Hey everyone ..I am doing a complete rebuild on my 250..I measured my cylinders and they were pretty much within specs except couple cylinders that had like .002 amount of taper..I measured my pistons and the measurements were all over the place..my engine lacked on oil changes so the pistons were worn down the middle..so my teacher told me i could get away with honing but he said it would be best to bore it out since i want to put new pistons and everything else new...i am going to bore it out .030 over...as far as my crankshaft here are my measurements i took 4 measurements on each main bearing and each connecting rod journal... Crankshaft Main Bearing Journal Size 1A)2.3985 B)2.3983 C)2.3985 D)2.3985 2A)2.3985 B)2.3985C)2.3982 D)2.3983 3A)2.3984 B)2.3984 C)2.3984 D)2.39824A)2.3982 B)2.3982 C)2.3980 D)2.3983 5A)2.3984 B)2.3983 C)2.3982 D)2.3983 6A)2.3984 B)2.3983 C)2.3982 D)2.3983 7A)2.3983 B)2.3984 C)2.3982 D)2.3984 My Main Bearin Journal Diameter Spec is 2.3983-2.3990 For my Connecting Rod Bearing Journal I took 4 measurements as well and they are as follow : 1A)2.1231 B)2.1230 C)2.1232 D)2.1231 2A)2.1231 B)2.1231 C)2.1231 D)2.1232 3A)2.1231 B)2.1232 C)2.1231 D)2.12314A)2.1231 B)2.1231 C)2.1231 D)2.1231 5A)2.1230 B)2.1231 C)2.1231 D)2.1232 6A)2.1232 B)2.1233 C)2.1234 D)2.1233 My Connecting Rod Journal Spec is 2.1232-2.1240 So my teacher told me that the crankshaft was within specs the only thing off was probably the surface finish ...he told me i could reuse the crank like that without grounding it down..but I wanted to ask you guys what was my best option to go with...I have the money to spend so if grinding down the crank helps me out in the long run then ill do it. I just want your input. As far as the cylinder head i just got it shot blasted and cleaned up so i started cleaning the valves so I could measure them..i ended up checking the head warpage with the straight edge and feel gauge...a .003 feeler gauge wouldn't go in on the outer cylinders but towards the center it would go in...so I tried the .004 feeler gauge and that one didn't go in...my teacher said therefore I have .003 head warpage which he said its fine and i can get away with without resurfacing the head...i would like to know if he is correct about me having .003 head warpage..I did read on the Chiltons manual that .003 is the wear limit on the head warpage..As far as the valve seats I am definately replacing the exhaust seats but I was wondering if i should replace the intake ones as well or just grind them down.. I am trying to get as much input and opinions on this..this is my first rebuild and I am doing it all by myself at school..we have all the tools needed and I feel I am headed in the right direction...so any tips and hints on this would be very appreciated..this motor will be going in on a daily driver ..I want to keep it up pretty much stock but im willing to do little modifications (if it doesnt require much work)so I can get more power...nothing to crazy though...thanks alot and I hope to hear from you guys! Your fellow Pal, Valente
being you have all the tools and equiptment, I would do it all... bore to the next size piston...turn the crank to the next size bearing..replace valve guides, seats and grind valves.(check spring tention).deck the block and mill (surface grind) the head. be sure and check to see what size pistons, rings and bearings you can get before...boring/turning...:Handshake sometimes a...crank kit is the best way to go...new radiator. enjoy...:Handshake
The things I cant do at school is turn the crank over and deck the block I am gonna bore the block .020 over...I have been looking around for prices on master engine rebuilt kits and today they told me $535 for the master kit plus valve seats and guides...on another site that my friend ordered his kit from called www.enginekits.com he got his kit for a cheap price but when he received it some parts were rusty so im not getting my kit from that site although it was $377..does anyone know where i should buy my kit from?
Try NAPA for the kit, I've gotten two from them that turned out great. For the 6 cylinder the original shim head gaskets are not available anymore, only the newer thicker composite style which are about twice as thick. So I would advice having the head milled to get the compression ratio back to stock. And also it'll take care of the warpage. So it's like killing two birds with one stone! This page should have all the tech specs you need: http://www.classicinlines.com/Tech.asp It's so awesome that your school has an auto shop! They closed down the one at my school to turn into it into an art class. Luckily this forum was like a shop class for me, I joined back when I was 15
We had our auto shop for 45 years until this Jan..it took them 5 years of saving tax money and we finally got our new shop!! We got a deal with snap on and absolutely EVERYTHING in our shop is SnapOn which is pretty cool.i get half price on snapon tools as well but yea we have our new machine shop which is pretty neat im learning alot and I'm only 20 but im getting off subject here haha ..so I should definately mill the head since they dont sell the original shim head gasket right?What about decking the block is that necessary?I got all my specs after doing a lot of research..I compared specs and they all seem to be the same..The specs that I have been using are the ones that I found on Mitchell since we have access at school but the only specs that i dont have are Connecting Rod Bore Measurement and the Block Main Bearing Bore.Im waiting on Napa to get back on me on the price but hopefully I have this engine running by the end of summer..I am going to be in the shop every day this summer hope to get some feedback
Check the block with a straightedge like you did with the head. If its still good theres no use in spending more money. Be sure to get a quality rebuild kit, try asking the guys on fordsix.com/forum or PM Gene Fiore on here. He has a wicked 6 cylinder. http://mmb.maverick.to/member.php?u=3948 Welcome by the way! Hope you stick around. We need more young guns i'm 23
Ok so check the block with a straightedge the same way..im guessing the maximum warpage allowed on the block would be .003 as well as the head or am I wrong..and you still recommend milling my head even if my block warpage is right? I see that you live in Riverside by the way..I live in Vista..not too far from you
I would, I think the stock gasket is around .020 and the modern ones are around .045 Which is more than double. If you don't mill it your compression ratio is going to drop, which you don't want. Especially since the 6 cylinders already have low compression to begin with. Just milling it down so that the compression ratio remains the same as stock would be best. We have pretty crappy fuel out here in Cali not to mention expensive, so the stock compression should be able to run 87 just fine. As for the block it should not exceed 0.030, if it does you can mill the block instead of the head to compensate for the gasket. Although I would check to make sure the pistons have enough room. I'm not that savy on the 6 cylinders so I don't know off the top of my head if you can deck it without any problems.
Allright cool...I am going to take it to a machine shop so that they can do that..ill be posting pics as I progress..
...another concern would be...what shop to do the machine work. around here, out of 5-6 shops, we have to pick one for heads one for cranks and one for blocks. seems like one shop isn't good for all the work. mark your crank/block/head(s) so as to get back the ones you gave them... take your mics. with you when you pick the parts up and check them there. I've had one head totally screwed up and a block with one cyl. bored...egg shaped. the guy said "they didn't do that block because their bore machine can't bore egg shapes"... one crank to be polished, only to come back...10/10...come to find out....wasn' my crank... with all the att. to detail that you have done, don't let someone else screw it up for you... one (2) last thing(s)...check all the parts to make sure...that what you ordered is in the box/package. don't just assume that the number on the box/package is what is in it...and i have gotten used parts for new ones...someone put their old part in the box and returned it for a refund...good luck...:Handshake ......
I actuallyfound a good shop around the area..my teachers have done business with them for years..Theyre good people and I like their work ...I was going to do the boring and honing myself but after seeing couple students overbore their block too much i got a little scared since its my first time...come to find out our dial bore gauge was .002 off..so I dont want to go trough what my classmates did so i am going to get the boring and honing done professionally for $130 I believe the guy said...I found my master rebuild kit with NAPA for $421 which includes everything except the oil pump and cam and crank sprocket..I thhink thats a good deal but I am going to keep looking...hopefully next week I start getting the machine work started!
