the block on either end of the liner (top and bottom) and you are trying to do a weld repair here that won't take the bore too far out of round, or distort it too much. If there is corrosion or electrolysis present you will first need to clean out any traces of the oxidation or other forms of contamination prior to attempting welding. A carbide burr would likely be a good choice. Then you might also consider a dip in a degreasing bath of some sort along with a careful steam cleaning afterwards. An additional wipe down with acetone possibly followed with a wipe down with alcohol might not be a bad idea either. The main thing is clean, clean, clean. You can minimize distortion issues by doing any welding in a manner similar to the way that you might torque head bolts on a single cylinder, staggering your welding from side to side and as evenly as possible around the diameter of the bore. As opposed to simply starting at one point and continuing around until you have met the point where you started. I am guessing that you will be machining and truing the bores after the welding has been completed, so it makes sense to try to limit excessive distortion as well as a lot of extra weld deposit. Over depositing weld metal will only cause longer machining times and possibly introduce a softening of the base material that could be detrimental to the intent of the work. I might be way off base here with my understanding and suggestions, so please try to give all of us a bit more information to better understand your task. Best regards, Allan

By labib

Date 01-22-2009 21:05

Hi aevald,first of all thanks,Find attached a photo of Alum. bottom engin block that has a mechanical circumferential wear where the six liners fit to the block on either end of liner(top and bottom). The problem is how to avoid oval form due to heat input by applying Aluminum TIG welding of six liner(top and bottom). By other way what is the W/P?
Rgds labib

By aevald

Date 01-22-2009 21:48 Edited 01-22-2009 21:51

Hello again labib, I am going to ask some questions again here. The picture that you have included; are you planning on building up the I.D. of the bore that is shown and then remachining and decking the top of the block to accept new liners? In my experiences you would be machining the bore back to the tolerance to accept the new liner including a step in it to set the height of the liner and also machining the top of the entire block to ensure that it is flat so that the head will seat onto it properly. As well, you would machine the bottom of each bore at the same time to properly accept the new liner.
With all of this said, there is a possibility that you could make arrangements with someone who is knowledgeable in heat-treating of aluminum and discuss with them whether you might need to have the blocks normalized in an oven to relieve the welding induced stresses prior to performing any machining on them. This brings us back to your original question. If you are able to perform the necessary welding and determine the requirements for normalizing these blocks, the amount of out-of-round that might be induced by the weld repairs will become a non-issue since you will be machining and correcting any distortion through the finish machining that will need to occur to fit the new liners. I hope this makes some sense and possibily others might have some additional information to include here for you. Best regards, Allan

Edit: noticed your question about "W/P", I'm thinking that this might be referring to a "Welding Procedure". If you are asking about this in reference to some documentation that you have on this job it is possible that this is the reference.

By DaveBoyer (*****)

Date 01-23-2009 04:39

Aftyer all that welding & post weld heat treatment You may need to line bore the main bearings, or at least check them for alignment.

By aevald

Date 01-23-2009 06:53

Hello Dave, very good point! Best regards, Allan