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Engine Rebuild

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Morris56

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I could use a little advice from the experts here. I am starting on my BT7 engine rebuild and was looking for some info on the oilway repair kits. When I opened up the engine everything was caked in a very fine poweder which looked like rust with none of the characteristics. You could wipe it right off and there was not pitting. The engine had not been run in many (at least 10) years. The engine was not locked up and everything appears to be in good shape (after the teardown). I suspect this "rust bloom" may have been the result of water mixed with the oil from either a bad head gasket or from a leaking oilway. I was going to install one of the oilway repair kits just as a preventative measure... but before machining the block - I wanted to know if anyone had experience with these on a Healey engine. The block is already at the machine shop to be bored .030 so if I'm going to do it - now is the time. Is there any way to check whether this needs to be done.

And while I'm at it. For the camshaft re-install - I read on here somewhere about needing to ream the bearings after they were installed but I haven't been able to find those comments again through the search engine. I can't remember doing this on my MGA and found nothing about it in my manuals. Any advice on this?

Thanks in advance for all the help
 
I have never installed the oilway repair kit. It does appear to be a "possible" solution to a rare problem. I think installing this kit would require a very skilled, knowledgeable machine shop to make it work.

Go here scroll down, & click on "instructions click here". It will take you to detailed installation instructions.
https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=60214&SortOrder=1

I believe I would have a good shop pressure test the oilway to see if the repair is even needed. I think it is a rare problem & certainly not in the preventive category. If it were needed, make sure that the shop would be comfortable with the results. I think if I actually had a block with this problem, I would look for another block rather than do this repair. At the very least, I would press Moss for detailed references on who has actually done this repair & actually talk to the folks that have done it.

Standard cam bearings are usually at finished size & don't require reaming.

Sometimes the cam bearing bores are not in alignment & require line reaming of special undersize bearings (semi finished) to get the finished bores straight. Out of line cam bearing bores are rare on the Healeys. Again, I would go by the engine shop's suggestions. They can easily check the bearing bores for alignment. I'm not even sure where you can get "ream to fit" cam bearings for the Healey.

Since you are not totally familiar with rebuilding Healey engines, I would definitely suggest that you check around to find a shop that is well experienced with the many quirks of these engines. I know you already have a shop, but make very sure. There are many pitfalls.

Good luck,
Dave
 
Dave is absolutely correct, you need a very good machine shop if you are going to try it.

I have had this problem with two different blocks. The first time was about 6-8 years ago and I tried the oilway repair kit - it was not sucessful. I believe that the critical part is sealing the tubes in place, if the sealant is not bonding well, oil can go around the end of the sleeve and still get into the water jackets.

I was told at the time that Southern Carburetor developed the kit. However, there must have been more recent developement because the kit I got several years ago included a tube for the cross block gallery and the long fore/aft main gallery. There was no tube for the cylinder head vertical passage. Currently the kit has the cross block and the vertical for the head but not the long main gallery. I wonder why they changed the kit substantially. Maybe the weak spot is the vertical one that I didn't do and that's why my attempt didn't work.

Because this is very slow seepage thru the pourosity of the block, pressure testing is difficult to do. When I did mine the shop tried pressure testing and it seemed fine, but what I was having was about a pint of oil into the water in 500 miles or so which is a very small ammount.

You will not have water in the oil. Because the oil will run at 40-50psi and your water system is at 7psi. So the oil wins, besides water won't penetrate like oil will.

I suggest the rust bloom on the inside of the block may be due to a PO rebuilding the motor and hot tanking it which removed the factory primer paint and normal condensation from sitting for years may be what you are seeing.

My current block developed the problem 2 years ago and I am still running it. I just flush the system every 2000 miles or so. I add a cup or so of dish detergent to the water and run at idle for an hour or so and then drain and flush - crude but it works. I run synthetic oil which may make the problem worse because of the finer molecules.

Hope this helps,
Dave Phillips
 
Thanks for the info gentlemen. I took my parts down yesterday and we talked about oilway repair. We'll try the pressure testing... but I would guess we'll see similar results as you (Dave P). If I no "significant issues appear... I'll just probably let her be.

As far as the hot tanking the motor... it doesn't look like the engine had ever been touched... eveything is still at spec original. Of course that doesn't mean no one along the way tried to "clean it up". But when I tore it down - it had rust bloom around the rocker and through the lifters... but about a quart of pretty decent looking oil floating in the sump. Some mysteries are best left unsolved... but I'm sure this one will come back to haunt me.

Thanks again for sharing you knowledge... it really helps out a Healey Newbie

Ben Selfe
 
As another Healey newbie, is it still recommended to hot tank the block before a rebuild? As far as I know my car has not run in about 12 to 15 years and even then the condition of the engine is unknown. I have the head off and the pistons are standard, bores are smooth and there is only about .001" ridge on the bore top. My speedo indicates 76977 miles (origional?). I have not checked bores for ovality yet but I am thinking new bearings, new rings and hone bores. Thanks and have a good day!

John
 
In my mind, hot caustic tanking is still preferred to remove the rust from inside the water jackets. This will require new cam bearings. Remove the aluminum engine ID tag before hot caustic tanking.

Due to environmental & cost concerns, many shops are using high pressure solvent cleaning or high temperature baking instead. I don't think it gets the rust out of the water jackets as well.

I would seriously consider a .010" overbore & new pistons for the best job. Also grinding the crank .010 on mains & rod journals. New cam chain & tensioner. Definitely a new oil pump. Head & block mating surfaces perfectly flat.

Carefully check the cam lobe & lifter surfaces for ANY signs of pitting or wear marks. Replace if there is any doubt.

There really is no good "short" stopping point when you consider the trouble & cost to remove the engine & take it apart.

You could cut a lot of corners, but how soon do you want to do it all over again?
D
 
+1 on everything Dave says, but just be certain you can get the cam bearings before the block goes into the tank. Availability may be pretty good now, but they were very scarce some years ago.

The crankshaft may be fine with just a polish; the original 50 year-old crank from my 100/6 engine is still a perfect std/std.
 
Dave,
Is the Healey oil pump a problem? I usually check to make sure the clearances are within spec and if not purchase a new one. It sounds like you recommend a new one regardless. I also noticed that you can purchase the internal gears and shafts, not recommended? Moss lists a standard and upgraded pump, which do you recommend? I also noticed that the first oversized pistons from Moss are +.020. Can +.010 oversized pistons be purchased somewhere? I don't want to skimp on the rebuild and do something stupid. I really appreciate the thoughts from those much more experianced than I. Thanks for your opinion and have a good day!

John
 
Hi John,
The oil pump is just too critical to take a chance on. Even with new internals, the housing can still be worn. I would use the high capacity new pump. If you replace the cam, the pump drive gears should be new to match. DWR recommends the hi cap pump if you are running below 6,000 rpm & the standard pump if running sustained over 6,000 rpm.

Some of the "good" pistons are metric sized so the first oversize may be about .020", which is fine. Be absolutly sure to get the pistons in hand first & have the cylinders bored exactly as the piston instructions state. Same with rod & main bearings & crank grinding.

If you replace the cam & lifters, have the shop hardness check every cam lobe & lifter for a hardness of RC 58 or higher. Even one soft lobe or lifter will ruin everything. Even with the best suppliers, one can slip through.
D
 
Hi John,
a one thou wear ridge or 77000 miles does not sound very much to me so I'm wondering why you would want to do a full rebuild. Do you know how the engine was running beforehand? Was it relatively quiet and was the oil pressure OK? In this case it may be that a new head gasket, and a head overhaul will be enough to give you an engine that will last another 70000 miles.

I guess it depends on what you want and what you enjoy doing!

good luck
Richard
 
A wear ridge in itself doesn't show much. The real questions - are the bores perfectly round, are they not tapered, do they have the correct clearance on the pistons.
D
 
Richard,
I don't know anything about the running condition of the engine except it has been about 12 to 15 years since it ran. I know that the rear cylinder intake valve leaks. It looks like the engine is probably origional as the number is about the correct time period and it looks like the engine and tranny have been apart sometime in the past. I thought that as long as I have the engine out I should at least check the bearings, replace cam chain, check cam and lifter contact points and the oil pump. Sounds like replacement of the oil pump is prudent. Thanks for your help and have a good day!

John
 
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