Another Engine Noise question.

[ericstammer]

Okay guys perhaps that is my issue , i checked last time but was with head gasket resting in place , didn't seem to notice movement . however bare block to bare head. ( right now I have pistons 3 and 4 out for inspection. ) but # 1 with bare head to block will raise up about .020"!
how do you guys check w or w/o head gasket in place ?

[ericstammer]

Thats it ! just got done cleaning the dome on # 4 , and started pulling valves as I found out the guy did not use the valve seals I provided. didn't want to machine the head where they go i guess , but he install some racing seals ( story for a little later. )
but heres what i found.
the first time i ran it and it knocked it was only a short time, perhaps i missed it, being hard to see with ....yes i know ..the pitted tops on the domes. but this last time i ran it more while trying to drag. so perhaps its become more predominant. i have to go back and review my pics.
Im thinking Deans thicker head gasket will solve that issue, i just want to confirm measuring head thickness.
i was suspecting #4 as i used a pretty helpful diag. tool last night .... iPhoneX slo mo. ill post video. It became clear that it was very poss 4 on TDC.
Story for another post. and ill post video.

[JT68]

Suggest you remove the domes. Zero chance of interference and you won't be married to an expensive gasket/won't need premium/ can easily swap heads in the future if needed w/o issue. Its a better solution overall.

[Linda]

Why remove the domes?
I think I would just look for a better head, or use the thicker gasket until one is found.
Linda

[JT68]

Why remove the domes?

With the domes gone, the problem is over.

Simple lathe operation. It will completely fix the problem without buying&building another head or an expensive gasket.

The compression is too high anyway. He'll never miss them!


If he wanted to be fancy, could MILLonly the offending side for a 1/2 dome, but it still may contact, --- not really worth the effort--- there is no need for the domes.

Another head is certainly a good solution too.

I think an earlier post said he had new flatop pistons too. That would fix it too assuming the rings will seat.

[fj20spl311]

I am with JT, except I vote for new pistons and have the block bored.

[Gregs672000]

You already have the flat tops. Problem solved. Compression is useful if all the other components are upgraded too. Otherwise it just becomes an issue that's more hassle than its worth for power "gained." You'll probably be back to stock ratio.

[JT68]

All theses are viable solutions! If it were I , I would go the Phil route and bore it, but then it becomes a pretty much a full rebuild....

New flattops are fine but in my experience there is less than 50/50 shot at the rings seating with STD. bore-- that is because with STD. bore pistons the manufacturers stay to the small size of the piston tolerance for obvious reasons.
(so especially with even a slightly worn bore, the piston/ring clearances will be pretty wide. - almost never optimal)

cutting the domes is pretty straight forward and economical. Bob sharp did it 50 years ago, still an excellent approach.

[ericstammer]

All excellen points, and leaving me with some thought.
I have a lot of new parts in this motor now ,incl new rings, though as JT, said i think the ring gap is still a bit high.
Talking before w Dean he said using the flat top pistons would def redice compression. But maybe w shaved head be back to stock as mentioned. But they do feel looser in the bore than the old domes. (Just by feel havent measured)
To add to the mix. I have a complete running 70 r16 smog motor. I could put that in and then take the time and i would have this motor bored and bite the bullet and go with new pistons but doesnt solve clearance atill without either going to flat tops then or the thicker head gasket.
And..i also have a U20 motor from a parts car that when i bought eng ran , but how well ,i dont know.
Descisions descisions.

[ericstammer]

And other issue is finding reliable machine shop as this last one has kind of let me down. Both with the cam brg installed incorrectly and the issue w head. It also looks as if new valves may not have been lapped.
Btw it does have brass intake seats. Good ? Bad?

[Linda]

Sounds like you have lots of options. That's a good place to be!
Perhaps a nearby owner has a machine shop referral
Lots of good info in this thread
Linda

[ericstammer]

Yes just puts my JT stainless ex a little farther down the list

[Gregs672000]

Wow, pretty frustrating situation after spending this much time and coin on this engine. Good thing is that you can do much of the work yourself. Looked like a nice car if the engine pics were representative. What's important to You? What kind of Budget? Given what's a likely need for over sized pistons, doing the rebuild is going to cost pistons, rings, machine work (bore and hone), and you have concerns about the work done on the head. The head is probably ok. Why do you think they didn't lap the valves? I believe the brass intake seats are OK if they're in good shape, stainless for exhaust is my understanding but I'm no expert (JT?). Given that they were not transparent in what was done, I would seek another shop. Setting proper valve height is important on U20 engines, I assume the same for R16, and using different components can change things, but again what do I know?

Is power important to you? The U20 will produce more but is a bit more expensive to rebuild if needed. Guess I would explore that engine a bit... soak cylinders in penetrating oil, see if it will rotate, change oil, feed some good fuel (gravity feed?) and fire it up if it will, then decide. Swapping in the whole drive train would also give you a 5 speed trans (which should probably be opened up at least to make sure it's good and has been modified to keep the 5th gear from walking off).

Of course, the other option is that you could just go with the thicker gasket and see if the rings will seat. Worst case scenario is that they don't and you have to bore it oversize. Nothing else will change like bearings etc. So you're risking the cost of the thicker gasket, but its not cheap at $218. And would it then be a "half assed" (in your mind, not saying it is) rebuild that will cause concerns for you, real or imagined? The cost on a set of 20 over flat tops (aftermarket but should be totally fine) is only $220 with rings. I bet Dean would swap them out for your standards.

If more power is not important, then I would 1) install the running R16 you have and 2) properly rebuild the one that's 3/4 there while enjoying the drive, then swap her in. You can probably sell the standard pistons, or see if Dean can work something for an oversized set. Could also pull the 5 speed and prep it for use with the new R. Then sell off the U20 and the other R with trans and pay for most of your rebuild.

Sorry to hear of your struggles. Keep at it, you'll solve it.

[Linda]

Why not just take the head off the complete running 70 R16 you have and put it on this motor? Measure, of course , but hopefully you could be mobile and it would be easier than swapping the whole motor. Then proceed from there
Linda

[Lorna c]

wow bummer . I know how frustrating it is to struggle and everything you know isn't working . (and you know wayyy more than me ) you'll solve it tho . take a break from pondering it , start again with simplest explanation first and work your way through it again making sure you've not missed or skipped over something . hopefully it's not a total redo or all those other senerios, hopefully you've only skipped over something and your driving soon. can wait to see what this is now .