Missing main caps a big problem?
 

I’m going to look at a couple of 8BA blocks tomorrow for a rebuildable core. The guy thinks he has the main caps but hasn’t located them yet. How big of a problem is it if they are missing?

Second question: one block has reportedly been sleeved. Would this interfere with boring it to 3 5/16? I plan to use a 4” Mercury or Scat/Eagle crank... thanks! Ken

Re: Missing main caps a big problem?
 

missing caps requires a line bore for sure. caps are not too hard to find I have a few from busted blocks

what is the block bored to now? how much more to get 3 5/16

Re: Missing main caps a big problem?
 

Will have to measure myself when I see the engines tomorrow. Reportedly CA blocks with no visible cracks, stored away for decades by someone. Will see tomorrow’s whether they’re truly uncracked ...

Re: Missing main caps a big problem?
 

Strange as it sounds, it is possible to use main caps from different engines. Apparently Ford processes were good enough to get repeatability between blocks as far as machine work goes. Now, not just any set of caps is going to work with any block. But if you have enough to select from it is possible to locate a match. I helped a local mechanic shop (one that did a lot of flathead work) come up with some replacement caps.

Re: Missing main caps a big problem?
 

yeah, I have a 5 gallon bucket of caps and have been able to match a few to other blocks

Re: Missing main caps a big problem?
 

Just understand that matching caps is your time. Time cost money, so the cost of the block needs to be relative to your time. Missing caps would bring the cost of a block down by 1/2 in my book.

Re: Missing main caps a big problem?
 

If you have a bucket of salvaged caps available it is less of a problem than if you don't.
If you don't have any caps I'd say it's a deal breaker.

If the block has been sleeved it probably does rule out going to 3-5/16". I just sleeved two blocks and I'd probably go 60 over, but not .125. Some sleeves have thinner walls than the ones I used so maybe worse.

Mart.

Re: Missing main caps a big problem?
 

I had this problem in 1960 with my '51 Ford. I busted a middle main cap. I went to the junkyard and got some scrap caps, and then stopped at the auto parts store for some "Plasti-Gage". The first cap fit perfectly. Everyone seems to underestimate the quality of Ford engineering in this period. It was second to none.

I'll bet they all would have fit perfectly.

Re: Missing main caps a big problem?
 

No, they won't all fit perfectly.

Re: Missing main caps a big problem?
 

As others have mentioned missing caps are not a deal breaker if the block is found to be good no cracks. Now about the sleeves I have sleeved many blocks all of which were then bored to 3-5/16. The correct sleeve will allow boring to that size. If your looking at a block that has say one sleeve chances are it will be a thin wall sleeve which would not work for the bore your interested in going to. And finally as Tim wrote above a block without caps has a greatly reduced value. This savings however would be short lived since the cost to line bore the block would be expensive. But finding any block that's good in my opinion is worth getting. Good luck
Ronnieroadster

Re: Missing main caps a big problem?
 

Don't pay more than $100 for that block. Even that is $50 too much.
Does it have any cracks? It's a total gamble.

I think most folks would reinstall the caps if engine was good.

Re: Missing main caps a big problem?
 

I worked at a machine shop that did machining on anything that came in the door from flatheads to failed engines from cars that were so new that crate engines were not even available to the dealer yet. Once and a while a customer would come in with a good block that was missing caps and if it was something common like a small block Chevy or Ford we had buckets of old main caps. It was a tedious process but we would just go through the caps trying what we had by installing and torqing them down and then measuring them with a bore gauge. Eventually we would find caps that were nearly within spec and once this was accomplished everything would get line honed and it was good to go.

Re: Missing main caps a big problem?
 

If you give the blocks a very thorough inspection (especially in the valve transfer area) and they appear to be good, then it is really not a big deal putting new main caps on one - it is just a bit of money.

It will cost you roughly $250 - $350 to install a different set of caps and have the block align bored and honed. If the block is good, then I think it is worth it. Hell, in many of my performance builds, I have the blocks align bored anyway (but that is because I'm changing the main caps).

Re: Missing main caps a big problem?
 

Sincere thanks to everyone for their input; it really helped prepare me for looking this block over! The main caps were not there, but I bought the engine anyways since there were no cracks visible between the valve seats and cylinder bores, or in the pan rails. The seller has promised to send them if he finds them, but I judge this possibility to be quite remote based on the diverse quantity of parts I saw!


https://live.staticflickr.com/65535/...c3414aa7_b.jpg605543F9-BD9B-40E3-9FBC-0A3CB26A7028 by kenhenry_06268, on Flickr


Was not expecting a 3/4 cam! Someone must have had too many Wheaties before attempting to remove it. On the plus side there are adjustable lifters in it. Hopefully they were not ruined...



https://live.staticflickr.com/65535/...8706fc47_b.jpg62C30A71-DBD0-42B1-8D2E-3381DF5871E3 by kenhenry_06268, on Flickr

Re: Missing main caps a big problem?
 

I should have mentioned this engine was $200 and a 5 1/2 hour drive for me each way, in Glastonbury, CT. It is unsleaved without much ridge in the bores. Still need to measure them. He had another 8ba with sleeves in it that I did not look over. Are these truck exhaust manifolds? I'm guessing they won't work in a 51 car with the outlet so far forward. They are not set up for a crossover pipe. The water pumps also must be for a truck, but the oil pan has the sump in the middle and no clean out, which would make it fit the cars, correct? Front cover is cast iron I think...


https://live.staticflickr.com/65535/...cb463b90_b.jpg5B283DA7-4EC2-4DFA-A7A1-383573F6BD9A by kenhenry_06268, on Flickr


https://live.staticflickr.com/65535/...690d8ded_b.jpg5E361AEC-3B8E-4EB1-90B6-02CE32B80AE6 by kenhenry_06268, on Flickr


https://live.staticflickr.com/65535/...ebcb61c5_b.jpg85758FBF-A350-471D-A809-A356CD8FDF52 by kenhenry_06268, on Flickr


https://live.staticflickr.com/65535/...2cd80be6_b.jpgCDF40E15-ADFC-4D96-B7C6-4FEB8D2BC927 by kenhenry_06268, on Flickr

Re: Missing main caps a big problem?
 

From what I can tell by the pictures, I think you did just fine on this deal! All the spare parts add up (like the oil pan). Keep us posted after you have it cleaned up, magged and pressure tested!

Re: Missing main caps a big problem?
 

It is true these flatheads are line bored often. The process involves removing material from the bottom of the engine. This creates material to bore. This raises the crankshaft gear up closer to the camshaft gear. If you take ten thousand of there’s nothing left. A used crankshaft gear might give necessary clearance between gears. Good luck

Re: Missing main caps a big problem?
 

Ken, Be sure to read ALL the links shown here about "align boring". Seems to be differing opinions as to which process is best.
https://www.google.com/search?q=how+...hrome&ie=UTF-8

Re: Missing main caps a big problem?
 

Well, 2020 must be officially over because I just got a text from the seller that he found the caps! Thanks everyone for your input, Ken

Re: Missing main caps a big problem?
 

That's great news. If the other motor is a similar price it might be worth snagging that as well. (I can't remember the exact details).

Mart.