Dear All My 211 Flathead V8 21 stud engine has gone to get rebuilt and the builder has said the bores are oval. Is this someting that happens to the engine? It has +60 pistons in it and he is asking if i can get +80s. The questiona are How far can you go with this block and can they go to +80s Is it better to put liners in it and go back to std pistons The reason why we are looking to keep the engine is all the white matal works is in fantastic condition. Im in the Uk and not may folk i can ask over here Help.... Thanks Marc
Bores wearing oval is not unusual. Since the piston is pushing a connecting rod that has its other end constrained on a moving rod journal, it makes sense that the wear would be on the rotational plane of that journal (mostly on the outside of the bore). Someone should be along shortly to comment on availability.
I have heard of guys punching them .125. They are a heavy casting. All engines wear the bores and it is seldom even. That is one reason we bore them.
How oval is it? How long do you need it to last? (how many miles will it get driven while you own it) Sometimes we do work to engines that they don't really need to fulfill their mission of giving us some fun for a little while. I've been just honing and re-ringing engines lately, and driving them a bit, and they're usually fine.
"the builder has said the bores are oval....." “When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind.” So said Lord Kelvin - born William Thomson June 26, 1824, Belfast, United Kingdom. Died: December 18, 1907. In 1968 Chrysler published service limits for the 426 street Hemi.
You should be able to bore it .080 or up to .125 with no problem, at least, you could when it was new. Sonic testing will tell you if corrosion has taken a toll. I wouldn't hesitate to bore it that much. Just how bad are the bores? Are the cylinders tapered? Are they smooth? If they are within reasonable limits I would hone and rering and let it go at that. A lot depends on how much you plan to drive it and how hard. For casual, hobby use of a few hundred or a few thousand miles a year the engine does not need to be perfect. By the way if the cylinders are oval you could rering and pin the rings in their grooves. Hudson and Rolls Royce did this.
How did you decide that it was time to have the engine rebuilt? Does the builder you're working with have any background of working with this type of engine?
Is this where Ford got the name "Blue Oval" ? I'd ask him just how much out of round they are. Most engines wear more on thrust faces and you bore and hone them to make the round again.
The block should be okay to the .080 bore however its not a very good idea to go to the .125 size. For a very good oversize piston for the 221 which has a stock bore size of 3-1/16 contact Egge machine in California. Egge should have the .080 pistons you need. Be sure to order the rings along with the pistons Egge casts their own pistons but has to outsource the ring sets. Ronnieroadster
If the block passes "sonic" why not bore another .060 & use STD 239" pistons & rings? Would probably be a lot more economical & easier than going with some expensive aftermarket units!!
Dear All They have ultrasound the block, and the thinnest point is 0.135 - so the conclusion is it could be done to 80tho but we are going to put finished liners in, and re bore and put in plus 15tho pistons in so it should be nice and round... I’m sorry I could not be more precise with I my original message. I did find the " Just buy some oval pistons" comment funny - my wife was asking why I was Laughing – and it was pointless trying to explain to her the issues of having oval bores and not sure what direction to go due to wall thickness and piston sizes….etc etc But a big thanks to all for the comments it helped me a great deal Marc
Genious way to make 8 cylinder performance when the racing rules only allow 4 cylinders, and don't specify round cylinders. Making a street engine of the same design... That's probably more questionable. Anyway, Honda have built some interesting engines through the years.
Yep the NR750 - Here's a pic of myself and the old Japanese guy who owned mine from new before I bought it a couple years ago. I sent it to the US, flipped it and the profit paid for my 34
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