Rebuilding a P18 - Do I need line boring?

[woodie49]

I am beginning a rebuild of a P18 block I have had for a number of years.  I had to source the main caps separately as they were not with the block. The block had been worked some years back before I bought it and the cylinders mic out good, but my machine shop guy tells me that I need to have the block and caps line bored (which he doesn't do - it seems like there aren't many places in Ca. that do), and it is expensive enough to make me wonder if it is worth working with this block. He says there is an alternative (maybe it was line honing?) which can be done provided the forward facing edges on the caps and the block line up almost perfectly, otherwise the boring bit gets caught up on the leading edge of the cap and the process won't work. My center caps are each about .010 proud of the block. Can these be ground a bit to take up the difference? Should I try to source another set of caps hoping to get this measure closer? I assume the caps are all the same width. Is there an acceptable alternative to line boring that is more affordable. Has anyone had this done lately and knows what it should cost? 

[Young Ed]

I have always heard it is required if you don't have the matching set of blocks and caps or didn't mark their orientation before removal. 

[thebeebe5]

 You'll get mixed opinions on this if you have the original main caps, but at our shop every block gets checked. 

 If you sourced the main caps from another block then I would absolutely have the line bore or line hone done! 

[dpollo]

If you assembled it the way it is, you would not be able to turn the crankshaft.   When a replacement cap was fitted to a block, it was adjusted by shimming. The cap itself had slightly oversize bolt holes.  I have never seen this done, and would not care to do it on an engine that I cared about.

A machinist could advise you on how to proceed but you may indeed be correct that it will be cheaper to start with a block which has its original caps.

[Plymouthy Adams]

I concur with the line bore given you do not have the original caps...if you go with this process, do ensure proper marking of the end caps to the block on completion of the line bore so not to have any issues when removed for the final clean and assembly.  Your machine shop will be able to advise you 

Edited July 31, 2017 by Plymouthy Adams

[Dartgame]

I have a 1953 block that I received with two sets of main caps. I decided to check a few of them to see if I could determine which was the correct set. I have a dial bore gauge to check. what I found was that all the caps would interchange in their correct location i.e. Main on main position, #1 cap on #1 position etc. What this leads me to believe is that the caps were machined to a specification rather than to a specific block. A costly way on doing things, certainly not what I would have expected. Now, whether I could drop a crank into the block is another question. I don't have a good set of bearing shells to test this. I do not know the answer.

What you might try is Bolting on the caps and seeing if they have overlap on the bearing shell parting lines. If they do, you have no alternative but to line bore. If they look good try installing the bearing shells drop in the crank and install a cap with a bearing inserted one at a time and see if the crank gets tight or turns smoothly. I'd then talk to your machine shop to see if they can verify whether it truly needs a line bore.

[knuckleharley]

Can you give us an idea of what "so expensive" means?

Line boring shouldn't be that expensive. It's not a difficult setup,and if you have the tooling,it's quick and easy to do compared to many other machining operations.

Maybe you were quoted a high price because the machine shop didn't have the tooling,and have to buy it?

If it were me,I'd call around a few machine shops within a day's drive of where I lived,and get some quotes. I'd probably start by talking to everybody I could find that drag races,drag boat races,or circle track races,and find out what shops they used.

Beyond that,if you are on a budget and not in a hurry,contact your local community college auto repair class instructors and see if one of them will do it for you as a student project. That would be practically free. They need projects to teach students how to do things,so they only charge for materials. You might find one that can take it right away,but be prepared to wait months for a class cycle to get to the point where a project like that is needed. You really can't beat the price,though.

[woodie49]

4 hours ago, knuckleharley said:

Can you give us an idea of what "so expensive" means?

Line boring shouldn't be that expensive. It's not a difficult setup,and if you have the tooling,it's quick and easy to do compared to many other machining operations.

Maybe you were quoted a high price because the machine shop didn't have the tooling,and have to buy it?

If it were me,I'd call around a few machine shops within a day's drive of where I lived,and get some quotes. I'd probably start by talking to everybody I could find that drag races,drag boat races,or circle track races,and find out what shops they used.

Beyond that,if you are on a budget and not in a hurry,contact your local community college auto repair class instructors and see if one of them will do it for you as a student project. That would be practically free. They need projects to teach students how to do things,so they only charge for materials. You might find one that can take it right away,but be prepared to wait months for a class cycle to get to the point where a project like that is needed. You really can't beat the price,though.

Machine shop here (I am in Central Cal on the Coast) sends them to So. Cal. and it is about $1200.00 for a V8, maybe less for for the L-Head given less mains, but still not cheap.  I called a shop in No. Cal. which would be closer to me and they were talking in the area of $1000.00 and about 5 weeks wait.  There are only a few shops I can find In Ca. that do actual align boring, but most can do the line honing, apparently a somewhat different process (and assuming I am remembering correctly the alternative process), which is something like $150.00. If my cap surfaces were closer to the block surface, I could do that and that cost seems OK to me. This may be a regional thing with the shops in Ca. being speed shops and focused more on high end builds. I seem to remember doing this years ago and not thinking it was really expensive. But I think we used to blue print a SBC (and this may be part of that process) for around $500, which was a lot of dough at the time.

I could be getting completely snowed here except that my experience with the machine shop i used has all been good and reasonable prices. My understanding of what needs to be done is that the caps will be shaved a couple thousandths and then a horizontal shaft with a cutter is centered on the first cap and block pair and it advances through the length block to cut each pair exactly in line and to proper size. If anyone has had this done recently, I would appreciate some cost info. If there is another alternative, I would appreciate feedback on that. I have thought to bolt in the crank and test the bearing clearance with plastiguage to see if it runs different cap to cap, maybe take two readings on each bearing set, but I wonder if this would work or if i could expect an issue to develope over time. 

[knuckleharley]

12 minutes ago, woodie49 said:

Machine shop here (I am in Central Cal on the Coast) sends them to So. Cal. and it is about $1200.00 for a V8, maybe less for for the L-Head given less mains, but still not cheap.  I called a shop in No. Cal. which would be closer to me and they were talking in the area of $1000.00 and about 5 weeks wait. 

Ok,I agree that is a lot of money.

I honestly can't figure out why it is so expensive. It's not a hard job or a complex setup,and if you are set up to do one engine,you can't pretty much do them all and only have to buy new cutters and hones,which can be used on multiple engines.

Call around the local trade schools and community colleges and see what they say.

[Frank Elder]

Where you live has a lot to do with pricing.

[DJ194950]

20 hours ago, woodie49 said:

I am beginning a rebuild of a P18 block I have had for a number of years.  I had to source the main caps separately as they were not with the block. The block had been worked some years back before I bought it and the cylinders mic out good, but my machine shop guy tells me that I need to have the block and caps line bored (which he doesn't do - it seems like there aren't many places in Ca. that do), and it is expensive enough to make me wonder if it is worth working with this block. He says there is an alternative (maybe it was line honing?) which can be done provided the forward facing edges on the caps and the block line up almost perfectly, otherwise the boring bit gets caught up on the leading edge of the cap and the process won't work. My center caps are each about .010 proud of the block. Can these be ground a bit to take up the difference? Should I try to source another set of caps hoping to get this measure closer? I assume the caps are all the same width. Is there an acceptable alternative to line boring that is more affordable. Has anyone had this done lately and knows what it should cost? 

I called my favorite engine rebuilding shop and talked to them, while my "guy" there was on vacation the other person in the office said they could help you but did not know pricing etc..I explained that line homing was Not just what was needed but rather a line bore and maybe then a line hone. I was told that they could deal with that, so- call next week and talk to Steve

They build and balance many race engines and the owner is a long time racer. A well established company and Steve knows Mopar flat sixes well.

Central Balancing and Machine,

Modesto, Ca.

209-538-8956.

Hope the person I talked to- a lady but she has been there for many, many years knew what I meant but seemed to totally understand.

At least a good contact a little closer to your location.

Get er' done, best of luck-keep the forum up to date.

DJ

[John-T-53]

2 hours ago, woodie49 said:

Machine shop here (I am in Central Cal on the Coast) sends them to So. Cal. and it is about $1200.00 for a V8, maybe less for for the L-Head given less mains, but still not cheap.  I called a shop in No. Cal. which would be closer to me and they were talking in the area of $1000.00 and about 5 weeks wait.  There are only a few shops I can find In Ca. that do actual align boring, but most can do the line honing, apparently a somewhat different process (and assuming I am remembering correctly the alternative process), which is something like $150.00. If my cap surfaces were closer to the block surface, I could do that and that cost seems OK to me. This may be a regional thing with the shops in Ca. being speed shops and focused more on high end builds. I seem to remember doing this years ago and not thinking it was really expensive. But I think we used to blue print a SBC (and this may be part of that process) for around $500, which was a lot of dough at the time.

I could be getting completely snowed here except that my experience with the machine shop i used has all been good and reasonable prices. My understanding of what needs to be done is that the caps will be shaved a couple thousandths and then a horizontal shaft with a cutter is centered on the first cap and block pair and it advances through the length block to cut each pair exactly in line and to proper size. If anyone has had this done recently, I would appreciate some cost info. If there is another alternative, I would appreciate feedback on that. I have thought to bolt in the crank and test the bearing clearance with plastiguage to see if it runs different cap to cap, maybe take two readings on each bearing set, but I wonder if this would work or if i could expect an issue to develope over time. 

Alternative/Power Performance in SLO by chance? With Harry the head man?

There is a shop across the bay from me in Hayward that does line honing. I think my block was around $200-300 when I had it done in 2012 if I remember correctly.

Al Hubbard Machine Shop. Wade is the owner, great guy.

And yes you should absolutely have it honed or bored with your situation. I think $1k is too much.

 

 

[rekbender]

21 hours ago, woodie49 said:

I am beginning a rebuild of a P18 block I have had for a number of years.  I had to source the main caps separately as they were not with the block. The block had been worked some years back before I bought it and the cylinders mic out good, but my machine shop guy tells me that I need to have the block and caps line bored (which he doesn't do - it seems like there aren't many places in Ca. that do), and it is expensive enough to make me wonder if it is worth working with this block. He says there is an alternative (maybe it was line honing?) which can be done provided the forward facing edges on the caps and the block line up almost perfectly, otherwise the boring bit gets caught up on the leading edge of the cap and the process won't work. My center caps are each about .010 proud of the block. Can these be ground a bit to take up the difference? Should I try to source another set of caps hoping to get this measure closer? I assume the caps are all the same width. Is there an acceptable alternative to line boring that is more affordable. Has anyone had this done lately and knows what it should cost? 

I don't know if there is any real advantage in trying another set of caps, but I have a set from a 218 parts engine I'll be glad to send you for the postage. The center caps are stamped 2 and 3.

[woodie49]

I am using a machine shop in Morro Bay. From my limited understanding, line honing is done by many machine shops and is about $150.00, line boring is done by only a few and is , at least so far, fairly expensive.  I need to understand this further and should be in Morro Bay later this week to clarify the processes.

I will talk to the two shops mentioned above - thank you guys for your efforts and the referrals - and hopefully have a better sense of where to go with this.

 

[woodie49]

6 hours ago, rekbender said:

I don't know if there is any real advantage in trying another set of caps, but I have a set from a 218 parts engine I'll be glad to send you for the postage. The center caps are stamped 2 and 3.

If it looks like I need to go in the direction of trying to match the block and cap faces, This might help me get there.  I will first do a little more homework so I understand this. Thank you for your help.

[packratc]

 I took  my 218 apart for the second time and this time it was not at my own shop. When I went to put down my main caps I ended up moving them again. Prett sure they're in the right order but don't now if they are turned around. Do the casting numbers all end up on the same side? In other words, are the casting numbers on all the mains toward the front of the crank shaft or the back? Yep! I feel like a dummy.

[Plymouthy Adams]

yes, line bore should be done as you have lost the entire set, often in the case of just one a replacement over bored mount with undercut side can be installed as a replacement...a floater if you will....these were sold for this exact purpose.