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461-69bird · 09-15-2021, 05:36 AM

Looks like I've got a head gasket gone. Had water leaking from block to head joint above centre exh port.

While changing this, is it worth going through the rest of the engine? First time with a solid roller cam. Hasn't done more than 3000 street miles and about 100 passes.

Any thoughts appreciated

Dragncar · 09-15-2021, 05:54 AM

You are going to want to see if your heads are warped, how much. It will give you a idea of what you have going on. Might take a peek at your rod bearings then decide. You could ring and bearing it if you wanted. Not sure I would do much more than that on a street engine barely broke in.
You need to find out why it blew the head gasket. Detonation ?

steve25 · 09-15-2021, 06:08 AM

You now need to get the heads milled such that looking at the deck surface is like looking into mirror.
So finding a shop that can do this is your first order of business.

It's the very fine finish that stops / minimizes the abrading of the head gasket on the head side which is where yours failed.

Unless your track times have been slowing down abnormally I don't think you need to rebuild it, but once you get it back together you do need to do a hot compression test and record those numbers for a base line reference.

In this way the next time you question what condition the motor may be in you have something to go by!

461-69bird · 09-15-2021, 03:32 PM

Thanks guys.

I'm sure it's not detonation. It did get hot last year at the track when I lost the belt on the way back to the pits and got to 250 before I noticed.

Not had any drop in performance or any problems when driving it.

How much can be taken off the heads, KRE, before the intake has to be milled as well?

73LeMans · 09-15-2021, 04:02 PM

Id consider checking the valve springs to see if they are still providing optimum value. The heat certainly didn't help them, but its more the mileage that concerns me. Depending on how aggressive the cam profile is and how much pressure your springs provide, they should be making your preventive maintenance checklist.

steve25 · 09-16-2021, 06:02 AM

Depending on how your Intake port match and bolts line up now you could wack .030" off and not have issues if you wanted to up the compression, but for a clean up mill if the heads are still straight and to get the needed finish you should only need to mill off .004" to .006" at most.

chiefbigb · 09-16-2021, 07:02 AM

Take the heads to a good shop and let them decide what needs done. Do not wack .030 of and assume you have room to do so in the valve pockets.

461-69bird · 09-22-2021, 11:45 AM

Quote:

Originally Posted by 73LeMans

Id consider checking the valve springs to see if they are still providing optimum value. The heat certainly didn't help them, but its more the mileage that concerns me. Depending on how aggressive the cam profile is and how much pressure your springs provide, they should be making your preventive maintenance checklist.

Sorry for the simple question, do the springs get checked fitted to the head or do they need to be removed?

Also what did you mean about mileage being a concern?

Steve C. · 09-22-2021, 12:07 PM

My opinion if you decide to test the spring pressure. Remove the springs and find a reputable shop that has a bench valvespring tester. Most shops use a Rimac machine. Make sure it's calibrated, then test the springs at their VERIFIED installed height with their retainers that are in use.

Some might suggest and you can use a 'on the head' type of valvespring tester. However as mentioned before their reading can vary, sometimes a lot, compared to the bench tester.

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