mercruiser 4.3 overhauling

[ste80]

good day to everyone;
i'm rebuilding my 4.3 engine and i if possible i would like to recieve some info from expert people in the forum.
my original motor was a EFI 4.3 2001 due to some issue i had romoved that motor and now i'm overhauling and installing a 4.3 lx 4 barel (200 hp) and as said in other thread i'm saving and using some parts from my old 4.3 efi.

i brought all pcs in the mechanical shop for machining. i did: cilinder boor check and machining. new piston rings new bearing new cilinder planarity both head machined ecc ecc.
when i was in the shop i brought there both come shaft ( EFI and LX) and they said that EFI was better so they installed EFI one ( it should be same shaft)
now i have a doubt;
wich vlaves lifter should i use? LX or EFI?

i have 2 mai topics now, on manual i sow this 2 sentence



and

when i bought LX motor it was totally disassmebled so i don't know wich roller was going in wich cilinder, and especially direction.

and now that my camshaft is the one from EFI should i use EFI lifter accordinglly to last sentence or it doesn't really matter?

thanks

 

[ste80]

i thnk that EFI roller are 811844 1 instead lx 811844 . i don't know the extra (1) that is present in a lot of the code on efi model what is for

 

[Scott Danforth]

The same base motor from GM is used for both

 

[Scott06]

good day to everyone;
i'm rebuilding my 4.3 engine and i if possible i would like to recieve some info from expert people in the forum.
my original motor was a EFI 4.3 2001 due to some issue i had romoved that motor and now i'm overhauling and installing a 4.3 lx 4 barel (200 hp) and as said in other thread i'm saving and using some parts from my old 4.3 efi.

i brought all pcs in the mechanical shop for machining. i did: cilinder boor check and machining. new piston rings new bearing new cilinder planarity both head machined ecc ecc.
when i was in the shop i brought there both come shaft ( EFI and LX) and they said that EFI was better so they installed EFI one ( it should be same shaft)
now i have a doubt;
wich vlaves lifter should i use? LX or EFI?

i have 2 mai topics now, on manual i sow this 2 sentence

View attachment 405487

and
View attachment 405488
when i bought LX motor it was totally disassmebled so i don't know wich roller was going in wich cilinder, and especially direction.

and now that my camshaft is the one from EFI should i use EFI lifter accordinglly to last sentence or it doesn't really matter?

thanks

As SD nmentioned same roller. You can use rollers on any lobe used or new. The comment in the manual is for hydraulic flat tapped cams where the lifter wears in to a specific cam lobe

 

[ste80]

As SD nmentioned same roller. You can use rollers on any lobe used or new. The comment in the manual is for hydraulic flat tapped cams where the lifter wears in to a specific cam lobe

thanks, to both scott for the replay

what is confusing me is that in the manual the picture where they said this is for same roller that i have got see below




i was thinking the same about model and about fact that cilinder block is same but the sufix (1) on roller name and differenc in spare part price was confusing me. i was thinking that the difference is related to the fact that EFI is usint head with final number 113 and has roller roket arm ,

insted LX is using 181 head with normal roket arm.





one more things;
what about studs? studs also are different EFI is 173391 and is little bit longher then LX 17339 , if i remember well EFI is 7,192, and lx something like 7,182 or something like that.
originally i was thinking to use EFI because is new and better, but really scarred about it
thanks in advance

 

[cyclops222]

DIY can cause unexpected problems that then require a mechanic.
Motors are not like LEGOS.

 

[Scott Danforth]

thanks, to both scott for the replay

what is confusing me is that in the manual the picture where they said this is for same roller that i have got see below

View attachment 405495


i was thinking the same about model and about fact that cilinder block is same but the sufix (1) on roller name and differenc in spare part price was confusing me. i was thinking that the difference is related to the fact that EFI is usint head with final number 113 and has roller roket arm ,
View attachment 405496
insted LX is using 181 head with normal roket arm.
View attachment 405497




one more things;
what about studs? studs also are different EFI is 173391 and is little bit longher then LX 17339 , if i remember well EFI is 7,192, and lx something like 7,182 or something like that.
originally i was thinking to use EFI because is new and better, but really scarred about it
thanks in advance

the marking the lifters is so you have them rolling in the same position you take them out

regarding the rocker arms, you are mixing and matching various generations.
you should be using the 1996 and later vortec heads.

some light reading.

complete history of the 4.3 liter with casting numbers

thought I would post the complete history of the 4.3 liter that I could find. These are links and articles that I have bookmarked for my own use, however they should help many people. it may help some people when looking for parts or sourcing a salvage yard motor or a reman. keep in mind that...

forums.iboats.com

 

[Lou C]

It is more complex than what meets the eye, many subtle changes. When I did the heads on mine I was tempted to upgrade to the Vortec heads but because I myself don't have the experience/knowledge to know all the pitfalls I decided to stick with the way GM built it and kept the same casting # pre-Vortec heads. About the roller lifters, I did basically the same thing shown in the Merc manual, just to check the cam lobes and rollers which surprisingly were all in good shape for 29 years old at the time. I think mix and match is risky unless you know exactly what you're doing, otherwise leave it as GM built it.

 

[Lou C]

As SD mentioned same roller. You can use rollers on any lobe used or new. The comment in the manual is for hydraulic flat tapped cams where the lifter wears into a specific cam lobe

that's what I thought as well, could it be they gave advice for the older style flat tappet but used the pic from the newer style roller lifter?

 

[ste80]

DIY can cause unexpected problems that then require a mechanic.
Motors are not like LEGOS.

sorry not clear what you mean.
i bought this motor in pcs so this components were already disassembled. when i do this job i normally mark everithing.
i brought cilinder block head shaft and whatever in garage where there was a mechanichs and they installed the came shaft from efi ( also pistons) because after check they condidered better. so not clear your comment sorry

 

[ste80]

the marking the lifters is so you have them rolling in the same position you take them out

regarding the rocker arms, you are mixing and matching various generations.
you should be using the 1996 and later vortec heads.

some light reading.

complete history of the 4.3 liter with casting numbers

thought I would post the complete history of the 4.3 liter that I could find. These are links and articles that I have bookmarked for my own use, however they should help many people. it may help some people when looking for parts or sourcing a salvage yard motor or a reman. keep in mind that...

forums.iboats.com

thanks, i was thinking to mix only if they were same ( due to the fact that EFI were newer) but i think i will install all from LX model then. but unfortunatelly i bought them already disassembled so i don't know if rotation will be the same because they are not marked . can it cause problem? shell i buy all rollers new? or i can use them also if working 180 deg from original position?
thansk

 

[ste80]

It is more complex than what meets the eye, many subtle changes. When I did the heads on mine I was tempted to upgrade to the Vortec heads but because I myself don't have the experience/knowledge to know all the pitfalls I decided to stick with the way GM built it and kept the same casting # pre-Vortec heads. About the roller lifters, I did basically the same thing shown in the Merc manual, just to check the cam lobes and rollers which surprisingly were all in good shape for 29 years old at the time. I think mix and match is risky unless you know exactly what you're doing, otherwise leave it as GM built it.

thanks, actually it is what i wanted to do, but now i had this idea but maybe better to go back on original condition and use all as it was. the problem as said is that components were disassembled so i don't know if rollers will be in same cilinder ( that maybe yes) but not sure if they will be in same position or 180° turned.

in this motor when motor was in mechanical shop the mechanics did piston assembling and shaft and camshaft assembling they put the EFI cam shaft on because they said it was better ( they said is the same they told me they checked also on the late with dial gauge) and pistons from EFI ( they checked clereance and machined cilinder bore cosequentelly because LX had 3 pistons of one type and 3 pistons of other type ; as you can see from below picture


i cecked the sn of the cam shaft and pistons and EFI and LX has same components or EFI camhaft is new on but on mercruiser parts they said replace old. xxxx number ( lx number)

no i just bigh doubt wich lifter i should use LX as original or EFI due to the fact that camshaft is from efi or if i have to buy new lifter)

IMO i should use LX one but not relly sure

 

[Lou C]

I'm thinking of all the possible mis-matches, if the rollers are not in the same cylinders, I don't think that will cause a problem with roller lifters.

 

[ROY WILLIAMS]

4.3l engine of the oils/water and the water gasoline!
the ignition timing ATDC 2 DEG 600-700 RPM .

 

[Scott06]

that's what I thought as well, could it be they gave advice for the older style flat tappet but used the pic from the newer style roller lifter?

No those are rollers. In general pretty much have seen that rollers can be reused with different cam etc. my other hobby is a 65 GTO, guys reuse roller lifters with different cams all the time, it’s seen as an advantage going with a roller , which on a pontiac V8 is pricey. Buy a good set of roller lifters like Morell and you can swap cams down the road.
I recall seeing in Mercury remanufacturing video how they were testing and reusing cams and roller lifters. In reality getting a bucket of parts might not be worth the risk considering most Chevy parts are relatively cheap in boat and engine part terms

 

[ste80]

No those are rollers. In general pretty much have seen that rollers can be reused with different cam etc. my other hobby is a 65 GTO, guys reuse roller lifters with different cams all the time, it’s seen as an advantage going with a roller , which on a pontiac V8 is pricey. Buy a good set of roller lifters like Morell and you can swap cams down the road.
I recall seeing in Mercury remanufacturing video how they were testing and reusing cams and roller lifters. In reality getting a bucket of parts might not be worth the risk considering most Chevy parts are relatively cheap in boat and engine part terms

thanks. so you suggest to go for new lifters? i know that in USA the cost are relly heeper for this parts, the problem is that in itlay is not like there because we do not have many chevy car. tomorrow i can go to auto repair shop and check, but i don't think it will be easy also because they will ask for car sn or nameplate that i do not have

or otherwise between EFI and LX maybe i shuld keep lx (due to the difference of pn of the lifters 811844 vs 811844 1)

 

[ste80]

I'm thinking of all the possible mis-matches, if the rollers are not in the same cylinders, I don't think that will cause a problem with roller lifters.

i hope the same. lifter are all same, so it should be ok, i was wondered when i sow that rthings mentioned in the manual this is why i asked.

 

[ste80]

the marking the lifters is so you have them rolling in the same position you take them out

regarding the rocker arms, you are mixing and matching various generations.
you should be using the 1996 and later vortec heads.

some light reading.

complete history of the 4.3 liter with casting numbers

thought I would post the complete history of the 4.3 liter that I could find. These are links and articles that I have bookmarked for my own use, however they should help many people. it may help some people when looking for parts or sourcing a salvage yard motor or a reman. keep in mind that...

forums.iboats.com

hi scott; i check your nice post about 4.3 model but can i ask you something that is making me confused?
my iron cast is 10227196
i was looking the part of cams; and i have some doubt now.
you said that in 95 there was the cams 10241693 and in 96-98 the cams 10241692
if i'm looking the mercruiser code for EFI and lx for example i can see that
lx is the number 824327 and EFI number 803186;
if i go online and i put those number it seems the same cams



or




or





from above picture it seems that 803186 replaced the 824327


when i was on the mechanical shop i brought both of them , saying to check if they were same and wich one was better. thy installed the efi one, but now i'm really worry after looking your thread if they are same.


pistons i do not have bigh doubts, also because before to bring there i checked the spamped number inside of the piston and i brought there all for check, and they machined cilinder accordingly to pistons size

for lifter i will use LX lifter if i will not find new one at this point i would be much more sure that they are ok and same for studs

what do you think?

 

[Scott06]

hi scott; i check your nice post about 4.3 model but can i ask you something that is making me confused?
my iron cast is 10227196
i was looking the part of cams; and i have some doubt now.
you said that in 95 there was the cams 10241693 and in 96-98 the cams 10241692
if i'm looking the mercruiser code for EFI and lx for example i can see that
lx is the number 824327 and EFI number 803186;
if i go online and i put those number it seems the same cams

View attachment 405528

or


View attachment 405529

or


View attachment 405530


from above picture it seems that 803186 replaced the 824327


when i was on the mechanical shop i brought both of them , saying to check if they were same and wich one was better. thy installed the efi one, but now i'm really worry after looking your thread if they are same.


pistons i do not have bigh doubts, also because before to bring there i checked the spamped number inside of the piston and i brought there all for check, and they machined cilinder accordingly to pistons size

for lifter i will use LX lifter if i will not find new one at this point i would be much more sure that they are ok and same for studs

what do you think?

Te later one replaces the earlier part number so it is the same. If you look up mercruiser lifter part numbers they are the same i think, one supersedes the other.
Given you got it as a pile of parts , Not sure how you tell if they are ok. Even in the US from summit racing they are about $300 a set.
risk is if the engine had water in the oil or something if they are ok.

 

[Scott Danforth]

if you are running a carb, I would go for a slightly more aggressive cam than the stock ones.