Cam Replacement in a 351W GT40 boss engine.

[mrbobolina]

Does anyone have experience with this, what is involved? Can this be done without pulling the engine?

Two of my lifters were concaved pretty badly and about 4mm shorter than the rest, which I discovered doing a head gasket replacement.

I am not sure I must replace the cam, but I think it makes sense. I swaped out the concaved lifters with lifters from the other head to get a measurement of sorts on how much the lifters are actually traveling? The intake lifters on the 2 and 3 cylinders ports rise about 1/8 of an inch less then the remaining lifters. Yes I know this is not optimal.

The motor seemingly ran fine all summer last year, and the only reason I found the problem is again because I was replacing my head gaskets.

For those who care, the backdrop on the story is. I was replacing the head gaskets because they were seeping, and after removing the heads, I observed discoleration that showed moisture getting into the pistons. Oil was not milky, so we were safe there. Compression however was lower than accpetable all the way around, about 100-120, and the two cylinders with the bad lifters would not stick their compression and hit 90 as a peak then woudl drop to 0 at every crank (lifters were sticking). I did not do the oild in the lifter hole test to get them moving, because I forgot to. Instead I jumped straight to pulling the heads out. A leakdown test on my heads shows the intake valves were not holding comression so I had them rebuilt and are now pending install. This brought me to lookiing at my lifters for inspection, resulting in a dropping of my head, dragging of my feet and flinging of a wrench acoss the driveway. Never liked that wrench anyway.

So I know I need to replace the lifters, however if the cam is going too then I want to match them up. I am just not sold that it MUST be replaced. I am pretty mechanical, however I am waaaaaaaaay outside of my level of expertise here, and am learning on the fly and doing enough research online to confuse the **** out of myself. I figured it was time to ask those who have been there seen it done that.

[mrbobolina]

Okay so me being me, I did some research as to what good versus bad cams look like, and what is acceptable cam lobe wear. I did a google search "accptable cam lobe wear", and found a number of forums and data. The one that actually had something sound came from Summit Racing.

http://www.tpub.com/content/construc...346-140178.htm

So then I decided to take the cam out, even though I have never done anything like this since the clearance from the head I mentioned in my previous post seems far ouside of what would be accptable or so I presumed. I found a good link that illustraded how to remove the cam for our motors...

http://www.spartaperformance.com/caminstall.htm

I removed the ski pole and went to task. Everything went just as diagrams except one thing. The crank pulley is slightly different on our 351's than the illustion. We have a two piece pulley which I did not pay attention to and I pulled the pulley off the base, like a dummy, so I need to press it back on - which should be alot of fun to figure out. (enter profanity and dropping of head here). For those who are not sure why this is important, the mark that lines up with your timing nail thing on the block is on the pulley. So when you remove the pulley and still have the base on the block you had best have TDC set right because your timing mark is now wrong, untill you repress the pulley with TDC established. UGH.

Anyway the cam slides right out and no probs. I did take pictures of the cam and lifters to show what I experienced. Why? Well all of my compression read 100-120 which was lower than it should have been. Whitelake said 150-175 is wear you want to be. I had leaking valves which contribute to this. Another factor I learned is if the lobes are worn and your lifters are flat your engines pistons will not expand fully and can somehow lead to a valve leak. This is what I read online so don't shoot the messanger

Anyway all of the lobes had wear, so they were losing their peak. I understand this is normal since you have hardened steel rubbing on hardened steel. The two lobes that had the 0-90 compression where the lifters were sticking were totally rat, and almost fully round and roughed up. This occures for a number of reasons, likley low oil causing the lifters to essentially weld to the cams as they spin. That ticking you may hear in a motor is the weldings potential occuring, and the lifters chizling the cam. Good times.

I never had any ticking until I started the motor this last time to do the compression test, and it dissipated after 30 seconds. I am not the original owner though, and one of my heads is a replacement that the past owner had done, so this likley started before my reign. The motor never had a problem pulling heavy skiers so easy to ignore a problem like mine developing.

My thoughts are for those of you hitting 90-100 compression and have no leaks and are not missfiring, there is a really high liklihood your lifters and or cam could be tired and needing replacement according to the machine shop who did my headwork. The parts just wear out.

I was unaware of all of this untill a week ago. Who would have thought a headgasket replacement would have led to all of this? I know I did not. Hopefully this experience helps someone out there.

[Lewy2001]

What type of oil have you been running in this engine???

[mrbobolina]

10w30

[Chexi]

Have you been running oil with zddp? The engine should be run with straight 40 weight with zddp. I've heard of people using some split weights with decent results, but I don't recall anyone using 10w30

[mrbobolina]

Sorry just checked the service record. It is 40w. Not sure what the **** I was thinking.

[ski4evr]

might be a good time to upgrade to roller lifters since you have everything apart.

[mrbobolina]

Yeah I was thinking that, however I just had the heads done three days ago. Upgrading to rollers seems to be requiring, cam, lifters, springs, rockers, rods, and the valves with valve seals. I am early on the research to know how accurate that early assestment is. Either way I would be looking at $750-$1000.

FYI Part number for the Cam replacement is RA 050019. Local CC quoted me $800 and $16 per lifter, and I need all 16 lifters. So easily over 1K. The highest marine performance cam I could find if I wanted to convert the motor do a racing boat is not even $800. I am trying to get the specs of the cam from PCM and they will not hand it over, so lame. Summit and Comp Cams are quoting $350-$400 out the door for cam, springs and lifters, which is where I am leaning trying to keep the performance as close to stock as I can. Mostly because more HP equals more gas used.

Rolers makes the smartest sense no question, just may not be the most economical for me today.

[teamseal]

$800 ?!?!?!?!?!?!? for a cam Shaft? wow! Funny cause I just looked up the number you gave and the price list retails that cam shaft at $560.00 The lifters list at $16 ea.

[mrbobolina]

Welcome to California markup....

So for those who are entertained.

I am not looking to beef up my HP at the cost of fuel economy, nor have a power upgrade that I have a loud loping power motor for skiing that makes the sound system compete for noise pollution dominance. Basically I would like to stay within the stock boat. I reached out to CC to find the spec on the Cam, the lifters and the spring rate to be sure I don't drop something in the engine that creases new problems or adjustment requirements. CC had no clue. They sent me to PCM who just sent back a part number, and would not give me a spec.

Personally I feel it is total BS that PCM tries to control the knowledge of their parts so you cannot go aftermarket. I get that they are protecting their own interest, however being cornered into spending way to much money on a part is really poor business. Thank god for the internet though....

I did my research to find out who makes or sells marine cams, and then called. Explaining I had no cam specs to offer I was able to get some recommendations. So Summit Racing quoted the Crane cam, model number 443501, lifter 99280 and springs 96803. I called crane who also quoted the same stuff. Price out the door was $382. The tech guys at Summit were pretty knowledgeable, and were able to tell me what some of the numbers meant on the cam.

Comp Cam had slightly better specs all the way around and were going to take a standard ford cam, and shave it to match a similar marine spec they build for Chevy motors. The marine model number spec would be 12-232-3.

The third option was Cam Research Corp. I said I have a boat and need a new cam can they help, the guy said, let me guess, 351W? Spooky right?

Well as it turns out Cam Research only works with ford stuff so it was more default guess than anything else. Their cam specs were better at the low end torque, better at the mid and better at the high then stock, and stronger than both summit and crane. Trying to understand more about why, the explanation was simple. They have been working on ford cams for boats the past 20years and actually test the cams themselves in the boats in the water. They get the performance a boat driver wants versus what a car drive would want. I said okay well assume I have a boat full of 8 people and 250 lb single skier. I don't want to roll start to get them out of the water how will this cam perform? He laughed and said they invented this cam with me in mind for exactly that scenario. we walked through all of the specs of the competing cams and explained where I would feel the difference and why that matters. I like to understand stuff so this is all vital for me to make an educated decision.

Cam Researches cam is supposed to not be louder than stock, better low, better mid and high over stock as mentioned earlier, as well as slightly improved gas. Trying to understand how the lobes on the cam could have been shot if my oil was not low? He asked the question I was asked - what kind of oil? I said I did not know the brand only it was 40W on the receipt. We talked a bit about what the wrong oil can do on a flat tappet lifter cam setup like we all have in our boats, or at least most of do. You can have full oil and if the oil does not have the proper lubricating features, zinc(zddp) the one coming to mind however there are a few others. Anyway if you do not have the right oil your tappets while oiled, are not lubed correctly and can weld to the cam anyway. BRUTAL!!! Why would anyone put the wrong oil in? A few years back apparently the oil companies changed the ingredients in the oil and did not say anything so many boat owners got screwed and their cams got chewed as did their lifters. FUn fun fun. Is this what happened to me? I have no idea. It is possible.

I asked okay well what are some things I am not thinking of that I should to be sure I never have to crack this engine open again? He said he would get a few gallons of cheap oil, and run it through the engine, and let it drain. Hopefully it grabs allot of the metal parts and runs them out. Next he mentioned change the filter 2-4 times this year and keep a filter magnet on the filter itself to keep the shavings from flying back into the block as best I can. Finally use Joe Gibbs oil or Brad Pen in the boat to remove the potential of having the wrong oil type in there moving forward.

I am gonna do all of this, granted it is a bit overkill however I really have better things I would like to be doing then pretending to be a mechanic

Oh one final thought. All the vendors asked what are my RPMs at launch, and high speed. My answer was uhhhhhhhhhhh. I am watching the skier, the speed and obstacles. RPMs are not on my mind at all unless something is broken. If we know what the RPM is for a 12 year old versus a 250lb person vs a full boat and a huge tube in the back, the right cam makes a major impact on how the boat reacts and ultimately planes off. Without RPM knowledge and the Cam spec I admit I am taking a bit of a blind leap of faith, but I am not with to many other options if I don't want to fork over PCMs prices.

[AirTool]

I'm thinking a machine shop should be able to measure the lift and advance of your cam....then you match it looking in a TRW, crane, or other cam book.

scrap the PCM parts idea.

the roller rockers is a no brainer.

[TRBenj]

Cam Research will steer you right, Ive had one of their cams in my '90 for 5 years.

To my knowledge, there is nothing special about the PCM cam other than the price- I would bet its the same one that came in the marine/industrial long blocks right from Ford.

Sounds like you should have done a little more research on oil... I would venture over to CorrectCraftFan.com if I were you and start reading.

Dont bother with roller rockers- the price/hp is hard to justify, especially if you want to stay stock. Also dont bother with a roller cam conversion- that is not an inexpensive upgrade.

[AirTool]

Dont bother with roller rockers- the price/hp is hard to justify, especially if you want to stay stock. Also dont bother with a roller cam conversion- that is not an inexpensive upgrade.

I'm going to do a 180 and agree. The economic solution is to just use the correct oil.

[TX-Foilhead]

Sorry to hear about this, I was lucky and have used mobil1 20w50 because it was cheap at wallyworld before I heard about ZDDP. Fortunately it had plenty and I've switched to the Valvoline oils because wallyworld seems to have stopped selling the mobil1 in that weight.

Don't be scared of more power, in a boat it means less time getting out of the hole or less throttle to do it. Either one saves you some gas. Big blocks are actually more fuel efficient if your running lots of ballast because torque is really what you need.

Anyway, sounds like your on the right track with the cam, I'd be intrested to know how it does I'm thinking about adding one myself.

[mrbobolina]

Before I start a new thread, has anyone replaced their cam bearings with the motor still in the boat? Every You Tube video I see has the engine out of the car, and upside down. I was thinking I can drop the oil pan and just reach up past the crank and put the bearing where it needs to go then press away. Yes I know the oil holes need to line up and I am rolling my eyes at how insane what I just said sounds, but I don't see another option without pulling the motor out.