Forged bits, brands and engine build advice

[dac69er]

What are the go to brands for forged parts nowadays?

I'm not going mad with power, about 300-350ish and 1.4-1.5 bar boost.

I wanted to stick with a stock thickness head gasket (1.2mm?) But should I go with a MLS one or stock Toyota?

Also, dished or flat pistons for my expected power output? I would like to maintain the cr if I can, but if it is a real pinch point, I will have to go dished.

Arp headbolts, stock or arp stud upgrade?

Should I only rebore if needed, or should I go up to the next size anyway?

Crank looks good from initial look. Do people generally get it ground and go with 0.25 oversize bearings or just get the current one polished?

Should I get the block decked anyway, or leave if ok?

What brand engine bearings are people using? I've used ACL on my stock rebuilds in the past.

Will I benefit from uprated valve springs if not going above stock rev limit (or not by much)?


Is there anything else worth considering for 300-350 bhp max? Perhaps a mild port and polish on the head? Race spec cam cover?

Thanks

 

[dac69er]

Just to add, I have fully rebuilt 2 4efte engines before, but they were just stock rebuilds, so after advice relating to getting more power and going forged.

 

[gorganl2000]

What are the go to brands for forged parts nowadays?

I'm not going mad with power, about 300-350ish and 1.4-1.5 bar boost.

I wanted to stick with a stock thickness head gasket (1.2mm?) But should I go with a MLS one or stock Toyota?

Also, dished or flat pistons for my expected power output? I would like to maintain the cr if I can, but if it is a real pinch point, I will have to go dished.

Arp headbolts, stock or arp stud upgrade?

Should I only rebore if needed, or should I go up to the next size anyway?

Crank looks good from initial look. Do people generally get it ground and go with 0.25 oversize bearings or just get the current one polished?

Should I get the block decked anyway, or leave if ok?

What brand engine bearings are people using? I've used ACL on my stock rebuilds in the past.

Will I benefit from uprated valve springs if not going above stock rev limit (or not by much)?


Is there anything else worth considering for 300-350 bhp max? Perhaps a mild port and polish on the head? Race spec cam cover?

Thanks

wossner pistons seem to work well with scat/maxspeed/etc. rods (these rods all seem very similar)

i prefer dished pistons, because they match the stock ones and may lower the CR slightly vs flat top ones (relatively speaking)...a slightly lower compression ratio will be better for more boost, but your engine may not be as responsive as the flat top counterpart (relatively speaking)..but this must be considered in regards to headgasket thickness, non-interference, etc....if you have poor gas quality, the lower CR may be more forgiving

i've always used the oem 4efte headgasket, and never had any issues...i was always deterred by some of the horror stories i heard over the years with some members using MLS headgaskets, so i just avoided them

having used both stock and arp headbolts, i'd suggest arp for the power you are after,,,you will sleep better at night knowing the extra strength is there...i've seen stock bolts run up to 25psi, but i still don't recommend them for your purposes.

if the bores are fine as it is, and a modest hone is all that is required, then buy the size pistons to match it...if the bores could do with a refresh, then rebore to the next size up, you will get a few extra CCs

crank,,if it only needs a slight polish, then keep it that way an use oem bearings to match, ...grinding reduces the journal sizes and may make it relatively weaker,,,,a regrind to undersized bearings tends to be done when the crank has been damaged (spung bearing)

block decking,,,i have no idea about...no one in my immediate group has ever done it.

i personally prefer and use genuine/oem toyota bearings (rod and crank), thrust washers, oil pump, headgasket, timing belt, valve stem seals, crank shaft and cam seals
but some guys have raved about ACL race bearings and taiho engine bearings

stick with the stock valve springs if keeping the stock rev limit or close to it---remember the 4efte head is revved to 7500/8000rpm using preprogrammed ecus from ages ago...though i'd still stick to 7500rpm max on the stock set up

i'd agree with getting the valve cover "race specced" with the two breather connections,,,can be easily done by yourself and/or a competent welder/machine shop with the appropriate fittings

the stock intake manifold, head and TB should be good for your power demands 300bhp

the extra cost for a ported head, uprated cams, aftermarket valve springs, etc...these things may go well together later on if you wanted to do more and you could just call it a race spec head

 

[dac69er]

Thanks for the effort in replying, there were lots of questions there

Stock pistons aren't dished, they are flat topped. I would rather have a more responsive engine at the expense of a little less top end power. I'm not going mega boost anyway, but wanted to see what others opinions were on this....

 

[SKINY]

Excellent information there

 

[Jay]

Wouldn't touch the bores unless I had to TBH, same would go for the deck but if you are using a thinner head gasket make sure it's totally within spec. I had serious issues with a metal gasket, the stock gaskets are a lot more forgiving.

 

[dac69er]

Sounds like I would be best off with a hone of the bores to clean them up, then a stock Toyota headgasket

I will go with arp headbolts I think.

What pistons and rods have people used? Dished or flat top?

 

[gorganl2000]

Thanks for the effort in replying, there were lots of questions there

Stock pistons aren't dished, they are flat topped. I would rather have a more responsive engine at the expense of a little less top end power. I'm not going mega boost anyway, but wanted to see what others opinions were on this....

no problem

well it depends on how you look at it i suppose...i call them dished because they have a slightly raised lip around the circumference ,,,so not completely flat at the top
https://www.toyotagtturbo.com/community/index.php?threads/4efte-pistons-rods.88764/

 

[gorganl2000]

possibly look for the estimated CR when you search for pistons...sometimes its stated

you may also have a CR in mind for your build...and id suggest you use some kind of calculator to estimate your final CR based on the combination of parts you plan to use, as the type of pistons , headgasket thickness, block decking, head skimming, etc. will affect your CR

for reference
the "5efte" (using oem 4efte pistons and 4efte headgasket in a 5e) seems to work well around 9.0 CR for turbo applications,,runs decent boost levels and is responsive

the stock 5efhe n/a CR is 9.8,,,guys run turbo on those, but you have to be very careful with tuning and gas quality,,,boost may be limited, but its very responsive

iirc the stock 4efte has a CR of 8.2,,,that's on the low side for safety i suppose but you can run a lot of boost there,,,may be a bit laggy off boost compared to the higher CRs, especially with bigger turbos

 

[dac69er]

I was going to aim for around stock cr.

What brands of forged components do people go for? Anything to avoid?

 

[Calum122]

@dac69er I would recommend ringing around shops before making a purchase. I ordered some Scat rods back in January/Feb time and I've still not seen them. I was contacted relatively quickly to say they were out of stock, eventually leading to, we're going with another brand (what brand I haven't been told). But I'm still yet to see anything.

Every time I've phoned up, I've always been given the time of day etc. But I'm blocked until I get my parts, I can't progress with the engine build.

They also said, things like Pistons are back order too! So you may be in for the long haul.

 

[dac69er]

I think everything is back order. That is what is driving prices up

I get the feeling the pistons will be reasonably easy to get, just not sure about the rods......

 

[dac69er]

i have spoken to wossner and my engine builder.

i want to aim for 300bhp @ around 1.4 bar.

i want a reponsive road car with good power.

the cr of dished wossner pistons is 7.65:1 and the flat top is 8.37:1. stock is 8.2:1 as previously mentioned

my engine builder has suggested going with the flat top pistons and a 1.4mm headgasket. he reckons with the head and block skim, then the thicker headgasket, i should be pretty close to stock cr.

whats everyones opinions on that?

i have been speaking to someone else and they did mention there being issues with engines that had flat top pistons having headgasket failure???


safest bet is dished pistons, but i dont want to miss a trick and have an engine that isnt as reponsive as it could be.

 

[Jay]

Don't think I've seen any local guys use flat-top pistons, probably more of a safety factor tbh.

Higher compression will help drivability but could invite knock.

Knock is bad.

Also means that if you aren't seeing the power figure you want you can safely add more boost on a lower CR engine!

 

[gorganl2000]

7.7 cr is on the very low side as even the stock 8.2 is low
i'm a bit surprised the flat top pistons are lower than the dished,,,guess they sit lower in the cylinder
anyways, between those two..i'd go with the dished at 8.4,,,i don't think it will affect your target bhp, though your response won't be much different to a stock 4efte

for comparison and consideration....the stock head gasket it 1.2mm uninstalled and 1.0mm after installation...so all else being held constant, a 1.4mm head gasket will lower your compression even further ---less responsive

 

[dac69er]

7.7 cr is on the very low side as even the stock 8.2 is low
i'm a bit surprised the flat top pistons are lower than the dished,,,guess they sit lower in the cylinder
anyways, between those two..i'd go with the dished at 8.4,,,i don't think it will affect your target bhp, though your response won't be much different to a stock 4efte

for comparison and consideration....the stock head gasket it 1.2mm uninstalled and 1.0mm after installation...so all else being held constant, a 1.4mm head gasket will lower your compression even further ---less responsive

Sorry, just updated that as got the. The wrong way round!!!!!

Dished are lower compression compared to the flat tops.

Would a 1.2 MLS headgasket stay around 1.2mm or would that also compress to 1mm? Never used one before!

The concensus seems to be dished as it's the easy option. But most people probably don't care about off boost performance and are happy with the big bang of power when the boost does come in.

Bigger engines seem to get away with higher cr on turbo applications, but smaller tends to need a bit less according to what I have read. I don't want a det machine, but I also don't want a lazy old engine that is hard work to drive around off boost.

 

[gorganl2000]

mls headgasket doesn't compress,,that's the observed claim...so in theory the 1.2 mm gasket will slightly reduce your CR with either piston
you need to consider your gas quality and tune,,,in combination with CR...so you get the best set up for your purposes

on a side note, we once installed 5efhe pistons (slightly raised crown pistons) in a 4efte and it was able to run about 20psi on a tdo4l on pump gas here (reportedly around 90/95 ron),,,it was moderately more responsive than the stock 4efte...back in the day, some guys ran "shaved" 5efhe/4efe pistons, which would be essentially "flat top" pistons and they held up fairly well on different builds...with a tune of course

you really need a CR calculator or someone who can do this for you,,,that's the only way to really estimate your final CR

and speak to your tuner/builder,,get an idea of what is reasonably attainable on pump gas and if your bhp goal is achievable...the better quality your pump gas, the greater the knock resistance

 

[dac69er]

I've used a cr calculator.

With a 1.4mm headgasket I should be around stock 8.2:1. With a 1.2mm headgasket, I would be closer to 8.5:1.

8.5:1 seems a good place to be for a turbo application. 8.2:1 is a bit on the low side, not sure why Toyota went with that on the 4efte?

I've also estimated the dynamic compression, based on valve timings and that is about 7.7:1 on a 1.4mm h/g and about 8.1:1 ( I think) on a 1.2 h/g.

I always use the premium unleaded which ranges from 97-99 Ron.

I was interested to know what cr others go for. I get the impression everyone just slaps in a low compression piston and whacks the boost up as it's either a track car or they don't really know/care what it's like off boost???

 

[gorganl2000]

i can't speak for the 4efte...personally, i've long moved away from those
on the 5Es, i've tried to achieve between 8.7 - 9.1 CR...i like response and they can handle decent boost if required

i figure toyota was being very safe at the oem 4efte 8.2 CR...and rightfully so, given some users will push the envelope and varying operating conditions around the world where these cars have been shipped

you have fairly decent gas quality...so that's a bonus for you

 

[dac69er]

There isn't realistically a huge difference in a 4e and 5e.

Doing research online, the bigger the engine, the higher cr you can generally run. Not entirely sure why this is as there are other factors involved, not just the size of the engine???

With a 5e, you would get higher static cr by default as it has a longer stroke and the same size combustion chamber as a 4e. Maybe you end up with a similar dynamic cr on a 5e as a 4e with the cam timing?
If you can run cr as high as that with no issues, I reckon I should be good aiming for 8.5:1 static cr???