Help needed refurbishing 51 Merc engine

L

lesbliss

Member
After losing compression on my 51 Merc flathead I decided to tear it down and see what was wrong. Found tons of sludge and 5 valves stuck open also lots of varnish on pistons. Every thing is cleaned now and I am ready to grind the valves. I'm having to work in my carport and the homeowners assoc. will not allow me to pull the engine. So far have not found anyone in the Las Vegas area that will come to the house and has the proper equipment to grind the valve seats. I sold my set of stones and pilots several years ago. Valves look good with no pits. My question is can I just lap in the valves or must they be ground? Used to make that work on Model A's. If that isn't workable does anyone have a source for the proper tool that can be rented,borrowed our bought at a resonable cost, or a mobile mech in the area that can grind them?

Thanks a lot

Les Bliss
 
It's obvious that the primary source of compression loss is the stuck valves. Once everything is loosened up and depending on condition no valve seat grinding may be necessary. Just some lapping. It all depends on the condition of the components and you have them in hand and are the only one who can make that determination.
 
I agree with 51Merc-CT, you needed to get the valves moving as the primary cure. If the valves and seats look good, why bother going further when it sounds like your pistons, etc. are going to be needing some attention sometime in the near future?

I have a some valve seat cutters and reamers (old Tru-Bor brand) that I have used successfully on a single valve seat with the engine in place, but I wouldn't recommend doing and entire valve job that way. I seriously doubt you're going to find someone with the old stuff to make house calls.

Considering that you aren't doing an entire rebuild now, perhaps a quick lapping is your best way to go.
 
Free the valves up, a gentle lap in and put it back together. Get it back running again and get the association off your back.

If the valves hadn't been sticking you wouldn't have even pulled it down.

A more thorough engine refurb can come later down the line - who knows - you might never get to the point where you feel it needs it.

Mart.
 
I have been looking at getting a set of "Neway" valve seat cutters since I have 4 engines that could potentially use some valve work. There have been some vary good comments on this and other sites about how well they work. I have been on the "Cylinder Head Supply" website, and it looks like you can get what you need for a 3-angle valve jobs (cutters, pilots, and arbors) for around $400 dollars. Since I have multiple engines to do and a scrap block to practice on, I am seriously contemplating purchasing them. Just my thoughts. Interesting website in any event. There are lots of YouTube videos of them being used, and they look pretty slick.

No matter which way you go, try to post your results if you do go ahead with this.
 
I have also been looking to get a set of Neway. Sent two emails to Woodward Equipment and so far no reply.
 
If you are in the NW area, Centenial Hills area, and if you are not in a hurry, you could get me to come out if the Neway cutters are ok for you. I'm not there now
 
I don't know if Auto Zone has valve grinding tools or not but if they do they will loan them for free but you do have to pay a refundable deposit. I think the deposit is based on the value of the tool being loaned.
 
I have the neway cutters,they do a real nice job,but I also have the proper ford pilot that goes right down into he lifter bore as well as the guide bore.
Lawrie
 
You say there are not pits so all you need is a stick, rubber suction cup and some paste and away you go .Sounds like you have done it before so go for it .Ted
 
Don't go too mad with the lapping and you should be able to get away with not having to readjust the valve gaps. (Don't mix any parts up, just do one at a time.)

To be honest I'd probably just unstick the sticking ones and go out and thrash it to within an inch of it's life.

Mart
 
I would go the extra and find a way to cut the seats... IMO, lapping will not true up a seat...

I've got the pilot for the Flathead Ford, and the cutters... NOT cheap.

The first recent (i.e., 10 years ago) valve job I did I used a new split type valve guide (so it could expand to fit the hole for the valve guide) and the 5/16" pilot that fits that guide.
I checked out how it felt by shifting things around and decided that was accurate enough for an engine with .002 stem to guide clearance... And, I've got lots of experience.

Doing seats in the car takes a lot more effort and care than on the bench- the 45 degree angle of the V-8 makes it even more difficult. I would not like this to have been my first valve job... Get a set of junk yard ohv heads to practice on.

Karl
 
A sludged engine is usually a sign of running too cool and/or running fuel rich. The valve faces and seats are probably fine but need to be cleaned. A cleaning and light lapping is all it should take.

Lonnie
 
lesbliss said:
After losing compression on my 51 Merc flathead I decided to tear it down and see what was wrong. Found tons of sludge and 5 valves stuck open also lots of varnish on pistons. Every thing is cleaned now and I am ready to grind the valves. I'm having to work in my carport and the homeowners assoc. will not allow me to pull the engine. So far have not found anyone in the Las Vegas area that will come to the house and has the proper equipment to grind the valve seats. I sold my set of stones and pilots several years ago. Valves look good with no pits. My question is can I just lap in the valves or must they be ground? Used to make that work on Model A's. If that isn't workable does anyone have a source for the proper tool that can be rented,borrowed our bought at a resonable cost, or a mobile mech in the area that can grind them?

Thanks a lot

Les Bliss
Click to expand...

You must have a bunch of a-holes for neighbours if they get upset about pulling an engine from your car on your own property.

GB
 
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