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GaWajn

Engine reconditioning questions

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Hey guys,

I am in the process of reconditioning a 1952 flat head inline eight. I have a few questions. I am rebuilding a driver quality car ... not a show queen.

1 - Let's say that all the cylinders are good except one. Can you bore out just one cylinder ... shave some weight off the oversize piston to match the others, and will that work OK, or is it a NO-NO? I am not asking if it should be done or not as an ethical question ... but a purely mechanical one. Will this create problems ... or will it work reasonably well?

2 - When you clean up an engine ... and have the cylinders honed ... and reuse the same pistons ... are slightly oversize rings a way to go ... or use original spec? Is there a case to be made for one or the other?

3 - In the case that I need to change all the pistons ... Is aluminum the way to go ... or cast Iron like the original? Again this is a purely mechanical question. Will aluminum work better or worse? I am not rebuilding the engine for the purist ... but to enjoy the driving of it for many years.

4 - Is it advisable to re-seat the cleaned up original valves ... or do they absolutely need to be replaced?

5 - Are all the parts suppliers out there supplying good quality parts ... or is there a company that I should be checking out? Who makes the best quality carburetor rebuilding kits for these old engines?

I know that there are many of you out there who have gone through the same thing that I am. I appreciate you taking the time to respond to my questions. It will be of great value to me as I try to set the best course for my rebuild

Thanks

Stephen

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Hey guys,

I am in the process of reconditioning a 1952 flat head inline eight. I have a few questions. I am rebuilding a driver quality car ... not a show queen.

1 - Let's say that all the cylinders are good except one. Can you bore out just one cylinder ... shave some weight off the oversize piston to match the others, and will that work OK, or is it a NO-NO? I am not asking if it should be done or not as an ethical question ... but a purely mechanical one. Will this create problems ... or will it work reasonably well?

2 - When you clean up an engine ... and have the cylinders honed ... and reuse the same pistons ... are slightly oversize rings a way to go ... or use original spec? Is there a case to be made for one or the other?

3 - In the case that I need to change all the pistons ... Is aluminum the way to go ... or cast Iron like the original? Again this is a purely mechanical question. Will aluminum work better or worse? I am not rebuilding the engine for the purist ... but to enjoy the driving of it for many years.

4 - Is it advisable to re-seat the cleaned up original valves ... or do they absolutely need to be replaced?

5 - Are all the parts suppliers out there supplying good quality parts ... or is there a company that I should be checking out? Who makes the best quality carburetor rebuilding kits for these old engines?

I know that there are many of you out there who have gone through the same thing that I am. I appreciate you taking the time to respond to my questions. It will be of great value to me as I try to set the best course for my rebuild

Thanks

Stephen

Stephen I see you've changed forums now. Just wondering if your looking for different answers.

Question # 1. No I wouldn't

Question # 2. What you should have said is you've cleaned up the engine and have measured everything and the cylinders are within specifications to only need a honing so what type of rings should I use on stock pistons? The answer is your only honing the bores so use the size that's in there already weather it's a stock, .030 over etc. If it has stock pistons your going to have to file fit stock rings anyway.

Question # 3. I would use aluminum pistons if I could get them-just less reciprocating weight using cast pistons.

Question # 4. You need to get the valves out of there so you can inspect the valve face and margin, you will need to measure the stem diameter and the taper of the stem diameter. You will need to inspect the valve seats and measure the wear on the valve guides, measure and inspect the valve springs for height and spring pressures (2).

Question # 5 there are good suppliers for your engine.

I have had a photo look at your car's engine, and for myself and anybody who I was doing that job for I would go through the entire engine especially the the bottom end. When taking that block apart make sure to look under # 3 piston as I said in the other thread you posted. Once that engine is out and upside down with the pan off I would if possible remove all the pistons and rods except # 4 and if the inspection below #3 looks bad # 3, then remove their caps and remove the crank leaving (depending on the condition of # 3) those two in the bores. having the crank out of the way will make it easier for you to KNOCK those piston assys. out. #4 looks like it might need some persuasion.

You should have posted pictures HERE also, for people to see the condition of the engine so far.

I hope your not trying to pit thread against thread, as most of us Pontiac people look at both.

D.

Edited by helfen (see edit history)

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I am not pitting anything against anything ... I just want to keep the original thread uncluttered with sub content.

In my eyes ... a new thread was needed for an in depth discussion on the situation. I may be wrong ... but I like things categorized and separated.

General engine restoration conclusions over there ... engine specific fact finding over here.

It is my intention to remove the crank for a thorough inspection and analysis.

You input is apreciated ...

and here are the missing photos ...

post-81771-14313898198_thumb.jpg

post-81771-143138981986_thumb.jpg

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You might be surprised how well that bore cleans up yet. It it needs a 20 thou bore I'b be doing it to all the cylinders personally, and use aluminium pistons.

Valves are relatively cheap, if in doubt, replace.

I don't think oversize rings are necessary if you have just honed, you'll be setting the ring gap anyway. It all comes down to the bore measurement though, no point honing a bore that is already worn 10 thou over or is oval shaped.

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