QV4C Valve Lash
 

Have a set of 1100's with 40 hours. Recently completed Mercury Racings required valve lash maintenance, no change all were within spec. This process is a major pain with a full stagger set up. Interested in thoughts on this process, overkill or just good preventive maintenance?

No btchin... do it. Valve lash is important, even more so on the high hp stuff... the valve needs time to sit on the valveseat to transfer heat out of the valve to the head... thats how the valves are cooled, also excessive lash can increase valve train wear dramatically with the high spring pressures of high output high rpm engines... granted you wont hVe the insane spring pressures like a pushrod engine but still man up an do it. If u use a remote starter control it makes it a much easier job... rm

Thanks for the feedback! Seemed like excessive maintenance given how difficult this was and how good these engines ran. Sincerely appreciated your perspective.

Gary

No problem my brother, another thing to consider is now that you have a little time on the engines everything is seated in, so nothing should move around much, plus merc is hoping your going to pay out the azz to have their service dept do it and take your money for doing so. They want to see you and your money as often as possible, if they recommend 40 hours you can do it every 50 or 55 hours. Rm

Merc racing for these are the first 25 hours not 40 hours for all oils changes and the Valve lash checked and adjusted then for that end every 75 hours there on after.; This should be in your owners manual under maintenance intervals as well but not the procedure as how to.

Will add - I have not been to the current Merc racing school as of late so I really do not want to wing it per how to do all of that correctly.

IMO you should buy all the related service manuals and check for all the Service Bulletins per engine and engine serial number to help with whatever you are going to address. Not many experience people out there with these engines to count on for the advance tech help either like per say the SCI engines.

It is a good idea to check lash. If the lash starts to go away it is a warning there are problems.

Why does this engine have solid cam followers that need lash checked? Don't most modern 4 valve engines have hydraulic valve lash adjusters which require no maintenance?

No idea why Merc does that. They did the same thing with the 1075s. A lot of companies will refresh the 1075s with a hydraulic roller valvetrain then its good for a couple hundred hours instead of 25...

I actually didn't know the QV4C had solid lifters, I just assumed they evolved to hydraulic like the rest of the world.

Because solid stuff wears faster and requires more maint which is profitable for them considering they currently have the market cornered.......

Solid equals higher rpm capability and i think you can run more spring pressure and greater ramp opening angles on the camshaft... which equals more hp... all these high dollar bottom ends are good for more rpm than the valve train... id rather run solids and adjust em once or twice a year... something is way out of adjustment you might catch a valve train issue before yo drop a valve and blow up a bun h of high dollar parts

Its just a finger, its over head cam. How could you make it hydraulic? How the hell do you adjust it?

Bro it doesnt wear faster cuz its a solid valve train... usually solids will be in an engine with a lot more valve lift that spins a LOT more rpm, like 10k and have steeper ramp angles on the cam lobes to really slap the valve open. If you ran solid valve train on an equal cam grind as the hyd the solid would not wear any faster...

I wouldnt build an engine with out roller valve train and id probably go with the solid stuff so i could rev it harder.... solid roller lifers are less coin too

Even tho the lifter rides against the cam there is an oil port that supplies the lifter to give it the hyd effect,

Id rather run the solids in that too,

almost all dohc motorcycles are solid shim under or over bucket and go thousands of mile between valve adjustments...

When you float your hydraulic valve train is when bad chit starts to happen in a hurry...

Its not you moms grocery getter its an 1100 hp beast...

I had a 302 sbc i spun 10k rpm with .690 lift solid roller, the cam lobe opening ramp was so steep it was insane. It slapped the intake valve open so violently, that when you put a rag o er the 3.5 header muffler opening at idle you could hear the ping of the sound wave the engine generated in the header and flowmaster copy mufflers i made... it sounded like a two stroke sound wave...lol

Well completed the QV4c 1100 lash. 44 hours all were within spec. Job isn't horrible but takes better part of a day.