We hope that the oil "has nowhere to go" except to seal around the piston rings. The point is to see if you are getting low compression numbers because your rings are leaking or if the problem is elsewhere, like the valve seats, or head gasket.
7mgte stock rebuild-sort of
- Thread starter supraficial
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So since the compression jumped after oil you would say that it is the rings not sealing properly, meaning new rings would hopefully solve my compression issues? I'm thinking of a re-main kit, that includes rings, all bearings, and full gasket kit. After machining of course.
Is there anything else you think could've happened to the compression in the last cylinder from the previous test to now? I don't think compression testing could've damaged the ring but then again it is 25 years old and full of surprises..
Is there anything else you think could've happened to the compression in the last cylinder from the previous test to now? I don't think compression testing could've damaged the ring but then again it is 25 years old and full of surprises..
Compression "jumped" in #1. Probably rings are a contributing factor there.
In 2-6 compression came up a bit. This is more likely just a faster rotating crank due to better lubrication.
#6 compression is awful, there's something else wrong there. That's either a BHG, hole in piston/broken ring or valve damage. Something just isn't right in that cylinder. Maybe it's even the gasket between #5 and #6 bringing up the number for #5. I don't know, I would be done with diagnosis there, since whatever you do, a rebuild is in order. I'd finish diagnosis after removing the head and inspecting the cylinder bores to see if a rebuild is feasable.
In 2-6 compression came up a bit. This is more likely just a faster rotating crank due to better lubrication.
#6 compression is awful, there's something else wrong there. That's either a BHG, hole in piston/broken ring or valve damage. Something just isn't right in that cylinder. Maybe it's even the gasket between #5 and #6 bringing up the number for #5. I don't know, I would be done with diagnosis there, since whatever you do, a rebuild is in order. I'd finish diagnosis after removing the head and inspecting the cylinder bores to see if a rebuild is feasable.
Ill remove the head and check to see if the issue is the valves leaking or the piston/ring leaking. Hoping its the head gasket. If it's not that easy, which I'm expecting, ill dissemble take it to a machine shop get the crank magnafluxed the block pressure treated, maybe decked if I have to. Then hoping to use standard bearings and rings, as well as the valve stem seals that came with a cometic gasket kit, ARP bolts, etc. Anything I'm forgetting?
Forgot to mention a new head gasket after checking, and oem or metal depends on shop fees and if I am able to drop that much money at one time on machining alone.
Has anyone ever used the mizumo auto or the Evergreen rebuild kits? I would be replacing the oil pump and water pump and tensioner as well as the rings and bearings and thrust washers. I already have a Cometic gasket kit so I wouldn't use their gaskets, does anyone have any opinions? I searched and the I only found one guy had used the mizumo auto kit with 10k miles no problem so far.
Forget about the cheap Chinese rebuild kits. If it's a mild build, get a set of NPR pistons, new bearings (I like ACL), a new oil pump and water pump from Toyota, ARP head studs, and a Titan/Cometic MHG. ARP rod bolts are a good idea. Have a good machine shop bore and hone the block with the pistons in their possession. Make sure the machine shop bores the block with the timing tensioner torqued down, and decks the block with the timing cover attached. Have the machine shop check the rods and resize if necessary. Have them check and polish the crank, it will probably be in good shape if it's never been rod-knocked.
This is exactly how I built my 7M, I beat on it daily for the past year and it still runs fine.
This is exactly how I built my 7M, I beat on it daily for the past year and it still runs fine.
Could I make due with all the name brand rings and bearings, possibly mhg, but definitely arp studs; just on the stock pistons and rods if they are in decent shape?
What HP are you running after this rebuild? The search came up with a pretty unanimous decision that ACL bearings won't last past 400 hp, not that I'm saying I plan on having a stronger engine, just kind of worries me that they have a cutoff that is well in the 7m potential range.jake8790;1933997 said: