Cam locked up in head

[FB71]

FB71, any suggestions on what to use to flush out sludge on vehicles that may have had poor maintenance or may have sat for an extended time.
I'm thinking seafoam, trans fluid, or diesel fuel; in controlled amounts, < 1/2 quart, in the oil just before changing it. Let it idle, no driving on diluted oil, and drain it.
The other option is to just change the oil when it gets dirty and not wait for 3K miles.
Just thinking, a lot of festivas that are being put back on-line are likely to need some sort of "cleaning out".

I do advocate Seafoam, because it will dissolve sludge and varnish, not just dislodge it.

I do not advocate trans fluid or Kero/diesel. Neither have sufficient lubricity to maintain protection of parts in high pressure locations (rod bearings, cam lobes) and actually contain less detergent than modern engine oil. In fact, kero and diesel contain no detergents. They simply act as a solvent and dispersion agent, removing lubricant from important places.

Products like Seafoam do not disperse lube, although they will reduce its viscosity. They act as detergents vs solvents, when used in the appropriate quantities.

[FB71]

I have one here already taken apart to look at. Valves can hit pistons.

If you have a Mazda B series engine that has experienced valve to piston contact, then the head or block has been milled more than 0.006", or it had an incorrect (too thin) head gasket.

I have built many, many engines in my life. More than slapping parts together. I blueprint each part, balance them (when applicable), and verify all clearances. This includes valve to piston clearance.

There are specifications for crank centerline-to-deck distances, cam centerline-to-deck distances, valve lift and duration specs, etc. If all of these are within spec on a Mazda B series, THERE IS NO VALVE TO PISTON CONTACT. I verify this on every build by bringing each piston to top-dead-center, and, while observing the interior of the combustion chamber with a borescope, rotate the cam thru one full revolution. This actuates both intake and exhaust valves, across their entire cycle, at full lift.

If all of these clearances are within spec, the only event that would cause valve to piston contact is overevving of the engine, causing the valves to overlift, or 'slingshot', and a corresponding stretch of the connecting rods and deflection of the piston pin. Rods can stretch 0.002" to 0.003", and pins can deflect 0.001" or more. Valves can slingshot 0.003" easily. So, when piston-to valve clearance is only 0.005"-0.006" to begine with, over-rev can easily cause contact on even a perfect engine.

[Sandm849]

I didn't even know you could order a different thickness head gasket for our applications. With this being said has anybody used the rock auto gasket set or head gasket. Any good or bad experiences?

[FB71]

I didn't even know you could order a different thickness head gasket for our applications. With this being said has anybody used the rock auto gasket set or head gasket. Any good or bad experiences?

you can't really order one. I've simply found that different manufacturers have slightly different thicknesses. Felpro is ok, Cometic is very good, Reinz is ok. Stay away from 'shop brand' stuff. Usually too thin and seals poorly.

[Sandm849]

So I guess for the head gasket I should go with felpro. And well I guess I should with the rest of the gaskets too. A couple bucks now could mean a pain down the line.

[Stig]

hey i know this is old.. but i just got an 88 carbed festy for free.. it had a seized cam sheered the gear just like you said.. i took the cam out the very front journal was scoured up badly and it dug into the cam and thats how mine seized, i smoothed it out put an new cam in it and it runs like a top.. i noticed the oil was kinda caked on the inside of the head as leaked oil does on the outside, dont think the p/o took care of this lil thing.. i noticed people talking about seafoam in this thread is it really good cuz i see so many threads saying seafoam kills engines.. i was gunna get that quaker engine flush but i need something to disolve the gunk in the engine so i dont see anymore scour marks etc..

[92festie]

ive heard both sides of the whole "seafoam situation", more good than bad tho, but i have yet to use it

[zoe60]

Aspires have the plate but their cams don't have a fuel pump lobe. You would need an electric fuel pump if you use an Aspire head. My '89 has an Aspire engine and I had to replace the cam and rocker arms with some from a Festiva. I did get them from a newer fuel injected model though, and they worked perfect with my mechanical fuel pump. You need the rocker arms because the Festiva cam isn't right for roller lifters.

[1988redfordfestiva]

rip the pan off check the strainer for metal and bearings deposits someone must of never changed the oil and or starved the engine