Home | Register | Login | Contact Us

 
Auto Math
Classifieds
Forum
Gallery
Games
Garage
Tech Articles
Utilites
 
FAQFAQ    SearchSearch    RegisterRegister    Log inLog in    Log in to check your private messagesLog in to check your private messages    Forum Subscriptions1/4 Mile Table 

Fixing Someone's Rebuild Failure

 
Post new topic   Reply to topic    SMOKEmUP.com Forum Index -> Other - Engine Discussion
View previous topic :: View next topic  
Author Message
73yota
Newbie


Joined: 22 Feb 2010
Posts: 4
Location: Arizona
282.84 points



PostPosted: Mon Feb 22, 2010 3:02 pm    Post subject: Fixing Someone's Rebuild Failure Reply with quote

So the engine I'm rebuilding is a Toyota 18r. The guy never ran it due to the fact that when he was nearing completion of the rebuild the engine would not turn over. It was binding up on the crank-piston journals (the rod caps were on backwards). So I tore it down and found a piston in backwards as well.

Question: Can I just pull the crank out and rotate the piston 180 degrees to the right position or do I have to pull it out and do it?
Back to top
View user's profile Send private message
squeeezer
Member


Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Mon Feb 22, 2010 6:22 pm    Post subject: Reply with quote

that actually sounds like MORE work Laughing
_________________
Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5578
Location: grassvalley, ca
71842.50 points


1933 Willys Coupe

PostPosted: Mon Feb 22, 2010 6:54 pm    Post subject: Reply with quote

I would definitely mic the rods to see if they are still round. And I would pull the engine apart to double check EVERYTHING.
Back to top
View user's profile Send private message
clay
Moderator


Joined: 24 Nov 2002
Posts: 3209
Location: South Carolina
318129.23 points


1972 Chevrolet Nova

PostPosted: Tue Feb 23, 2010 12:29 am    Post subject: Reply with quote

If the piston is backwards on the rod as I think you are describing, then you would have to look if the piston has valve reliefs. If it does, then I would say that you definately can't just spin the rod / piston assembly. I agree with af2, I would check everything at this point. When something as major as an engine locked up with a rod cap on backwards and the guy putting it together obviously didn't know why, leave nothing to chance - check everything. Clay
_________________
I have done so much with so little for so long, I can now do anything with nothing.
Back to top
View user's profile Send private message
squeeezer
Member


Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Tue Feb 23, 2010 1:31 am    Post subject: Reply with quote

rod caps on backwards=start over and re-size rods
pin offset an issue on this motor??? id guess no
but it is foreign

_________________
Back to top
View user's profile Send private message
73yota
Newbie


Joined: 22 Feb 2010
Posts: 4
Location: Arizona
282.84 points



PostPosted: Tue Feb 23, 2010 2:57 am    Post subject: Reply with quote

Yes, the engine is totally apart now. I don't trust a single thing this guy did.

af2: I will double check to make sure the rods are still round thank you for the good tip. I haven't done that yet

Clay: the pistons are completely flat, the reason I know the piston is in backwards because an arrow is stamped on top of it and they are all supposed to point forward, one is pointing backwards.

squeeezer: I'm not too keen on terminology, what is pin offset? The way I know the rod caps are on backwards is that each side of the cap has a different amount of markings on it. One of the combination is supposed forward.
Back to top
View user's profile Send private message
10sec.et
Member


Joined: 29 Mar 2006
Posts: 3483
Location: Houston,Texas
347040.52 points


1969 Oldsmobile Cutlass

PostPosted: Tue Feb 23, 2010 3:45 am    Post subject: Reply with quote

73yota wrote:

Clay: the pistons are completely flat, the reason I know the piston is in backwards because an arrow is stamped on top of it and they are all supposed to point forward, one is pointing backwards.



make sure the chamfer on the rod (big end) is correct. if you just spin the rod/piston assy around, the chamfer may be on the wrong side. you may need to separate rod/piston and correctly assemble the two.

_________________
af2 wrote:
It seems we can look at our magical Balls and come up with a fix?

Back to top
View user's profile Send private message
clay
Moderator


Joined: 24 Nov 2002
Posts: 3209
Location: South Carolina
318129.23 points


1972 Chevrolet Nova

PostPosted: Tue Feb 23, 2010 9:06 am    Post subject: Reply with quote

Pin offset refers to the wrist pin not actually being in the middle of the piston. I think it is offset to reduce side loading and piston noise in factory setup. I don't think any of the higher end racing pistons are offset. That may be why the mark is there to denote which way to install the piston if there are no valve reliefs. Clay
_________________
I have done so much with so little for so long, I can now do anything with nothing.
Back to top
View user's profile Send private message
MufflerBearings69
Member


Joined: 22 Jul 2007
Posts: 746

25364.28 points


1968 Ford Galaxy

PostPosted: Tue Feb 23, 2010 10:06 am    Post subject: Reply with quote

clay wrote:
Pin offset refers to the wrist pin not actually being in the middle of the piston. I think it is offset to reduce side loading and piston noise in factory setup. I don't think any of the higher end racing pistons are offset. That may be why the mark is there to denote which way to install the piston if there are no valve reliefs. Clay


This is what Nissan says at their factory sponsored tech school... One of the tidbits I retained from 10 years ago....

I know this isnt a Nissan but theres a good chance its the same deal.

Glad to hear you tore it down and are redoing the whole engine- who wants to redo 96% and have the remaining 4% thwart their efforts?! Been there, done that! Not worth it! Very Happy

If its a press fit pin, the local shops here charge less than 10 bucks to R&R so I wouldnt even bother sorting out if I could run it backwards etc I would just have it pressed and move on. Just my 2 cents.

_________________
Budgets were meant to be broken.
Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5578
Location: grassvalley, ca
71842.50 points


1933 Willys Coupe

PostPosted: Tue Feb 23, 2010 8:17 pm    Post subject: Reply with quote

73yota wrote:
Yes, the engine is totally apart now. I don't trust a single thing this guy did.

af2: I will double check to make sure the rods are still round thank you for the good tip. I haven't done that yet

Clay: the pistons are completely flat, the reason I know the piston is in backwards because an arrow is stamped on top of it and they are all supposed to point forward, one is pointing backwards.

squeeezer: I'm not too keen on terminology, what is pin offset? The way I know the rod caps are on backwards is that each side of the cap has a different amount of markings on it. One of the combination is supposed forward.



Nice!!!! Very Happy
Back to top
View user's profile Send private message
squeeezer
Member


Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Tue Feb 23, 2010 9:08 pm    Post subject: Reply with quote

af2 wrote:
73yota wrote:
Yes, the engine is totally apart now. I don't trust a single thing this guy did.

af2: I will double check to make sure the rods are still round thank you for the good tip. I haven't done that yet

Clay: the pistons are completely flat, the reason I know the piston is in backwards because an arrow is stamped on top of it and they are all supposed to point forward, one is pointing backwards.

squeeezer: I'm not too keen on terminology, what is pin offset? The way I know the rod caps are on backwards is that each side of the cap has a different amount of markings on it. One of the combination is supposed forward.



Nice!!!! Very Happy








adam i think he just needs the longest rods avail. so he too can turn 10k Laughing Laughing Laughing

_________________
Back to top
View user's profile Send private message
73yota
Newbie


Joined: 22 Feb 2010
Posts: 4
Location: Arizona
282.84 points



PostPosted: Wed Feb 24, 2010 6:55 pm    Post subject: Reply with quote

First off, Im sorry but I couldnt figure out how to insert the pictures the img button and alt+p werent really working for me lol. If someone could do a repost and fix that I would greatly appreciate it.

ok so correct me if im wrong, because the book doesnt say anything about this, but the picture shows it.

http://co106w.col106.mail.live.com/att/GetAttachment.aspx?tnail=0&messageId=a0aa375a-217f-11df-a74d-002264c17d5e&Aux=4%7C0%7C8CC83A3895EDA00%7C%7C

This is a picture from my repair manual that shows how to assemble a piston. It points out the markings for the rod and the piston that are supposed to line up and face forward, but not for the cap. However, in this picture the side of the cap facing forward has three oval/lump random shapes. Or whatever you want to call them.

VVVVVV Here is my cap that has those same markings VVVVVV


http://co106w.col106.mail.live.com/att/GetAttachment.aspx?tnail=0&messageId=17f229eb-2180-11df-b775-00215ad965d0&Aux=4%7C0%7C8CC83A436F3F470%7C%7C

VVVVVV And finally the other side that only has one mark VVVVVV


http://co106w.col106.mail.live.com/att/GetAttachment.aspx?tnail=0&messageId=fab57260-217f-11df-bf33-00237de46188&Aux=4%7C0%7C8CC83A3E6A04B90%7C%7C


The problem that Im having is that the guy that installed the rod caps put them in opposite of what the top repair manual picture shows.

(( ONLY THE ONE OVAL/LUMP MARKING FORWARD, AND THE THREE THE PICTURE SHOWS BACKWARDS ))

Was he just stupid putting these back in or were they in fact that way when he pulled them off to begin with and the book is wrong?

Im siding with the book on this one, even though none of the 4 manuals I have address this issue.
Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5578
Location: grassvalley, ca
71842.50 points


1933 Willys Coupe

PostPosted: Wed Feb 24, 2010 7:01 pm    Post subject: Reply with quote

Do you see the bearing tangs? They need to both( upper and lower) be on the same side of the rod.

I hope he didn't mismatch the caps.

You need to check that.
Back to top
View user's profile Send private message
73yota
Newbie


Joined: 22 Feb 2010
Posts: 4
Location: Arizona
282.84 points



PostPosted: Thu Feb 25, 2010 2:27 am    Post subject: Reply with quote

Ok so the tangs, the little notches the bearing fit into need to be on the same side. Is that ALWAYS the case?

How would I check to see if they are mix matched? Just try each cap on each rod one at a time while checking to see if they will bind up?
Back to top
View user's profile Send private message
10sec.et
Member


Joined: 29 Mar 2006
Posts: 3483
Location: Houston,Texas
347040.52 points


1969 Oldsmobile Cutlass

PostPosted: Thu Feb 25, 2010 3:05 am    Post subject: Reply with quote

"tangs" always same side. to check if the rod is round, you really need a dial bore gauge. this one is a cheap one but would accomplish what youre trying to do....... http://www.rjtool.com/p-1266-dial-bore-gauge-range-2-to-6-graduation-00005.aspx. or you could just take all the rods to a local machine shop and have them checked. however, i dont know how much patience they would have with figuring out which caps go where if they are mixed up.
_________________
af2 wrote:
It seems we can look at our magical Balls and come up with a fix?

Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    SMOKEmUP.com Forum Index -> Other - Engine Discussion All times are GMT - 5 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum
Home | Contact Us | Automath | Cam Files | Dyno Search | Forum | Garage | Picture Gallery | Reaction Timer

Copyright 1997-2018 SMOKEmUP.com All rights reserved.
Advertising Info     Disclaimer     Privacy Policy