New engine down on power
New engine down on power
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Discussion

Lee 420r

Original Poster:

6 posts

76 months

Tuesday 6th August 2019
quotequote all
Hi, I have just fitted a new engine to my 420r race car but I am now down on speed on the straight compared to others, about 6-8 kph on average, any thoughts about why?

Roblot

36 posts

99 months

Tuesday 6th August 2019
quotequote all
Just a thought for what's it worth. A session on a rolling road dynamometer might through some light on the problem, if you can get access to one. This would help to estimate just how much down in power you actually are ( if at all).
Hope you get it sorted and let us know more about the problem and answer !

HustleRussell

25,951 posts

180 months

Tuesday 6th August 2019
quotequote all
Throughout the race? or only when the engine gets hot, for example?

Also, slower compared to what? your own data at the same circuit in the same conditions?

Lots of variables.

My Dad had a disappointing season in R300s with a Duratec engine many years ago, it turned out that the oil pickup pipe was too close to the bottom of the sump. Once the engine was hot, the top end would get starved of oil and it'd go slow until it cooled down again.

DCL

1,228 posts

199 months

Tuesday 6th August 2019
quotequote all
In terms of power, there very little internally with the Duratec that can go wrong with a brand new factory engine apart from perhaps the cam timing. If it is a rebuilt or secondhand engine, then there's potential for all sorts of things from bent valves, poor cam clearances, to simply being worn out. It's also worth looking at why the last engine failed and check the mapping, induction, and exhaust.

anonymous-user

74 months

Tuesday 6th August 2019
quotequote all
Are you getting full throttle?

sfaulds

653 posts

298 months

Tuesday 6th August 2019
quotequote all
HustleRussell said:
My Dad had a disappointing season in R300s with a Duratec engine many years ago, it turned out that the oil pickup pipe was too close to the bottom of the sump. Once the engine was hot, the top end would get starved of oil and it'd go slow until it cooled down again.
Neither your Dad's R300 or the posters 420R have an oil pickup pipe.

Lee 420r

Original Poster:

6 posts

76 months

Sunday 11th August 2019
quotequote all
DCL said:
In terms of power, there very little internally with the Duratec that can go wrong with a brand new factory engine apart from perhaps the cam timing. If it is a rebuilt or secondhand engine, then there's potential for all sorts of things from bent valves, poor cam clearances, to simply being worn out. It's also worth looking at why the last engine failed and check the mapping, induction, and exhaust.
Hi thanks for the reply, the engine is new direct from Caterham, how can I check the timing? Is there anything else I should be thinking about?

Lee 420r

Original Poster:

6 posts

76 months

Sunday 11th August 2019
quotequote all
jsf said:
Are you getting full throttle?
Hi,
Yes checked that one, thanks

Lee 420r

Original Poster:

6 posts

76 months

Sunday 11th August 2019
quotequote all
Roblot said:
Just a thought for what's it worth. A session on a rolling road dynamometer might through some light on the problem, if you can get access to one. This would help to estimate just how much down in power you actually are ( if at all).
Hope you get it sorted and let us know more about the problem and answer !
Hi,
Thanks for your reply, I run the car in Malaysia so not really much like that about (that you can trust) I just know that in the speed traps other cars are quicker but I am doing a fast overall lap time, compared some rpm data and I'm quicker onto the straight but just drops off. I feel it after 5000 rpm really

HustleRussell

25,951 posts

180 months

Sunday 11th August 2019
quotequote all
sfaulds said:
HustleRussell said:
My Dad had a disappointing season in R300s with a Duratec engine many years ago, it turned out that the oil pickup pipe was too close to the bottom of the sump. Once the engine was hot, the top end would get starved of oil and it'd go slow until it cooled down again.
Neither your Dad's R300 or the posters 420R have an oil pickup pipe.
Well it is nearly 10 years ago but the engine did have an oil pickup issue of some kind from new. It wasn’t the only one either. Simon Lambert ended up green lighting a replacement engine.

Lee 420r

Original Poster:

6 posts

76 months

Sunday 11th August 2019
quotequote all
HustleRussell said:
Throughout the race? or only when the engine gets hot, for example?

Also, slower compared to what? your own data at the same circuit in the same conditions?

Lots of variables.

My Dad had a disappointing season in R300s with a Duratec engine many years ago, it turned out that the oil pickup pipe was too close to the bottom of the sump. Once the engine was hot, the top end would get starved of oil and it'd go slow until it cooled down again.
Hi,
Thanks for your reply, yes from the start engine is not running hot I think, must admit I can't be totally sure because I use it in Malaysia and it is always 34 degrees air temp!

Lee 420r

Original Poster:

6 posts

76 months

Wednesday 14th August 2019
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Hi all, have found that the exhaust manifolds are leaking because they have distorted, would this cause much of a power loss?

anonymous-user

74 months

Wednesday 14th August 2019
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It wont help. You should check you dont have an exhaust port to header overlap issue, it wouldn't be unknown to have the exhaust gaskets masking the port, easy mistake to make.

BertBert

20,679 posts

231 months

Sunday 18th August 2019
quotequote all
jsf said:
It wont help. You should check you dont have an exhaust port to header overlap issue, it wouldn't be unknown to have the exhaust gaskets masking the port, easy mistake to make.
Just curious as to how this happens?

anonymous-user

74 months

Sunday 18th August 2019
quotequote all
Gaskets stamped out incorrectly, wrong size gaskets installed, ported heads not matched to exhaust headers, port matching plates missed on installation.