Jump to content
HybridZ

post me some questions


Recommended Posts

grumpy i have sort of a complex question i was hoping you could help. we are in the process of rebuilding my brothers 93 honda prelude. the car is turbo'd and pulls ten pounds of boost. the engine had a ton of blow by when we tore it apart. the number four piston had gotten hot and the ring lands were melted and fell apart when we took the piston out. i bought another piston and rod and honed all the cylinders. we put the motor back together and the motor ran without any blowby. i let the car idle for twenty minutes without revving it up. after that we took the car for a test drive and after a quarter throttle the motor cut out and fell on its face. it wasnt building boost either. we found out why it wasnt building boost (not tightening a clamp on the intercooler). we got the car going again and i advanced the timining probably 5` and the motor started and ran fine. we even jacked it up and put it in third gear to see if it would cut out. it ran awesome. built boost and was great. we took the car out on the road and again after quarter throttle. and the motor started having extreme blowby again. this thing has been a fing headache for two years. my two major questions are why is the motor building so much blow by. i even bought the most expensive rings. and what do you think is going on with the timing. when the motor is cold it starts great and doesnt cut out. that would be to much advance right? and why would it only fall on its face under a load. any advice or experience would be much appreciated . thanks for your time.

Link to comment
Share on other sites

Thank's heaps Grumpy for all the info I took a chance on dual plane with a 100 shot last night at our local track worked well but I need much bigger tyres as wheel spin absolutely killed my times but I now what you mean about your saying about 60 mph I was still fish tailing in top gear when I crossed the line at over 95 mph which has convinced me go 350 + bigger diff + bigger tyres its to much of a hand full of fun for me in its stock config with a chev thanks again.

Link to comment
Share on other sites

150plusZ

The things ID suspect is DETONATION damage to the piston,and excessively fast ignition advance,and total timing, probably combined and probably a overly lean fuel/air ratio, ID verify the timing and posting some clear pictures of the sparkplugs would sure help, and knowing if the cam was properly degreed in the engine would help also, if the cams installed a couple degrees off youll find it can run like crap under load.

I don,t know your ring gap or piston to cylinder wall clearance either, but those could easily come into play here

Link to comment
Share on other sites

the car has upgraded 450cc injectors so i dont know if it would run lean or not. the sparkplugs are very dry looking with a gray looking deposit on it. im definetely not a master mechanic so i dont know anything about cylinder wall clearances. the pistons fit tight when we put them in and were fairly hard to slide down the cylinder. not much room between the piston and cylinder. now that the motor has blowby again what can i do to cure that possibly let the motor run for twenty or thiry minutes at idle to seat the rings? im just not knowledgable enough at this stuff also generally do turbo'd cars run with more advance or retarded? wish i had a camera

Link to comment
Share on other sites

the car has upgraded 450cc injectors so i dont know if it would run lean or not. the sparkplugs are very dry looking with a gray looking deposit on it. im definetely not a master mechanic so i dont know anything about cylinder wall clearances. the pistons fit tight when we put them in and were fairly hard to slide down the cylinder. not much room between the piston and cylinder. now that the motor has blowby again what can i do to cure that possibly let the motor run for twenty or thiry minutes at idle to seat the rings? im just not knowledgable enough at this stuff also generally do turbo'd cars run with more advance or retarded? wish i had a camera

 

Im not a huge car guy but did you clearance anything or just slap it together?

Link to comment
Share on other sites

im no mechanic by any means. everything checked out when i put the motor together. i put it together using a chilton book and followed their directions, much better to have actual input from a human being than search through a book for n/a cars. i live in the middle of nowhere and the only thing anybody here knows how to work on is old v8s

Link to comment
Share on other sites

the more I read here the more I suspect the ring gaps were never addressed or clearanced correctly and that as the engine heats under load the friction developed from rings butting and expanding to almost lock the cylinder wall to the pistons or detonation problems are causeing or at least adding to the problem

Link to comment
Share on other sites

thanks grumpy. ran a compression check and number 3 cylinder was only at 60psi. i dont understand maybe a cracked cylinder wall? we honed the cylinders and used brand new chrome moly rings. oiled the cylinder walls and thought the install went well. two of the plugs were very clean looking little gray. other two were brown?

 

also the car is at zero vaccum at idle until it pulls boost? wasnt doing that just yesterday. pulled the dip stick out and it was shooting oil about two feet up. sweeeeeet

 

the motor also had no blowby before we fixed the boost problem. when the motor gets boost it treats the rings like a red headed step child. still dont make sense cause the motor fell on its face before the blowby started up again.

Link to comment
Share on other sites

Link to comment
Share on other sites

im going to tear the motor down again to check some things i neglected when putting it together. one thing that bothers me is the head was milled down by my brothers mechanic because he had overheated it and it warped. the compression is probably just to high with running 10 pounds of boost. also just had 89 octane in it till we filled it up with 92 still probably needs some octane boost.

 

 

that is a cool calculator. takes alot of guess work out of it

Link to comment
Share on other sites

The engine I have is using a set of bearing spacers.

It is a 400 block and is using a forged, large journal, 327 crank.

The spacers appear to be an actual set of 400, .010 mains, that have been modified.

Is that what is used for spacers, Main Bearings? They have a Clevite Part # MB2562P.

 

Thanks,

John

Link to comment
Share on other sites

grumpy i have a quick question for you. When i rebuilt my motor i neglected to inspect the threads for the spark plugs. So i completely assembled the motor and when i was putting the spark plugs in i noticed the threads on the number 4 cylinder was cross threaded. How do i straighten then back out without taking the head off again. I would just retap the threads but im worried about getting metal shaving in the cylinder. any ideas?

 

thanks joe.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...