Possible production of a block guard as a alternative to Sleeves?
10-25-2005, 01:16 PM
#1
Registered User
Thread Starter
iTrader: (3)
Join Date: Jul 2003
Location: Escondido
Posts: 11,373
Likes: 0
Received 0 Likes
on
0 Posts
Possible production of a block guard as a alternative to Sleeves?
So I recently discussed this with a buddy who is a mechanical engineer. We looked at some pics of a VQ35 and he couldn't see any reason why this wouldn't work. Honda guys have been using this method for years as a alternative to sleeving. Typically sleeves cost around $1000-1500 plus the labor to install them. In the 4 cylinder world a block guard runs around $100-200 and is much easier to install. Of course for the Z I would expect it to run us closer to $300-400 but thats certainly a significant savings for an equal amount of safety.. My question is who would be interested and what if any would be the cons/difficulties in using something like this. Heres a pic of one that was made for the QR25DE in the Sentra SE-R Spec Vs. They have a VERY similar black design to ours. 
Heres the link from that board: http://forums.thevboard.com/viewtopi...+guard&start=0
I am trying to reach the guy on that board who had them made now to see what was involved in getting that done and to see if he knew if the machine shop he uses could get this done for the VQ.
Heres the link from that board: http://forums.thevboard.com/viewtopi...+guard&start=0
I am trying to reach the guy on that board who had them made now to see what was involved in getting that done and to see if he knew if the machine shop he uses could get this done for the VQ.
10-25-2005, 01:48 PM
#3
Registered User
Thread Starter
iTrader: (3)
Join Date: Jul 2003
Location: Escondido
Posts: 11,373
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by failsafe306
Dumb question: how do they work, exactly?
10-25-2005, 01:55 PM
#5
Registered User
Thread Starter
iTrader: (3)
Join Date: Jul 2003
Location: Escondido
Posts: 11,373
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by 350Zteve
I have a turbo charged Honda and pay pretty close attention to the forums. The feedback on block guards is pretty bad. Lots of info about them but most of its bad.
10-25-2005, 01:58 PM
#6
block guards were not very commonly succesful.. not common enough anyway.
i was just discussing block guards with Gurgen (i think) last week...
the problem is that our cast blocks do not have perfectly similar water jackets and sleeve shapes on the unmachined side of the sleeve. Putting in a block guard would put side load on various parts of the sleeves, depending on how they fit in your particular casting.
they are also known to eventually walk down the block.
i wouldnt be completely against the idea of using one if correctly machined... however I would probably want to set it down a good 1/4 maybe, probably weld it in, and then cyrogenically treat the block to help take off any tension. However I am not an engineer or a machinist... this is just my best guesses as to about how it would be.
i was just discussing block guards with Gurgen (i think) last week...
the problem is that our cast blocks do not have perfectly similar water jackets and sleeve shapes on the unmachined side of the sleeve. Putting in a block guard would put side load on various parts of the sleeves, depending on how they fit in your particular casting.
they are also known to eventually walk down the block.
i wouldnt be completely against the idea of using one if correctly machined... however I would probably want to set it down a good 1/4 maybe, probably weld it in, and then cyrogenically treat the block to help take off any tension. However I am not an engineer or a machinist... this is just my best guesses as to about how it would be.
10-25-2005, 02:10 PM
#7
Registered User
Thread Starter
iTrader: (3)
Join Date: Jul 2003
Location: Escondido
Posts: 11,373
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by phunk
block guards were not very commonly succesful.. not common enough anyway.
i was just discussing block guards with Gurgen (i think) last week...
the problem is that our cast blocks do not have perfectly similar water jackets and sleeve shapes on the unmachined side of the sleeve. Putting in a block guard would put side load on various parts of the sleeves, depending on how they fit in your particular casting.
they are also known to eventually walk down the block.
i wouldnt be completely against the idea of using one if correctly machined... however I would probably want to set it down a good 1/4 maybe, probably weld it in, and then cyrogenically treat the block to help take off any tension. However I am not an engineer or a machinist... this is just my best guesses as to about how it would be.
i was just discussing block guards with Gurgen (i think) last week...
the problem is that our cast blocks do not have perfectly similar water jackets and sleeve shapes on the unmachined side of the sleeve. Putting in a block guard would put side load on various parts of the sleeves, depending on how they fit in your particular casting.
they are also known to eventually walk down the block.
i wouldnt be completely against the idea of using one if correctly machined... however I would probably want to set it down a good 1/4 maybe, probably weld it in, and then cyrogenically treat the block to help take off any tension. However I am not an engineer or a machinist... this is just my best guesses as to about how it would be.
Thats actually what I was thinking about. I had been reading about block guards on some other forums and it seems that if they are installed slightly lower on the cylinder walls and welded in people had good success. I am actual IM'ing with the guy who had them made for the QR25 and he has not had any issues with them yet. According to him they have taken the QR25 past 400 WHP with a block guard successfully. For them thats a big deal. That motor is known to let go past 260 WHP..
Trending Topics
10-25-2005, 02:18 PM
#8
Originally Posted by MIAPLAYA
Really? I had heard the opposite...Guess I'll go check out Honda Tech and see what issues they had...
Hopefully the cost of sleeving a VQ will start to come down as it becomes more popular.
10-25-2005, 02:21 PM
#9
Registered User
Thread Starter
iTrader: (3)
Join Date: Jul 2003
Location: Escondido
Posts: 11,373
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by 350Zteve
Honda-Tech is the best source. I was building a turbo motor for my crx a couple months back and did a ton of reading on whether to block guard or not and the vast majority said don't do it. This of course was all data specific to Honda engines, but the basic design is similar to the VQ with the floating sleeves. Overheating was one of the biggest problems noted. I do seem to recall, however, that welding them in a few millimeters below the deck had better results.
Hopefully the cost of sleeving a VQ will start to come down as it becomes more popular.
Hopefully the cost of sleeving a VQ will start to come down as it becomes more popular.
10-25-2005, 02:25 PM
#11
Registered User
Thread Starter
iTrader: (3)
Join Date: Jul 2003
Location: Escondido
Posts: 11,373
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by teh215
They seem like a good idea but, wouldn't they tend to create a hot spot in the cylinder near the top which would be bad?
10-25-2005, 02:27 PM
#13
Registered User
iTrader: (2)
Join Date: Oct 2005
Location: Houma, LA
Posts: 171
Likes: 0
Received 0 Likes
on
0 Posts
Hello guys.. One of your members asked me to chime in here..
I have the block guards made for the QR25DE. There are miniscule variations between blocks.. however, with Nissan's new die casting process, there is very little variation. I have installed, sold and personally used 10 of these in the QR. Fitment was the same every time.. I had to sand 2 of them slightly because they were a little snug. I had mine tapered very slightly.. this keeps them from sinking any lower than the deck. The lower it goes, the tighter it gets.
If you guys are concerned about those issues.. There is another option. I can have the guard made about .030" larger than the gap, and your machine shop can cut the block .015" on each side. This will make for a perfect fit, since the block guard is perfect in every dimension, and the same every time. This way, you will have a register in the block for it to seat against.. so it can't sink.. And, you will have a perfectly machined match.. so, no worries about loading issues.
I am willing to have these made.. however, I will need at least 10 orders, and someone to send me a spare block to have them modeled. PM me if you are interested..
Travis
I have the block guards made for the QR25DE. There are miniscule variations between blocks.. however, with Nissan's new die casting process, there is very little variation. I have installed, sold and personally used 10 of these in the QR. Fitment was the same every time.. I had to sand 2 of them slightly because they were a little snug. I had mine tapered very slightly.. this keeps them from sinking any lower than the deck. The lower it goes, the tighter it gets.
If you guys are concerned about those issues.. There is another option. I can have the guard made about .030" larger than the gap, and your machine shop can cut the block .015" on each side. This will make for a perfect fit, since the block guard is perfect in every dimension, and the same every time. This way, you will have a register in the block for it to seat against.. so it can't sink.. And, you will have a perfectly machined match.. so, no worries about loading issues.
I am willing to have these made.. however, I will need at least 10 orders, and someone to send me a spare block to have them modeled. PM me if you are interested..
Travis
10-25-2005, 02:55 PM
#14
Registered User
iTrader: (8)
Join Date: Sep 2002
Location: Charlottesville, Virginia
Posts: 5,753
Likes: 0
Received 4 Likes
on
4 Posts
Originally Posted by MIAPLAYA
Well there are coolant passages drilled into the block guard so that coolant can still flow through like it did before..
10-25-2005, 02:57 PM
#15
Registered User
Thread Starter
iTrader: (3)
Join Date: Jul 2003
Location: Escondido
Posts: 11,373
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by teh215
I am not engineer but, wouldn't the heat retention of the spacer itself be different than just the coolant? If I am over analyzing this please let me know.
10-25-2005, 03:08 PM
#16
Registered User
iTrader: (8)
Join Date: Sep 2002
Location: Charlottesville, Virginia
Posts: 5,753
Likes: 0
Received 4 Likes
on
4 Posts
Yeah, but i would think that the sleeve would act like a heat sink covering the entire cylinder wall placing the highest heat buildup at the bottom of the cylinder where it is least important. Again, just my guess
10-25-2005, 03:11 PM
#17
Registered User
Thread Starter
iTrader: (3)
Join Date: Jul 2003
Location: Escondido
Posts: 11,373
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by teh215
Yeah, but i would think that the sleeve would act like a heat sink covering the entire cylinder wall placing the highest heat buildup at the bottom of the cylinder where it is least important. Again, just my guess
10-25-2005, 03:16 PM
#18
Registered User
iTrader: (12)
Join Date: Sep 2005
Location: MD
Posts: 1,473
Likes: 0
Received 0 Likes
on
0 Posts
dont get a block gaurd i had it in my integra before i sleeve the block the block gaurd sucks and will do **** for your motor if your going to go in there do it right man no point in ****ing around with it.
10-25-2005, 04:12 PM
#19
Registered User
Thread Starter
iTrader: (3)
Join Date: Jul 2003
Location: Escondido
Posts: 11,373
Likes: 0
Received 0 Likes
on
0 Posts
Well I read a freaking TON of posts on Honda Tech about block guards...it seems there mixd reviews. Theres a lot of people with them with no issues and some who had a couple. But it seems like most of the people who hate on them are following the internet standard of bandwagon jumping on hatred...I guess we need to hear from the motor builders here about what they think...
10-25-2005, 04:21 PM
#20
Registered User
iTrader: (12)
Join Date: Jun 2003
Location: Man in the Sun
Posts: 2,222
Likes: 0
Received 0 Likes
on
0 Posts
The guys that I knew who used them on Honda's had issues....mainly due to the installation. Sometimes they are a little too big for the jacket and the installers will "tap" them in flush to the top of the bore. This basically distorts the bore in the jacket and can cause all kinds of uneven piston wear in the bore and a ton of other issues as well. To do it right, each guard has to be individually shaped and sanded so it basically drops into the jacket without any effort, then welded in place.