Hi, I have a nice 91 Q45 with 80k miles. I bought it with a bad engine. The owner had pulled it out and I had a real basket case. I got a engine from some japanese guys in CA. real nice looks new. I got it all together and it started right up. Sounded great! After adjusting idle and letting it warm up a little we took it for a spin. OMG it sounded like it was going to explode. I pulled over and adjusted I guess it is the cas and it quieted down a little.
I changed the gas and ran techtron thru it but to no avail. It is currently set about 5 degrees retarded but still rattles. A freind put his snap on box on it and it showed a bad o2 sensor I changed it and still the same. Although it seems to run better when it is cold. When it warms up.... rattle rattle rattle
I have ordered a service manual and I should have it by tuesday or so. I am afraid that mabe it has jumped time. Whatcha think?
Horrible valve clatter on my Q45
You're running 5 degrees retarded? So 10 degrees BTDC? What was the spark timing before you adjusted it? Cam timing problems can lead to problems, but vavle clatter sounds like something else. Cam timing can only be off by a little, or else you would be hitting the valves. What kind of oil are you running, and have you looked at it since getting it together? Is the "new" engine really new or rebuilt? I would look at the oil and check the oil pressure first.
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Every JDM engine we recieve gets a day or two of labor and many parts to make it suitable for reinstallation. EGR gets cleaned [rattle/knock?] What did you do about the Japanese header [no precats] the US ecu has a hard time correcting for the changed O2 sensor back pressure......we always remove JDM and swap back old US manifolds to get things to work well.
We always replace the chain guides as many arrive broken!
We always replace the chain guides as many arrive broken!
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Unscrew the oil pressure sender switch and connect a gauge! 14 psi hot at idle is minimum.
The point is before you install a JDM engine, you pull the front cover and replace the chain guides and oil chain and front and rear seals. Reseal both valve covers, replace all the hoses [about 35], replace the both KS, coolant temp sensor and the harness. Change the spark plugs and water pump.
Then you install the engine............otherwise you will be nickel and dimed to death pulling the plenum multiple times plus have all the problems you are encountering.............changing 30+ engines has taught us this!
The point is before you install a JDM engine, you pull the front cover and replace the chain guides and oil chain and front and rear seals. Reseal both valve covers, replace all the hoses [about 35], replace the both KS, coolant temp sensor and the harness. Change the spark plugs and water pump.
Then you install the engine............otherwise you will be nickel and dimed to death pulling the plenum multiple times plus have all the problems you are encountering.............changing 30+ engines has taught us this!
Well, The mystery is solved although not to my liking:( I changed the egr and a few other of the emission controls and no luck. I put a hose on the oil pressue port and had a freind start it. (I didnt have a gauge) Lots of pressure. I am now pulling the mtr back out after detirming the chain is rattling and must be loose. Is there a parts kit that includes all the things nessary for installing the chain guides?Thanks for the help
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
We find that about 60% of the JDM engines have cracked or failed guides.......primarily age not miles related.
Those engines get idled and sit in traffic alot..........30k of Japanese miles might be the same as 100-120k of US highway miles.They take the 55 mph speed limit very seriously but at least they change the oil every 90 days.
But they never do underplenum work dumping the cars at 6 -7 years [30-40-50k]..............even the crooks won't buy them used.........why there are so many JDM used Q motors in US.
Please follow my list of must do changes under the plenum when you get the engine out.
Those engines get idled and sit in traffic alot..........30k of Japanese miles might be the same as 100-120k of US highway miles.They take the 55 mph speed limit very seriously but at least they change the oil every 90 days.
But they never do underplenum work dumping the cars at 6 -7 years [30-40-50k]..............even the crooks won't buy them used.........why there are so many JDM used Q motors in US.
Please follow my list of must do changes under the plenum when you get the engine out.