Merc block -next step - cam, valves and guides?

Jack 34pu

Jack 34pu

Senior Member
OK, the decission has been made to bore to .060 and see if clean and go further if necessary. No sleeves at this point. Now - what about cam, valves, springs, and guides? Stock cam looks good and worst lobe is only .0004 diff than rest. I'm open to brand suggestions for stock size. (no Chevy valves) Remember - daily driver.
 
If your valves will grind alright use them, if you need new ones you can bye Chevy valves cheaper that the flathead ones. The only trouble with C valves and a stock cam you will have to butt grind alot if useing stock lifters. I wouldn't use adjustable lifters, there is only one co. that make good ones but they cost $215.00 +ship. Also with a stock cam adjustable lifter may not screw down far enough and you still will have to butt grind some.
 
The next step is to determine the status of the original components and use as many/much of that as are deemed satisfactory. If this is a 49 or newer Merc. the original cam would be a great choice for a high torque street driver. A previous post stated the valves can be re-ground and re-used unless badly worn or deteriorated. Most of the guides can usually be salvaged. But, it all comes down to cleaning and carefully inspecting the original pieces. If you have to pay someone to do that job it is sometimes less expensive to buy a new "kit" of parts. If the lifters have not been maintained in lobe relationship they should be re-ground or replaced with new.
 
JWL said:
The next step is to determine the status of the original components and use as many/much of that as are deemed satisfactory. If this is a 49 or newer Merc. the original cam would be a great choice for a high torque street driver. A previous post stated the valves can be re-ground and re-used unless badly worn or deteriorated. Most of the guides can usually be salvaged. But, it all comes down to cleaning and carefully inspecting the original pieces. If you have to pay someone to do that job it is sometimes less expensive to buy a new "kit" of parts. If the lifters have not been maintained in lobe relationship they should be re-ground or replaced with new.
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Please follow this advice from JWL...
 
Here is a cam mfg that has some good flatty combination's worth looking at. They do good job on cams great web site for you to pick up some engine info.

http://schneidercams.com/Flatheadv-8.aspx

There are others like isky that do a great job also. Schneider has a dozen or so choices. Some not really for a daily driver but still in the cam business in a big way. Hope this helps. JWL & Old Ron will have some thoughts on cam choices for sure. Bronze guide liners are worth a look at also easy to do and work good I have done many with good success just 11/32 liners no secret there.You already have the stock guides to put the liners in.They can be done any time You just give the guides to the shop to do as they don't need the engine to do the guides, they need valves to measure for for clearance.

Ronnie :)
 
I have been down the same road as Walt with the Chev valves. I had the adjustables screwed all the way and still too much valve length. All in all I would recomend sticking with stock valves. My experience with adjustables is you do not want to make a lot of adjustments as the threads will give up their resistance and loose the adjustment. I had to replace all of them because I screwed them up and down. Make the adjustment in the down direction (tighter) in small increments.
 
If you plan to use an aftermarket cam, I feel it is imperative to ask the cam-grinder (not the seller - they likely wont know and will BS you) whether the billet used for the grind was made of US stock or chinese stock. Just because the cam is labelled Made in USA does not mean it's made from US stock. US stock has a higher Rockwell hardness rating than chinese stock and is usually much higher quality. Chinese billets are usually made from powdered iron. A chinese billet will absolutely require that you run 1200-1500ppm ZDDP in your oil. Failure to do this will likely result in cam failure after a few months. It has happened to many SBC owners.
 
Agree with 26roadster, Pete ground a cam for me recently, and it was so pretty I hated to put it in the motor.
 
254 F Sneider cam, Chev valves- runs nice, good lower end... Just a tad of lope at idle... in a 59ab bored .060, 4" crank, Next time, bore it .125- otherrwise, love it- Karl
 
Well I guess I'll throw my 2 cents in. For a daily driver I stick with the stock cam. If you want something that has has a nice sound and runs well on the street. I'd recommend the L-100 by cam techniques. Now for the valves and guides. SS valves are a cheap racing valve that you should stay away from for any application. SS with Chrome stems are excellent, but pricey for a Flathead. OEM valves are a two piece unit that have ss heads and Hi quality stems. The chevy valves can be bought from PAW for about 3 bucks apiece. Now for guides, these can be knurled for a .001-.0005 stem to guide clearance. Most new guides are too loose, check em. Now when installing the giude in the block I don't use the rubber seal. I use a small amt of RTV on the int guide and never seize on the exhaust guides.
Every engine builder has his own way of doing things and differ from one builder and another. The only wrong way to do this is one that doesn't work.
Keep em runnin.
 
Ron,

The guides are not real bad but I was going to replace them anyway. I remember hearing about knurlizing when I was a kid but seem to think it was a short term solution and didn't stop oil from being sucked up thru. Mine are not close to .0005" - 001" so I guess I have to decide which direction to go.
 
You will be seeing a lot of different opinions emerging already!! Pete is the local dangerous radical, JWL is our conservative, and Ron is a bit toward radical from the center point...

On stock cams, '32-36 are somewhat hotter than the generally similar '37--about 1951, then '52-3 heat up considerably from the middle period...
Does anyone have good numbers for the later cams?? Merc ones differ from Ford in the later years, but I've never found real info on them.
 
The stock cam is an 8CM. Looks real good and a few have suggested that it would be fine for daily street use. Waiting to here more feedback on knurlizing the valve guides. Will probably replace springs and valves. A couple of the valves have pitting at the top of the stem from water in port and setting them lower with a light grinding may ruin the guides - right?
 
Jack 34pu said:
The stock cam is an 8CM. Looks real good and a few have suggested that it would be fine for daily street use. Waiting to here more feedback on knurlizing the valve guides. Will probably replace springs and valves. A couple of the valves have pitting at the top of the stem from water in port and setting them lower with a light grinding may ruin the guides - right?
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The 8CM cam is .338 lift--(in open 10*btc--close 50*abc)--(ex. open 50*bbc--close10*atc)---int. setting .010-.012 ex setting .014-.016 if you can find a pair of Ford EAB heads they will work better than the Merc heads, mill the EAB for .050 piston clearence, get a early 60's rochester 2G carb for your four bolt manifold and Bubba's dist. converision and you will gain power. or just leave it a stock Merc. either way is good.
 
Great - I have a set of EAB heads but one has some pitting around one cyl edge so may have to be cleaned up. I assume you mean .050" without head gasket.
 
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