Jump to content

PORT WORK GOOD BAD


Recommended Posts

I Had a guy locally port a set of cylinders for me and he made all the ports and tranfers ALOT BIGGER,he made them lower and i see most say to raise them,but thats not what he did.

 

well i went out for a test run at the dragstrip and its slower now......im running 7.80's at 83mph now,but was running 7.10's at 93mph before he reworked the cylinders......can i just resleeve the cylinders to fix them.

 

the cylinder where done by vito before the reworking.....it was there superstock porting,i added a vito 4 mil crank last month and was told i needed to have the cylinder reported,so i tried someone locally.....he also made the transfer a circle like shape,and not the square shape they come with.

 

what should i do?

Link to comment
Share on other sites

  • Replies 52
  • Created
  • Last Reply

Top Posters In This Topic

When you port for a 4 mill they usually start by lowering the ports since the piston will fall 2mm farther down in to they cylinder. Then raise them a little to get the durations that they want.

 

When you port for a stock crank they just opean the tops of the ports.

 

So when you take a pair of cylinders that have already been ported for a stock stroke crank, then lower the ports down to match the extra stroke your left with ports that are way to big and not optimal for performance. That is why most of the time you cannot report a pair of cylinders for a 4 mill once they have been ported for a stock stroke crank.

 

Good luck with the refund. Get another pair of cylinders and have them ported for a 4 mill by a reputable banshee builder. Then swap your cylinders out for the new ones.

 

josh

Link to comment
Share on other sites

I know this doesn't help or solve your problem, but this is a perfect example of how easy it is to actually F UP a cylinder instead of making it better.

 

For the DIY porters, be prepared to go through a set or two before you figure it out OR give up and put them in the hands of a professional.

 

Did the guy that ported your cylinders give you any setup advice? Like timing, compression to shoot for, jetting, etc?

Link to comment
Share on other sites

I Had a guy locally port a set of cylinders for me and he made all the ports and tranfers ALOT BIGGER,he made them lower and i see most say to raise them,but thats not what he did.

 

well i went out for a test run at the dragstrip and its slower now......im running 7.80's at 83mph now,but was running 7.10's at 93mph before he reworked the cylinders......can i just resleeve the cylinders to fix them.

 

the cylinder where done by vito before the reworking.....it was there superstock porting,i added a vito 4 mil crank last month and was told i needed to have the cylinder reported,so i tried someone locally.....he also made the transfer a circle like shape,and not the square shape they come with.

 

what should i do?

 

 

I would be real interested in seeing some pics of this port work! An oval port window for the transfers is not ideal unless the entire port tract matches. If you want to send them over, hell, I would inspect them and mic them free of charge just to see this.. It is possible that we can correct them but sounds like they might be hogged too much to be helped. How did they run on a normal ride? Pipey, no power anywhere, etc?

 

 

B

Link to comment
Share on other sites

did he give you any port timings or did he just grind away till they looked faster.a small properly shaped port will flow more than a large gouged open port.you better take blowits offer for a free inspection-that's like a sore dick(you can't beat it).i've said this before that i have seen ugly port jobs go fast and pretty ones go slow....circle like shape transfer????like to see that

Link to comment
Share on other sites

did he give you any port timings or did he just grind away till they looked faster.a small properly shaped port will flow more than a large gouged open port.you better take blowits offer for a free inspection-that's like a sore dick(you can't beat it).i've said this before that i have seen ugly port jobs go fast and pretty ones go slow....circle like shape transfer????like to see that

 

 

 

I am really thinking this thing has a dispersive flow pattern and is not scavenging right. There really is no way to make a transfer round while maintaining proper port flow. Velocity is key.

 

 

 

 

 

B

 

 

 

 

Link to comment
Share on other sites

I am really thinking this thing has a dispersive flow pattern and is not scavenging right. There really is no way to make a transfer round while maintaining proper port flow. Velocity is key.

 

 

 

 

 

B

i don't know how you would keep the tranfer roof angle right if the port is round....probably did'nt have the right tools and thats the only spot he could reach.even without seeing them i would guess they are FUBAR.hope i am wrong for his sake

 

Link to comment
Share on other sites

I would be real interested in seeing some pics of this port work! An oval port window for the transfers is not ideal unless the entire port tract matches. If you want to send them over, hell, I would inspect them and mic them free of charge just to see this.. It is possible that we can correct them but sounds like they might be hogged too much to be helped. How did they run on a normal ride? Pipey, no power anywhere, etc?

 

 

B

it still runs very strong on the bottomend and mid but it falls on the topend,almost like its not get enough fuel or something

Link to comment
Share on other sites

would upping the compression help ? its at 164psi now

 

 

No, but you might try jetting and timing changes to see if the problems will tune out. Actually too much timing will reduce top end performance so you may try bring it back a bit but I suspect the porting is not working with you. You must always rejet when you report. If you have not, there might be an issue right there.

 

Look at your plugs and let them tell you what it needs.

 

 

 

B

Link to comment
Share on other sites

No, but you might try jetting and timing changes to see if the problems will tune out. Actually too much timing will reduce top end performance so you may try bring it back a bit but I suspect the porting is not working with you. You must always rejet when you report. If you have not, there might be an issue right there.

 

Look at your plugs and let them tell you what it needs.

 

 

 

B

i did not rejet it so that maybe the case.....its only on the very top that it seems to not want to rev out.

Link to comment
Share on other sites

  • 3 weeks later...

PLEASE tell me that this is a joke......!???? :shoothead:

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.

Loading...

×
×
  • Create New...