compression

[xcluzivetyphoon]

is there a way to check compression with motor out of the vehicle...i pulled the motor to put new crank and bearings in... is there a way or any signs to tell if the rings need replaced? i just dont wana get this motor back together ... again, and then there be somethin else that needs fixed...any advice??

 

[bezerk]

Re: compression

if you did all that, i would have done a complete rebuild. i don't think it's pretty wise to do a compression check. if you put a new crank and bearing in there, because you bassicly want everything lubed. and i don''t think the assambly lube/grease is meant for turning it that hot.
why haven't you done it before you took it out?

 

[Windedv6]

Re: compression

if you did all that, i would have done a complete rebuild. i don't think it's pretty wise to do a compression check. if you put a new crank and bearing in there, because you bassicly want everything lubed. and i don''t think the assambly lube/grease is meant for turning it that hot.
why haven't you done it before you took it out?

You can do a leak down test without running your motor, But as mentioned before the minimum you should do is put new rings in while you this point.

John

 

[xcluzivetyphoon]

Re: compression

the reason why i was tryin get around that is.. i bought this truck, had a built motor already.. but a bad head gasket.. i rebuilt the top end, head work valve seals, decked, etc.. put the top end back together with cometic gaskets.. got it all back together, got it runnin.. was runnin great, hadnt got to drive it yet when we noticed a oil leak.. in the process of findingthe leak, found out the motor had a knock that you could only hear from underneath the car.. i get the truck on the lift.. pulled the oil pan thinkin maybe it was just a rod bearing and i could do it without pullin everything apart.. get the oil pan off.. find out that all the rods have play in em.. pulled one rod end cap off and bearing was trashed.. so i pulled the motor..

this trucks motor couldnt have more then maybe 1000 miles on the previous build that previous owner did.. everything still looked new inside and out.. head gasket blew because someone got cheap in the end and used $8.00 felpro headgaskets on the newly built motor.. and stock bore size head gaskets on a .30 over motor at that..

ok.. back to my point.. i didnt think there was a need i guess to check the compresion.. it was running good for the short time i had it running.. then i pulled everything apart, when i started getin into it even more.. i realized ALL the bearings where bad... found out the were bad because the crank had been turned on the last build and who ever assembled the motor decided to use stock bearing sizes instead of compensating for the machine work on the crank..and getting the right size..

i just didnt wana pull the heads back off the block unless i absolutely have to.. since the brand new cometic gaskets have 10 minutes of run time on them.. and end up have to spend another 200 on those too..

thus the reason for wanting to see if there was a way to check compression of the rings with it being this far apart.. the rings in the motor are newer, from the previous's owner's build.. and they might be fine.. im just wanting to take precaution because of the poor assembly of the rest of the motor so far fromt he previous build..

 

[bezerk]

Re: compression

you can reuse the cometics. To be honest i would go throught the whole engine..

 

[Windedv6]

Re: compression

Sounds like you got a bum deal for sure. As Berzek mentioned, you can reuse the cometic gaskets. I spray a light film of copper sealer on mine if I reuse them. Cometics like a very smooth finish (RA50) so if you have your motor out and at a a machine shop put a good finish on the deck (and heads). If someone that perviously built the motor didn't know how to size the bearings, I would be suspect on the ring gap. Correct ring gaps are important on any motor, but ecpecially on a hi temp turbo motor.

John

 

[xcluzivetyphoon]

Re: compression

so they are re-usable, ok.. that was the biggest thing i was worried about.

it wouldnt have been that big of a deal, but i didnt get a heads up on nuthing abou the car when i bought it.. all the carlot told me was it had a upgraded turbo and the headgasket was bad.. and for the price i seemed like a sweet deal.. then i get it.. and now its just one thing after another..:rant:

i should just post a thread and see if anyone knows the truck.. so i can get some more history on it..

 

[Windedv6]

Re: compression

Put the thread up with the serial number and see if anyone has a history for it. I noticed in your signature that it had a different turbo and 36# injectors. If the computer chip has not been modified (with the different injectors, turbo, etc) your tune was in the dark to begin with.

The best thing to do is to decide where you want to got with the build to be satisified then put it together correctly with a proven setup for that application. There are several time tested proven builds that had been somewhat perfected and popular here on the BB. Take your time and ask questions then decide where you want to end up, performance wise, cost wise and type of use.

John

 

[xcluzivetyphoon]

Re: compression

yea when i got the truck .. the one thing the dealrship said was.. it gets bad fuel cut..lol.. yea no crap.. the injectors are tiny. i have been wandering about the chipped ecu ever since i found out how modded it was.. ill try n get a thread up today.. i got the thing from a dealership right outside columbus ohio