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Well, I've done it. replaced intake manifold. lost compression. tried to crank it at tdc and tamper at zero. Read I should never crank at zero but advanced 8-12. Backfire thru carb. Like an idiot tried it twice and heard metal grinding against metal. Backed off lash and compression will jump to 10 and drop again. Not lash. when I turn it by hand to check compression on each cylinder it fights me while turning it around intake 7 then when I get over the 'hump' it lets me spin it a bit too easy. I verified before cranking I was at tdc on cylinder 1 not 6. I did the timing change awhile back if some of you remember and marks were spot on. Removed head on the passenger side and other than being disgusting I don't see anything destroyed. I will clean it up and install or should I have it machined at this point since it's out?
If the chain skipped would it be causing this? Cam damaged? From everything I've read everyone has a different opinion. I know for sure it's not lash and I did it EIOC so I know it's right when doing it. Even backing it off at this point zero compression.
Good news.
Sounds like you are "all-in" at 2000.
A little soon, but not too bad.
I think you have low CR right, so it might like it.
Anyway easy to change later. Just go up on one spring a little stiffer. See how it responds.
I think I am more concerned that the advance starts to come in at 850, very close to your idle.
It might cause your idle to wander/hunt.
I would like to see a little more distrib spring. Advance steady until 200-250 above idle.
After all this work setting up your distributor, why change it? Send the other one back. The $99 ones are no good anyway.
Drop that NAPA vac can in and you are almost ready to drive! Woo-Hoo!
You did a great job getting to this point.
Thanks guys. let's see what happens tomorrow/friday. After this hopefully I hold steady without so much advance with the new can. Then I have to adjust the holley. I have my vac gun ready to start tuning that.
Tonight at the vette meet I help organize I brought hotdogs for the crowd. Had to come in my wife's mini van to bring the bbq grill lol. miami every wednesday. I'm the idiot with the cigar cooking the hot dogs. the balding one. lol
I'm a bit confused as to how changing out an intake manifold would cause loss of compression. would be no need to even touch pushrod adjustment changing an intake.
However, now we see you have pulled the head. Have you leak tested those Valves?? would be the first thing I would be doing.
I agree the intake change shouldn't have done anything. I changed the lifters as well. Haven't leaked tested the valves yet. what's your take on having it machined? pretty bad shape from I can tell.
The picture with the head in front of the tire. Almost looks like the exhaust valves are not seating. But why?
A clean-up shave on the heads would help. If they are worth saving. Seldom does a machine shop let you go out the door without a complete valve job.$$$$$$$
Might as well change those heads afterall now.
Seriously though... are you sure you had the rockers adjusted correctly? Zero compression makes no sense otherwise..
Last edited by augiedoggy; Apr 5, 2021 at 08:27 PM.
machine shop here is 1600 for the entire engine. a mechanic I don't feel is very good wants 1000 to remove it put it back in and test. Every time I use a mechanic I get screwed (coming from the guy who just messed up his own engine). The son of the owner said his dad will probably do both heads with valves for 500 if I provide new springs valves etc. He does the labor only. I can order this stuff myself and do it. But the clean up has me worried. look at that condition.
you don't think keeping original is better? simply clean up?
The original heads are terrible performance wise and the single best upgrade you can make to uncorked the power in your engine is to replace those heads but it honestly depends on what your goals are. As is stands now a 4cylinder Toyota camry has more rear wheel horsepower than a smog era corvette engine.
Pretty much ANY 64cc heads will wake that engine up or at least allow other upgrades your going to keep doing make more of an improvement.
Last edited by augiedoggy; Apr 5, 2021 at 08:34 PM.
I hear you but heads are 800 bucks. I really am looking for stability. Would love to increase that power but to spend 1600 on heads alone is death.
There are plenty of options for much less. I paid $300 for my dart iron eagles complete with roller rockers used. You can upgrade to vortex heads for hundreds not thousands. Of course many here think if you replace the heads you need to go from one extreme to the other but its just not true. You absolutely dont need AFR heads with your goals and situtation.
Last edited by augiedoggy; Apr 5, 2021 at 08:43 PM.
The original heads are terrible performance wise and the single best upgrade you can make to uncorked the power in your engine is to replace those heads but it honestly depends on what your goals are. As is stands now a 4cylinder Toyota camry has more rear wheel horsepower than a smog era corvette engine.
Pretty much ANY 64cc heads will wake that engine up or at least allow other upgrades your going to keep doing make more of an improvement.
Well, Camry's have more front wheel horsepower anyway.
Get a real estimate. How much will it cost to rebuild those heads (if that's even what the problem is, did you identify the grinding metal sound?), vs the cost of a new (or new-to-you) set of heads that will flow much better.
You could even consider a complete engine swap at this point. That will only make sense if you do the work yourself, but parts may not cost much more than fixing up what you have.
All of my terrible suggestions introduce lots of new ways for things to go wrong, of course.
I would be hesitant to be off buying new Heads when You still don't know what the original no compression problem was or still is. Probably wasn't a need to remove the Head or Heads to diagnose what is wrong but now that You have at least flip them up side down and fill the camber with solvent and see if it all runs out past the Valve Seats.
well if the heads are the issue the fix may be cheap if I replace them with those aftermarket or clean them up myself new valves etc. Once I get in there on the other side and remove that one (they need a cleaning anyway look at that pic) I'll have a better idea.
That's what i'm going to do either tomorrow or wednesday and check. I'm glad I removed it. Look at that gunk. New gasket and a nice shave is what it needs. But like augiedoggy said may be better getting new ones and some more power instead of doing this.
zero compression
