888/302 camshaft selection

[racinrc14]

Re: 888/302 camshaft selection

Check out the link I provided in my other thread regarding exactly what you're talking about. Two manifolds (center riser), risers, and elbows with all mounting hardware for under $700 from ebasicpower. Problem is, I don't have the money at this time, so I am stuck with the exhaust I currently have, unless they are cracked, in which case it may mid-summer before I get her back on the water.

 

[WizeOne]

Re: 888/302 camshaft selection

Check out the link I provided in my other thread regarding exactly what you're talking about. Two manifolds (center riser), risers, and elbows with all mounting hardware for under $700 from ebasicpower. Problem is, I don't have the money at this time, so I am stuck with the exhaust I currently have, unless they are cracked, in which case it may mid-summer before I get her back on the water.

Well quit gabbin about it. Get on with the leak testing. Inquiring minds want to know.

 

[racinrc14]

Re: 888/302 camshaft selection

Looked them over today in the good light here at work. I didn't see any obvious signs of cracking, and there isn't much rust on them, or in them. Can I pressure check these puppies to find any internal cracking? If so, how? There's only so much I can see of the inside with a flashlight and mirror.

Getting a little off-topic, but I took the engine coupler to work also to have a good look at it. It's toast. The splines are razor sharp and actually look like they are 'rifled'. I mounted it on the lathe and gave it a spin, and it looks like it is out of runout by about .120". There goes another $150 or so.

 

[WizeOne]

Re: 888/302 camshaft selection

Sounds like you have the engine out and the exh manis pulled. Did I miss that somewhere? That is certainly the only way you could examine the coupler splines and the 'insides' of the mani's?

To pressure test for internal cracks on the manis, you would have to bolt on gasketed plates over the risor opening then make an adaptor to apply water or air into the forward end plates of the mani's.

What do the splines look like on the U-jointed outdrive shaft?

 

[racinrc14]

Re: 888/302 camshaft selection

Yes, the engine is out of the boat being rebuilt.

I looked at the outdrive shaft last night and it appears to be in ok shape. They're not square, but not sharp either. Plus, there's no burrs on any of the splines, as there are on the coupler.

I'm going to make some block-off plates today and put something together to check them with air pressure.

 

[Don S]

Re: 888/302 camshaft selection

Be sure to check the splines in the coupler itself. They are aluminum and will wear out faster than the splines on the steel shaft.

 

[WizeOne]

Re: 888/302 camshaft selection

Be sure to check the splines in the coupler itself. They are aluminum and will wear out faster than the splines on the steel shaft.

Don, that is what started this little exchange.

Getting a little off-topic, but I took the engine coupler to work also to have a good look at it. It's toast. The splines are razor sharp and actually look like they are 'rifled'. I mounted it on the lathe and gave it a spin, and it looks like it is out of runout by about .120". There goes another $150 or so.

Also Don, is it normal for the Merc coupler splines to wear like racinrc describes or is that due to an alignment issue? Aluminum splines? Yuck! That's not nice.

 

[Bondo]

Re: 888/302 camshaft selection

is it normal for the Merc coupler splines to wear like racinrc describes or is that due to an alignment issue? Aluminum splines? Yuck!

Ayuh,...

As with Any splines,...
Lack of Grease is a pretty Common Killer...
Alignment is Right up there with it,....
Combined,...
A Coupler just doesn't stand a Chance....

And,... I keep hearing about these Aluminum splined couplers,...
Yet,... Every junker I've come across is a Steel spline mounted in a rubber hub,+ Aluminum, or steel Hub assembley...

 

[WizeOne]

Re: 888/302 camshaft selection

Yet,... Every junker I've come across is a Steel spline mounted in a rubber hub,+ Aluminum, or steel Hub assembley...

That's what I'd certainly expect. Should be no different that a steel hubbed, rubber mounted aluminum prop.

 

[racinrc14]

Re: 888/302 camshaft selection

The splines in this coupler are indeed steel.

 

[wolf21851]

Re: 888/302 camshaft selection

Your Merc 888 did use the 351 cam. I cannot say exactly why they did, but they did. You might want to call Scott at Delta Cams (253 383 4152) in Tacoma Wa and ask him. He can also tell you what acceptable upgrades would work for your motor but as I recall their marine grinds did not differ much from the stock 888 cam. Delta reground cams have an excellent reputation and are far cheaper than new.

As for the intake mani, I do not know why Bubba says no, he might be mixing it up with a 351 swap which you are not doing. Yes, there is no problem with re-using your intake. However, it is a bit of a shame 'cause a nice little 4bbl will really wake that 302 up. You just have to learn to keep your 'foot' out of the throttle and it will get the same mileage as the two bbl.

A marine tec. where I live explained it to me since I am building a 302 marine engine...He said they use the 351w firing order to relieve pressure from the front of the crank by firing 1 3 instead of firing 1 5 which is right across from each other...he said to make sure I used the 351w firing order...