Last Ride Of The Season - Question on Lifter Noise

[Rick K]

Took my last ride today, to the launch. Ugh. Can feel the depression setting in already. Gonna have to figure out what I'm gonna do till next April. Anyhow, long story VERY short, rebuilt engine 2 seasons ago, and had 1 lifter giving me fits. Shop said everything mic'd out on the very low end of the tolerance level, so it was decided not to replace cam/lifters/push rods. Honed the block, put everything back together, new heads, timing chain, etc.

In retrospect, I should have just dropped the $$ and done it anyway.

I think I dropped that lifter within the last week. I didn't get the performance I'm used to today, and, I can feel a little bit of a miss on the #4 cylinder (pulled that wire, noise went away). Looks like a got a day-long job ahead of me. Question is, am I stuck with Mercruiser's OEM lifters and push rods, or can I go with something better performance-wise, maybe something that'll perform better at higher rev's?

Last Ride:

 

[Steve Craig]

Have a look at your exhaust gaskets before you pull the intake. Not sure if you can get a light & mirror in all the areas. A small exhaust leak can sometimes sound like a lifter, tick, tick, tick....... Doesn't explain # 4 acting up but a good starting point.

 

[geo737]

Hi Rick, It is quite disheartening when you have to put your ride up for the season. I missed this this season due to the work my boat needed this past summer. I've been off the radar for quite awhile putting it back together. With the issue you are experiencing, I'm sure others will chime in with additional advice and correct me if I give some incorrect info. From your description, there may be a few areas to investigate. I will go with you having a GM based Mercruiser, although your symptoms may apply to other engine families as well. A few things come to mind. You had mentioned what appeared to be a short block freshening up. Hopefully, the machine shop kept the lifters organized to run on the same position they were removed from-lifters develop a specific wear pattern to the cam lobes and shouldn't be mismatched when reassembled-this will cause excessive wear and eventual failure of the lifter/cam lobes. There may be a possibility of a bent pushrod-this will allow the lifter to not seat properly on the cam lobe causing the lobe to "slap" the lifter. another possibility is the rocker arm is loose and the valve for the #4 cylinder just needs adjusted-this would also cause the lobe to "slap" the lifter causing noise as you described-that would be a relatively easy fix by adjusting the valve and hopefully take care of the issue.( if you go this route, it may be a good practice to adjust all the valves while you're there if its practical) If you pull the lifter and pushrod, check the pushrod for straightness by rolling it on a piece of plate glass if you can or a known flat surface, you will easily see if it is bent. Inspect the bottom of the lifer for a convex surface-this allows the lifter to easily ride/slide on the camshaft lobe. If the bottom of the lifter is concave-time for a new lifter and possibly a new camshaft. If everything looks good, it may be a case of a collapsed lifter, which does happen and a component replacement should address the issue. Another thing to try if everything looks good , is to soak the lifter in some clean oil and "exercise" the plunger, as it may just have some dirt or carbon in the internal piston. As far as replacement parts, any good Chevrolet replacement parts should work well. Be careful of cheap, aftermarket "made in China" lifters/parts - try to source from a reputable parts company. I just rebuilt a replacement engine for my SeaRay and used as many factory Chevrolet and reputable aftermarket (Speed-Pro, Clevite,Hastings,etc.) parts as needed. Sorry if this is a bit long. , but hopefully it gets you going in a good direction

 

[Rick K]

Have a look at your exhaust gaskets before you pull the intake. Not sure if you can get a light & mirror in all the areas. A small exhaust leak can sometimes sound like a lifter, tick, tick, tick....... Doesn't explain # 4 acting up but a good starting point.

Steve, this is definitely a lifter issue (well, it looks as if everything points to that anyway). We checked the exhaust manifold for tell-tale signs of leakage and didn't really find anything. Of course, when you're on your head, bent in 16 different angles over a running engine it's a bit hard to tell.

Geo737, I think what's going to happen is that all the lifters/push rods, etc., will be replaced. For the money and minimal amount of time, I think it's worth it just to go in and make the change. As far as valve adjustment, we did that back in the spring, after about 6 hours of run time. This one lifter started out with a quiet tick, then progressively got worse, until I think it just collapsed. Also, lifters/rods were on a sort-rack, so they stayed in order.

I think in retrospect, I probably should have had the shop just punch out the block 10 over, then go from there, no matter what anybody thought. Sitll had to buy new pistons/rings, etc., so it wouldn't have been a big deal. Again, should've listened to my gut, instead of someone else. The advice I got was to keep it as is and just hone everything out, as the tolerances were so close to the low side.

And if it raps after replacing the stuff, well, I have this super cool 327F outta my old Chriscraft that I'm sure I could easily get 260 horsepower out of...

 

[geo737]

Hey Rick, As it sounds like your going pretty deep into the engine, would it be a possibility to convert to a full roller cam and slip away from flat tappets? Is your block capable of accepting the factory roller set-up? going to an aftermarket roller set would be a bit more pricey, but either way, the reliability would be greatly increased-it would help avoid future cam/lifter wear issues and you could run off the shelf oils without additives. Most off the shelf oil, has most if not all the additives removed to help a flat camshaft live- (DPPT I believe it is-zinc and other anti-wear ingredients), although oil for diesel engines still has the anti-wear and anti-sludging compounds in it. I had to start with a clean slate and built my engine from there. My old one was well, pardon the pun, basically a boat anchor when I tore it down-not worth saving. The block I acquired had the ability to be fitted with a factory roller set-up, had 4 bolt main caps, crossed drilled crankshaft and the block was drilled for a mechanical fuel pump. I was at the same decision point talking to the machinist who was doing the work- the cylinders were right at the edge of needing oversized. We could have left them, but decided to go .030 over and install forged pistons and cast iron rings for durability. I took his advice, as he builds engines for the local sprint car guys-so I figure he has a good take on what I was looking for. . If worse comes to worse, the 327 would make for fun cruising and getting some good power out of it would be an easy build/modify. I plugged the basic parameters into the desktop dyno for my build and it spit out conservative numbers of 380 FT/LB torque @ 3500, and 290 HP at 4500, so it should be a fun ride when I get it in the water next summer. Let us know how you make out.

 

[Rick K]

Not sure - it's an '81. It WOULD be fun to build that 327, wouldn't it? It's got a Carter AFB Carb on it that makes my Rochester look like an old 1 barrel LOL As I rememebr, that old engine used a LOT of gas! I'm sure my block is nowhere near like yours; it's just the run of the mill Merc 260, 2 bolt main, etc. It was in good enough shape, according to the shop, that a good hone was all it needed. I got the block back, and we assembled the engine and fired her right up - after, standing there for what seemed like 2 years with my drill and oil pressure pump tool thingy (real good description, I know...). The absolute LAST thing I wanna do it pull that engine. It's a bigger pain in the ass than anything else. And if I pull it, something else is difinitely going back in there.

It would be great to pull the valve cover and see a pushrod thrown thru a rocker arm. That'd be too easy though...