engine rebuild, running in help?
engine rebuild, running in help?
Author
Discussion

mojorider

Original Poster:

235 posts

287 months

Thursday 23rd October 2003
quotequote all
Just had new pistons, rings and bearings and am now in the first 500 miles using mineral oil. Keeping it under 2,500 rpm but the engine is sitting on 90deg. even in this cold weather.

I am told this is normal due to extra friction and shit oil at running in time. Is this true?

funinthesun

1,170 posts

293 months

Thursday 23rd October 2003
quotequote all
in what car??

mojorider

Original Poster:

235 posts

287 months

Thursday 23rd October 2003
quotequote all
98 450 chimaera

>> Edited by mojorider on Thursday 23 October 17:06

2 sheds

2,529 posts

312 months

Thursday 23rd October 2003
quotequote all
Rebuilt engine will produce more friction = heat, 90 seems Ok to me, if it were 100 i would be more concerned.
Tim

mojorider

Original Poster:

235 posts

287 months

Thursday 23rd October 2003
quotequote all
when should I see the temp drop. Also, got some nice ACT bits added, carbon trumpets and reshaped plenum

trefor

14,770 posts

311 months

Thursday 23rd October 2003
quotequote all
Most engines run at 90 deg anyway. Each engine has a different optimum temp, but I bet it's not far off 90deg in most cases.

simpo two

92,570 posts

293 months

Thursday 23rd October 2003
quotequote all
trefor said:
Most engines run at 90 deg anyway. Each engine has a different optimum temp, but I bet it's not far off 90deg in most cases.


Mine's very dependent on ambient temp - at the moment it's in the 70-80 region (unless stuck in traffic jam). However on that very hot Sunday it was 90-92 all the way, regardless of speed.

Boosted LS1

21,200 posts

288 months

Thursday 23rd October 2003
quotequote all
I used to run my cars and bikes in really gently as well but I did gradually up the revs and increase the load for short periods. Now I'm not sure how I will do it next time round. Breaking a camshaft in should be done at a few thousand revs IIRC from startup for 15-20 minutes.

I read a really good motor bike link suggesting you thrash the nuts off the engine fairly early. This was backed up by dyno evidence. They also said that when a bike is at the end of the production line the japs fire it up and rev it to red line to see if anything breaks. They know that after that the bike will be fine. It's suggested that the Jap companies might suggest riding slowly to make sure you don't stuff it just after you get it and also to make sure the bike passes it's warranty period. Oh, there's money to be made from servicing as well. I was very sceptical until I read the information. Not sure about thrashing my moly rings though. Here's the link:

http://mototuneusa.com/thanx.htm

It's bound to be controversial

gazzab

21,614 posts

310 months

Thursday 23rd October 2003
quotequote all
keep revs below 2.5K when cold. Probably not above 3K for first 100 miles?
But dont accelerate like a granny or the bores will not bed in and will glaze.
The engine builder should tell you what miles you can start increasing revs?
Dont sit at same revs on journeys - vary speed.

HarryW

15,998 posts

297 months

Thursday 23rd October 2003
quotequote all
Went for the easy option of getting it run-in on the bench dyno, under varying loads. So much more satisfying to be able to check out the results of the rebuild first hand straight away .
Agree with cams 20 mins at 2-2.5K, for the engine agree with the not above 3K when warm 2-2.5K when really cold, but do not labour the engine in a high gear this is just as bad if not worse than over revving IMHO.

Harry

gary_tholl

1,013 posts

298 months

Thursday 23rd October 2003
quotequote all
Good link. I've heard that a hard break-in is as good, or better, than the conventional easy-on-it one. I've never heard a good explanation (or had the balls to try it myself). He makes some good points, I just might try one like that next time.

Of course, I think his advice is more aimed towards brand-new motorbikes, which likely have better materials and machining than a 10+ year old chev (or rover/tvr/lotus/ford/whatever) block would.

Interesting reading in any case.


Boosted LS1 said:
I used to run my cars and bikes in really gently as well but I did gradually up the revs and increase the load for short periods. Now I'm not sure how I will do it next time round. Breaking a camshaft in should be done at a few thousand revs IIRC from startup for 15-20 minutes.

I read a really good motor bike link suggesting you thrash the nuts off the engine fairly early. This was backed up by dyno evidence. They also said that when a bike is at the end of the production line the japs fire it up and rev it to red line to see if anything breaks. They know that after that the bike will be fine. It's suggested that the Jap companies might suggest riding slowly to make sure you don't stuff it just after you get it and also to make sure the bike passes it's warranty period. Oh, there's money to be made from servicing as well. I was very sceptical until I read the information. Not sure about thrashing my moly rings though. Here's the link:

http://mototuneusa.com/thanx.htm

It's bound to be controversial

mojorider

Original Poster:

235 posts

287 months

Friday 24th October 2003
quotequote all
I am keeping it at or below 2500 rpm for 500 miles. Done some country roads, A roads and some motorway so far.

Spent most of the time between 2-2.5k, trying to vary the speed and rpm but tough on the motorway. The motorway is a nightmare, can only do 65 so not tickets for me.

Looking forward to the next 500 miles, told I can then take it to 4-4.5k