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Rebuilding an engine - New Vs Old & other q's


Scott
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I'm planning out my rebuild for the future and while pricing various bits and bobs up for curiosity I got to thinking about the rods. For the power I'm going to be running I don't think there is any point in me going for anything aftermarket but what about new stockers? Is there any reason that old stockers would be no use? Can the bush be replaced in the stock rods with a genuine part? Is it worthwhile buying new OE over aftermarket (price difference?). What is the accepted limit of stock rods? I've never heard of them being the weak part of the engine but it's always good to know for certain.

 

My thoughts at the moment are....

 

Clean, paint & rebore of the block (86.5mm)

Oversized forged pistons (Mahle any good? I take it they come with rings?)

Stock crank checked & balanced

Stock conrods checked & balanced

Pistons balanced

Clevite Thrust Bearings

Clevite Main Bearings

Clevite Big end bearings

 

I would love to get a set of billet caps but I wasn't sure about their fitting. Surely, like the cam caps, they are a matched set? Would the block need re-bored to match them? Would I then need oversized bearings? It seems like a lot of hassle when I definitely will not be crossing the 4 figure threshold.

 

I think I'm over-simplifying this in my head also as building the bottom end seems to be coming in rather cheap. I was expecting a huge list of parts required to do it so I guess I must be missing a load of stuff? Obviously I'm thinking new pumps/seals etc but that's a given. Are there a load of other aftermarket things I have missed? I understand that the processing of the block will be quite costly but that's not really something I can price accurately at the moment.

 

Thanks :)

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Scott if your going to all the trouble I would uprate the rods. Especially given the fact your changing everything else.

 

I went for Manley h beam rods. Not too pricey but good enough for my power plans.

 

If not chasing silly power I would not bother with changing the main caps. That is unless you are going to drag or race the car, then I might consider it but only as a safety margin.

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I'm going to just throw this out there, Scott... but if you're not going to run that much power, why not stick with a new stock motor from Toyota? They were only about £2.5k last time I looked and come with pretty much everything - of course, I'd get it professionally reassembled for peace of mind, though.

 

If you're NOT 100% SURE you'll stick with sub-600 hp, build the engine as strongly as you can afford to cover a) further changes of mind re HP, b) maximise the longevity of the motor, and c) ensure that no potential point-of-failure exists vis-a-vis non-new parts wearing/breaking.

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Scott if your going to all the trouble I would uprate the rods. Especially given the fact your changing everything else.

 

I went for Manley h beam rods. Not too pricey but good enough for my power plans.

 

If not chasing silly power I would not bother with changing the main caps. That is unless you are going to drag or race the car, then I might consider it but only as a safety margin.

 

I definitely won't be drag racing in a big way, maybe the odd run at santa pod with the club, so I think I'll just leave the main caps out for now. I'm definitely not going over 1k BHP, around the 800s/900s will be the absolute maximum I'm going to take the car. I might even not go past what I can get out of the 6765, will see how I feel.

 

Do you know what sort of limits the stock rods are good for? I was always under the impression it was into 1000bhp before they became a liability as they were very strong as stock?

 

 

I'm going to just throw this out there, Scott... but if you're not going to run that much power, why not stick with a new stock motor from Toyota? They were only about £2.5k last time I looked and come with pretty much everything - of course, I'd get it professionally reassembled for peace of mind, though.

 

If you're NOT 100% SURE you'll stick with sub-600 hp, build the engine as strongly as you can afford to cover a) further changes of mind re HP, b) maximise the longevity of the motor, and c) ensure that no potential point-of-failure exists vis-a-vis non-new parts wearing/breaking.

 

I'm in the process of single turboing my car with the intention of running around 700hp on the stock bottom end as is. I bought a spare engine in order to build up in my spare time for if/when the stock motor blows. If/when it does blow I want to be able to cover whatever power I want to throw at it hence why I'm not going for a new stocker.

 

My main queries is if the conrods are worth the outlay, same for the billet caps and what sort of pistons should I be looking at in a quality vs price scenario.

 

 

A few Toyota prices for you Scott

 

All are retail plus vat

 

Crank £749.75

Bare head £1797.36

Short engine £2258 with a £300 surcharge if you dont exchange your old bottom end

Full built engine £10,000

 

Thanks for that Dunk. The crank is actually cheaper than I thought it would be, if mine isn't absolutely bang on I think I'll just get a new one.

 

What does full built engine mean? Is that a forged internals engine from Toyota?

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I definitely won't be drag racing in a big way, maybe the odd run at santa pod with the club, so I think I'll just leave the main caps out for now. I'm definitely not going over 1k BHP, around the 800s/900s will be the absolute maximum I'm going to take the car. I might even not go past what I can get out of the 6765, will see how I feel.

 

Do you know what sort of limits the stock rods are good for? I was always under the impression it was into 1000bhp before they became a liability as they were very strong as stock?

 

 

I'm in the process of single turboing my car with the intention of running around 700hp on the stock bottom end as is. I bought a spare engine in order to build up in my spare time for if/when the stock motor blows. If/when it does blow I want to be able to cover whatever power I want to throw at it hence why I'm not going for a new stocker.

 

My main queries is if the conrods are worth the outlay, same for the billet caps and what sort of pistons should I be looking at in a quality vs price scenario.

 

You'll have to forgive me for forgetting that you're planning 800+! Billet caps are unnecessary - you'd have to line hone (££££) and I'm not convinced it's necessary for under 1000hp. Similarly, stock rods *have* lasted at 1000 hp - but for how long? Upgrade to avoid losing the rest of your motor. Mahle pistons are very well regarded, as are the Carillo rods - but there are a few (Armin, Krister) who have made 1000+ with CP pistons and Eagle rods (although the quality control is reputed to be an issue).

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You'll have to forgive me for forgetting that you're planning 800+! Billet caps are unnecessary - you'd have to line hone (££££) and I'm not convinced it's necessary for under 1000hp. Similarly, stock rods *have* lasted at 1000 hp - but for how long? Upgrade to avoid losing the rest of your motor. Mahle pistons are very well regarded, as are the Carillo rods - but there are a few (Armin, Krister) who have made 1000+ with CP pistons and Eagle rods (although the quality control is reputed to be an issue).

 

I remembered reading something about pistons being a bit iffy, it must have been the CPs as you say so I'll stay clear of them. The Mahle pistons seem good value for money.

 

I'm actually struggling to find anything on failed rods. The only failed rod I have ever known was on JPs engine but I don't think any rod would have stood up to whatever caused his issue. Plenty of info on failed rod bolts but obviously every bolt in the engine will be replaced with ARP (where possible).

 

I just don't fancy spending £1k+ for rods but if I was buying it would have to be H-Beams as I don't see the point in spending the money for A's given the price difference vs obvious strength benefits.

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Yes the parts guy said the same, i guess the cams and valves and head assembly add a chunk more but not 5k +

 

It's quite strange as the bottom end seems like reasonable value for money, in fact it's excellent value for money when you consider what MrT usually charge for stuff.

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It's quite strange as the bottom end seems like reasonable value for money, in fact it's excellent value for money when you consider what MrT usually charge for stuff.

 

Agreed

 

When you take out the crank at £750 the block, rods, pistons, rings and shells have cost you £1250 as long as you

give your old bottom end back which is pretty good in my book.

 

Just add a built head from Whifbitz for around £2k and a few other bits and job done for around £5k :) Hmmm :rolleyes:

Edited by Dnk (see edit history)
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Agreed

 

When you take out the crank at £750 the block, rods, pistons, rings and shells have cost you £1250 as long as you

give your old bottom end back which is pretty good in my book.

 

Just add a built head from Whifbitz for around £2k and a few other bits and job done for around £5k :) Hmmm :rolleyes:

 

Not too bad at all!

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I remembered reading something about pistons being a bit iffy, it must have been the CPs as you say so I'll stay clear of them. The Mahle pistons seem good value for money.

 

It was probably me who complained about the CPs. Lots of other people rave about them, but I refuse to trust them again.

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