Motor rebuild questions.
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fletcherson
Well-Known Member
Just measure everything to be sure it's within tolerance, and check the parts close for cracks, wear, etc...
Mike
Well-Known Member
What he said.
Be sure to run a dial bore gauge in those cylinders. The least bit of taper will destroy the radial tension in a new ring in the first 500 miles. And if you bolt on a brandy-new, shiny set of heads with good valve seal, you will end up with an eight cylinder oil pump.
Be sure to run a dial bore gauge in those cylinders. The least bit of taper will destroy the radial tension in a new ring in the first 500 miles. And if you bolt on a brandy-new, shiny set of heads with good valve seal, you will end up with an eight cylinder oil pump.
Bucketman
Member
Mike is right about the oil pumping V8. I was going to just use my short block until I used a bore gauge and found .005 taper from just below the ridge to the middle of the cylinder and it was about .002 out of round. If your taking it to a machine shop I would spend the extra money to have it bored, honed, decked, and have them install new cam bearings, freeze plugs should be included for around $350. You can put all the money you want into a worn out block but it will ultimately die after about 50,000 miles. A new set of pistons and rings for about $200 and new bearings for another $200. Figure $750 and you'll have a brand new short block good for 100,000+ miles. Everything else is just bolt on. Get yourself a decent cam for sound and your RPM range, and quit there until you get tired of driving it that way. I found on you tube, you can listen to just about any engine, with any cam. I picked the Pro Comp XE274H. I'm doing the 383 stroker build.
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Just from what guys where saying I didn't want to do the .30 over. I could go .10 over. Sucks because it's the same price.
If I didn't need new pistons. Would be saving a little there.
I was going to have them check the block, cylinders and hone, decked, and new cam bearings, and freeze plugs. Only bore it if need be.
If I didn't need new pistons. Would be saving a little there.
I was going to have them check the block, cylinders and hone, decked, and new cam bearings, and freeze plugs. Only bore it if need be.
fletcherson
Well-Known Member
Most older engines will have cylinder wear, it's just the nature of how they wear from the friction of the piston and the rocking action of it at tdc and the wear is not uniform in the bore, like brake pads and rotors... I don't know of any reason not to bore it if it needs it. .010, .020, .030 is fine. I have had many engines .030 over bore and never noticed any negative results, hell, I had a ford i6 that was .090 and it was fine. You likely won't notice any performance difference between those dimensions, just be sure the engine is sound so you aren't wasting your time and money. Jmo... Here's a general rule of thumb, if it is a good used engine, and you don't need a lot of power, just clean and freshen it up and run it, don't add hp heads to an old engine. If you want all the performance and compression, plan on doing it all. The added cylinder presure created with the new closed chamber heads will really show the age of an older worn engine. You really need to either measure it or have it measured so you know exactly what you have there, but I would plan on spending the money for Pistons and bore job. Most competent machinists will expect to bore it. Sometimes you get lucky with cranks and rods, but the bore is pretty standard for a rebuild.
Mike
Well-Known Member
@oino , if it was a fully-prepped race block, then making tiny bore changes is a good idea. You want to save the block as long as possible. For a street motor, a .030 overbore isn't going to hurt a thing. Plus, you will find shops will actually stock 4.030" pistons and rings, where 4.010" stuff will be harder to lay your hands on. And sometimes, pricier, because of shipping.
@Bucketman , the key word in your post is 'ridge'. If a cylinder is worn enough to have a ridge, then it needs to be bored. Full stop. Ring technology is pretty amazing, these days, but you can never overlook the basic fact that a ring is designed to seal a straight and a round cylinder. If a cylinder is not round, the ring cannot seal it. And if the bore takes on the shape of a funnel, the ring will not last in those conditions.
People tend to think there are various ways to rebuild an engine. But there are really only two ways. One way is the right way, and every other way is the wrong way. Save your nickels, grit your teeth, and do it right the first time you do it. Pinch the pennies and cut the corners and you'll end up paying to do it a second time. If you cannot afford to do it the right way, how can anyone ever justify paying to do it twice?
@Bucketman , the key word in your post is 'ridge'. If a cylinder is worn enough to have a ridge, then it needs to be bored. Full stop. Ring technology is pretty amazing, these days, but you can never overlook the basic fact that a ring is designed to seal a straight and a round cylinder. If a cylinder is not round, the ring cannot seal it. And if the bore takes on the shape of a funnel, the ring will not last in those conditions.
People tend to think there are various ways to rebuild an engine. But there are really only two ways. One way is the right way, and every other way is the wrong way. Save your nickels, grit your teeth, and do it right the first time you do it. Pinch the pennies and cut the corners and you'll end up paying to do it a second time. If you cannot afford to do it the right way, how can anyone ever justify paying to do it twice?
Bucketman
Member
Your cam will also have a lot to do with compression. "Overlap" or the amount of degrees both valves are open at the same time can reduce your compression. While your static compression may be 10.7:1 the amount of overlap can bring it down to 10:1. (http://www.wallaceracing.com/overlap-calc.php) Also your aluminum heads will dissipate heat faster so a higher compression ratio can be used with pump gas without preignition. Go to the Wallace racing link and I think you'll find just about any calculator you can think of. It has helped me quite a bit.
Mike
Well-Known Member
I need to make shift in getting ready to head to the salt mine. But the short answer to your question is cylinder pressure. You can juggle high, static compression ratios and wide overlap camshafts to maintain the same cylinder pressure as a low, static compression ratio and a stock cam. And the hint here is that is precisely what you want, and need to do. Do a compression check on a brand-new car, on a Cup car and on a Pro Stock car, and then ask yourself how that number could be so close, with three, completely different motors.
How can anyone give you a cam recommendation, without knowing your final compression ratio?
That is a bit like buying shoes without first measuring your feet.
Time to start getting myself ready for another wonderful night of cleaning up after heathens.
How can anyone give you a cam recommendation, without knowing your final compression ratio?
That is a bit like buying shoes without first measuring your feet.Time to start getting myself ready for another wonderful night of cleaning up after heathens.
Screaming Metal
Active Member
Ya'll need to take heed to what Mikes saying....Really and truely sometimes its hard to get everything round, straight and true with a light cut of only .008 and .002 honing....Its gotta be done on a good machine.
They'll probably want to do a light cut and finish things out with a good machine hone. Don't even play with the thought of using a bottle hone for this....it won't work. Use a bottle hone on a out of round tapered hole, and you'll just make it more so....
And Trying to prop up your compression ratio with the alum. heads and then comphensating with Cam, etc, etc, your in for heartache.
As Mike Said, save your money by doing it right the first time, cause the 2nd time around your just throwing dollars to the wind....
I might be outta place here to say this, But that last motor, oino, was a fraking fiasco. Build yourself a good, cheap motor. By CHEAP, I'm talking no alum. heads, no racing cam, no special intake and supernifty carb, just a good basic motor that will run when you hit the key and run on this crap fuel we now have.
Just a good old fashioned rebuild with quality parts, a mild rv cam, good basic small runner heads, a alum. dualplane intake like a Edelbrock C4B with a 450cfm or a 500 cfm carb with small primary headers.
It'll start good, run good, get good mileage, will stick with you for years and never let you down. Trying to use alum heads, then adjusting the recipe with the cam and all that....I don't think you can plan it out correctly.
I myself and others here do this shit for a living, and we don't 1/2 ass it, because if you do, it will come back around and bit you in the ass. I can tell you this from experience.
Keep it simple, keep it straight forward. Want .01 over, do it. You can true up your heads and use your gaskets to get 9 to 1, no ploblem.
I thought the name of this one was a low buck inexpensive motor for your T....am I wrong?
Wanna throw money at it all day, go build yourself a nice 900+ cu.in. Pro Comp Mountain motor....it'll be a nice Trailer Queen.
They'll probably want to do a light cut and finish things out with a good machine hone. Don't even play with the thought of using a bottle hone for this....it won't work. Use a bottle hone on a out of round tapered hole, and you'll just make it more so....
And Trying to prop up your compression ratio with the alum. heads and then comphensating with Cam, etc, etc, your in for heartache.
As Mike Said, save your money by doing it right the first time, cause the 2nd time around your just throwing dollars to the wind....
I might be outta place here to say this, But that last motor, oino, was a fraking fiasco. Build yourself a good, cheap motor. By CHEAP, I'm talking no alum. heads, no racing cam, no special intake and supernifty carb, just a good basic motor that will run when you hit the key and run on this crap fuel we now have.
Just a good old fashioned rebuild with quality parts, a mild rv cam, good basic small runner heads, a alum. dualplane intake like a Edelbrock C4B with a 450cfm or a 500 cfm carb with small primary headers.
It'll start good, run good, get good mileage, will stick with you for years and never let you down. Trying to use alum heads, then adjusting the recipe with the cam and all that....I don't think you can plan it out correctly.
I myself and others here do this shit for a living, and we don't 1/2 ass it, because if you do, it will come back around and bit you in the ass. I can tell you this from experience.
Keep it simple, keep it straight forward. Want .01 over, do it. You can true up your heads and use your gaskets to get 9 to 1, no ploblem.
I thought the name of this one was a low buck inexpensive motor for your T....am I wrong?
Wanna throw money at it all day, go build yourself a nice 900+ cu.in. Pro Comp Mountain motor....it'll be a nice Trailer Queen.
one finger john
Active Member
Chris, just don't run this dog into the ground. 350s can be found all day, although may be drying up now. How 'bout a GM engine for, what, $1200.00 brand new, manifold to pan from the dealership. Or find a running, in the car, 400.
You are still rebuilding engines "by committee". Ask everyones opinion on the subject, assemble using what your buddies tell you to do, then come here asking us to figure out what happened and how to fix it.
PLEASE, NOT AGAIN. I will not participate!
John
P.S. What happened to the "old" motor?
@one finger john , old motor now say old coming out rear mean seal.
Let's not get started on that thing.
Just starting new. Asking for advice.
You guys are my buddies. I moved to Texas don't really know anyone yet. My neighbor gave me a engine stand and new roller lifters.
Let's not get started on that thing.
Just starting new. Asking for advice.
You guys are my buddies. I moved to Texas don't really know anyone yet. My neighbor gave me a engine stand and new roller lifters.
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Screaming Metal
Active Member
Just my thought here....you need to pick up a cheap running motor, from a salvage yard for a few hundred. Clean it up and run it. OR, Get that used motor, or a good rebuildable core and have a good shop rebuild it, put your dressup parts on it.
OR, let them rebuild that motor you just bought, buy a set of heads from them, and put your dressup goodies on it. Alot of places will have a motor stand where they can run it in, and adjust it out. They'll be happy to mount the intake, carb your using, when they're ordering parts for the rebuild, you can purchase the RV cam....they can run them it in on the motor stand and tune it out, for a small fee.. Then, all you have to do is bolt it in.
That would be the simplist, easiest thing for someone not able to rebuild a motor themselves. After the last motor, and all that was involved. Remember the intake leak? Get yourself a running motor, and install it. Yes, it will cost you more, but, it'll be done right. New rebuilt motors have a nice warranty along with them, probably longer than state you'll want to keep your T is in now. One day you'll probably want to redo the body, suspension, paint, and that motor will still be trucking right along....
OR, let them rebuild that motor you just bought, buy a set of heads from them, and put your dressup goodies on it. Alot of places will have a motor stand where they can run it in, and adjust it out. They'll be happy to mount the intake, carb your using, when they're ordering parts for the rebuild, you can purchase the RV cam....they can run them it in on the motor stand and tune it out, for a small fee.. Then, all you have to do is bolt it in.
That would be the simplist, easiest thing for someone not able to rebuild a motor themselves. After the last motor, and all that was involved. Remember the intake leak? Get yourself a running motor, and install it. Yes, it will cost you more, but, it'll be done right. New rebuilt motors have a nice warranty along with them, probably longer than state you'll want to keep your T is in now. One day you'll probably want to redo the body, suspension, paint, and that motor will still be trucking right along....
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Screaming Metal
Active Member
Bore $140
Clean $70
Decked $125
Add a set of used heads from them, probably about: $225
Quality rebuild kit w/pistons, gaskets, bearings, timing set: $375-$450 (go .o3o over)
RV Cam: $110
Good OilPump if not in kit: $45
Run-In on motor stand: $50-$100...depending
Clean $70
Decked $125
Add a set of used heads from them, probably about: $225
Quality rebuild kit w/pistons, gaskets, bearings, timing set: $375-$450 (go .o3o over)
RV Cam: $110
Good OilPump if not in kit: $45
Run-In on motor stand: $50-$100...depending
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Screaming Metal
Active Member
What He Said!
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