59A cylinder taper

[V8guy]

Building a 59A for street use, the block is currently .030 over. How much cylinder taper can I allow, this will be going in to a cruise night and weekend back road drive car.
Thanks Mike

[Karl Wolf]

I used to work for a guy that started his automotive machining career in the WW2 navy.
Back then people would economize on engine overhauls.
My recall is that .009" taper, max, the rings would hold.
I would use about half that.

Karl

[Kurt in NJ]

the 49 mercury i used in a 46 ton and half had .010 taper, it just got rings,.001 undersize bearings, it went to many flea markets wit a 2 ton load, then got sold to a guy in california, when he made it there( in 4 days) he called and said it ran great, got 15 miles to the gallon and used 2 quarts of oil
keeping it under 60 gave me closer to 18 mpg, i suspect he was driving faster than 60
the chevrolet 350 had .014, got a ring and bearings kit, the crankshaft was worn, i put tapered shims under the inserts and told myself it would be good for 50K, still not burning oil at 52K
I have experimented with extreme reuse of parts,the Mercedes diesel i am driving now the engine is made of parts from 10 engines, the used piston rings has 180K, it uses some oil but the original owner say it is using less now than when it was new, and it starts instantly in sub freezing weather so the compression is good ( usually first compression stroke )

[cadillac512]

I've always used .007" taper as the upper limit with more modern V8 engines. Never had any trouble doing that, and they live a good long life.
Older stuff like inline 6 cyls and early long stroke V8's I've run a LOT of taper and gotten away with it...like up to .026" one time on a 262 Ford 6.

For what you want I'd not bat an eye at .015" as long as things are smooth and the ridge at the top is removed. Light hone job, cast rings and go! Just be sure the ring grooves in the pistons are in good shape and do a good valve job.


Terry

[Kurt in NJ]

My brother bought a model A engine that had .040 taper, it had run a irrigation pump, they put new rings in every year
A good valve job goes a long way.
I will cut the ridge some, but rarely hone any especially in chassis jobs, it’s almost impossible to get the honing debris out of assembled engines

[Bored&Stroked]

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One can "get away with" a lot of things - just depends on what you want to spend, how hard you want to run it and what your expectations are for the longer term.

How much money are you putting into this thing and is the budget the big issue? If so, then maybe you can do as others mentioned above. But, what is your time worth? If you're going to be pulling an engine, doing things like valve jobs (probably necessary), maybe grinding the crank and maybe putting new bearings in it . . . how much more would it be for some .060 pistons and rings?

I tend to always try to do the job as best as possible - if I have the money. Sometimes the job even takes longer than I'd like - so I can space the funds out.

Best of luck,
B&S

[GB SISSON]

I know I have posted these pics in the past, but to me, this is the definitve answer to 'rebuild'/'repair'. I have succesfully overhauled six or eight FH V8s using this as my guide. The ford company understood that not every engine in every car needed to be a factory fresh powerplant. Sometimes a person just needed to get a few more years outa the old sled.

[cadillac512]

Golly GB....don't keep us in suspense! What did Ford say about taper and new rings in that repair manual?
Terry

[GB SISSON]

.006 for max taper and hone for new rings. It's a great little manual and I think ford's common sense approach in the 1940s is still applicable today in many instances. I doubt I'll wear out my 'repaired' flatheads. My friend and I were discussing asphalt shingles the other day and he remarked, "At least at our age we can just buy the 25 year ones, not the expensive 40 year !"

[cadillac512]

Excellent. Thanks for the official info. Haha on the shingles deal...I've started considering similar things since "stuff" doesn't need to last quite as long anymore for me to fully enjoy it.


Terry