how do some of you guys prep your block for cometic hg, sand paper? gasket remover? razor? care to share some helpful tips
preping the block
- Thread starter JDM 1JZ
- Start date
yes. all of the above. i used sandpaper up to 1000 grit(going higher grit would be better) wraped around a piece of barstock(some on here use glass cuz its flatter). i used break parts cleaner to keep the block clean of metal grit during all of this. and you should look into useing permatex break quiet on your gasket. get arp's and torque them good and off you go.
and if you have to let the engine sit for awhile, remeber its iron, which can rust, so give the deck a thin coat of oil. this keeps the rust away.
and if you have to let the engine sit for awhile, remeber its iron, which can rust, so give the deck a thin coat of oil. this keeps the rust away.
JDM 1JZ said:
Take the block out and have a machine shop resurface it. There is no other way to do it right, or you can keep on buying MHG's. your choice.
What if you have never blown your head gasket though. Would it be possible to have the head machined without machining the block and still maintain reliability? I'm going to get mine done soon and I would rather not have to remove the entire block just to put on a MHG. Obviously that would be the safest thing to do but I have never blown my head gasket so I'm wondering if it's necessary.
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NDBoost
Guest
werd im with both of them. do it right the 1st time or spend the money down the road to fix what got fucked up:icon_bigg
howcome so many people just sand and clean the block and use the cometic gaskets for its "forgivness" spray gasket spray on there resurface the head and are always good to go? with good bolts and proper tq, i agree that its the "right" way to do it but i dont have the time or the money right now and i know theres plenty of people on here who have done otherwise and been fine on high boost and beating on there cars
how do you warp a iron block anyway? the only thing i can see that could cause bumps in the residue from the old gasket. id think the block would crack before it ever warped
how do you warp a iron block anyway? the only thing i can see that could cause bumps in the residue from the old gasket. id think the block would crack before it ever warped
The issue is not a warped surface, but the average surface roughness as defined by the the Ra number. Roughness is measured by special precision instruments that measure the vertical deviations when traversing the metal surface. Ra is the most commonly used parameter to describe the average surface roughness.
It is perfectly okay to lap the block in the car by hand. Many people have done it including some famous names we all know in the Supra community. The problem is that most people do not have access to a surface roughness meter and so they have no clue as to what Ra value they have achieved. Also, few people have a machinists straight edge to make sure they are not rounding the block edges or creating a non-level surface. Finally, unless you fill the ports and cylinders in the block with heavy grease, you are likely to get metal particles inside the engine.
So, to summarize, hand lapping can be done, but it takes skills, instruments, and care that go beyond what most people on this forum probably want to deal with. If you think you are up to it, go ahead, but don't just buy some sandpaper and scratch away for an hour... you will not achieve what is required.
Here is a nice Ra meter. It is $900 (the economy model)!
http://www.worldoftest.com/tr100.htm
It is perfectly okay to lap the block in the car by hand. Many people have done it including some famous names we all know in the Supra community. The problem is that most people do not have access to a surface roughness meter and so they have no clue as to what Ra value they have achieved. Also, few people have a machinists straight edge to make sure they are not rounding the block edges or creating a non-level surface. Finally, unless you fill the ports and cylinders in the block with heavy grease, you are likely to get metal particles inside the engine.
So, to summarize, hand lapping can be done, but it takes skills, instruments, and care that go beyond what most people on this forum probably want to deal with. If you think you are up to it, go ahead, but don't just buy some sandpaper and scratch away for an hour... you will not achieve what is required.
Here is a nice Ra meter. It is $900 (the economy model)!
http://www.worldoftest.com/tr100.htm
N
NDBoost
Guest
well put,3p141592654 said:
on average with an extra two sets of hands and some know how you can have a motor pulled within 4 hrs (if that). now half of your work is already done if the head is already off the car. Pretty much all you ahve to undo is the tranny mounts clutch slave cylinder ac lines and motor mounts etc. and the motor comes out! Ive pulled 2 motors and helped with about 6 pulls.
The last motor i pulled it took under 2 hrs to pull the thing, it took a tota of 4 hrs from prep work, to getting the tools the hoist, the leveller etc out of those 4 hrs only 2 were dedicated to disconnecting and pulling.
Its probably what? another.. 4-6 hours to take the block apart i would imagine, send it to a machine shop and have it done right. Hell they only wanted $85 to machine my block and totally clean it.
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and no other imput on how others did it in the car? i mean that sounds great and all but im more then half of the supra cumminity has probley done it in the car because what you basically just said was rebuild the motor in so many words and not everyone has that kinda time or resources ya know i know ive read people of using a gasket scrapper gasket remover and light sanding and using a 2mm or so cometic gasket for its forgiveness and being set and the brake spay to or whatever it is
you cant have the block perfectly straight by sanding the deck by hand. you just cant do it. youll neve be able (BY HAND) to get an even amount of material off the block.
and if you think its not possible to warp an iron block, think again. i should have taken pictures of the dip that was in the surface of the block thats in my car now. this wasnt something that you needed a straight edge to notice, you could see it and feel it with your hands.
and if you think its not possible to warp an iron block, think again. i should have taken pictures of the dip that was in the surface of the block thats in my car now. this wasnt something that you needed a straight edge to notice, you could see it and feel it with your hands.
im not talking about a completely trashed surfice though, the surfice as is now is fairly good compared to most motors i have had to do a hg on the only worrys are that the supra for some reason seems very sensitive to this kinda stuff, i just simply said im sure that more than half the community of kids here probley has not pulled there block and dont some kind of preperation work inside the car because lets face it the average person does not have the time to yank the motor pull the block apart to have it machined or money or capabilitys.
for a surfice that is in fairly good condition as far as i know and who knows i COULD be wrong because i do now have any kind of tools here at the momment til the weekend but what is the point of a bead type gasket or the cometics for its adaptability and forgiveness if its simply this big of an issue then
for a surfice that is in fairly good condition as far as i know and who knows i COULD be wrong because i do now have any kind of tools here at the momment til the weekend but what is the point of a bead type gasket or the cometics for its adaptability and forgiveness if its simply this big of an issue then
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NDBoost
Guest
if you want to be cheap, get some gasket remover spray, get a razor blade and goto town. Throw the HG on and pray that it sticks.
NDBoost said:
its not even a matter of being cheap i just wanna hear some imput from people that have done other methods because you have to agree not even is capable of pulling a bottom end a part and has time or money
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NDBoost
Guest
true, keep in mind when sanding wheredoes all that sand paper grit go? it goes in your oil passages water passages and into your cylinders. If your not careful or dont think of a method to limit or even prevent the sandpaper from going in the holes and cylinders you might have a good chance.
Otherwise have fun getting rod knock.
Otherwise have fun getting rod knock.
alright well thanks for the helpful insite, finally from someone, there are a few cars on here that run perfectly fine though, i do know of empera's car for one example hes a local and had no problems i was just looking for more insite he shared his mehtod
AM i correct though and if im not someone please correct me, the 2mm cometic is best choice for its forginess of surfices? the head is at a machine shop right now so that will be done right. i just figured it i got the head done cleaned the surfice sprayed some copper spray let it stand for a day id be alright. or should i go with a hks bead type gasket also for its i forget what it says on MVP but its supposed to be for bad surfices
AM i correct though and if im not someone please correct me, the 2mm cometic is best choice for its forginess of surfices? the head is at a machine shop right now so that will be done right. i just figured it i got the head done cleaned the surfice sprayed some copper spray let it stand for a day id be alright. or should i go with a hks bead type gasket also for its i forget what it says on MVP but its supposed to be for bad surfices
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NDBoost
Guest
im not giving you ass comments. I did the samething your asking about and guess what ive got rod knock less then 1k into the new 1.2mm hks mhg and its got rod knock.
Guess what it probably is that caused it, more then likely its a mixture between previous abuse & the blown head gasket. If your not going to prep the block, get scrubby pads gasket remover wd40 and goto town. Itw ill take you a good 2 hrs or so to get it clean enough for a standard mhg. But thats dependandt upon what HG your going with. But after doing this flush your oil and coolant ALOT before even turning the crank at all! And dont expect that MHG to hold up as well as a motorwith a properly prepped block/head.
People on this forum tend to get frustrated with others that take the "cheap" route on things. Because alot of them know in the end its not going to benefit you.
EDIT:
also you do not need to let the copper spray stand for a day, that would give it time to collect dirt dust etc. Spray it on and let it sit for 5 minutes about until it gets tacky. Put the head gasket on and put the head on as straight as possible. i used a 1.2mm HKS mhg had some fitment issues and struggled to get it on at first but overall its still holding up "ok". Given if i could do it all over again i would feel more comfortable taking my time and decking the block. id say best choice for forgiveness in Ra is stock HG but there are if/ands about the stock hg and how much power it can hold. a MHG will indeed hold up to higher heat etc, but requires more prep work. Stock HG wont hold up to as much but doesnt require as much prep. Ive seen people machine the head, scratch the old gasket material off the block and throw felpro stock HG on and drive liek that without blowing, but then agian they were stock
Guess what it probably is that caused it, more then likely its a mixture between previous abuse & the blown head gasket. If your not going to prep the block, get scrubby pads gasket remover wd40 and goto town. Itw ill take you a good 2 hrs or so to get it clean enough for a standard mhg. But thats dependandt upon what HG your going with. But after doing this flush your oil and coolant ALOT before even turning the crank at all! And dont expect that MHG to hold up as well as a motorwith a properly prepped block/head.
People on this forum tend to get frustrated with others that take the "cheap" route on things. Because alot of them know in the end its not going to benefit you.
EDIT:
also you do not need to let the copper spray stand for a day, that would give it time to collect dirt dust etc. Spray it on and let it sit for 5 minutes about until it gets tacky. Put the head gasket on and put the head on as straight as possible. i used a 1.2mm HKS mhg had some fitment issues and struggled to get it on at first but overall its still holding up "ok". Given if i could do it all over again i would feel more comfortable taking my time and decking the block. id say best choice for forgiveness in Ra is stock HG but there are if/ands about the stock hg and how much power it can hold. a MHG will indeed hold up to higher heat etc, but requires more prep work. Stock HG wont hold up to as much but doesnt require as much prep. Ive seen people machine the head, scratch the old gasket material off the block and throw felpro stock HG on and drive liek that without blowing, but then agian they were stock
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well yeah by stand i meant by letting the car sit with the head bolted on for a day, sorry i wasnt clear and sorry if i came off as a little rude, its just frustrating because im not even trying to be cheap, its just my only option
yeah i need something a little stronger because the car unfortinately has lots of upgrades, i pretty much dont wanan spend alot of money on this block because i have a spare motor im building up on the side, if that makes up for my cheapness route for now
yeah i need something a little stronger because the car unfortinately has lots of upgrades, i pretty much dont wanan spend alot of money on this block because i have a spare motor im building up on the side, if that makes up for my cheapness route for now
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NDBoost
Guest
if you just need this car running take it to stock boost and throw a stock HG on it.
Otherwise Cometic and use gasket remover and copper spray a gasket. But dont expect it to hold gobs of HP for a long time.
But yes Cometic is more flexible then a mhg
Otherwise Cometic and use gasket remover and copper spray a gasket. But dont expect it to hold gobs of HP for a long time.
But yes Cometic is more flexible then a mhg
Use a scraper get it spotless then a clean rag with some paint thinner.
Permatex Brake quiet and a Composite head gasket, forget the MHG if you're not going to have the block surfaced correctly.
The Cometic's ARE a MHG and aren't flexible in any way shape or form they just spec a higher number for the surface RA.
Permatex Brake quiet and a Composite head gasket, forget the MHG if you're not going to have the block surfaced correctly.
The Cometic's ARE a MHG and aren't flexible in any way shape or form they just spec a higher number for the surface RA.