PDA

View Full Version : diffrences in power



creeperxr7
08-20-2003, 09:15 PM
how much power will 0.40 over pistons give u over the stander size one .... and i their any disadvantages in boreing it over to this size.....................

MIKE 38sc
08-20-2003, 10:00 PM
Absolutaly nothing that you would notice. The difference is so minute that it would barely be noticable on an engine dyno.
I wouldnt bore the block anymore than it takes to get good clean bores. If youre looking to get some substantial power gain from this you better look elsewhere.
If you go to .040 you will be on the last overbore on that block and it will be junk if you have a problem and mess one of the bores up on it.:eek:

creeperxr7
08-21-2003, 04:11 AM
ya i know that 0.40 is like the limit but like i said before i got another block and i wanted some advice on which one to use.... if the 0.40 over or the standard one .... the standard one has cherry cylinders as for the 0.40 dont know till i take the pistons out and since i got a brand new set of standard size pistions just wanted some advice on that mike....SO NOT MUCH OF A DIFFRENCE IN POWER BETWEEN STANDARD BORE AND 0.40 OVER?

ThunderRoad
08-21-2003, 07:53 AM
you will pick up some compression gain...........:D :cool: FAST FREDDIE

MIKE 38sc
08-21-2003, 06:22 PM
Well sure you will get a very little increase in compression with an overbore.
But if you didnt know it was bored you would perceive NO increase of power, its just too small of a difference to tell.
I always go stock bore unless theres damage to the bores.
Thats the only reason to bore a block anyway.;)

creeperxr7
08-21-2003, 07:43 PM
what u suggest i do on my crank and camshaft regrinde or polish

MIKE 38sc
08-21-2003, 10:14 PM
creeperxr7 What are you doing?
Rebuilding again?
You need to have all of your crank journals checked with an outside micrometer at the 12 o'clock and 3 o'clock posistions to determine the amount of wear and to see how much the journals are egged.
You can then take that info and compaire to the engine specs and determine if you can polish or if you must grind the crank.

You must also intall the rod caps and torque them down without the bearings installed. Then you take an inside micrometer and make the same measurements as before on the crank.
The amount of egg you find on the rod bigend determines if you need to have the rods resized.;)

There is MUCH more to do but this is a start.

creeperxr7
08-22-2003, 03:15 AM
ya pretty much i need a car so their i go again! thanks for the info...

MIKE 38sc
08-22-2003, 03:21 AM
Creeper are you going to school for mechanics?

creeperxr7
08-22-2003, 03:25 AM
ya but havent learned anything i really didnt know yet .... just like introduction and how the engine works nothing i can relate on

MIKE 38sc
08-22-2003, 03:35 AM
Do you think your teacher would be receptive to idea of your engine rebuild being a class project under the teachers supervision? I know when I was going to electronics school I repaired and built many things as class projects. As long as you supply the parts maybe you could work something out with the teacher.
Do you think that might be possable?

creeperxr7
08-22-2003, 09:36 PM
MIKE the ? was already asked by other students in class altough that would be great.... but he said not the first semester .... that the 2nd semester we could bring in our own projects....also check ot my piston to bore visualy and i know that they bored to much pistons wobble in bore like crazy ....correct me if im wrong but isnt the clearence supposed to be .001 to .003 if it is they are way over that ..... i should of never trusted it and double checked those clearences to ..... its like when they say the spark plug are already gaped and u check them and they are way off. but you learn of your mistakes i guess...

MIKE 38sc
08-22-2003, 10:02 PM
The clearance is going to depend on what type of pistons you used. Forged or Hyper?

creeperxr7
08-23-2003, 09:58 AM
hyper and using them agian on the standard block also some thing i noticed mike spare me hear ok ......the machine shop should of recondition the rods wich he didnt now that i think about it cause everytime i went to pick them up he always had an excuse about not having the finished and they were in the same spot the hole time till one day i said i needed them now and waited their till he honed them out for the free floating configuration that may have been another reason.... the bearing that spun had the little lock notch still on the rod just that little notch is that normal... like they cut it and filed it down flush with the groove

got-sc?
08-23-2003, 03:35 PM
i know a shop owner here in texas that specializes in fords and guarantess me at the least 100 hp increase of a .30 bore over rebuil on my engine he says he will use steel forged true flat top pistons arp bolts and stuff guarantesss like i said at least 100 hp increase on the engine alone and the best part is hell do it all labor and pats for only GET THIS $1,500.00 bucks

MIKE 38sc
08-23-2003, 04:01 PM
Originally posted by got-sc?
i know a shop owner here in texas that specializes in fords and guarantess me at the least 100 hp increase of a .30 bore over rebuil on my engine he says he will use steel forged true flat top pistons arp bolts and stuff guarantesss like i said at least 100 hp increase on the engine alone and the best part is hell do it all labor and pats for only GET THIS $1,500.00 bucks
If I was you I'd run away from that guy as fast as I could.
He is LYING! You will not get 100 HP increase buy boring the block, thats just not true and is a bald face LIE.
Pistons are made from aluminum not steel so he lied again.
Do what you want, but you should run very fast from that JOKER.
That guy CANNOT do a proper rebuild for $1,500.00. NO WAY!

MIKE 38sc
08-23-2003, 04:06 PM
Originally posted by creeperxr7
hyper and using them agian on the standard block also some thing i noticed mike spare me hear ok ......the machine shop should of recondition the rods wich he didnt now that i think about it cause everytime i went to pick them up he always had an excuse about not having the finished and they were in the same spot the hole time till one day i said i needed them now and waited their till he honed them out for the free floating configuration that may have been another reason.... the bearing that spun had the little lock notch still on the rod just that little notch is that normal... like they cut it and filed it down flush with the groove
Creeper I'm sorry but the only thing I understood here was that youre using Hyper pistons. The piston skirt to cylinder wall clearance should be in the neiborhood of .0035-.0045 with those pistons.
Please try to tell me what youre talking about with the rods again. I just didnt understand any of that.

creeperxr7
08-23-2003, 07:00 PM
well i just tought that this could of been another one of my problems since they didnot get recondition ... i believe they would get out of round or twisted wouldnt they the was that was spun in that engine before got replaced....but the rest nothing was done to them.... my bearings showed like uneven wear spots. one of them was copper colored already.... the bearing that was spun #4 when i removed it from the engine was looking at ther rod and cap, well on the rod part were the locking notch is for the bearing it was still on their like it broke off the bearing and it spun..... i think

MIKE 38sc
08-23-2003, 09:11 PM
OK I think I see what youre getting at. You should take your rods and pistons to a good machinist and have them check the BIG ENDS. They will know what youre talking about. Tell them you want the rods reconditioned.
What that means is there going to remove a little metal from the cap to rod matings surfaces. That will make the hole eggshaped, they will then recut the holes making them round again. Then they will hone the holes to the finish fit for the bearings.
The going rate for rod reconditioning around here is about $8.00 per rod.

When you take your parts to the machinist take your crank, rods and pistons to them at the same time. That way they can test fit them and make sure everything is on the money before you get them to reinstall.
Talk to the machinist about getting new rod bolts, some may have stretched and that caused your problem or the big ends may be out of round or you may have made a mistake when you torqued down the rod bolts. Without me being there I cant tell what went wrong. But take all of those parts to them and have them check everything I mentioned on all of it and have them fix whatever is not what its supposed to be.

When you first built the motor did you have the machinist to measure the crank journals?
If so what did he tell you about them?

creeperxr7
08-24-2003, 01:29 AM
yes mike the motor the crank came out of had 52000 miles on it the crank was very cherry no scratches on their.... so he said he would have to polish it and they would all fall still under standard size ..... i have to cranks now actually i got 2 or 3 of everything so i will take pairs of each components and let him decide wich ones are the best........ill tell him what u told me and get new bolts dont want to mess up again......:eek:

MIKE 38sc
08-24-2003, 02:30 AM
Just take your time when reassembling it and check all the clearances as you build the engine. You may come across a mistake that the machinist made. He's only human and sometimes thing get by them.
If you find something thats not right stop what youre doing and get the problem straightened out. If the machinist made a mistake on something just take your problem parts to him and politely talk to him about the problem. I've not met one yet that would not correct there mistakes at no additional cost to you.

Dont assemble the engine if you find something out of spec. You will only end up in the same shape youre in now if you do. Building one of these engines is expensive enough without having to do the job twice.

Get your parts to the machinist and let us know how its going.

creeperxr7
08-24-2003, 06:22 PM
ok ... one last ? mike u think it would better and easier if he just built the block up for me.....

MIKE 38sc
08-24-2003, 07:47 PM
Yes Creeper that would be a good idea.:)

turbospeed
08-25-2003, 12:20 AM
about 5hp and 10lbs of tq from .40 overbore