420A Head gasket for non-interference

[DrewmHolland]

Recently I had to pull my head because of leaking valve stem seals causing me to burn oil and since I’m running a fully exposed timing belt I was wondering if it’s at all possible to have a non interference set up If I use a thick enough head gasket and how thick do I need to go.

The oem cams look pretty dull to me and I was even able to spin over the exhaust cam at tdc without issue just not the intake, don’t worry I was careful and I’m still making 180psi compression warm in all cylinders with a mostly dead battery anyway

 

[BLACK'98DSM]

Regular headgaskets are 0.040" and oversized gaskets are usually 0.060". Even an oversized gasket is nowhere near thick enough to avoid interference. I've seen people use multiple gaskets at once, but never liked the idea myself. What is your reasoning for wanting it to be a non interference engine? To avoid damage if the belt ever breaks? If you keep the belt replaced on proper intervals that isn't really something you need to worry about anyway. Unless you're worried about something damaging the belt since it's fully exposed. I would probably use at least a half timing cover on something daily driven. I also have a timing cover delete but mine is a race car only.

My thoughts are this. Even if you can space the head out enough to avoid interference, your compression ratio is going to be very low which is going to ruin your low end torque. Your valve timing will also be drastically changed so adjustable cam gears would probably be necessary. I would either add some sort of timing cover or stop daily driving it.

 

[97egl]

You'd be better of having custom pistons made with very large valve reliefs than using a thicker head gasket if you are actually serious about wanting a non-interference engine

 

[DrewmHolland]

I’ve been thinking that since the intake valves are larger than exhaust valves that I could grind out their valve reliefs to a larger diameter with a dremel and then shine it up and make it all look pretty

 

[steve]

Just maintain your engine and you won't have a problem. Everything you've mentioned is going to make it less powerful and then what's the point.

 

[97egl]

I’ve been thinking that since the intake valves are larger than exhaust valves that I could grind out their valve reliefs to a larger diameter with a dremel and then shine it up and make it all look pretty

I was talking custom made pistons. I don't know how much material there is to work with for putting that deep of reliefs in the stock pistons. I know they are pretty weak.

I would just put the timing belt cover back on and call it a day if it worries you that much. If its for appearance that you want to run without it maybe look into sourcing a clear cover or making one? Seems like less work than internal engine modifications and safer.

 

[DrewmHolland]

Just maintain your engine and you won't have a problem. Everything you've mentioned is going to make it less powerful and then what's the point.

You have a good point I guess just the thought of having an interference engine scares me but honestly everything works how it is and there’s nothing wrong with that

 

[1990TSIAWDTALON]

If needed.......Manley offers custom pistons