i have a erson roller cam .555 lift dur@50 IN238 EX246 when i took the timing cover off to replace the seals i noticed that the cam button was rideing aginst the cover is it supposd too? i dont know anything about cam buttons

i can post a pick of the inside of the cover if intersed it was just a cheepie chrome cover i was going to replace with a stock one thanks cope

I don't know if I'd describe it as riding on the timing cover so much as it should have a small clearance .0015 to .003 inch between the button and the timing cover. The cam will translate fore and aft while the engine is operating. In its foremost position the bumper will contact the timing cover. In its aft most position the back side thrust surface of the cam gear will ride against the block.

Bogie

 

how do i measure the clearance between the button and cover(clay?) mine is a roller cam button and i want to weld a piece of metal to he cover to strangthen it so it wont flex right?

 

how do i measure the clearance between the button and cover(clay?) mine is a roller cam button and i want to weld a piece of metal to he cover to strangthen it so it wont flex right?

1) Some covers that are made for this purpose have a small hole with a rubber plug. When assembled without the water pump and having an access into the engine so you can hook the cam with a pry of some type.

Then with a dial indicator is placed so its feeler is against the button nose. The cam is then pried for and aft. The amount of movement than read from the dial indicator. The problem with this method, while really good for initial set up when the engine is being built, it isn't user friendly once the water pump is installed and the engine mounted in the vehicle.

2) Another way is to use an extra long feeler gauge, these can be had from the web more easily than PEP Boys, then with the pan off reach up from below and measure the clearance. Again the cam needs to be pried to its aft most position. This technique can also be used on the assembly stand before the pan is put on the engine.

3) A third way to do this that some of my friends prefer, which works only when the engine is being assembled, is to leave the rear cam bore plug out. This allows the dial indicator to be set up there on the back of the engine. Aside from measuring on the back side of the cam, this processes is as involved as any other. When done you install the cam plug. I lack enthusiasm for this technique only because I like the rear plug installed first before the cam is put in so I can inspect the installtion for burrs or shavings that it's installation can cause.

Which ever technique you use, there is no simple easy way to set the button clearance, it's cut and try till you get there. You'll find later factory roller blocks with their thrust plate to be a blessing. All we need now is for a cam vendor to make and sell a flat tappet cam that uses the roller block and its thrust plate. This would be most helpful for classes that require flat tappet cams as it would eliminate this rinky-dink button adjusting process. If you're building a roller cammed older flat tappet block, I'd really consider a later model block to build from.

Bogie

 

this engine is allready built and assembled its a real sweet engine i got the car in trade from my bro who got it in a trade.the engine onley has about 100 miles on it and the previous owner who had the engine built ran it down the track a few times.here are the specs

355 CI balanced 4 bolt main
TRW forged pistons
Total Seal rings
GM fueler heads (casting # 462)
(.202/1.60 stainless valves
screw in studs and guide plates
mild port job
1.5 roller rockers
single springs w/inner dampners)
Erson mechanical roller cam & lifters
case hardened push rods
Edelbrock Victor Jr. intake

the cheepie chrome cover was pressed tight againt the button no clearance.so i want to get the clearance right so i dont have to worry looks like my onley option is to measure with a feeler guage.

what does it mean when u say the cam needs to be pried to its aft most position

 

heres a pic the prediator is onley for the track

 

Cam Button

The timing chain cover is not that expensive. I don't remember what I paid but it was well under $100. The one I have lets me check it anytime I want and there is no cover flex.

Bob

 

this engine is allready built and assembled its a real sweet engine i got the car in trade from my bro who got it in a trade.the engine onley has about 100 miles on it and the previous owner who had the engine built ran it down the track a few times.here are the specs

355 CI balanced 4 bolt main
TRW forged pistons
Total Seal rings
GM fueler heads (casting # 462)
(.202/1.60 stainless valves
screw in studs and guide plates
mild port job
1.5 roller rockers
single springs w/inner dampners)
Erson mechanical roller cam & lifters
case hardened push rods
Edelbrock Victor Jr. intake

the cheepie chrome cover was pressed tight againt the button no clearance.so i want to get the clearance right so i dont have to worry looks like my onley option is to measure with a feeler guage.

what does it mean when u say the cam needs to be pried to its aft most position

"what does it mean when u say the cam needs to be pried to its aft most position[/QUOTE]" You just need to be able to move the cam fore and aft to be sure youre getting all the possible clearance movement. In the aft most position, the back side of the cam gear hub should be in solid contact with the front of the block. This is where the factory hopes that with a flat tappet cam the angle of the lobe working against the lifter will keep the cam gears thrust face on the hub against the machined thrust surface of the block. When it's in that postion with the cam button installed, your going to measure and set the clearance between the button and the timing cover to the cam vendor's spec. The spec clearance is usually from .0015 to .0030 inch. So now with that clearance, that becomes the space the cam can move fore and aft in its bore because it's now restrained between the gear to block thrust surface (preventing rearward movement) and the button to timing cover thrust surface (preventing frontward movement). This restrains the amount of sideways (to the direction of rotation) movement the cam can make under the roller of the lifter. Flat tappets will tolerate rather more of this "skidding type" movement than a roller.

I button everything flat or roller tappet in these older blocks simply because you have to with a roller; but I like to do this with flat tappets as well as it reduces the work load on both the lobe and tappet.

Bogie

 

is it ok to use a stock cover as long as i reinforce the outside so it wont flex.
i would love to buy a new cover but its just not in the budget right now and it wont cost me anything to weld some steel to the cover.

do i ever need to check the clearance once i set it as long as the cover doent flex. i plan on buying a new cover this summer when i have the extra cash one like quater flash has.

i just want to be able to do some crusin and a day or two at the track befor i have the money to buy a new cover.

thanks for all the info bogie i leaned alot from this tread alone im just a young gearhead trying to do things right

 

is it ok to use a stock cover as long as i reinforce the outside so it wont flex.
i would love to buy a new cover but its just not in the budget right now and it wont cost me anything to weld some steel to the cover.

do i ever need to check the clearance once i set it as long as the cover doent flex. i plan on buying a new cover this summer when i have the extra cash one like quater flash has.

i just want to be able to do some crusin and a day or two at the track befor i have the money to buy a new cover.

thanks for all the info bogie i leaned alot from this tread alone im just a young gearhead trying to do things right

Look at your water pump, often there is an unused threaded boss on the bottom back of impeller housing. It's purpose is to use a bolt to reinforce the timing cover over the area where the cam button. A simple bolt is run in from the timing cover side with a nut between the bolt head and the pump boss. When you install the pump, this bolt is screwed out till it just touched the timing cover. Then with the bolt held from rotating, the nut is run up against the pump boss to jam the bolt in position. I prefer stainless hardware for this since it doesn't corrode. You can use a lock washer to insure the nut doesn't loosen or my favorite, a nylock nut. The latter turns in quite hard so be prepared when putting a wrench to it so the bolt doesn't move as well. I usually run a proper size/thread bolt thru the nylock nut first as this makes it slightly easier to run in when all this stuff is on the engine.

Bogie

 

nope there wasent one that would have been alittle easier but i will just weld a strap of steel across the front of the cover over the area where the button is and clean it up and paint it to look nice